Many years ago, I was given a classic frame (a 1948 or '49 Duckett) with hand cut lugs - and the down-tube had a deep crush in it, to half way through the tube. I took it to an old-time frame builder, and asked him if he could save the frame. When I went back a week later, he had used blocks just like yours to ease the dent out. He was left with a shallow dent the size of a pea, and he filled it with braze. Just as you did. I am well pleased with the repair.
Yes! now I can repair my kona frame and use it again, every one thought I should scrap that frame. Once I was working in my uncles metal shop and learn almost everything how to work with metal. And I have learned something new today.
i spoke to a framebuilder about the same thing and he said it'd be ok but will reduce strength of the steel in the area. He told me it's better to keep a dent on it for strength. Small dents are okay in low stress areas of the frame apparently.
I'm probably showing my age here, but many years ago a frame builder that I used replaced my entire top tube rather than attempt to repair a dent. He carefully sawed off the tube about 1/8" away from where it joined the seat tube and the same at the headstock end. He then filed away the remaining bits smooth before putting on a jig and brazing in a complete new tube. The frame was of course fillet brazed originally and although the repair and a respray cost me about half the cost of a new one I was very pleased with the finished result. The frame was built in Reynolds 531 butted tubing and I remember him saying that the heat of the brazing would always cause a slight loss of tube strength locally but because this was at a joint with another tube it was no detriment.
You are not showing your age. Replacing a tube (done properly) is perfectly acceptable. Repairing a dent is less labour and therefore less expensive. Thanks for watching and commenting!
Thought there where kids having fun in the background... they sound alot like Peacocks. Well, there they were in the backyard of your place. Thanks for the video.
Loved that fix. I have a dented frame, also on the top-tube and my local frame builder said, "Leave it." The tube is very thin and he felt like it might crack if it was forced 'back to round' or maybe he was just busy as hell and didn't want to get involved. So it remains...
Yes, you do have to be careful with thin tubes. I would roll it round, and fill any low spot with a little bondo, then repaint. This is safer than using heat and braze on thin tubes.
Thank you for making this video and explaining it clearly, i have recently decided to build a couple of old bmx gems I've been holding onto for some time. One is a Redline RA340 and the other a dented up 99' Dave Mirra Haro. I will definitely use your method to knocking down a couple of those dents, I was starting to wonder if it would ever happen now I can get it prepared and ready to have it chrome dipped. Thanks and regards, Mike D.👍🏼
I have a small dent in the front of a banshee 350 that I cut out hammered from the back and sanded smooth form the front, then taped it back in place with first clear tape then aluminum hvac tape and tac welded it completely around multiple times to prevent it from warping. It came out pretty good. My frame is a compound bend though so it took a long time to completely pop out the dent and mould it back, lots of hours of work 5-7 atleast.
Hey Paul, have you ever tried to pull the dent out first then fill what’s left of the dent if any? I know it’s not the same material but I do it all the time on 8mm thick 4” round copper tube. (Industrial radiator manifolds) but the principal will be the same, I Braze a rod in the middle of the dent then heat all around the dent until I see a rainbow colouring (like oil in water). Next I grab a pair of pliers pinch the other end of the rod then tap the underneath of the pliers with a hammer. You ideally need to tap in opposite direction the dent went in if that makes sense? Heat and repeat until the dent is out. Snap/wiggle the rod off file/fill/sand make good and paint. For really big dents you may have to pull in two or three places. Works great for me, all the best fella. Owen.
Bicycle frame dents are a little different because the tubing is often heat treated 4130 and thin wall (0.5mm) so being very careful is quite crucial to the success of the repair. The tubing can crack if it gets mistreated, and then the tube would have to be changed. Thanks for watching!
@kieran finney The top tube is usually not under as much stress as other tubes. It all depends how large the crack was, where it was, and the experience of the welder. If it was done 13 years and is now used as a city, I don't think you have much to worry about. Just check it visually every so often...
@@anarchistangler Yes, it happens a lot. The expansion chamber ends are plugged, air pressure added (no idea how much...) and gentle torch work can make it look like new!
You are a real engineer. Products should come from people like you, and all the other car and moty guys, and never from knock off shops in China and elsewhere. Any country run by people with half a brain would make sure this happens.
Hey, just found your channel. I rented a Brodie once on a trip to Sedona Arizona years ago, would have been 1999ish, I still remember it, a blue hardtail with a white logo and marzocchi bomber. It rode mint.
I'd probably buy one to keep if I saw it for sale....don't think too many made it to New Zealand where I live now. PS once this pandemic is over you should do a crossover episode with Allen Millyard.
First time one of your videos was suggested to me. Viewed and subbed. When your video views are that much greater than your subscribers, then you know your channel will grow quickly.
A wealth of information - I'd heard about the wood block method from a friend who wrenched for the USSR team in the mid 80's, but never seen it in practice.
I like the bike stand he uses. My consumer grade POS wobbles every time you touch the bike. His is rock solid. A poor carpenter blames his tools. A great carpenter always has great tools. Lesson learned.
Assuming the frame is steel, you could use an auto body stud welder and weld a stud to the low spot then heat around the dent then pull it with the slide hammer.
solid work ,enjoy the channel. id be interested to know if any pdr (paintless dent repair) techs have had any sucsess in doing a pdr on a dent like this. i did paint for a few local fame builders and a few large bike manufactures and have alot of experance working on this stuff but the idea of pdr a bike never crossed my mind untell watching this for some reason. if anyone reading this knows of someone who has let me know.
I would have filled the tube with water and freeze it while carefully observing, the ice will push the dent out. Its cold work and takes many hours in the cold watching for just the right moment to stop the cold treatment, but the results are spectacular.
Dear Mr. Brodie, I've got the same frame, a RM équipe from 1993 with a dent at nearly the same position, but it was a little bit smaler. After I've seen your video I tried to roll out the dent with selfmade tube-blocks like you declared and it worked very well. Many thanks for your video. Finally I put grease between tubeblock and framedent so I could press it harder by rolling out the dent. At least there was nearly no high spot and no dent left. For heating up I unfortunately don't have the right workshop so I was contented with the little leaving dent. Many thanks for giving your idea. I don't dare to file the frame because the tange ultimate ultralight tubewall should have a thickness of 0.6 mm. Is it really without problem to file the frame? Yours sincerely Rainer
Not disappointed. But i was hoping to see the dent come out of the frame. Glad to know this is how i would do the same repair. Thought there might be something new to learn, LOL. Thanks for bring us along. Peter.
Mr Brodie, Why not use a tack weld automotive dent puller? The type where you tack on a pull tab in the center of the dent and then after pulling you cut off and grind down the tab! Also can be done with adhesive pull tabs. I know steel tubing may be only less than .2mm wall thickness but if a snatch tool or puller were used gently it would raise those dent centers up and then the split blocks and body hammer could be used and so forth. Also to avoid heating the tube and weakening it I have uses 60/40 tin lead filler with a much lower flowing point to level up the low spot but now days the tack on dent pull is the way to go.
Cool! I just stumbled across you video. I have know your name for a long time. When I was a kid I worked for Norman Hill Bicycles at the time Derik Bailey was building frames him. I eventually went on to become a machinist. I still have my early nineties Rocky Mountain Blizzard. I wonder if you made that one.
I meant to ad that that dent looks like a garage-dent, not something that was a ride gone bad. They're harder to fix than when a handlebar swings around.
I just purchased a vanni losa frameset, has a very minor dent on the top tube, might have to try filling it with braze. Too bad i cant save the paintwork, in the end im a good painter so i should be able to recreate the finish. The finish is a white pearl base with candy red transitioning to orange, yellow till it reaches the seat tube.
You could use air pressure (inside the tube) to pop it up... That's the most efficient way to do it. You could also apply a little bit of heat to soften it up...
Yes I did watch a UA-cam video where someone did that. I know that's what they do with motorcycle expansion chambers to get the dents out. Some bicycle tubes are sealed, others aren't. Downtubes, for example, usually have a big airhole going into the BB. How to seal that? I don't know.
@@paulbrodie With a plug... Or you can even seal the end with a plate and then remove it. You do not need much pressure for that, especially if you heat the metal...
I've used regular plumbing solder / flux and a propane torch to fill some dents. Easy to file / sand to shape, and couldn't even tell it was dented. Not that it is better than real brazing, just an easier solution with very basic relatively cheap tools and what I had on hand. I did try a stud welder (welds the little pins on) and a slide hammer as I see mentioned in the comments, however, I couldn't get enough force to even budge the dent before the pins snapped (the dent wasn't even as bad the one one in the video here). Perhaps there are stronger pins available, never looked into it, was my dads stud welder from when he did autobody repair. I still have it and have another dented frame, perhaps I'll look into it again sometime. I'll say it was a cheaper BMX frame, chromoly tubing, so not sure the wall thickness compared to road / mountain bike frames, so I suppose results may vary with the stud welder. At any rate, nice video, makes me feel a little better about filling the dent on my frame, felt a bit guilty "hiding" the damage (I still own the frame, so not like I did it to sell, just to make it look better).
Yes, the autobody folks often use lead to fill low spots or dents on restorations. It is a perfectly valid way of doing things. There's always more than one way to do things. Thanks for watching!
When I got a dent in my trombone slide I took it to a repairman and he had a series of steel balls on a cable. He'd tap one small ball through the dent, then the next size up, and so on until the dent was gone. He did a really good job.
I've seen a bit of trombone repair and always found it fascinating. I good instrument tech I know was straightening a slide by hand by just bending it over his bench. It scared me watching with the size of the deflection, but he pulled it quite true in a few bends.
Thanks for making this. It is very timely for me. I made a lugged frame and used thin tubing for the top tube. Tange Prestige 7/4/7 in 31.8 I crashed yesterday and put a nice big dent in the top tube. I got most of the dent out with a tube block and I was planning to use cycle design system 48 silver brazing rod (what I have) to fill the remaining dimple since the tube is heat treated. Do you think that is this acceptable for heat treated tubing?
@@paulbrodie What if you use auto body shop lead, bondo or an epoxy filler to level out the dent. Once you have a majority of the dent out, you are cleaning up the cometics I assume.
Great video Paul thank you. Can I ask roughly what thickness of cardboard you use when you double it up in the mill? It looks like dense thin cardboard rather than the Amazon box stuff? Thanks!
ex-KEF engineer here. Just spotted a Reference Series 101 on your shelf. I'm still using mine 30 years after leaving KEF. Do you still have a working pair?
Those KEFs are my working pair. Listen to them every day in my shop. Bought them in '79 or '80, and couldn't believe I spent $600 for the pair.. Great speakers. Thanks for watching!
Hello Mr. Brodie! I have a question - I have a Salsa Moto Rapido with a dent under the down tube. Since it's an aluminum/scandium alloy, is there anything I can do to repair or reinforce it? Any feedback is appreciated. Thank you, and fantastic channel!
Hi Sean. Thanks for liking our channel! I have never worked with aluminum/scandium, so cannot say. If the dent has no sharp edges that might develop into a stress riser, I would just leave it.
Paul, love the videos as I am a hobby machinist and motorcycle fixer upper wanna be! Curious, when you adjusted the boring head the .076, does the boring head work similar to the lathe and half the amount dialed in? On a side note, one of my friends (who suggested your channel) just pulled the trigger on a Triumph cub! Yep, he went off the deep end for sure!!!!
Thank you Haslet Joe. On my boring head, when I dial in .050", it takes off .050". Not similar to a lathe. Your friend must be little crazy to buy Cub! At least there are Cub videos he can watch if he needs some inspiration :)
Hello Paul: Very interesting! I didn't know how dents are fixed. What would happen without fixing? Bending? Breaking? Does a frame lose static and stability with a dent or is it more an optical thing? Does it work only with bronze on a steel frame or would silver also do the job? Is it possible to repair also dents on aluminum frames? Thank you for replying.
Hello Jonas, If you didn't fix a small dent, as long as there was no sharp crease (to start a crack..), it would probably last a very long time. You could say most "small dents" could be considered cosmetic. As dents get bigger, a framebuilder has to decide when to fix and when to replace the tube. You can also use silver solder, lead, and bondo to fill the dent. I have never repaired a dent on an aluminum frame so no expert here. Thanks for watching!
You may have caused the tube to "warp" by heating one side. You may be able to straighten it by allowing to cool , then heat the opposite side, and allow it to cool naturally. That is how we correct the run out on driveshafts after welding on the yokes. All that is required is a small "dot" of heat on the "high" side to warp the tube back to zero run out.
There might be some truth to what you said. However, unlike a driveshaft, a bicycle tube never spins. Most people never look at a tube that closely, so as long as the dent is gone, the customer is happy. Thanks for watching.
What's the functional difference between the aluminium and wooden tubing blocks? Could you hold tubes in the mill for cutting using wooden ones? What are the advantages of the metal ones? The machined alu tubing blocks arlways seemto be machine to hightolerance. Does the parallelism of the sides actually matter when building a bike frame?
They can both work well. Wood is better for a bench vice, and aluminum in the mill vice. They can both be parallel if they are made well and not abused.
I’ve always seen the problem with dented bicycle frames 🖼, but I never 👎 thought 💭 of how to repair 👩🔧 them. I thought once a bicycle frame is dented, you’d have to fill the dent with Bondo, or a product of the like (after preparing the frame), and repaint the frame afterwards. Your friend, Jeff.
Jeff, yes you can use bondo to repair a dent. And I have done that too. The advantage of using bronze to fill is that down the road if you ever want to repaint the frame, the bondo will come off with the bead blasting and you will have to re-bondo. With bronze, it is not affected by bead blasting so it will save you an extra step in the paint process.
@@paulbrodie I guess the brazing material stays, because it’s applied at a way lower temperature 🤒 than welding. This should even save the integrity (strength))of the frame. I would not, however, repair 👩🔧 a bicycle frame with a severe dent, as if it’s been squashed by vise grips, or the frame tubing is distorted. Aluminum bicycle 🚴 frames can also be repaired by brazing in the dent. If the frame is also cracked, at the site of the dent, I’d scrap the frame at this point, because a cracked (or bent frame) is dangerous. Another repair 👩🔧 can be made to a bent frame, such as the frame tubing being bent near the headset steering tube. This often happens after a frontal impact with a hard object. Just remove the bent sections of tubing, and braze in two new sections of tubing. Voila!! Frame repaired 👩🔧. This is often a job, exceeding the cost of the bike, but unless sentimental value is a factor, go on ahead with the repair 👩🔧. Your friend, Jeff.
Hi Paul any tips for removing a dent from a curved tube on a cruiser type frame. Any ideas how I could go about doing it would be much appreciated. Great content thanks for sharing.
@@paulbrodie I've found some other information on dent removal using compressed air and heat. It's normally used on exhausts and tanks but I've seen one guy do it on a bike frame and worked really well. Just in the process of making a attachment to connect the air line to my frame. Thanks for the reply.
@@MrLethal1986 Yes, that process has been used to take dents out of 2 stroke expansion chambers. I think you have to be very careful with how much air pressure and the amount of heat. Good luck!
Greetings mr Paul….. I have an aluminum Bottecchia road bike that has a dent on the down tube by the bottom bracket,,,, does this method work on aluminium,,,, once again great video you and mr Mitch….
@@paulbrodie ah okok. Good for you. I think I might suggest my dad to also start a youtube channel, as he is a really good cook. Thank you Paul and GBU
love watching you work... thanks for sharing your amazing knowledge... 👏 once upon a time I taught autoshop.. richest town in the Bay Area... my kids drove Mercedes and Jaguars... which is why they hired me ;;☆》.. of many jobs... it remains my all time favorite... my biggest problem was getting them to go home... big fun... an honor question: I usually use brazing rod with the flux on the outside... is the separate flux better?
@@paulbrodie back when I learned how to braze... I recall the guy mentioning that issue.. but I was in a hurry and didn't pay attention to the details... I figured I would figure it out... I use the coated kind simply because it is easier in the small applications I have had... times are changing... thanks Mr Brodie... it's been a pleasure, sir
You might want to investigate the old way of doing body work with lead. Lead requires far less heat than bronze and as a result there is far less warpage. Greatly simplified, you clean the metal, apply a tinning compound, and then using a wooden paddle lubricated with beeswax you paddle the lead on using a very soft flame. A good video to show the method can be found here: ua-cam.com/video/87fuTnBS2bE/v-deo.html
Yes that is yet another way. When I left high school I worked in a machine shop and they rented space to an auto body shop that did restorations on MG TCs and other older cars. I got to watch lead applied and it is a pretty neat system. On a bicycle frame, it is pretty heavy.
@@paulbrodie thank you Paul! I have a set of torches, well my dad does anyway. I’m planning on powder coating this frame so I suppose I’ll need to braze it.
I wonder if you could use «lead» like the old school body guys use, instead of bronze. That process is used to weld 20 gage sheet metal without putting that much heat... Since the bronze here is only used as a filler...
I'm not sure how a magnet and a ball is going to take a dent out of a thin walled heat treated 4130 tube... A lot of the tubes are sealed, or only have a 1/4" hole at each end, so getting that ball in and out would be a trick in itself. Thanks for watching.
When building road bicycles from Chromoly, what is the typical wall thickness do bike manufactures and frame builders use? What thickness would the bare minimum that you should use?
Common tubes are 9/6/9 and 8/5/8. This would refer to wall thicknesses of 0.9mm / 0.6mm / 0.9mm. 7/4/7 is also available sometimes but that is very sketchy tubing to use because of the thin-ness. Make sense?
I use a much easier way to pop out dents in frames... An assortment of rubber freeze plugs, an adjustable compressed air source, and a little heat. Done in minutes. Works on steel and aluminum frames... and automotive header tubes as well. LOL
Many years ago, I was given a classic frame (a 1948 or '49 Duckett) with hand cut lugs - and the down-tube had a deep crush in it, to half way through the tube. I took it to an old-time frame builder, and asked him if he could save the frame. When I went back a week later, he had used blocks just like yours to ease the dent out. He was left with a shallow dent the size of a pea, and he filled it with braze. Just as you did. I am well pleased with the repair.
Thanks for commenting.
That this frame was repaired by Paul Brodie substantially increased its value.
You're so funny!
@@paulbrodie Double from $50 to $100
@@weedmanwestvancouverbc9266 Add a 0.
Thanks a lot Paul for generously sharing your knowledge. Only great people do that!
Thank you very much. I do enjoy sharing knowledge...
I’m impressed so much work to fix a dent! Well done
Thanks Francesco. Yes, building and repairing frames can be a Lot of work....
I really enjoy your videos, Paul. The content is always highly interesting and well cut. Thank you for sharing your Knowledge with us.
Yes! now I can repair my kona frame and use it again, every one thought I should scrap that frame. Once I was working in my uncles metal shop and learn almost everything how to work with metal. And I have learned something new today.
Dont , your kona will still be a deathtrap just with a plug covering the damage. This isnt a structural repair only cosmetic.
i spoke to a framebuilder about the same thing and he said it'd be ok but will reduce strength of the steel in the area. He told me it's better to keep a dent on it for strength. Small dents are okay in low stress areas of the frame apparently.
I'm probably showing my age here, but many years ago a frame builder that I used replaced my entire top tube rather than attempt to repair a dent. He carefully sawed off the tube about 1/8" away from where it joined the seat tube and the same at the headstock end. He then filed away the remaining bits smooth before putting on a jig and brazing in a complete new tube. The frame was of course fillet brazed originally and although the repair and a respray cost me about half the cost of a new one I was very pleased with the finished result. The frame was built in Reynolds 531 butted tubing and I remember him saying that the heat of the brazing would always cause a slight loss of tube strength locally but because this was at a joint with another tube it was no detriment.
You are not showing your age. Replacing a tube (done properly) is perfectly acceptable. Repairing a dent is less labour and therefore less expensive. Thanks for watching and commenting!
You just got a sub because you proved to me I was wrong about dented frames! Thank you
I am an addict to your shows. The idea of frame building is beyond the capabilities of my eyesight. An old man can dream :).
My oldest student in Framebuilding 101 was 75; his eyesight wasn't so great and his hands shook but he still finished his frame. Never give up!!
Bifocals.
Thought there where kids having fun in the background... they sound alot like Peacocks. Well, there they were in the backyard of your place. Thanks for the video.
Loved that fix. I have a dented frame, also on the top-tube and my local frame builder said, "Leave it." The tube is very thin and he felt like it might crack if it was forced 'back to round' or maybe he was just busy as hell and didn't want to get involved. So it remains...
Yes, you do have to be careful with thin tubes. I would roll it round, and fill any low spot with a little bondo, then repaint. This is safer than using heat and braze on thin tubes.
Mind blown ! How did I not find this channel until now ? Subscribed.
Thank you for making this video and explaining it clearly, i have recently decided to build a couple of old bmx gems I've been holding onto for some time. One is a Redline RA340 and the other a dented up 99' Dave Mirra Haro. I will definitely use your method to knocking down a couple of those dents, I was starting to wonder if it would ever happen now I can get it prepared and ready to have it chrome dipped.
Thanks and regards,
Mike D.👍🏼
Mike, thanks for watching. Now you can fix those dented BMX frames. Hope you have success!
Excellent craftsmanship, Thank you.
Thank you David.
Thanks a lot Paul...I learn a lot from you. From Buenos Aires, Argentina. Thanks.
Dario, thanks for watching from Argentina!
This is called, being a professional and knowledge throughout years of experience!!!
I have a small dent in the front of a banshee 350 that I cut out hammered from the back and sanded smooth form the front, then taped it back in place with first clear tape then aluminum hvac tape and tac welded it completely around multiple times to prevent it from warping. It came out pretty good. My frame is a compound bend though so it took a long time to completely pop out the dent and mould it back, lots of hours of work 5-7 atleast.
Glad you found the time to fix it...
Dude your so smart this is very useful
I've been around for a while and I have some experience. Thanks for watching!
At last! Some competition for the calls of the peacocks!
Peacocks are only noisy during mating season.
You, sir, are a real pro. Thanks for sharing your time-tested knowledge with us neophytes.
Hey Paul,
have you ever tried to pull the dent out first then fill what’s left of the dent if any? I know it’s not the same material but I do it all the time on 8mm thick 4” round copper tube. (Industrial radiator manifolds) but the principal will be the same, I Braze a rod in the middle of the dent then heat all around the dent until I see a rainbow colouring (like oil in water). Next I grab a pair of pliers pinch the other end of the rod then tap the underneath of the pliers with a hammer. You ideally need to tap in opposite direction the dent went in if that makes sense? Heat and repeat until the dent is out. Snap/wiggle the rod off file/fill/sand make good and paint.
For really big dents you may have to pull in two or three places.
Works great for me, all the best fella.
Owen.
Bicycle frame dents are a little different because the tubing is often heat treated 4130 and thin wall (0.5mm) so being very careful is quite crucial to the success of the repair. The tubing can crack if it gets mistreated, and then the tube would have to be changed. Thanks for watching!
@kieran finney The top tube is usually not under as much stress as other tubes. It all depends how large the crack was, where it was, and the experience of the welder. If it was done 13 years and is now used as a city, I don't think you have much to worry about. Just check it visually every so often...
What about an expansion repair like a motorbike expansion chamber. Is it possible?
@@anarchistangler Yes, it happens a lot. The expansion chamber ends are plugged, air pressure added (no idea how much...) and gentle torch work can make it look like new!
You are a real engineer. Products should come from people like you, and all the other car and moty guys, and never from knock off shops in China and elsewhere. Any country run by people with half a brain would make sure this happens.
Hey, just found your channel. I rented a Brodie once on a trip to Sedona Arizona years ago, would have been 1999ish, I still remember it, a blue hardtail with a white logo and marzocchi bomber. It rode mint.
And now, apparently, they have become collectible :)
I'd probably buy one to keep if I saw it for sale....don't think too many made it to New Zealand where I live now.
PS once this pandemic is over you should do a crossover episode with Allen Millyard.
@@mtnbikeman85 Allen is about 8000 mies away, but I would definitely sit down and have a cup of tea with him :)
You have an easy teaching style Paul, thanks for the lesson 👍
John, thanks for watching and commenting.
First time one of your videos was suggested to me. Viewed and subbed. When your video views are that much greater than your subscribers, then you know your channel will grow quickly.
Cool stuff, amazing workshop having the right tools to create sky’s the limit
David, thanks for watching 😉
A wealth of information - I'd heard about the wood block method from a friend who wrenched for the USSR team in the mid 80's, but never seen it in practice.
Excellent video! Great relaxxed teaching and explanations. I love to learn all about that stuff. All the best, Paul! Cheers from Germany
Thank you, thank you everyone!
@@paulbrodie so ein Käse
I like the bike stand he uses. My consumer grade POS wobbles every time you touch the bike. His is rock solid. A poor carpenter blames his tools. A great carpenter always has great tools. Lesson learned.
Assuming the frame is steel, you could use an auto body stud welder and weld a stud to the low spot then heat around the dent then pull it with the slide hammer.
Yes the frame is steel, but often the wall thickness is only 0.5mm and sometimes it is heat treated 4130 so that is not a very good solution, sorry.
I look forward to watching these every week, thank you Paul!!!
Already thought you are a Super Man, seeing you file convinced me. Great Videos
Always great handcrafting!👍👍
love it! The tip for handling for low temp intake was really helpful!
solid work ,enjoy the channel. id be interested to know if any pdr (paintless dent repair) techs have had any sucsess in doing a pdr on a dent like this. i did paint for a few local fame builders and a few large bike manufactures and have alot of experance working on this stuff but the idea of pdr a bike never crossed my mind untell watching this for some reason. if anyone reading this knows of someone who has let me know.
I do not have any experience with pdr, sorry.
I'm going to make a frame clamp just to enjoy that lovely sound it makes. Lol. 🙂
I'm told that my frame blocks are made from Eastern Maple. Any good hardwood will probably be just fine.
Good job! It's nice to see you do some woodworking too!
I would have filled the tube with water and freeze it while carefully observing, the ice will push the dent out. Its cold work and takes many hours in the cold watching for just the right moment to stop the cold treatment, but the results are spectacular.
I don't think I have that much time or a freezer that big!
Thanks for this video. Learned a lot!
Dear Mr. Brodie,
I've got the same frame, a RM équipe from 1993 with a dent at nearly the same position, but it was a little bit smaler. After I've seen your video I tried to roll out the dent with selfmade tube-blocks like you declared and it worked very well. Many thanks for your video. Finally I put grease between tubeblock and framedent so I could press it harder by rolling out the dent. At least there was nearly no high spot and no dent left. For heating up I unfortunately don't have the right workshop so I was contented with the little leaving dent. Many thanks for giving your idea. I don't dare to file the frame because the tange ultimate ultralight tubewall should have a thickness of 0.6 mm. Is it really without problem to file the frame?
Yours sincerely Rainer
You don't have to file the frame. It sounds like you were careful and made it better. Congrats!
@@paulbrodie Many thanks.
Wow long time no-see, hope you are doing well in this COVID-19 situation. We are very envious of your workshop here in Havana
Hi Peter! I do remember you! Hope you are doing well :)
I always place a drop of oil on my frames before doing the repair with the block of wood. It does help a lot
Not disappointed.
But i was hoping to see the dent come out of the frame.
Glad to know this is how i would do the same repair.
Thought there might be something new to learn, LOL.
Thanks for bring us along.
Peter.
Mr Brodie, Why not use a tack weld automotive dent puller? The type where you tack on a pull tab in the center of the dent and then after pulling you cut off and grind down the tab! Also can be done with adhesive pull tabs. I know steel tubing may be only less than .2mm wall thickness but if a snatch tool or puller were used gently it would raise those dent centers up and then the split blocks and body hammer could be used and so forth. Also to avoid heating the tube and weakening it I have uses 60/40 tin lead filler with a much lower flowing point to level up the low spot but now days the tack on dent pull is the way to go.
I know your method works on regular steel. Will it also work on heat treated thin wall 4130?
Cool! I just stumbled across you video. I have know your name for a long time. When I was a kid I worked for Norman Hill Bicycles at the time Derik Bailey was building frames him. I eventually went on to become a machinist. I still have my early nineties Rocky Mountain Blizzard. I wonder if you made that one.
No, I only worked at Rocky from 84 to 86. Sorry!
Excellent! Thanks for sharing.
I meant to ad that that dent looks like a garage-dent, not something that was a ride gone bad. They're harder to fix than when a handlebar swings around.
I would think the heat from the brazing would seriously affect the strength of the heat-treated tubing.
If you're careful not to overheat, it is not a problem..
Gangster! Thanks for your time!
Peacock?
Yes, I have 2 male peacocks :)
I just purchased a vanni losa frameset, has a very minor dent on the top tube, might have to try filling it with braze. Too bad i cant save the paintwork, in the end im a good painter so i should be able to recreate the finish. The finish is a white pearl base with candy red transitioning to orange, yellow till it reaches the seat tube.
Bondo is another way of repairing a dent, and there will be less paint lost with no heat. Sounds like a sophisticated paint job. Good luck!
Great work Mitch.
Yeah a little bit of a bend from your frame block and torquing the top tube back and forth.
Good work mr Paul newman !!!
Interestingly, Paul Newman and I have birthdays on the same day January 26.
Mr .Paul you is good work super video Thank for the video
You are welcome. Thanks for watching!
You could use air pressure (inside the tube) to pop it up...
That's the most efficient way to do it. You could also apply a little bit of heat to soften it up...
Yes I did watch a UA-cam video where someone did that. I know that's what they do with motorcycle expansion chambers to get the dents out. Some bicycle tubes are sealed, others aren't. Downtubes, for example, usually have a big airhole going into the BB. How to seal that? I don't know.
@@paulbrodie
With a plug...
Or you can even seal the end with a plate and then remove it. You do not need much pressure for that, especially if you heat the metal...
3:45 Peacocks! Interesting video. Always thought the Brodie bikes were sweet.
Could a stud be brazed on. Knock the dent out with a slide hammer? Great looking repair!
If it was a cheap frame with thicker hi tensile steel, yes. But thin wall heat treated 4130 steel, no. It would most likely crack.
Such an awesome video, great channel that's a very cool trick to do with the wood blocks 😀 👌
I've used regular plumbing solder / flux and a propane torch to fill some dents. Easy to file / sand to shape, and couldn't even tell it was dented. Not that it is better than real brazing, just an easier solution with very basic relatively cheap tools and what I had on hand. I did try a stud welder (welds the little pins on) and a slide hammer as I see mentioned in the comments, however, I couldn't get enough force to even budge the dent before the pins snapped (the dent wasn't even as bad the one one in the video here). Perhaps there are stronger pins available, never looked into it, was my dads stud welder from when he did autobody repair. I still have it and have another dented frame, perhaps I'll look into it again sometime. I'll say it was a cheaper BMX frame, chromoly tubing, so not sure the wall thickness compared to road / mountain bike frames, so I suppose results may vary with the stud welder. At any rate, nice video, makes me feel a little better about filling the dent on my frame, felt a bit guilty "hiding" the damage (I still own the frame, so not like I did it to sell, just to make it look better).
Yes, the autobody folks often use lead to fill low spots or dents on restorations. It is a perfectly valid way of doing things. There's always more than one way to do things. Thanks for watching!
Great work
Damn! I guess I want worry about the little pea size ding on the top tube of my Yo Eddy
A very small dent is usually cosmetic only. It is part of the "patina" of the frame as it ages....
super good video, thanks for sharing !
Rodrigo, thanks for watching!
When I got a dent in my trombone slide I took it to a repairman and he had a series of steel balls on a cable. He'd tap one small ball through the dent, then the next size up, and so on until the dent was gone. He did a really good job.
Sounds like a well done repair.
I've seen a bit of trombone repair and always found it fascinating. I good instrument tech I know was straightening a slide by hand by just bending it over his bench. It scared me watching with the size of the deflection, but he pulled it quite true in a few bends.
@@roscoeschieler7752 Sounds like he did a good job!
@@roscoeschieler7752 TY
The title should be : How to fix a dent in your bike STEEL frame.
That was simply therapeutic.......All is right in the world for 15:27.
Thank you London Pickering.
OMG - you've got a Whippet safety? Beautiful machine 😍.
Built the Whippet in 2012
Brilliant craftsmanship. Is this an aluminum frame?
Thanks David. No, this is a steel frame...
Thanks for making this. It is very timely for me. I made a lugged frame and used thin tubing for the top tube. Tange Prestige 7/4/7 in 31.8 I crashed yesterday and put a nice big dent in the top tube. I got most of the dent out with a tube block and I was planning to use cycle design system 48 silver brazing rod (what I have) to fill the remaining dimple since the tube is heat treated. Do you think that is this acceptable for heat treated tubing?
Yes, you just have to be careful. The silver will melt at a lower temperature than bronze which will be good for your thin walled tube :)
@@paulbrodie What if you use auto body shop lead, bondo or an epoxy filler to level out the dent. Once you have a majority of the dent out, you are cleaning up the cometics I assume.
@@norberthofer5830 Yes, those are all good suggestions. I would choose bond over lead, it's much lighter!
@@paulbrodie Thank you for response.
Very nice work 👍🏻🇨🇦
Great video Paul thank you. Can I ask roughly what thickness of cardboard you use when you double it up in the mill? It looks like dense thin cardboard rather than the Amazon box stuff? Thanks!
Thank you. I'm not in my shop to measure, but it's a dense file folder, maybe .030" thick. Best guess.
absolute legend
ex-KEF engineer here. Just spotted a Reference Series 101 on your shelf. I'm still using mine 30 years after leaving KEF. Do you still have a working pair?
Those KEFs are my working pair. Listen to them every day in my shop. Bought them in '79 or '80, and couldn't believe I spent $600 for the pair.. Great speakers. Thanks for watching!
Nevermind, I see you have a dent video. Does filling the dent add strength or is it for looks? Thanks
Hello Mr. Brodie! I have a question - I have a Salsa Moto Rapido with a dent under the down tube. Since it's an aluminum/scandium alloy, is there anything I can do to repair or reinforce it? Any feedback is appreciated. Thank you, and fantastic channel!
Hi Sean. Thanks for liking our channel! I have never worked with aluminum/scandium, so cannot say. If the dent has no sharp edges that might develop into a stress riser, I would just leave it.
Paul, love the videos as I am a hobby machinist and motorcycle fixer upper wanna be! Curious, when you adjusted the boring head the .076, does the boring head work similar to the lathe and half the amount dialed in? On a side note, one of my friends (who suggested your channel) just pulled the trigger on a Triumph cub! Yep, he went off the deep end for sure!!!!
Thank you Haslet Joe. On my boring head, when I dial in .050", it takes off .050". Not similar to a lathe. Your friend must be little crazy to buy Cub! At least there are Cub videos he can watch if he needs some inspiration :)
love you, man
You are very kind.. Thank you!
Hello Paul: Very interesting! I didn't know how dents are fixed. What would happen without fixing? Bending? Breaking? Does a frame lose static and stability with a dent or is it more an optical thing? Does it work only with bronze on a steel frame or would silver also do the job? Is it possible to repair also dents on aluminum frames? Thank you for replying.
Hello Jonas, If you didn't fix a small dent, as long as there was no sharp crease (to start a crack..), it would probably last a very long time. You could say most "small dents" could be considered cosmetic. As dents get bigger, a framebuilder has to decide when to fix and when to replace the tube. You can also use silver solder, lead, and bondo to fill the dent. I have never repaired a dent on an aluminum frame so no expert here. Thanks for watching!
You may have caused the tube to "warp" by heating one side. You may be able to straighten it by allowing to cool , then heat the opposite side, and allow it to cool naturally. That is how we correct the run out on driveshafts after welding on the yokes. All that is required is a small "dot" of heat on the "high" side to warp the tube back to zero run out.
There might be some truth to what you said. However, unlike a driveshaft, a bicycle tube never spins. Most people never look at a tube that closely, so as long as the dent is gone, the customer is happy. Thanks for watching.
I have watched videos about an induction dent removal system for car bodywork and I wondered whether this would work on bicycle frame tubes.
Car bodies and bicycle frames might be a little like apples and oranges...
What's the functional difference between the aluminium and wooden tubing blocks? Could you hold tubes in the mill for cutting using wooden ones? What are the advantages of the metal ones? The machined alu tubing blocks arlways seemto be machine to hightolerance. Does the parallelism of the sides actually matter when building a bike frame?
They can both work well. Wood is better for a bench vice, and aluminum in the mill vice. They can both be parallel if they are made well and not abused.
I’ve always seen the problem with dented bicycle frames 🖼, but I never 👎 thought 💭 of how to repair 👩🔧 them. I thought once a bicycle frame is dented, you’d have to fill the dent with Bondo, or a product of the like (after preparing the frame), and repaint the frame afterwards. Your friend, Jeff.
Jeff, yes you can use bondo to repair a dent. And I have done that too. The advantage of using bronze to fill is that down the road if you ever want to repaint the frame, the bondo will come off with the bead blasting and you will have to re-bondo. With bronze, it is not affected by bead blasting so it will save you an extra step in the paint process.
@@paulbrodie I guess the brazing material stays, because it’s applied at a way lower temperature 🤒 than welding. This should even save the integrity (strength))of the frame. I would not, however, repair 👩🔧 a bicycle frame with a severe dent, as if it’s been squashed by vise grips, or the frame tubing is distorted. Aluminum bicycle 🚴 frames can also be repaired by brazing in the dent. If the frame is also cracked, at the site of the dent, I’d scrap the frame at this point, because a cracked (or bent frame) is dangerous. Another repair 👩🔧 can be made to a bent frame, such as the frame tubing being bent near the headset steering tube. This often happens after a frontal impact with a hard object. Just remove the bent sections of tubing, and braze in two new sections of tubing. Voila!! Frame repaired 👩🔧. This is often a job, exceeding the cost of the bike, but unless sentimental value is a factor, go on ahead with the repair 👩🔧. Your friend, Jeff.
@@jeffreyhickman3871 Sorry, I do not subscribe to your methods of fixing frames.
Hi Paul any tips for removing a dent from a curved tube on a cruiser type frame. Any ideas how I could go about doing it would be much appreciated. Great content thanks for sharing.
I would use bondo. Scratch and sand it with 80 grit emery cloth, then fill and sand. Paint. Thanks for watching!
@@paulbrodie I've found some other information on dent removal using compressed air and heat. It's normally used on exhausts and tanks but I've seen one guy do it on a bike frame and worked really well. Just in the process of making a attachment to connect the air line to my frame. Thanks for the reply.
@@MrLethal1986 Yes, that process has been used to take dents out of 2 stroke expansion chambers. I think you have to be very careful with how much air pressure and the amount of heat. Good luck!
Greetings mr Paul….. I have an aluminum Bottecchia road bike that has a dent on the down tube by the bottom bracket,,,, does this method work on aluminium,,,, once again great video you and mr Mitch….
Tony, it might work. But, I have almost zero experience with aluminum bicycle frames, so, if you do try, be very careful!!
Such an amazing job 👏🏽
Hi Paul. Great video btw 👍🏻. Can you do same approach to fix aluminum frame ?
Using frame blocks yes. Be very careful with heat. Too hot and the aluminum will lose its' heat treating..
Do you accept dent and paint repairs? If yes what would be the best way to contact you for quick inquiry?
@@ardytjahjono9307 Sorry Ardy, I'm retired with a youtube channel...
@@paulbrodie ah okok. Good for you. I think I might suggest my dad to also start a youtube channel, as he is a really good cook. Thank you Paul and GBU
I would leave that exposed, no paint, maybe an autograph though 😂
So, how'd you do it with ovalised tubing like Columbus Max (the clamp)? That'd be cool to see :-)
this only works on tubing that is round...
@@paulbrodie I wondered if you'd figured out a way to defy the oval 😉
Is that JOHN TOMAC in the photo on the wall next to that column drill in the background?
You bet! Good eye :)
love watching you work... thanks for sharing your amazing knowledge... 👏
once upon a time I taught autoshop.. richest town in the Bay Area... my kids drove Mercedes and Jaguars... which is why they hired me ;;☆》.. of many jobs... it remains my all time favorite... my biggest problem was getting them to go home... big fun... an honor
question: I usually use brazing rod with the flux on the outside... is the separate flux better?
Flux is flux. If you don't have an automatic fluxer a coated rod will work.
@@paulbrodie back when I learned how to braze... I recall the guy mentioning that issue.. but I was in a hurry and didn't pay attention to the details... I figured I would figure it out... I use the coated kind simply because it is easier in the small applications I have had... times are changing... thanks Mr Brodie... it's been a pleasure, sir
@@richardcarew4708 I don't think flux coated rods are the very best solution, but much better than no flux at all.
You ever try an automotive dent puller? The kind that welds a small stud on
Have not. Bicycle tubing is very thin (often 0.5mm) and heat treated so I'm unsure how well that method would work...
I just wondered. I stumbled onto your channel yesterday and have seen many videos. So impressive. Love your work.
@@jack002tuber Thank you for stumbling :)
You might want to investigate the old way of doing body work with lead. Lead requires far less heat than bronze and as a result there is far less warpage. Greatly simplified, you clean the metal, apply a tinning compound, and then using a wooden paddle lubricated with beeswax you paddle the lead on using a very soft flame. A good video to show the method can be found here: ua-cam.com/video/87fuTnBS2bE/v-deo.html
Yes that is yet another way. When I left high school I worked in a machine shop and they rented space to an auto body shop that did restorations on MG TCs and other older cars. I got to watch lead applied and it is a pretty neat system. On a bicycle frame, it is pretty heavy.
Please tell us about the motorcycle. Is it a trials bike ?
Yes, I am a trials rider :)
great video man! one general question, does this filling in job help with strength or is it more cosmetic?
Thanks Bruce. I would say it's mainly cosmetic. If you don't have a set of torches, you could use bondo (auto body filler..) It works well too.
@@paulbrodie thank you Paul! I have a set of torches, well my dad does anyway. I’m planning on powder coating this frame so I suppose I’ll need to braze it.
@@BruceChastain You can powder coat over Tig, braze, nickel silver, and silver solder.
I wonder if you could use «lead» like the old school body guys use, instead of bronze. That process is used to weld 20 gage sheet metal without putting that much heat... Since the bronze here is only used as a filler...
One item in this video that confirmed my suspicion: Yes that is a peacock that can be heard :-)
100% correct.
They are very good burglar alarms
Thanks for sharing 👍
I enjoy your videos but this one probably would have been easier with a magnet and internal ball
I'm not sure how a magnet and a ball is going to take a dent out of a thin walled heat treated 4130 tube... A lot of the tubes are sealed, or only have a 1/4" hole at each end, so getting that ball in and out would be a trick in itself. Thanks for watching.
When building road bicycles from Chromoly, what is the typical wall thickness do bike manufactures and frame builders use? What thickness would the bare minimum that you should use?
Common tubes are 9/6/9 and 8/5/8. This would refer to wall thicknesses of 0.9mm / 0.6mm / 0.9mm. 7/4/7 is also available sometimes but that is very sketchy tubing to use because of the thin-ness. Make sense?
@@paulbrodie THANK YOU! THANK YOU! THANK YOU!
@@deltafour1212 You're welcome. Go online to some of the companies selling bicycle tubing and you will see what is being offered...and the prices!
Is replacing the top tube the best option?
It is an option. It is a choice. Depends on the size of the dent, and if there are sharp edges. Thanks for watching...
I use a much easier way to pop out dents in frames... An assortment of rubber freeze plugs, an adjustable compressed air source, and a little heat. Done in minutes. Works on steel and aluminum frames... and automotive header tubes as well. LOL
On our frames, all of the top tubes were sealed. How would you do that? Where would you put the rubber freeze plug?
I would drill a small hole at the head tube/ top tube interface, then cap each end of the head tube.@@paulbrodie