I had a big bronze spill a couple years ago, no steam explosion, though the concrete did spall a bit. There just isn't that much water in concrete that is kept dry out of the weather. If it was outside and had moisture from recent rain, it might have been different. But the little spill you had probably wouldn't be much of a problem even then. One day I'll take on the cast iron challenge and get set up to cast it. You make it look like child's play. Great vid lucky.
Concrete is not just one thing. It can vary in mix proportions, aggregate type, additives, finish method, and porosity. Pure Portland cement, without aggregate is waterproof, and used to line water tanks. Concrete with different mixes can vary greatly in the ability to absorb or hold moisture. This may explain why different people have different experiences with molten metal spills on concrete.
You (and Martin) are my masters, thanks for knowledge sharing. In regards to cost of cast iron scrap, I am lucky to get more or less unlimited supply of disk brakes from a friend who has car workshop, Those disks are also relatively easy to cut. 👍👍👍👍👍👍
I found it interesting that when you were pouring, slowly because of the volume of metal, I found I was tilting my head to the left to match the crucible. Thanks for the video.
I have worked with continuous cast silicon iron that would perfectly pass your drill swarf test. My friend who is a 40 year plus tool and die maker argued that it's not iron, until I showed him the label from Carpenter and he tried a bit of it himself. It's used for transformer laminations, or products that require a great ability to run high magnetic fields through them. Like a very efficient loudspeaker motor that I was prototyping in 1997 and 1998. As always I learn from your videos. Thanks for taking the time to make them. I love your explanations. And your methods. Mark
@@luckygen1001 Not a chance. the carbon in the cast iron is not good in a magnetic circuit like a transformer. But Iron and silicon are. MY point is that the silicon iron alloy is available continuous cast and it drills and machines exactly like steel. But it has very low carbon content. In a magnetic circuit the lower the carbon content of the iron the better.
@@KravchenkoAudioPerth Misunderstanding cleared up. I have noticed that some transformers have super thin laminations, is it because they run at a higher frequency?
@@luckygen1001 Transformers run more efficiently with many laminations. Most power transformers are running 50 or 60 hertz depending what part of the world you are in. And the second reason to use layers is that it a lot easier to work with thin layers built up into what ever shape you require. I design loudspeakers. I'm stealing from the transformer guys. :) I am not in any way a transformer expert.
Great to see a new casting video luckeygen! Always a treat. If you ever have a mind to....it would be great to see a test of woodflour (or corn flour) vs seacoal using the same continuous cast iron -- not for fine surface finish as you did in the past video, but if there's a difference for the sand expansion defect you got this time. Does the flour give the sand more resiliency? Maybe pack both a little hard, to force the defect and see which one is less?
Sawdust is used in sand molds because it burns and shrinks, so it minimizes the sand expansion defect problem. I should have known better and rammed the cope surface more gently.
The steam is when the concrete has some excess moisture content. Concrete is hygroscopic, absorbs moisture I,e from the ground. You may have dry ground a low water table or the shed has a moisture control barrier DPC ( damp proof course) membrane under the floor, to help control moisture content of your shed floor. No moisture = no steam from the super heated contact with metal.
I live in a damp area and have wondered about my floor absorbing moisture from the ground also my floor does not have a moisture control barrier underneath it.
recheck the part of the video where the molten iron poured onto the ground and you'll hear very quick sounds of two pops where it did react with some moisture. The moisture was almost dried up so the popping was very quick but it was there. As always I very much enjoyed your videos. Later!
I have used cores made from portland cement and sand, never had a problem with the cores exploding. Cores made from portland cement have a lot less water than concrete. When are you making another video, it has been awhile?
I think your "expansion defects" are shrinkage porosity.. your riser is a good size for the casting but it's connected to the casting too far away and possibly by a channel that is too thin. Being too far away or too thin lets that section cool first and prevents "draw" from the riser by the casting and as you can imagine as the rest of the casting cools it cannot draw metal during cooling and that is the source of your expansion defects. Two of the golden rules for porosity free casting is always sprue to the thickest part and make sur your reservoir (riser area) is enough to provide draw during cooling.
I was wondering what the difference is between ductile iron and regular pure iron. I had an instructor at college who showed us a piece of pure iron. He said it was highly resistant to corrosion and that it was both tough and malleable. It may have been wrought iron. I also machined up some parts recently using an old milling machine drawbar as the stock. It made short chips like malleable iron and it was lovely stuff to machine. It was nothing like the cold rolled steel I generally use. It seems like the wrong material for making a drawbar from though. Regards, Mark
When I machine ductile iron in my lathe the chips are really long but with cast iron the chips are always short chips. The most convincing test is to bend a piece until it breaks and look at the fracture.
The metal looked like it had cooled quite a bit between putting it into the pouring trolley and you had started to take it over, then as slowly as it had flowed into the mold, it looks like maybe the metal had started to chill as it flowed in, folded over itself, and created a large scab on top of the casting? That's what it kinda looks like to me tbh. Ive melted a few pieces of durabar, which is continous cast iron scrap that I had gotten and it was quite nice to cast with, even with thicker stuff like that larger disk.
The gate into the riser was way too small so it took forever to fill up the mold. If the metal was too cold why did the bottom of the casting come out perfect? If my sand is rammed too hard that is what happens although I have never seen this defect so bad.
@@luckygen1001 Yea, Ive seen it while doing brass quite a bit, the metal would be a bit too cold while flowing in and was right at that point, so the bottom will be nice, but as the metal fills up in, the shell of the metal that's against the sand will get pulled under by the metal flowing in and shove it down causing it to want to fold down while new metal flows in around and against the folded down skin section and causing that defect.
I have been busy doing a lot of jobs on my rural property which can take a lot of time but it feels great that I have uploaded another video. It has been well over four months since I uploaded my last video which is way to long.
I've been thinking of casting gray iron to make my own lapping plates. Melt, pour a cylinder, cut and machine. Is it practical to pour it into a steel pipe to cast and cut the pipe to make round bar stock?
@@luckygen1001 Thank you for the comment. It's probably easier for me to make a 6" + sand casted cylinder than find one at the scrapyard. It is annoyingly hard to order small bits of iron to play with here in nowhere, canuckistan. The big guys wont sell to me and the little ones won't order for me unless they increase the price of the material by 5x. Broken Car engines and casings seem like an easy source of iron and mangled wheels aluminum. It would be nicer not to be using mystery metal it seems unless you have an account it is a pain in the butt.
@@robertfontaine3650 This is why I cast my leftover iron into cylinders using sand molds. It is very useful to use in my lathe and milling machine. It is the same in Australia where I live, they will not deal with the little guy.
I have never used a piano frame but I suspect it would be good iron to melt down. The only way to find out is to melt some. If it turns out to be good iron to melt down you will have a large supply of good iron for the future.
@@markfryer9880 I am a bit ashamed to admit it but we have burned few (total wrecks anyway) in art projects :) Just hit with hammer what is left to break apart...
Nice to see a video from you again, and many thanks for the mention. Sorry about the steel die - I should have known because I did not make that die and knowing who did I strongly suspect that he used wash ground steel plate so sorry about that. The die you did use is to me a bit of an unknown, I did not make it and it may be that it was cut into foundry cast square blocks - I just don't know but dies cut from con cast bar usually have some evidence of the original round shape. Also I do not remember ever buying any ductile iron so any of that in the collection is a bit of a mystery. However all the bits shown near the end of the video are con cast iron that I bought and machined so they should be good to go. There seems to be some mixed ideas as to that rattail defect. It does look like a rattail to me although I have not had the pleasure of "kicking its tyres" in person. I certainly do not believe that it is any sort of shrinkage defect. Do you use an anti-expansion defect additive in your sand (e.g. wood flour)? It seems to that many fail to understand the unique shrinkage behaviour of grey iron and they seem to expect it to behave like, say, aluminium. Grey iron goes through a distinctive expansion phase as the graphite forms although it does shrink as the austenite solidifies. This behavior markedly effects how iron needs to be fed and indeed if the composition is right (big IF) there is no net liquid to solid contraction on solidification. This is one of the reasons that cast iron is said to be "God's gift to the foundryman". In view of the remarkable freedom from chill I wonder if there is an anti-chill additive (e.g. tin ) in the iron??.... Martin
Thanks for watching my video. After cutting up tons of scrap iron to melt it is not hard to spot steel and ductile iron in my scrap pile. I do recall seeing square con cast iron for sale at a model engine show but not that big. I am not sure as to what the biggest con cast iron round bar that can be purchased? If a sand casting defect is shown in a youtube video there will always many opinions as to why it happened. The only thing I add to my sand is coal dust and I know to be careful not to ram my sand too hard. I did ram the drag side softly but forgot to on the cope side softly. So I did send someone a close up photo of the defect and it shows how the cope surface dropped so much it cracked before filling up. Also the crack is always in the center that defect. When the mold did fill up the crack also filled up. I have read that cast iron can expand quickly in the mold so the places that freeze last the molten iron level will drop. It can be very hard to prove that is the case and using different scrap it can be very hard to pin down the cause of shrinkage. I have read that tin is added to make cast iron hard wearing in engine blocks. When the G.M.H iron foundry closed about 12 years ago in Melbourne I had a good look at all the alloys they used to add to their iron and tin was there, also copper was added. Sulphur was also added to the molten iron in the form of iron sulphide. That was the biggest eye opener for me to see what they add to cast iron.
@@luckygen1001 I have an old Flocast catalogue and it lists con cast iron up to 465 mm diameter but they do note that "some sizes may be static cast". I can remember buying it at 300 mm diameter. There were three grades - basically Ferritic, pearlitic, and Ductile (1F, 2P, and 3D). they did mention non round shapes but these appear to have been specials. I too have noted the diversity of opinion on YT when one shows shrinkage or gas defects - most of the opinion seems to be just plain wrong! Tin in Iron (at about 0.1%) seems to be a pearlite stabilizer at the expense of ferrite so it would indeed likely increase the hardness, I seem to recall that it sort of counteracts the effect of section thickness on structure. I have heard of Cu additions but cannot recall what for - I will try to find out. However for the life of me I cannot see why S would be added it is generally regarded as a bad impurity and efforts are usually made to keep it low and close to zero for SG irons. I have three or so articles on Tin in iron and can copy and send to you if you wish.... Martin
Bill, Further to the above it appears that Copper acts similarly to tin particularly in SG irons, i.e. suppresses ferrite favors pearlite and helps prevent chill, both seem to lower sensitivity to section thickness but it looks as though copper needs to be about 1% against 0.1% for the tin. Maybe you should do some experiments with these additions....Martin
@@olfoundryman8418 Years ago I was displaying my cast iron model steam engines at a show and a fellow came up looking at my models . He then told me he was a mechanical engineer working in the iron foundry at G.M.H. in Melbourne. What followed was a long lecture on all the faults in my castings and how to eliminate them. He was so wrong and had never melted any cast iron in his life so here was another armchair expert. So I told him that the iron foundry where he worked used mostly steel scrap to make cast iron and ductile iron so sometimes the sulphur level would fall to below a certain point in cast iron and the innoculants they were using would not work as well. So they would add small amounts of sulphur to bring it back to the proper level. He was not very pleased when I said this and you are right it would never be added to ductile iron. When iron foundries got rid of their cupolas and used induction furnaces to melt steel to make cast iron the low sulphur became a problem. The foundry magazines I have got have many articles about this problem and when I visited the G.M.H. iron foundry after it closed and seen the iron sulphide, so yes it is true they add sulphur to only cast iron. So the moral to this is just because someone works in a foundry it does not mean that they understand WHY things are added to a melt!
If sand is rammed too tightly the sand grains expand quickly at a certain temperature and if there is no room to expand the mold will rupture as seen in the video.
@@luckygen1001 - i don’t know. It just seems like what you cast was a huge piece of metal and maybe it needed a second riser, or the runner cooled down too quick and couldn’t prevent the shrinkage.
@@danstephens9500 - I know but maybe 1 riser wasn’t sufficient for such a big piece of metal being cast. Maybe it needed a 2 risers, with bigger runners.
@@shortaybrown The riser looks like it only shrank about 10% of the distance to the part. So no need for more riser size or more risers. It looks to me like it shrank a perfectly appropriate amount.
I had a big bronze spill a couple years ago, no steam explosion, though the concrete did spall a bit. There just isn't that much water in concrete that is kept dry out of the weather. If it was outside and had moisture from recent rain, it might have been different. But the little spill you had probably wouldn't be much of a problem even then. One day I'll take on the cast iron challenge and get set up to cast it. You make it look like child's play. Great vid lucky.
I was thinking that you lost all interest in melting cast iron.
Concrete is not just one thing. It can vary in mix proportions, aggregate type, additives, finish method, and porosity. Pure Portland cement, without aggregate is waterproof, and used to line water tanks. Concrete with different mixes can vary greatly in the ability to absorb or hold moisture. This may explain why different people have different experiences with molten metal spills on concrete.
Between You and Oldfoundryman it seems like the best Foundryman on UA-cam are from Australia.
Thank you for watching my videos.
You (and Martin) are my masters, thanks for knowledge sharing. In regards to cost of cast iron scrap, I am lucky to get more or less unlimited supply of disk brakes from a friend who has car workshop, Those disks are also relatively easy to cut. 👍👍👍👍👍👍
Do you make videos of your iron melts?
@@luckygen1001 right now, no, busy but will do I Dec after Melbourne trip
Building new oven (200 l drum) and metal flasks in between
Cheers
Thank you for continuing to make your great videos sir!! 💪💪
Thank you for watching my latest video.
I've certainly learnt something about cast iron here! Thanks lucky! 👍😊
Much respect luckygen. I’m into learning iron casting from your videos.
I found it interesting that when you were pouring, slowly because of the volume of metal, I found I was tilting my head to the left to match the crucible.
Thanks for the video.
When I was pouring the mold I was beginning to think I would not have enough metal to fill up the mold.
I have worked with continuous cast silicon iron that would perfectly pass your drill swarf test. My friend who is a 40 year plus tool and die maker argued that it's not iron, until I showed him the label from Carpenter and he tried a bit of it himself. It's used for transformer laminations, or products that require a great ability to run high magnetic fields through them. Like a very efficient loudspeaker motor that I was prototyping in 1997 and 1998. As always I learn from your videos. Thanks for taking the time to make them. I love your explanations. And your methods.
Mark
Am I getting that right, cast iron is used for transformer laminations? I have dismantled many transformers and the laminations are very thin.
@@luckygen1001 Not a chance. the carbon in the cast iron is not good in a magnetic circuit like a transformer. But Iron and silicon are. MY point is that the silicon iron alloy is available continuous cast and it drills and machines exactly like steel. But it has very low carbon content. In a magnetic circuit the lower the carbon content of the iron the better.
@@KravchenkoAudioPerth Misunderstanding cleared up. I have noticed that some transformers have super thin laminations, is it because they run at a higher frequency?
@@luckygen1001 Transformers run more efficiently with many laminations. Most power transformers are running 50 or 60 hertz depending what part of the world you are in. And the second reason to use layers is that it a lot easier to work with thin layers built up into what ever shape you require. I design loudspeakers. I'm stealing from the transformer guys. :) I am not in any way a transformer expert.
@@KravchenkoAudioPerth Thanks for your answer.
Great demo, thanks! Enjoyed watching.
Thanks for watching.
Very interesting remarks you pointed out! No steam explosion, because the floor was bone dry.
Yes you are right and it would be a different story had the concrete floor been outside exposed to the rain.
@@luckygen1001 Yep. Water on the ground is the most dangerous part in this process - spills turn to molten bullets.
Love your videos. Please do some more. 😍
Great to see a new casting video luckeygen! Always a treat. If you ever have a mind to....it would be great to see a test of woodflour (or corn flour) vs seacoal using the same continuous cast iron -- not for fine surface finish as you did in the past video, but if there's a difference for the sand expansion defect you got this time. Does the flour give the sand more resiliency? Maybe pack both a little hard, to force the defect and see which one is less?
Sawdust is used in sand molds because it burns and shrinks, so it minimizes the sand expansion defect problem. I should have known better and rammed the cope surface more gently.
The steam is when the concrete has some excess moisture content. Concrete is hygroscopic, absorbs moisture I,e from the ground. You may have dry ground a low water table or the shed has a moisture control barrier DPC ( damp proof course) membrane under the floor, to help control moisture content of your shed floor. No moisture = no steam from the super heated contact with metal.
I live in a damp area and have wondered about my floor absorbing moisture from the ground also my floor does not have a moisture control barrier underneath it.
@@luckygen1001 If that is the case then I would expect that as you get further away from the exterior walls and doorways the slab will be drier.
recheck the part of the video where the molten iron poured onto the ground and you'll hear very quick sounds of two pops where it did react with some moisture. The moisture was almost dried up so the popping was very quick but it was there. As always I very much enjoyed your videos. Later!
I have used cores made from portland cement and sand, never had a problem with the cores exploding. Cores made from portland cement have a lot less water than concrete. When are you making another video, it has been awhile?
@@luckygen1001 , I just uploaded a video on mold wash. Soon will be another.
I was expecting the concrete to spall when it hit. No idea why it didn't.
Most people say it will spall but here is video proof that does not happen all the time.
I think your "expansion defects" are shrinkage porosity.. your riser is a good size for the casting but it's connected to the casting too far away and possibly by a channel that is too thin. Being too far away or too thin lets that section cool first and prevents "draw" from the riser by the casting and as you can imagine as the rest of the casting cools it cannot draw metal during cooling and that is the source of your expansion defects. Two of the golden rules for porosity free casting is always sprue to the thickest part and make sur your reservoir (riser area) is enough to provide draw during cooling.
Hello, what type of cast iron can I use for press???

I was wondering what the difference is between ductile iron and regular pure iron. I had an instructor at college who showed us a piece of pure iron. He said it was highly resistant to corrosion and that it was both tough and malleable. It may have been wrought iron. I also machined up some parts recently using an old milling machine drawbar as the stock. It made short chips like malleable iron and it was lovely stuff to machine. It was nothing like the cold rolled steel I generally use. It seems like the wrong material for making a drawbar from though.
Regards,
Mark
When I machine ductile iron in my lathe the chips are really long but with cast iron the chips are always short chips. The most convincing test is to bend a piece until it breaks and look at the fracture.
@@luckygen1001 Would a "spark test" be of any use to identify cast iron?
@@bobvines00 A spark test can be very misleading for inexperienced people. It takes a while to learn what the different sparks look like.
For your question at the end, my guess is very old concrete, clean and dry, no oil stains to speak of, nothing to flash to steam.
I was thinking the same thing, not enough moisture means no steam explosion. That concrete floor was poured in 1996.
@@luckygen1001 Was the slab poured after the shed was built?
@@markfryer9880 Yes it was.
The metal looked like it had cooled quite a bit between putting it into the pouring trolley and you had started to take it over, then as slowly as it had flowed into the mold, it looks like maybe the metal had started to chill as it flowed in, folded over itself, and created a large scab on top of the casting? That's what it kinda looks like to me tbh. Ive melted a few pieces of durabar, which is continous cast iron scrap that I had gotten and it was quite nice to cast with, even with thicker stuff like that larger disk.
The gate into the riser was way too small so it took forever to fill up the mold. If the metal was too cold why did the bottom of the casting come out perfect? If my sand is rammed too hard that is what happens although I have never seen this defect so bad.
@@luckygen1001 Yea, Ive seen it while doing brass quite a bit, the metal would be a bit too cold while flowing in and was right at that point, so the bottom will be nice, but as the metal fills up in, the shell of the metal that's against the sand will get pulled under by the metal flowing in and shove it down causing it to want to fold down while new metal flows in around and against the folded down skin section and causing that defect.
Long time no see. We've missed you.
I have been busy doing a lot of jobs on my rural property which can take a lot of time but it feels great that I have uploaded another video. It has been well over four months since I uploaded my last video which is way to long.
hey old friend how are you doing, nice video : good to see you again !
Great to see you again and I trust you found the video useful.
I've been thinking of casting gray iron to make my own lapping plates. Melt, pour a cylinder, cut and machine.
Is it practical to pour it into a steel pipe to cast and cut the pipe to make round bar stock?
Very risky if you do not dry out the pipe, better to use sand with 4% water content.
@@luckygen1001 Thank you for the comment. It's probably easier for me to make a 6" + sand casted cylinder than find one at the scrapyard. It is annoyingly hard to order small bits of iron to play with here in nowhere, canuckistan. The big guys wont sell to me and the little ones won't order for me unless they increase the price of the material by 5x. Broken Car engines and casings seem like an easy source of iron and mangled wheels aluminum. It would be nicer not to be using mystery metal it seems unless you have an account it is a pain in the butt.
@@robertfontaine3650 This is why I cast my leftover iron into cylinders using sand molds. It is very useful to use in my lathe and milling machine. It is the same in Australia where I live, they will not deal with the little guy.
Quality learning
You have come to the right place for that.
I'd try melting cast iron but it's brutal on your furnace. Especially my little homemade bucket of fire....
What would happen if the mould was tilted a little?
The cast iron tends to splash if I did that
How well would old piano frame do as a source of scrap cast iron?
I have never used a piano frame but I suspect it would be good iron to melt down. The only way to find out is to melt some. If it turns out to be good iron to melt down you will have a large supply of good iron for the future.
They are a bitch to cut down and dispose of!
Mark from Melbourne Australia
@@markfryer9880 I am a bit ashamed to admit it but we have burned few (total wrecks anyway) in art projects :)
Just hit with hammer what is left to break apart...
Nice to see a video from you again, and many thanks for the mention. Sorry about the steel die - I should have known because I did not make that die and knowing who did I strongly suspect that he used wash ground steel plate so sorry about that. The die you did use is to me a bit of an unknown, I did not make it and it may be that it was cut into foundry cast square blocks - I just don't know but dies cut from con cast bar usually have some evidence of the original round shape. Also I do not remember ever buying any ductile iron so any of that in the collection is a bit of a mystery. However all the bits shown near the end of the video are con cast iron that I bought and machined so they should be good to go.
There seems to be some mixed ideas as to that rattail defect. It does look like a rattail to me although I have not had the pleasure of "kicking its tyres" in person. I certainly do not believe that it is any sort of shrinkage defect. Do you use an anti-expansion defect additive in your sand (e.g. wood flour)?
It seems to that many fail to understand the unique shrinkage behaviour of grey iron and they seem to expect it to behave like, say, aluminium. Grey iron goes through a distinctive expansion phase as the graphite forms although it does shrink as the austenite solidifies. This behavior markedly effects how iron needs to be fed and indeed if the composition is right (big IF) there is no net liquid to solid contraction on solidification. This is one of the reasons that cast iron is said to be "God's gift to the foundryman".
In view of the remarkable freedom from chill I wonder if there is an anti-chill additive (e.g. tin ) in the iron??.... Martin
Thanks for watching my video. After cutting up tons of scrap iron to melt it is not hard to spot steel and ductile iron in my scrap pile. I do recall seeing square con cast iron for sale at a model engine show but not that big. I am not sure as to what the biggest con cast iron round bar that can be purchased?
If a sand casting defect is shown in a youtube video there will always many opinions as to why it happened. The only thing I add to my sand is coal dust and I know to be careful not to ram my sand too hard. I did ram the drag side softly but forgot to on the cope side softly. So I did send someone a close up photo of the defect and it shows how the cope surface dropped so much it cracked before filling up. Also the crack is always in the center that defect. When the mold did fill up the crack also filled up.
I have read that cast iron can expand quickly in the mold so the places that freeze last the molten iron level will drop. It can be very hard to prove that is the case and using different scrap it can be very hard to pin down the cause of shrinkage.
I have read that tin is added to make cast iron hard wearing in engine blocks. When the G.M.H iron foundry closed about 12 years ago in Melbourne I had a good look at all the alloys they used to add to their iron and tin was there, also copper was added. Sulphur was also added to the molten iron in the form of iron sulphide. That was the biggest eye opener for me to see what they add to cast iron.
@@luckygen1001 I have an old Flocast catalogue and it lists con cast iron up to 465 mm diameter but they do note that "some sizes may be static cast". I can remember buying it at 300 mm diameter. There were three grades - basically Ferritic, pearlitic, and Ductile (1F, 2P, and 3D). they did mention non round shapes but these appear to have been specials.
I too have noted the diversity of opinion on YT when one shows shrinkage or gas defects - most of the opinion seems to be just plain wrong!
Tin in Iron (at about 0.1%) seems to be a pearlite stabilizer at the expense of ferrite so it would indeed likely increase the hardness, I seem to recall that it sort of counteracts the effect of section thickness on structure. I have heard of Cu additions but cannot recall what for - I will try to find out. However for the life of me I cannot see why S would be added it is generally regarded as a bad impurity and efforts are usually made to keep it low and close to zero for SG irons.
I have three or so articles on Tin in iron and can copy and send to you if you wish.... Martin
Bill, Further to the above it appears that Copper acts similarly to tin particularly in SG irons, i.e. suppresses ferrite favors pearlite and helps prevent chill, both seem to lower sensitivity to section thickness but it looks as though copper needs to be about 1% against 0.1% for the tin. Maybe you should do some experiments with these additions....Martin
@@olfoundryman8418 Years ago I was displaying my cast iron model steam engines at a show and a fellow came up looking at my models . He then told me he was a mechanical engineer working in the iron foundry at G.M.H. in Melbourne. What followed was a long lecture on all the faults in my castings and how to eliminate them. He was so wrong and had never melted any cast iron in his life so here was another armchair expert. So I told him that the iron foundry where he worked used mostly steel scrap to make cast iron and ductile iron so sometimes the sulphur level would fall to below a certain point in cast iron and the innoculants they were using would not work as well. So they would add small amounts of sulphur to bring it back to the proper level.
He was not very pleased when I said this and you are right it would never be added to ductile iron. When iron foundries got rid of their cupolas and used induction furnaces to melt steel to make cast iron the low sulphur became a problem. The foundry magazines I have got have many articles about this problem and when I visited the G.M.H. iron foundry after it closed and seen the iron sulphide, so yes it is true they add sulphur to only cast iron. So the moral to this is just because someone works in a foundry it does not mean that they understand WHY things are added to a melt!
@@luckygen1001 Ah ha! The problem is that he was an engineer not a metallurgist 😊.... Martin
What causes expansion defects?
If sand is rammed too tightly the sand grains expand quickly at a certain temperature and if there is no room to expand the mold will rupture as seen in the video.
.......... at 10:17 timeline......iMac !
Yes it is a mac and it will be stripped down for scrap metals to melt in my furnace.
Glad there was no explosion, whatever the reason
same here, I really don't need explosions in my foundry.
You’re riser wasn’t big enough, that’s why it shrunk.
Next time use a riser the size of a beer can.
That will work.
So what happens if I use a riser the size of a beer can and it still shrinks?
@@luckygen1001 - i don’t know.
It just seems like what you cast was a huge piece of metal and maybe it needed a second riser, or the runner cooled down too quick and couldn’t prevent the shrinkage.
The riser is supposed to shrink. It shrinks as the metal is drawn in to the mold cavity. That;s how a riser works.
@@danstephens9500 - I know but maybe 1 riser wasn’t sufficient for such a big piece of metal being cast. Maybe it needed a 2 risers, with bigger runners.
@@shortaybrown The riser looks like it only shrank about 10% of the distance to the part. So no need for more riser size or more risers. It looks to me like it shrank a perfectly appropriate amount.