Good and surprising information - I expected the sawdust to give a coarser finish, and it was the opposite! Great tip on reducing machining speed! Made me recall that, a few decades ago, an uncle of mine had an engine head welding and repairing shop and I remember the heads were faced on a big lathe on a huge face plate at a speed of around 40 to 60 RPM and it puzzled me how good the finish was at such low speed, rarely needing to go through the surface grinder (which was also huge).
I think that the powdered charcoal , or coal Dust would be easy to obtain by Buying any of the many Charcoal Briquets that are used for barbeques. It would be a simple matter to break Down the briquets with a hammer and a terry cloth towel. I also think that he coal powder helps keep the mold surface hot as it catches fire ahead of the pouring iron, and helps Flow of the iron. Great Test! Enjoyed it!
Hi Luckygen1001, a very interesting video. Just a word of caution when selecting wood to create sawdust from, don't use Treated Pine as the fumes will contain poisonous compounds from either LOSP or CCA. LOSP Light Organic Solvent Preservative and CCA Copper Chrome Arsenic.
That's interesting. Anyone who owns a woodworking drum sander would have an endless supply of fine wood dust. I'm glad your Colchester is as noisy as mine!😄
There are other ways of obtaining coal dust, or rather substitutes for it. Essentially it's the carbon, and its properties, we're after. One way could be to grind down regular charcoal using the missus' kitchen grate. When I think about it, perhaps buying your own would avoid unnecessary confrontation. I would avoid using charcoal briquettes as they usually contain clay. Clay that binds water, this might have a negative impact. Although the amount of water we're talking about here is minuscule, so it'll probably work just fine. If a fully DIY approach is desirable then a technique from the wilderness survivalists might work. Small squares of cotton cloth is placed into an air--tight tin. I cannot stress the air-tight part enough. The tin is placed into a fire for half an hour to an hour depending on its size and the amount of cloth. The end result is essentially thin woven sheets of charcoal. They are as you might imagine extremely brittle and should be easy to grind down to dust.
I'm admittedly curious if any of the adhesives in the manufactured board that was used to generate the sawdust are playing a role in how it burns during the casting process as described at the end of the video, as opposed to say, starting with intact lumber whose treatment was no more than kiln-dried. I'm also curious now if the type or types of wood used for the sawdust plays a role in suitability, and if grain-size of the sawdust matters.
I did think of that before I tried using sawdust. The adhesives will burn but are only a small percentage of the total amount of sawdust. I think pine has a lot of resin in it and would be the best to use. Having used this method only once I am hoping that others will try other types of wood to see how it will work and then get a better idea as to what works and what does not work.
Never thought of using sawdust. I buy powdered graphite several quarts or larger at a time, but I cast 1/1000 the the volume and quality you do. I'd might want to cook the sawdust a bit to drive off more hydrogen and such. Awesome work on your end as always!!
Good to know, Ill have to give it a try sometime with some sawdust. I have piles of sawdust from the belt sander from when Im making patterns, so Ill just try some of that. I know you can slow the speed down, but usually what I see with the chilled castings, the chilling is usually the worst where you need to drill through it or mill a slot in it, and not everyone has carbide drill bits or carbide endmills to get through it, lol. I'd be interested to see your weight/percentages of ferrosilicon that your using for your pours also, that seems to be a bit of a hidden bit of info that most people cant find. Im also interested to see how much the sawdust will choke up the sand over time also, and how much it decreases the green strength over time with all of the burnt fines mixed in to it.
I started to use 0.25% ferrosilicon on the first rotor melt and was the right amount but other rotor melts I found that I needed about 0.35% or higher.
Well I learned something useful in this video. And having a Cabinet shop that I work in part time gives me access to a lot of saw dust. Now I can experiment. I have read of using wood flour, meaning dust from sanding wood as well. Maybe you have as well. Perhaps a further experiment?
This was really interesting-I had been wondering about coal dust as well as grinding up charcoal briquets. As I was watching I was wondering about using whole wheat flour. I had once tried it when casting aluminum and had really interesting results-mostly in the amber color it imparted to the surface of the aluminum. I like the idea of using the organic material in the facing sand. I had mixed in with the entire batch. The one other thing I learned on that occasion was that it was best to do the casing outdoors or under a really good fume hood.
I am hoping that anyone watching this video will try other organic materials and see how they work. Using coal dust gives aluminium a brown stain and the reason why it does that is because of it's low melting point.
Two questions: 1. When you added the sawdust to the (slightly damp) sand, didn't the sawdust just suck the water out of the sand and become damp sawdust? So, starting with very dry sawdust seems unnecessary. 2. Is there a way to post-heat-treat the chilled castings so that the chilling is removed?
Damp sawdust will always have less moisture than sawdust made from green timber. I did find that I had to add slightly more water to my sand than usual. You can heat treat iron castings but it needs a long time to anneal it at high temps.
how about heat treatment after the casting? would that eliminate the chill? like baking steal to normalise it only with cast iron i read somewhere that is what wood working planes foundries do to reduce all streses from the casting before machining so it may remove any hard points too
A very interesting Session! I see the edges you were commenting on are shiny. I am almost sure this would be caused by carbon from the coal dust leaching into the metal and effectively surface hardening it.
Dried coffee grounds could be a good saw dust alternative. Likely to be more uniform in material and shape, whereas the particle board saw dust may vary in wood to glue ratio and so forth. Ooh! I hope it's the wood particles doing the trick and not the glue! Anyway, very cool. I'm enjoying your experiments.
Torrefaction, or pyrolysis: heat sawdust to 500-800°C ( generally ~550°C is most ideal) in an inert atmosphere (absent oxygen) to get char (biochar). Much better consistency, much better chemical purity, than coal. Because the dust retains the cell structure of wood, you get slightly different surface effects.
I appreciate you working so hard for the sake of our education. Do you think it's possible, or have you tried, using sodium silicate/sand as a castable refractory?
it was a statutory requirement that the detaching bell gear on coal mine cage systems had to be annealed in a specific way I saw it done once about 50 years ago. Consisted of a huge timber fire, fan blown for a day then covered and left several days to cool Seemingly no great science involved, merely the experience of generations of shaft fettlers.
Since coal is basically carbon, couldn't you use crushed charcoal, sieved like you did with the saw dust? It would get rid of much of the non-carbon parts of the wood dust and retain the carbon parts.
Short answer : no. Longer answer at the end of the video. In actuality, most coal is nowhere pure carbon but contains a large fraction of volatile compounds that break down at high temperature and create that gas layer our host talks about.
What about using "corn flour" which is usually just pure starch. From a chemical point of view it is almost the same as cellulose just the structure of how the glucose subunits connect is different, linear vs branching. However wood also has lignin that contains a lot of cyclic carbon, as per the benzene structure. The advantage of starch may be that it is very fine and "off the shelf", also very consistent in its composition so your results are more reproducible over time. Just an educated guess...
When you heat up corn flour/starch, you create dextrin, which if it isnt all burned up from the sand, it makes the sand very gummy and eventually wants to start molding. Ive tried that before in the past and it didnt work out so well, and after the mold started growing throughout the sand, it ended up just getting tossed.
@@ChirpysTinkerings Ah that sounds logical, perhaps a pre-bake of the sand/starch mix at the right temperature in a closed tin with a gas vent will push it past that point while still having useful characteristics, but then you are messing around as much as you are to get the sawdust so why bother? Perhaps wheat bran put through a blender is closer to sawdust.
flour wasnt used as a binder, it was added so when the metal hit it, it burnt and would decrease the strength of the core, causing it to collapse slightly, which would prevent problems with something similar to hot tearing/shrinkage defects around the core, and would also help with removal of the core after the casting had cooled.
While not nearly as cost effective as coal slag, I've made my own refractory sand with silicon carbide, aluminum oxide and pure powdered graphite for the high detail faces, depending on what I'm pouring. Pure graphite can take the most heat and sticks the least, but all three can be had in the 1500 grit area and finer if you like.
Hi there, so how do you apply it? I think two ways: one is mixed and used as contact sand, the other could be spaying it like a refractory paint. I have tried my own mix using m200 quartz powder but it peeled off and cracks when it dries. I guess it is a matter of running more tests.
@@miketxs3150 Two methods, though one is a bit more labor and prep intensive. If doing graphite alone, you can dust it in with a traditional talc bag (I like to use cheese cloth or an old panty hose from the missus' stash) or a fine mesh strainer. Those spatter guards you set on your frying pan also do it in a pinch but need a bit of shape modification so it doesn't just waft all over your work area in a breeze. The other is to sonicate a batch in water for several hours, then add it to a very thin mix with sodium silicate (powder) for dispersion through a spray bottle. 5:1 water to powder and I've gone all the way up to 8:1, depending on if I'm using technical grade or lab grade powder base.
@Mark Harriss Yes, hence the line in my first response "depending on what I'm pouring". Graphite is the universal cure of sorts in regards to temperature resistance, but it's not the cheapest. When mixed in the right proportions with a few other additives, it makes a fantastic base layer for a ceramic shell. =)
Hi, I live in Adelaide, have a homeshop and dabble in aluminium casting too, I need some help with iron casting and was wondering if I can get in touch with you. cheers
@@luckygen1001 In a state, ready to pour from the crucible, I have a vage memory of 1800 degrees celsius. But I could be wrong, not much though. So, to melt ferrosilicon, and handle the dross and all, You need to take it up to around that temp again. I could ask my former colleagues, if needed?
Hello, I like your creativity I want to make a similar furnace, what is the diameter of the waste oil nozzle? What pressure should be maintained in the used oil cylinder?
When you say coal dust are you referring to dust from charcoal or coal that is mined from the ground? I have both so just curious as to which you are referring to.
Hello my friend. When you say adding sawdust to sand, do you mean adding sawdust to sand or adding sawdust to green sand? by the way, do you add water? What is the binder in this sand?
Good day sir. I have a different question at the moment. So I am doing my dissertation on crucible steel via 'co-fusion' of wrought iron (actually low carbon construction steel) and cast iron, with minute amount of charcoal. I use coke as fuel in a oblong pit furnace made from clay, and fuel with charcoal and coke. I use a 1200W hair dryer feeding air in the tuyere. I got 1357 C only, no matter how much air I blow in, how much fuel I put in and even when I create a chimney, flue above the pit. Nothing works. Can you help me? Should I get a stronger blower or add another one?
@@luckygen1001 I meant to say I use wood and charcoal to start a fire and then I put coke in the furnace. My question was how would I increase the coke burning temperature? Do I increase airflow or the amount of fuel?
@@luckygen1001 I now remember you saying that in a previous video some time ago. I've got to get a waste oil set up built for melting at higher temperatures.
Luckygen...You are by far the most knowledgeable and instructional person on UA-cam describing metal casting. Great stuff...and really impressive
Good and surprising information - I expected the sawdust to give a coarser finish, and it was the opposite! Great tip on reducing machining speed! Made me recall that, a few decades ago, an uncle of mine had an engine head welding and repairing shop and I remember the heads were faced on a big lathe on a huge face plate at a speed of around 40 to 60 RPM and it puzzled me how good the finish was at such low speed, rarely needing to go through the surface grinder (which was also huge).
I think that the powdered charcoal , or coal Dust would be easy to obtain by Buying any of the many Charcoal Briquets that are used for barbeques. It would be a simple matter to break Down the briquets with a hammer and a terry cloth towel. I also think that he coal powder helps keep the mold surface hot as it catches fire ahead of the pouring iron, and helps Flow of the iron. Great Test! Enjoyed it!
Hi Luckygen1001, a very interesting video. Just a word of caution when selecting wood to create sawdust from, don't use Treated Pine as the fumes will contain poisonous compounds from either LOSP or CCA. LOSP Light Organic Solvent Preservative and CCA Copper Chrome Arsenic.
That's interesting. Anyone who owns a woodworking drum sander would have an endless supply of fine wood dust. I'm glad your Colchester is as noisy as mine!😄
Yep easier than using a electric saw. My colchester has been working very hard since it's birthday in 1966.
There are other ways of obtaining coal dust, or rather substitutes for it.
Essentially it's the carbon, and its properties, we're after.
One way could be to grind down regular charcoal using the missus' kitchen grate. When I think about it, perhaps buying your own would avoid unnecessary confrontation.
I would avoid using charcoal briquettes as they usually contain clay. Clay that binds water, this might have a negative impact. Although the amount of water we're talking about here is minuscule, so it'll probably work just fine.
If a fully DIY approach is desirable then a technique from the wilderness survivalists might work.
Small squares of cotton cloth is placed into an air--tight tin. I cannot stress the air-tight part enough.
The tin is placed into a fire for half an hour to an hour depending on its size and the amount of cloth.
The end result is essentially thin woven sheets of charcoal. They are as you might imagine extremely brittle and should be easy to grind down to dust.
I'm admittedly curious if any of the adhesives in the manufactured board that was used to generate the sawdust are playing a role in how it burns during the casting process as described at the end of the video, as opposed to say, starting with intact lumber whose treatment was no more than kiln-dried.
I'm also curious now if the type or types of wood used for the sawdust plays a role in suitability, and if grain-size of the sawdust matters.
I did think of that before I tried using sawdust. The adhesives will burn but are only a small percentage of the total amount of sawdust. I think pine has a lot of resin in it and would be the best to use. Having used this method only once I am hoping that others will try other types of wood to see how it will work and then get a better idea as to what works and what does not work.
Never thought of using sawdust. I buy powdered graphite several quarts or larger at a time, but I cast 1/1000 the the volume and quality you do.
I'd might want to cook the sawdust a bit to drive off more hydrogen and such.
Awesome work on your end as always!!
Very interesting.
Not easy to find coal dust in several places, took me 2 months (prepandemic) to obtain a 5kg bag. Time to give sawdust a try myself.
You were very lucky to get a 5 kg bag because I have to buy it in 25 kg bags.
Good to know, Ill have to give it a try sometime with some sawdust. I have piles of sawdust from the belt sander from when Im making patterns, so Ill just try some of that. I know you can slow the speed down, but usually what I see with the chilled castings, the chilling is usually the worst where you need to drill through it or mill a slot in it, and not everyone has carbide drill bits or carbide endmills to get through it, lol. I'd be interested to see your weight/percentages of ferrosilicon that your using for your pours also, that seems to be a bit of a hidden bit of info that most people cant find. Im also interested to see how much the sawdust will choke up the sand over time also, and how much it decreases the green strength over time with all of the burnt fines mixed in to it.
I started to use 0.25% ferrosilicon on the first rotor melt and was the right amount but other rotor melts I found that I needed about 0.35% or higher.
Well I learned something useful in this video. And having a Cabinet shop that I work in part time gives me access to a lot of saw dust. Now I can experiment. I have read of using wood flour, meaning dust from sanding wood as well. Maybe you have as well. Perhaps a further experiment?
This was really interesting-I had been wondering about coal dust as well as grinding up charcoal briquets. As I was watching I was wondering about using whole wheat flour. I had once tried it when casting aluminum and had really interesting results-mostly in the amber color it imparted to the surface of the aluminum. I like the idea of using the organic material in the facing sand. I had mixed in with the entire batch. The one other thing I learned on that occasion was that it was best to do the casing outdoors or under a really good fume hood.
I am hoping that anyone watching this video will try other organic materials and see how they work. Using coal dust gives aluminium a brown stain and the reason why it does that is because of it's low melting point.
Two questions:
1. When you added the sawdust to the (slightly damp) sand, didn't the sawdust just suck the water out of the sand and become damp sawdust? So, starting with very dry sawdust seems unnecessary.
2. Is there a way to post-heat-treat the chilled castings so that the chilling is removed?
Damp sawdust will always have less moisture than sawdust made from green timber. I did find that I had to add slightly more water to my sand than usual. You can heat treat iron castings but it needs a long time to anneal it at high temps.
how about heat treatment after the casting?
would that eliminate the chill? like baking steal to normalise it only with cast iron
i read somewhere that is what wood working planes foundries do to reduce all streses from the casting before machining so it may remove any hard points too
What about flour? It burns with a very close consistency as coal dust. I learned this in doing explosion tests of various dusts.
I guess all such combustible material would work. Just don't use gun powder dust lol
Question, would annealing be able to fix the chilling issues and make the casting more machinable/malleable?
Yes it will.
A very interesting Session! I see the edges you were commenting on are shiny. I am almost sure this would be caused by carbon from the coal dust leaching into the metal and effectively surface hardening it.
Before you revealed the side-by-side comparison, I guessed wrong. Nice little experiment.
This is why I had to mark each one as it is very hard to tell which is which.
Dried coffee grounds could be a good saw dust alternative. Likely to be more uniform in material and shape, whereas the particle board saw dust may vary in wood to glue ratio and so forth. Ooh! I hope it's the wood particles doing the trick and not the glue! Anyway, very cool. I'm enjoying your experiments.
Sometimes at work we get some hard castings and we use a ceramic insert to machine it and it looks like a mirror.
This was very good information. Thank you so much.
Quite interesting session. Troubleshooting is fun no matter what the subject. Thanks for the look!
Have you considered trying ferrotitanium or aluminum? In specific qualities it should help inhibit carbide formation.
If I could get ferrotitanium I would try it, I have tried aluminium but it does not seem to as effective as ferrosilicon.
For some reason i wonder if sugar would work. Iv seen molasses been used to mix with beach sand here on youtube.
I have seen that as well.
Torrefaction, or pyrolysis: heat sawdust to 500-800°C ( generally ~550°C is most ideal) in an inert atmosphere (absent oxygen) to get char (biochar). Much better consistency, much better chemical purity, than coal. Because the dust retains the cell structure of wood, you get slightly different surface effects.
Maybe charcoal dust would work too🤷🏼
I appreciate you working so hard for the sake of our education. Do you think it's possible, or have you tried, using sodium silicate/sand as a castable refractory?
No I have not.
Will a reheat normalizing soak remove the hard chill spots from the casting?
Yes it does work but temperature and length of time needs to be correct. (trial and error)
it was a statutory requirement that the detaching bell gear on coal mine cage systems had to be annealed in a specific way I saw it done once about 50 years ago. Consisted of a huge timber fire, fan blown for a day then covered and left several days to cool
Seemingly no great science involved, merely the experience of generations of shaft fettlers.
Since coal is basically carbon, couldn't you use crushed charcoal, sieved like you did with the saw dust?
It would get rid of much of the non-carbon parts of the wood dust and retain the carbon parts.
Coal has a lot of aromatic carbon that volatizes, he explains the benefits of that in the video near the end.
Short answer : no. Longer answer at the end of the video. In actuality, most coal is nowhere pure carbon but contains a large fraction of volatile compounds that break down at high temperature and create that gas layer our host talks about.
What about using "corn flour" which is usually just pure starch. From a chemical point of view it is almost the same as cellulose just the structure of how the glucose subunits connect is different, linear vs branching. However wood also has lignin that contains a lot of cyclic carbon, as per the benzene structure. The advantage of starch may be that it is very fine and "off the shelf", also very consistent in its composition so your results are more reproducible over time. Just an educated guess...
I tried wheat flour but it did not give the finish I wanted. If you want to try something else be prepared to do a lot experimenting.
When you heat up corn flour/starch, you create dextrin, which if it isnt all burned up from the sand, it makes the sand very gummy and eventually wants to start molding. Ive tried that before in the past and it didnt work out so well, and after the mold started growing throughout the sand, it ended up just getting tossed.
@@ChirpysTinkerings Ah that sounds logical, perhaps a pre-bake of the sand/starch mix at the right temperature in a closed tin with a gas vent will push it past that point while still having useful characteristics, but then you are messing around as much as you are to get the sawdust so why bother? Perhaps wheat bran put through a blender is closer to sawdust.
@@DanielSMatthews I think the sawdust is much easier to get, especially if your making patterns and have/use a belt sander, lol.
@@ChirpysTinkerings Yep sawdust is so easy to get.
They used to use flour as a binder for sand cores which were baked before use. perhaps flour would work for facing sand.
flour wasnt used as a binder, it was added so when the metal hit it, it burnt and would decrease the strength of the core, causing it to collapse slightly, which would prevent problems with something similar to hot tearing/shrinkage defects around the core, and would also help with removal of the core after the casting had cooled.
While not nearly as cost effective as coal slag, I've made my own refractory sand with silicon carbide, aluminum oxide and pure powdered graphite for the high detail faces, depending on what I'm pouring. Pure graphite can take the most heat and sticks the least, but all three can be had in the 1500 grit area and finer if you like.
Hi there, so how do you apply it? I think two ways: one is mixed and used as contact sand, the other could be spaying it like a refractory paint.
I have tried my own mix using m200 quartz powder but it peeled off and cracks when it dries. I guess it is a matter of running more tests.
@@miketxs3150 Two methods, though one is a bit more labor and prep intensive. If doing graphite alone, you can dust it in with a traditional talc bag (I like to use cheese cloth or an old panty hose from the missus' stash) or a fine mesh strainer. Those spatter guards you set on your frying pan also do it in a pinch but need a bit of shape modification so it doesn't just waft all over your work area in a breeze.
The other is to sonicate a batch in water for several hours, then add it to a very thin mix with sodium silicate (powder) for dispersion through a spray bottle. 5:1 water to powder and I've gone all the way up to 8:1, depending on if I'm using technical grade or lab grade powder base.
@Mark Harriss Yes, hence the line in my first response "depending on what I'm pouring". Graphite is the universal cure of sorts in regards to temperature resistance, but it's not the cheapest. When mixed in the right proportions with a few other additives, it makes a fantastic base layer for a ceramic shell. =)
I cannot find ferrous silicon can you tell me where to find it and put a link in the description where are you bought it from because I melt cast-iron
www.castmetalservices.com/products/melting
Hi, I live in Adelaide, have a homeshop and dabble in aluminium casting too, I need some help with iron casting and was wondering if I can get in touch with you. cheers
Just put a comment on any of my videos and I will reply.
At what temperature do You have to bring the ferrosilicon, to melt it?
Ferrosilicon does not melt it dissolves in molten iron.
@@luckygen1001 I guess You don't have the temperature, then? I worked at a ferrosilicon plant for ten years, so yes. It does melt, when hot enough...
@@qivarebil2149 What is the melting point of ferrosilicon?
@@luckygen1001 In a state, ready to pour from the crucible, I have a vage memory of 1800 degrees celsius. But I could be wrong, not much though.
So, to melt ferrosilicon, and handle the dross and all, You need to take it up to around that temp again. I could ask my former colleagues, if needed?
Hello, I like your creativity
I want to make a similar furnace, what is the diameter of the waste oil nozzle?
What pressure should be maintained in the used oil cylinder?
When you say coal dust are you referring to dust from charcoal or coal that is mined from the ground?
I have both so just curious as to which you are referring to.
Coal dust is not ground up charcoal.
Here in the US, it's referred to as "sea coal" in the foundry world. Basically pulverized bituminous coal.
Climb up into your roof space, the dust up there is bloody good stuff.
Hi sir may you please show how to make a drawback core with green sand
Hello my friend. When you say adding sawdust to sand, do you mean adding sawdust to sand or adding sawdust to green sand? by the way, do you add water? What is the binder in this sand?
Adding saw dust to green sand and the binder is bentonite
@@luckygen1001 thx Master.
A coffee grinder could grind that sawdust real fine.
Hey how about used and dried coffee grinds as sawdust?
Good day sir.
I have a different question at the moment. So I am doing my dissertation on crucible steel via 'co-fusion' of wrought iron (actually low carbon construction steel) and cast iron, with minute amount of charcoal. I use coke as fuel in a oblong pit furnace made from clay, and fuel with charcoal and coke. I use a 1200W hair dryer feeding air in the tuyere. I got 1357 C only, no matter how much air I blow in, how much fuel I put in and even when I create a chimney, flue above the pit. Nothing works. Can you help me?
Should I get a stronger blower or add another one?
Charcoal burns too quickly use only coke it burns the hottest.
@@luckygen1001 I meant to say I use wood and charcoal to start a fire and then I put coke in the furnace.
My question was how would I increase the coke burning temperature?
Do I increase airflow or the amount of fuel?
@@emel60 Try increasing the airflow.
Could you add charcoal dust to your sand
No, charcoal does not burn like wood does.
The glue may give you porosity?
There was no porosity in the castings that used sawdust as a facing sand.
Great video!
Great vid and information..Thanks.
Thanks for sharing!
Very interesting lucky!
how about ground up lump charcoal used for BBQ
Aint coconuts used in forges how would coconut sawdust work?
it would be easier to burn the wood and smash the charcoal into a powder than saw it and sieve etc....
Excellent news.
You use propane for fuel right?
Only to preheat my furnace before switching to waste oil.
@@luckygen1001 I now remember you saying that in a previous video some time ago. I've got to get a waste oil set up built for melting at higher temperatures.
@@docvencil2222 Waste oil is always cheaper than propane.
@@luckygen1001 Do you use cooking oil or motor oil? I can see waste being less expensive than propane.
@@docvencil2222 Motor oil but I use hydraulic oil when I can get it.
Хорошо было бы на русский перевод субтитры
Просто используйте гугл переводчик.
I thought the sawdust one looked better.
If they need coal dust, I can give them my used handkerchief.
I had thought that maggie thatcher had closed all the coal mines in england 30 years ago?