# Oxy-Acetylene Torch Question



## HTRN (Oct 25, 2012)

You may have seen my other post about the powder not melting. I was told I needed more heat, so I went out and bought a Victor medium duty oxy-acetylene torch kit. I'm going to use propane instead of acetylene and that should give me the heat I need. What I know about welding equipment you could write on the head of a pin and have room left over.

My question is, after having searched and watching videos, I'm not sure which tip to use. It looks like a welding tip in most of the videos, but want to make sure. Does it matter which tip I use? I know Either way I'll need one for LP, just not sure which to buy - welding or cutting.

Thanks,

Dan


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## steyr223 (Oct 25, 2012)

I have used both but only due to not having a welding tip
I have read on this form the Rosebud is the best and
of course you know not to blow your powders all over 
the place (I did)
Watch steves video on I think melting your gold foils
If you haven't already
Steyr223. Rob


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## qst42know (Oct 25, 2012)

A number 3 welding tip can melt two ounces of gold in a couple minutes. Takes longer to carefully heat the dish than melt the gold. If you have large quantities to melt you could bump up to a heating tip. 

I'd stay away from the cutting attachment as I can envision blasting all your powder out of the dish by accidentally bumping the lever.


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## maynman1751 (Oct 25, 2012)

I use a cutting head myself. Start with a low flame to heat the dish, gradually increasing the oxygen to a hotter flame. Add the powder and again lower the flame as not to blow the powder out. It doesn't take long with that kind of heat. Once your powder is red hot again increase the flame to do the melt. Make sure that your low flame is not too lean of oxygen or it will soot the dish. You want a blue flame but with some yellow at the tip of the flame. If you don't understand what I'm saying.........ask! As qst42 says, don't hit the cutting lever!


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## HTRN (Oct 25, 2012)

Thanks everyone. I've been reading up on oxy-acetylene/propane but couldn't find anything to cover melting gold. So, I got it that it's not so much the tip, and I know not to use the cutting lever, just be careful no matter what tip I use. The guy at the welding supply company said to use 3psi propane and 20 psi oxygen. Any thoughts on those numbers?

Dan


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## grance (Oct 25, 2012)

I'm going to have to buy a torch soon my step dad is tired of me barrowing his and its a pain to move. I was looking at hydrogen torches the other day and even seen a gasoline/oxy torch on ebay lol I'm going to get a plain old oxy/ace but its fun to see what else is out there


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## element47.5 (Oct 25, 2012)

No...use roughly equal pressure numbers of propane and oxygen, and nowhere near 20 lbs of oxygen unless you are cutting steel. You want 4-4, or 6-6, or 8-8. Easy. Bigger tip = more pressure. 

The cutting head is not a bad choice; just that it's heavy to hold. The Rosebud tip is somewhat overkill, and the velocity of the flame coming out of the other tips may be high, possibly causing powder to blow away. This is of course an issue under all conditions, you always have to be sensitive to it, but it's not that hard to deal with. If you're using the cutting head, what you want is for the lever NOT to turn on high pressure oxygen (which is what you use for cutting steel) so the way to achieve that is to not supply the torch with HP oxygen in the first place.


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## Geo (Oct 26, 2012)

remember you beginners, theres two different types of flame. oxidizing and reducing. oxidizing is when the flame is oxygen rich and starved for fuel. this flame tends to add quite a bit of oxygen to your melted metal which will "gas off" as the metal cools causing bubbles and an ugly, uneven texture especially with silver. a reducing flame is rich in fuel and starved for oxygen.this flame takes longer to heat but does not lend oxygen to the melted metal as badly. a reducing flame is when the blue part of the flame is at its longest. still hot enough to melt steel and most other metal besides the PGM's.


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## butcher (Oct 26, 2012)

I have used most all of the torch tips from my torch to melt gold; any will work if used properly, and somewhat dependent on the size of your melt.

I suggest you try this, pick the medium size brazing tip (this will give you all the heat you need and a flame that will be easier to control, light the torch with gas and add oxygen, adjust the flame using knobs, large blue flame with a small bright blue cone, yellow tips to the large blue flame, this is the flame you want, use a small version of this flame for heating (keeping torch back from your work using the end of the large flame, for melting we will readjust this flame size to a larger version of this flame and use the hot small cone in the center to melt with.

Prepare your dish, I would preheat the dish and sprinkle on a little borax to coat the dish (you do not need more than a coating that seems to wet the dish, heat dish slowly till hot at first only letting the flame tip lap at the dish this drives off moisture, heating the dish too fast will crack it, also use the flame on the outside of dish to heat the dish evenly.

Once dish is hot I add my dry gold, the gold can be added first if it is easier for you, or you can allow dish to cool and add it.

If you are afraid of blowing away, your gold you can put it in tissue paper, and spray it with a mist of alcohol in cool dish this is not necessary once you get the hang of using your torch.

The hard part is not blowing the fine gold out of your dish, a smaller flame and using the outer flame torch far back slowly bring the yellow tip of your flam up to the dish and to the gold in the dish, try concentrating on heating your dish and not the gold at first, playing the yellow portion of the larger flame on the outer of the dish, the rim of the dish and let flame barely lap at the gold powder, it will take a little while to fuse the gold, when gold is fusing you can bring flame in closer, still concentrating on heating the dish, work the gold powder into one glob, when fused well you can bring in more heat and your torch in on the gold and dish, bring the torch in closer slowly while heating until you can heat with heat the hottest part of your torch, the small inner blue cone, when gold begins to melt, readjust the torch for a larger flame and blue cone, use this blue cone to chase the gold around in your dish pushing small balls of gold into one melted liquid glob of molten gold, this gold being pushed around the dish with the small blue cone of your torch flame, if you are going to lift the dish and pour out the gold be sure to heat your pliers before grabbing the dish, if pouring keep the dish and gold hot with your torch, when finished it is best to back off on heat with your torch slowly, so the dish does not cool so fast that it cracks.

Now we need to teach you welding with your torch, torch tips are chosen by thickness of your iron, take two pieces of iron clean the metal where you wish to weld them together, butt them together, using the blue inner cone heat both pieces of iron (begin at one end of weld), in this one spot, use this blue cone of flame to make both pieces red hot then cherry hot then melting in a small circular motion push around this small molten spot with your torch until the two molten sides melt to one spot, in small circular motion slowly move this molten spot down the length of the weld where the two metals join, melting and mixing these two molten metals, doing this without a filler rod is a good way to learn to weld, after you can do this without a welding rod , adding a welding rod will be easier, now get a coat hanger for a welding rod and try this again this time weld the two pieces of metal together adding the metal from your coat hanger (welding rod to melt the three metals together). If welding a larger thick metal to a thinner piece of iron focusing most of the heat on the larger piece, so they melt about the same time.

Be careful with your torch learn to use that tool safely, they are a great tool to have, but if not treated properly or learning a few things about them they can also be dangerous, but can be very safe to use if you learn how, and treat it properly.


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## ericrm (Oct 26, 2012)

DO NOT USE YOUR ACETHYLENE HOSE KIT WITH PROPANE


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## HTRN (Oct 26, 2012)

Thanks for all the helpful info, folks. I'll practice with the torch before hitting a dish of gold powder. I've been to a few welding forums, and watched a slew of welding videos (from installing regs and hoses to lighting and adjusting the torch) just to get the jist of using it. Now, I'm waiting on a friend of mine who has an extra oxy bottle for me. (Better than a $150.00 for a new bottle.) 

I'll play with it a bit before trying to melt the gold. 

Dan


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## resabed01 (Oct 26, 2012)

Excellent thread, it answered several of my questions, thanks guys!
I do car restorations as one of my other hobbies so purchasing a torch setup was justified for that and recovering gold as well. I just love buying tools but i have no place to store them... :lol: 
Good tip about turning down the oxygen. It makes sense that if I'm not cutting steel I don't need it turned up so high. I will try that on my next melt. I was having trouble controlling the flame settings and I bet this will help. 
I fumbled through the first few melts pretty good. I carefully weighed the gold before and after so I know I didn't blow any powder out of the dish. My first melt I was scared of overheating the dish and while I did get a BB there was still lots of smaller BBs embedded in the fused borax. The second melt I came in closer and hotter with the torch and captured these. I guess those dishes can get good and hot.

Still waiting to melt that 1ounce button!


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## GotTheBug (Oct 26, 2012)

Butcher that was awesome!

Just one thing to add; if you use a cutting head and want to avoid the possibility of hitting the lever and blowing values all over your shop floor, simply open your lever valve all the way and then use the base valve, the one next to your fuel valve, to adjust the flame. That way even if you bump the lever, you shouldn't have much, if any, change in the oxygen level, which you would normally want if cutting metal.

Paul.


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## element47.5 (Oct 26, 2012)

> DO NOT USE YOUR ACETHYLENE HOSE KIT WITH PROPANE



Why not? I've done so many times and have never read an admonition not to do so anywhere else. This is a serious question, do you have a real reason not to change fuel gases within the same hoses/regulators? 

As a practical matter, most users will probably have one (or the other) fuel they prefer and use, but changing out the tip is really not a big deal. What IS a big deal, starting perhaps 5-6 years ago, is that the TANK fitting has changed on propane cylinders. The acetylene fitting and the propane fitting used to be exactly the same. 

There is very, very little stress on the fuel regulator and hose. Acetylene will redissolve into the acetone-wetted whatever it is within the cylinder and maintain its pressure under about 15 lbs within the bottle. Propane has a vapor pressure in the 125 lb range, meaning, it will force itself back into being a liquid above that pressure. Should the pressure above propane rise much higher than that, the tanks are NOT built to handle the multi-thousand lbs of pressure as are oxygen or nitrogen tanks. Fuel tanks are designed (and req'd by law) to self-vent upon overpressure. 

So fuel regs are subject to a measly 125 or so lbs pressure; while oxygen regs are routinely subject to 3000 lbs pressure. Yes...it is the fuel that can blow up and burn, but IMHO, it is the mishap from extremely high oxygen pressure physics that is FAR more dangerous in the universe of welding equipment. The fuel--if it is leaking, you can and will smell it way, way below its explosive limit and vent the premises. The oxygen tank torpedo formed by a busted-off regulator because you didn't CHAIN YOUR TANKS that can go thorugh concrete block walls and bounce off and take your leg off, you don't get any second chances with that one.


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## qst42know (Oct 26, 2012)

Acetylene does not degrade rubber but propane does. Be sure you get the right grade of hose.

http://www.russet.co.nz/documents/Welding_Hose_What_hose_is_needed.pdf


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## HTRN (Oct 27, 2012)

element47.5 said:


> > DO NOT USE YOUR ACETHYLENE HOSE KIT WITH PROPANE
> 
> 
> 
> ...



When I bought this kit, I told the welding guy exactly what I was using it for - melting gold and using propane. When I got home and started reading the owner's manual, I read about the "R", "RM", and "T" grade hoses. "T" is for acetylene and other gasses. I called the welding guy and he assured me it would take some time, at least a year, before any degradation of the hose. I also went to a welding forum and got pretty much the same info.

I'm not going to worry about it and use it for a while.

Dan


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## ericrm (Oct 29, 2012)

good for you Dan...

one of the motto of gold refinning forum is safety first

for any other person who are looking to buy some welding kit, buy the right stuff from the start, it will avoid you a years later to forget that you bought the wrong hose


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