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Discussion Starter #1 (Edited)
I'm looking at buying an oxy-acetylene set up. I'm only want to use this mainly for heating up metal to bend or cut. I think a 40cf tank would be great but I can a 20 cubic ft. oxygen tank and 10 cubic ft. acetylene tank for waaaayy cheaper. From what I can tell there is a pretty big difference between the 2. Do you know about how long this should last? Like am I only going to be able to bend a couple pieces of metal and cut off 1 bolt or should it last a bit longer than that.

I'm just now starting to do my research and thought I would start with the size of the tanks first.



Thanks in advance!!!!
 

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IMHO I wouldn't bother. Think of it this way, a large Ox tank is 240 cu ft and if I'm doing any amout of cutting it won't last a day and that's with a small tip.
In the end tho it boils down to how much you really plan on using it. Are you only going to burn off or heat up one or two bolts a year then it'll last you years. I'd say, and this is a rough guess only, you'd be able to burn maybe 20' of 1/4" plate before the tank was dry.
Not only that but you're going to have to watch that you don't overdraw the acetylene. The max is 1/7 of the cylinder capacity per hour, any faster than that and you start drawing off the acetone which will screw up your mixer in short time.
If you want to go cheaper and avoid paying demurrage on two cylinders what about going with a larger ox cylinder and a 20 lb propane tank......Mike
 

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If you want to go cheaper and avoid paying demurrage on two cylinders what about going with a larger ox cylinder and a 20 lb propane tank......Mike
:ditto: on the larger O2 bottle and 20 lb. propane.

I bought a 60 cu. ft. O2 bottle. They're big enough for most projects and small enough to be easy to move for outside work. The propane cylinder will outlast several oxygen bottles, unlike acetylene which needs to be replaced every second bottle of O2 for a much higher price.

A word of caution: Acetylene tips don't work with propane, you need a set of propane/natural gas tips for cutting and heating, and welding tips weren't available when I set up for propane 30 years ago. Burning with propane requires a slightly different technique. It takes a few seconds longer to pre-heat before you start cutting. If you have natural gas in the shop, that's even cheaper.

If you're making long, straight cuts in 1/8' to 1/4" plate, use a skill saw set at maximum depth with a plywood blade, steel, not carbide. It cuts faster and straighter, but wear hearing protection and safety glasses. It leaves a sharp burr on both sides of the plate that needs to be dressed with a grinder, but you can cut right on the line for a minimum of redressing.
 

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:ditto: on the larger O2 bottle and 20 lb. propane.

I bought a 60 cu. ft. O2 bottle. They're big enough for most projects and small enough to be easy to move for outside work. The propane cylinder will outlast several oxygen bottles, unlike acetylene which needs to be replaced every second bottle of O2 for a much higher price.

A word of caution: Acetylene tips don't work with propane, you need a set of propane/natural gas tips for cutting and heating, and welding tips weren't available when I set up for propane 30 years ago. Burning with propane requires a slightly different technique. It takes a few seconds longer to pre-heat before you start cutting. If you have natural gas in the shop, that's even cheaper.

If you're making long, straight cuts in 1/8' to 1/4" plate, use a skill saw set at maximum depth with a plywood blade, steel, not carbide. It cuts faster and straighter, but wear hearing protection and safety glasses. It leaves a sharp burr on both sides of the plate that needs to be dressed with a grinder, but you can cut right on the line for a minimum of redressing.
1/4" steel with a plywood blade... I dont think so...
 

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Another thing to consider is the cost to get your tanks filled/replaced. The small tanks will cost just about the same as large tanks. At least that is the way it goes around my area.
 

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I am a refrigeration guy so I have several of these setups laying around. For infrequent use on the GTs it is very handy and cost effective. My implements are the sears style 3pth. The bend quit a bit when pushed hard. I have done most of the straightening on a single 10cf tank with a nice small rosebud tip. For the occasional cutting of a bolt or piece of steel it is fine, it is not designed for production work. I have been happy with mine. The 10cf tank is about $15 for a refil and I cant remember how much the O2 tank is.

As to draw down of the 10CF tank, the lines are to the torch are 1/4 not 3/8. If you have a tip that is too big it usually doesnt stay lite. It will just pop and go out. The lines cannot provide enough gas to keep it going. Also check out your local HVACR supply house before you buy. They have more tips and accesroies than TSC.

If you are just going to heat up and bend metal, you may want to check out a turbo torch and a B tank.
 

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....straight cuts in 1/8' to 1/4" plate, use a skill saw set at maximum depth with a plywood blade
You mean a carbide blade meant for steel...right? I've never heard of a plywood blade that'll cut steel. Mind you I've tried it a few times unintentionally when I'd cut into my steel workbenches, doens't work all that well :fing20:
If you're cutting aluminum yes on the plywood blade but a carbide wood blade will last longer.....Mike
 

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You mean a carbide blade meant for steel...right? I've never heard of a plywood blade that'll cut steel. Mind you I've tried it a few times unintentionally when I'd cut into my steel workbenches, doens't work all that well :fing20:
If you're cutting aluminum yes on the plywood blade but a carbide wood blade will last longer.....Mike
No! I mean a steel plywood blade, no carbide at all, and correctly oriented for cutting plywood, not backwards like you do when cutting aluminum.

My FIL told me about this 35 years ago. I was, of course, hesitant about ruining a perfectly good blade until I picked one up for cheap at a going out of business sale several years later. Even then I wasn't going to waste steel trying it out until I had a project that needed it.

A couple of years later my neighbour and I collaborated on a set of heavy duty bumpers for our trucks that required straight line cuts in 1/8" steel floor plate (checker or diamond plate) totalling over 30' per set. We were doing this on the cheap and toting a 160 lb. sheet of plate to a metals shop for shearing was not in our plans or budget and some of the cuts couldn't be made on a shear anyway.

I was amazed at the results with the first cut. Right on line, fast (compared to a torch), straight and only a small burr on both sides of the plate to be removed. The burr gets bigger with extensive cutting, especially if you do any plunge cuts which really wear the teeth, so save the plunge cuts for last. I used the same blade on another major project several years later and though it didn't cut as fast or straight because of the previous plunge cuts, it still beat a torch hands down. For a $2.99 blade and about $0.90 worth of electricity, I got approximately 90' of cutting between the 2 projects. Not too shabby. If I ever have another project like that, I'll spend the money on a new blade at regular price and call it a bargain.

Kbeitz, I never had a need to try 1/4", but after cutting 1/8" I would not say it can't be done. I've had many people tell me that 1/8" can't be done. A couple were convinced when I demonstrated with my projects. Those are the limits my FIL gave me, along with another gem that might interest you.

Use metal strapping for a band saw blade to cut leaf springs. Apparently the first cut takes a while until the edge of the strapping gets roughed up, after that, it slices through the spring with relative ease without destroying the temper.

The process for both is called Friction Sawing. I read an article on it in Popular Science or some such magazine in the late 70's or 80's (I had subscriptions to 3 such magazines at the time) that bore out much of what my FIL told me.

These are low budget tools to do a job which can be somewhat better done with the correct (higher priced) tools.

:sorry1: I didn't mean to highjack the thread.
 

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I have a set of those "Kangaroo pouch" torches,I bought them in the 80's when I started doing my own auto repairs,and they were a Godsend!--but they suck for cutting,there isn't enough pressure/volume in a 20 cubic foot oxogen tank to do much over 1/4",I once used up a whole tank in 15 minutes trying to cut off 4 leaf spring u-bolts,and barely got it done!..I use a grinder ,circular saw with a metal abrasive cutting wheel,or a sawsall whenever possible to save oxogen,as its getting quite costly to fill a tank here (and a pain,if you dont have an account at a welding supply or go there often,even though you can "own" these small tanks outright,the places I go to refill them always give me a hassle)..

I would opt to get the larger sized O2 tanks that you can own outright with no lease,I think they are a 55 cubic foot,and use propane instead of acetalyne as suggested..I now have a "real" set of full sized torches and tanks a friend gave me when his bussiness was sold,and I've only filled them once in 3 years..but it was "fun" convincing the guy at the welding store to fill the O2 tank ,when I had no "account" there--I have a friend who runs a junkyard with an account there who buys thousands of dollars worth monthly there,he said as long as I pay cash,I can just tell them its for him and pay for it..but its worth getting the larger tanks and torches,they cut 200% better and heat things quicker,dont seem to use up the oxogen as quick as you'd think either..

The small torches are handy for lighter uses,I brazed many body repair panels on with mine,cut muffler pipes,clamps,etc,and removed many a rusted bolt with them..the fact they are more portable is nice,but dont expect them to do what larger tanks and torches will...
 

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Discussion Starter #10
Thanks guys for the info. So has propane taken the place of acetylene now? Seems to me like it's better to use propane? Plus I know I can get a pretty cheap ( big ) bottle from an RV or something? ( or is this different?)

Thanks
 

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I'll have to try that Bob, never woulda thunkit

So has propane taken the place of acetylene now
I wouldn't say, at least not that I've noticed. I think it's cheaper, a bit safer as you can use it up to tank pressure, you're not limited to 15 psi because of instability like acetylene. You can draw a lot faster from a propane tank as there's no acetone to worry about and the tanks are lighter.
I know when we're using large rosebuds at work (1 1/2 to 2" dia) we have to crank up the pressure to 30 psi or so.
Be advised, you're supposed to use a proper hose for propane, it's a different compositon that acetylene hose. As well, as Bob said, you have to use proper tips, usually two piece with slots cut along the side, not holes.....MIke
 

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Acetylene burns a few hundred degrees hotter and you pay for that extra heat. That's why I mentioned a need for a slightly different technique when using propane. Some guys don't like it if they've burned with acetylene for a long time. A big advantage with propane is if you have a party and run the bar-b dry, you have a reserve stash with your torch. Of course the reverse is true as well. Cost is the big advantage. A 20 lb. bottle lasts a long, long time compared to even a full sized bottle of acetylene.

Mike, give it a whirl and don't forget the safety equipment.
 

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I'm looking at buying an oxy-acetylene set up. I'm only want to use this mainly for heating up metal to bend or cut. I think a 40cf tank would be great but I can a 20 cubic ft. oxygen tank and 10 cubic ft. acetylene tank for waaaayy cheaper. From what I can tell there is a pretty big difference between the 2. Do you know about how long this should last? Like am I only going to be able to bend a couple pieces of metal and cut off 1 bolt or should it last a bit longer than that.

I'm just now starting to do my research and thought I would start with the size of the tanks first.



Thanks in advance!!!!
I have a similar set (Victor) on occasional use for heating is ok but if you cut with them it empty the tank fast.

In one year I used them maybe 8 to 10 times. The last times I used it (the oxygen was around 1000 psi) to cut 1/4" thick 2 piece of 6” long and 2 of 2" and I empty the tank.
 
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