turbo torch question

[umahunter]

anyone know if i can adapt a acetylene turbo torch unit to run on propane anyone done it ??

[welds4d]

I don't know if the handles are the same, but I do know that the tips themselves are different. I wouldn't try to use an acet. tip on propane, but if the propane tips will plug into the acet. handle I don't see where that would be a problem.

[DSW]

The handles are definately different. The QD on the propane ones are larger.

[Rick V]

Originally Posted by DSW

The handles are definately different. The QD on the propane ones are larger.

My error DSW... but I had no idea what QD meant ... add in the fact that you mispelled "definitely", I figured it was just another typo and that you meant OD for outer diameter. Now, looking down at my computer keyboard, I must admit that the Q and the O are not really side-by-side!

[rlitman]

Originally Posted by DSW

The handles are definately different. The QD on the propane ones are larger.

I think if you actually tried, you wouldn't have said that.
In this picture, the left two are Propane / MAPP nee propylene tips
The right two are acetylene tips.

Upper left is a TurboTorch brand tip marked "T-4 LPG"
Lower left is a Rothenberger MAPP tip marked 12mm.

Upper right is a TurboTorch brand "A-14" acetylene tip.
Lower right is a Goss brand "GA-14" tip.

All four fit in both my LP and acetylene torches (and the dozens of other assorted QD air/fuel tips I have are ALL the same size), BUT just because they fit, doesn't mean they should be interchanged.

Since we're talking about air/fuel mixtures and not oxy/fuel, the ratios are different from what Rick posted, but the idea is the same. The orifice in an LP tip is indeed different than in an acetylene tip. The venturi holes are also likely different in size. I suppose I can test an LP tip with acetylene gas when I've got some time to show the difference in flame . . .
The point is, you will need to match your tip to your fuel gas.

Anyway, the real difference between the handles is the hose fitting. The acetylene handles have an "A" sized fitting, and the red ribbed rubber hose that goes with it is incompatible with LP based fuel gases (they rot the hose from the inside out).
The LP handles have a "B" sized fitting, and the black hose on my torches with the LP handles appears to be of the same composition as my "grade T" welding hoses.

I don't see why the propane setup couldn't be used with a regular welding acetylene regulator (and the correct "A series" tip), except that the hose is heavier.
I suspect that the higher flow rates required by the propane tips would have problems with the smaller diameter hose choking their flow (too low a flow in a swirl torch will overheat the tip), even if you can find an "A" sized hose rated for propane use.

[Rick V]

My Hooper Welding Suppy Tip Charts - http://www.hoopersupply.com/tipchart.html for Weld/Braze Tip Data says,
The approx. Oxygen consumption ration by volume for various gasses is as follows:
1 oxygen to 1 acetylene
2 oxygen to 1 Mapp®/Natural gas
4 oxygen to 1 propane/propylene
Now I know your torch is an acetylene/air torch, not an acetylene/oxygen torch, but the ratio of acetylene/air should be the same as for acetylene/oxygen.
In other words, compared to acetylene, propane needs 4 times as much oxygen or air by volume to burn correctly.

In theory...
Two portions (by weight) of acetylene requires 5 portions of oxygen (by weight) to burn with a neutral flame.
2 H2C2 + 5 O2 → 4 CO2 + 2 H2O
One portion of propane (by weight) requires 5 portions of oxygen (by weight) to burn with a neutral flame.
C3H8 + 5 O2 → 3 CO2 + 4 H2O
So by weight, 10 parts of oxygen will combust 4 parts acetylene or 2 parts propane.
In other words, compared to acetylene, propane needs 2 times as much oxygen by weight or air to burn correctly.

What's it all mean?

1. Running propane with your current acetylene tip, your torch will be oxygen/air starved - expect a wimpy yellow flame because you're getting only 1/4 of the air volume needed for complete combustion.
2. If you used a tip with a smaller hole (orifice) say of 1/2 the size (1/4 the cross-sectional area), you should be in the ball park for complete propane combustion. However you are now flowing only 1/4 the fuel gas volume so you will likely end up with a nice tiny blue flame! Add in that the combustion temperature in air will drop from 2,500°C (4532°F) with acetylene to 1980°C (3596°F) with propane and... it doesn't look too good!

You really need to modify the torch to increase the air flow by 4 times, keeping the original tip used for acetylene. I don't know whether that is possible.
The theory seems to confirm what DSW said, "The handles are definitely different. The OD on the propane ones are larger."

[DSW]

Originally Posted by Rick V

The theory seems to confirm what DSW said, "The handles are definitely different. The OD on the propane ones are larger."

Actually I said Qd not Od as in Quick Disconnect, but I can understand the misread looking at it quickly, but the result is the same. The propane tips will not fit my acet handle and vise versa.

[DSW]

Opps, Looks like I stand corrected.

I didn't have the fittings to put side by side to double check. I knew the torch handles were different and would not interchange but my memory failed me on the tips. I thought the fittings were larger ( I sold the propane torch and all the tips to someone else a while back since I nolonger use propane for plumbing pipes.)

[rlitman]

Originally Posted by DSW

Opps, Looks like I stand corrected.

Don't feel bad. I always assumed they were different too, and never tried until after I read your comment. I just had to look.

[umahunter]

thanks for the info guys i i gust went ahead and got an adapter to run the torch i have off one of the baby acetylene bottles

[rlitman]

Originally Posted by umahunter

thanks for the info guys i i gust went ahead and got an adapter to run the torch i have off one of the baby acetylene bottles

Careful. The A-2 swirl tip (the smallest they make), actually draws more gas than you are supposed to use with an MC tank. The A-5 is the largest tip you are supposed to use with a B tank.

[umahunter]

thanks i thought to check into that after the fact. cant use the torch yet as i have a leak around the valve on the handle that will need to be repaired first. then i will just put it back on the original bottle. im going to see about getting a handle for the small tank for the lil small plumbing jobs as i dont want to buy benzomatic propane torches anymore since they wont repair them anymore