How much O/A gas?

[wbpace]

Assuming I get a low gas torch like a Henrob or a Meco Midget, how much gas should I plan for building the airframe?. I know that larger tanks are more economical to fill, but I probably don't want to keep them around once the airframe is done. So I am thinking about leasing large tanks while I do the majority of the welding, then buying some small tanks for finishing up and future small welding tasks.

Any suggestions on tank sizes and information on how many refills were needed would be helpful.

Thanks,
Bill

[n3480h]

Think I burned through an M tank just learning to gas weld. Another for tabs, engine mount, tail, rudder, elevators, carrythrough, turtledeck structure. I bought a started frame, but spent a few hours replacing cold welds and completing a few missing welds. Can't say how much would be required for the entire airframe. I'd go with at least an M tank. Much larger gets to be a pain to haul for refils. Acetylene had a big price hike in the last couple years because a high volume acetylene facility blew up.

Tom

[wafer]

I have 25 lbs tanks, and filled them 3 times for my LTS from start to finish. I had very little welding experience also...

Mike

[wbpace]

So let me see if I am understanding correctly. From information I found here (http://cholla.mmto.org/welding/bottles.html), a 25 pound tank is a B tank (23 in tall x 6 in diameter). A B tank holds 40 cubic feet. That suggests 120 CF from start to finish in Mike's case.

Tom, it appears that you used 20 or 30 CF (I am assuming you meant MC tanks) to complete your airframe which, if you bought it substantially complete, sounds fairly consistent with Mike's numbers.

This is really helpful, guys. Thanks.

[wbpace]

I answered my own question about the cylinder weight (25 lbs is the filled weight of a B cylinder). An excellent pamplet can be found here: cholla.mmto.org/welding/safetygram13.pdf.

[peterzabriskie]

Jan 2, 2012 16:22:59 GMT -5 wbpace said:

I answered my own question about the cylinder weight (25 lbs is the filled weight of a B cylinder). An excellent pamplet can be found here: cholla.mmto.org/welding/safetygram13.pdf.

Good Reading ! ! I found the pdf by using your first link
cholla.mmto.org/welding/bottles.html
then clicking on the "safety memo" at Safety with Acetylene.

I would recommend this as required reading for all of us new to welding.....many many safety issues that could save a life, maybe your own.
-Pete

[n3480h]

Related - this month's Sport Aviation has an excellent artical about OA welding, written by Budd Davisson.

Tom

[chuck59]

Jan 2, 2012 22:43:51 GMT -5 n3480h said:

Related - this month's Sport Aviation has an excellent artical about OA welding, written by Budd Davisson.

Tom

I noticed an error when he said, "both tanks wide open" The oxygen is wide open, it has a seat so it doesn't leak. The acetylene should be just cracked in case of a fire/burnt through hose, etc. to be able to be closed immediately.

[n3480h]

Good catch Chuck! That's exactly right, the oxygen tank has top packing and must be fully opened. The Acetylene tank does not, so just crack it open til it registers on the gage. Also, once the tank valves are open and pressures are set at the regulators, open the torch acetylene valve a little and light it, then open the torch oxygen valve a little to set the flame feather. Shutting the torch off with the torch valves, its oxygen off first, then acetylene. Then close the tank valves. Once the tank valves are closed, back the regulator adjustment knobs out until they are loose, and then bleed off the residual pressure in the hoses by opening the torch valves. Close the torch valves after the pressure is bled off. This prolongs the life of your regulators and hoses.

Tom

[oahupilot]

I own a meco midget its a great torch, fyi.