Acetylene cutting-torch malfunction - HELP!

[Joel_BC]

I've got a Victor O/A rig. With ordinary brazing and welding tips, everything is working fine, and is work-safe. The torch handle is a 'standard' Victor (medium-size) one.

For cutting, rather than a separate torch, I have the common set-up where the cutting head fits on the welding-torch handle. My cutting head was reconditioned by a reputable company about year and a half ago. Then it worked fine. Since then, I've put no more than 90 minutes of use on it, generally in brief sessions of 10 minutes or so.

But now the oxygen-control valve (the one high up on the cutting head, not at the hose end of the handle) seems stuck. When the torch is lit - with the main oxygen valve fully open, and the oxygen-control valve supposedly closed (as in normal procedure) - the flame shows a lot of oxygen right from the start! No yellowish, smokey, loose, flame to begin with. That is without squeezing the extra-oxygen lever.

I'd send the cutting head back to the company that rebuilt it, except: a) they are 500 miles away; b) they might not believe how little time I've put on the head since the rebuild; c) I'm curious about how the cutting-head mechanism work, and thinking I should be able to fix something that is probably simple.

Is there a simple explanation and maintenance procedure?

 

[the_whingnut]

the simplest problem is trash in the needle valve. all it takes is a small amount of corrosion, dirt or debris to keep the needle valve from operating correctly. i have the same torch here in from of me. this is what you can do to try and do the simple fix, before you have to ship it off.

with the cutting assembly removed from the torch body

take the cutting tip off the torch head.

once done inspect all internal openings for debris (they need to be clean of everything (DO NOT USE SOLVENTS) just wipe out with a lint free cloth))

inspect the o-rings on the cutting assembly to torch body connections they must be clean, and free of tears / not missing chunks

if your o-rings are whole / in good shape thats one less thing to worry about, if not replace them before you use the torch again.

next under the needle valve "wheel" there is a valve bonnet remove it counter clockwise using the apparatus wrench or the correct size wrench (DO NOT use a crescant / adjustable wrench) *******you may have to place the cutting assembly in a vise please use old leather to cushion it***********

once off inspect for debris and dirty, then inspect the needle valve stem/ seat for debris and dirt, clean with lint free cloth (no abrasives)

you torch should now be disassembled less the oxygen lever (if it works don't fix it)

you will need clean / oil free compressed air (if you can) and blow out the torch from the cutting tip connection then from the needle valve spot.

if you reassemble the torch and its still having issues then send it on for repairs.

but 9 out of 10 times your o-rings get damaged and little bits break off and clog the needle valve.

worst case the needle valve has been damaged from trash and will be bent or the seat will be scratched.

if you are handy with lap compound you can redo the seat/ needle if the threads are undamaged or send it out for repair/ replacement.

 

[Joel_BC]

whingnut, thanks for taking the time for a detailed reply. I have a clean-air comressor. I'm hoping that, if/when I take the ox-control needle valve assembly apart, there are no tiny springs or anything there that I could easily lose!

I do have replacement O-rings on hand.

 

[the_whingnut]

when working with small valves and parts like that i will loosen everything with tools then hand disassemble with a clean white cloth or paper towels under it for easy ID of parts and bits if i drop them.

 

[Joel_BC]

I went through the disassembly and cleaning... learned things about the inside of the cutting attachment in the process. But... the oxy valve assembly attached to the knob looked good, but for some reason I could not get the valve to close sufficiently. Nothing obvious, but the seat was probably worn or damaged.

I ended up ordering another one ($120 plus tax & shipping). Sigh... It's always more satisfying to fix something than to give up and buy! :/

 

[the_whingnut]

for 120 bucks i hope you got more than a cutting head.

 

[Joel_BC]

for 120 bucks i hope you got more than a cutting head.

Nope. Just the cutting attachment. But mind you, we're talking Canadian prices.

Getting it rebuilt would cost about $60 - plus tax and shipping in two directions.

And I didn't have time to poke around looking for a used one in good condition.

Prices on tools in Canada are higher by comparison with the US (but lower than Europe, Japan, etc). General cost of living is higher... but all in all, so are wages. Still, with cost of living being what it is today, I'm glad I live the frugal, DIY-type sufficient-self lifestyle.

 

[the_whingnut]

fair enough. I keep forgetting the exchange rate and that once you get above Kentucky the cost of living just gets higher as you go up the map.