Topic: Welding Noob questions

[mystic_1]

The wall thickness on these frames is, what, 1/16"?  No problem at all for a 110v welder in the right hands.

mystic_1

[Spikeybike]

now run some beads and post some pics, and i (we) can give you some pointers   

[Tim in Ohio]

OK...  I still haven't tried my hand with the mig yet, I need to get a tank of shielding gas first.  But I did get up the courage to fire up the oxy-acetylene torch that my dear old Grandpa used to use.  I have a couple of questions on that.  I was using it to heat up some lug nuts that are stuck on my old Ford truck.  This oxy-acet rig has literally not been touched for at least 15 years since he died.  Here are a couple pics:

Acetylene gauges:

Oxygen gauges:

Torch:


I read a recent post about an air compressor tank that blew up, and since these gas tanks have the surface rust on them, I had a slight fear that when I opened the valves the whole thing would explode and castrate me instantly.  (Strangely the thought of death didn't enter my mind... just getting my balls blown off...)

Well, I went ahead and fired it up.  I did get a flame going, which was exciting.  (I had my auto-darkening welding helmet on).  I had the gauges set at 7 for the Acetylene and 40 for the oxygen.  Everything worked fine.  After I extinguished the flame, I looked at the gauges and the working pressure gauge for the Acetylene seemed to have climbed way up to 25.  I fiddled with the adjuster on the valve to try to get it back down... nothing.  Then I messed with the oxygen valve some and the acetylene gauge dropped back down to 7.  What is the explanation ?  Spikey?

[Spikeybike]

Well, I went ahead and fired it up.  I did get a flame going, which was exciting.  (I had my auto-darkening welding helmet on).  I had the gauges set at 7 for the Acetylene and 40 for the oxygen.  Everything worked fine.  After I extinguished the flame, I looked at the gauges and the working pressure gauge for the Acetylene seemed to have climbed way up to 25.  I fiddled with the adjuster on the valve to try to get it back down... nothing.  Then I messed with the oxygen valve some and the acetylene gauge dropped back down to 7.  What is the explanation ?  Spikey?

first of all you should have the gas set closer to  4 or 5 , the oxy's good at 40 .. but i doubt thats what causing the pressure fluctuation,  ,    it could be as simple as pressure build up in the hoses, then you stop using them and it slowly goes down. ... or it could be faulty gauges, (i've seen ones in much worse shape work just fine though).   or a slow leak in the hoses

i would absolutely check those hoses for leaks , if there that old and unused,  just open the valves all the way and run the lines through a pail of water and watch for bubbles ..

also MAKE SURE you clear the hoses of any gas after each use (close the valves and pull the trigger till the gas stops)

i'll talk to my boss in the morning and see what he thinks , i've never had that happen before

[mark]

.............  Everything worked fine.  After I extinguished the flame, I looked at the gauges and the working pressure gauge for the Acetylene seemed to have climbed way up to 25.........What is the explanation ?

It's called 'creeping' and it isn't good. Note that the low pressure acet. gage has a 'red line' above 15psi... That's because acetylene does nasty things(explodes) at pressures above 15psi.


quote from http://www.deir.qld.gov.au/workplace/subjects/rural/plant/operate/welding/index.htm

"# Regulators can fail in two ways - by the controlled forward flow of gas which is known as regulator creep or by the reverse flow of another gas in the gas lines. Regular maintenance should avoid these situations.
# Either of these failures can be recognised by a higher than expected reading on the operational or low pressure gauge. The gauge needle creeps beyond the pressure set for actual welding or cutting.
# Excess pressure or the presence of a different gas in a regulator can cause fire and explosion in varying degrees of severity, resulting in damaged equipment and operator injury.
# Operators should never use equipment fitted with a regulator in which a creep condition is known to exist. "

Some can be repaired, but it might cost more than simply replacing the faulty regulator.

[Spikeybike]

yeah and i for got to add the regulators are most likely the culprit,   i think even if thats not what's happening, (witch it most likely is)  you should replace the the regulators anyway.  or at the very least gut them and replace all the seals (not that hard)