Hello everyone - I picked up a great deal on an AC/DC Tig welder and am eagerly looking forward to learning to weld. Before I start however I have a few questions/concerns that I haven't been able to answer to my satisfaction from searching the internet and reading some beginner welding books and manuals. Here goes:
Is there a maximum distance that the ground/return clamp can be placed from where you are actually welding? Similarly, is holding the workpiece between the torch and ground inherently dangerous? Electricity flows through the path of least resistance which would be the clamp normally but can that change with the position or distance that the clamp is from the torch (or if your hands have gotten sweaty inside your gloves)?
What happens if the return clamp slips off the object like a round pipe or some other similar object that makes it hard to clamp to? Is the resistance of my gloves and skin and insulation of the concrete floor, etc enough to prevent the current from flowing through my body? I have a wood table that I will probably be working on. All of those materials are non-conductive I believe so what happens to the flow of the current without the clamp?
Here are my non-safety related questions:
About back gassing - I'm primarily interested in welding tubing for motorcycle and bicycle frames, exhausts systems and creating furniture. What are the best setups that you use? I've read about using stoppers/corks with a hose that pumps gas in. What do you do about the leakage that you get from around the welding area before it is welded shut? If you continually run gas into the tube don't you have to worry about a pressure buildup that would pop the end caps off? How do you regulate the flow of gas so you have enough to prevent weld contamination but prevent excess pressure?
Also when modifying an already existing medal object how do you determine what the alloy is of the metal is? I would think it would be pretty critcal when choosing the electrode, filler metal, and amount of gas - especially if you are adding a piece of metal to something instead of just fixing or repairing a break in a homogeneous piece of unknown metal.
Thanks,
Brett