thick peice of steel for welding table

[rocketeir]

i found(yes found under my parents barn) a 40"x38"x1/2 peice of steel. I plan to use it for my welding table. I have used grinders,sandpaper,paint stripper you name it i have tried it. To try to get the top to be bare metal so it conducts well. Though all my efforts make the top look decent it isnt very conductive. I clamped my work lead to the metal and layed a peice of exaust pipe on the table to see how it worked and it cept arcing at the clamp and then at the bottom of the pipe and made very crappy welds. any advice? also how much would a peice of metal that size regularly cost me?

[wb5jhy]

Your 1/2" plate should work fine. I always attach my work clamp to the workpiece whenever possible. In your case the tubing doesn't have much contact with the table in the first place. At least use a c clamp or vise-grip to clamp the tubing to the table.
If the surface is really pitted from rust you might want to work it over good with a hard grinding wheel and smooth out with a 50 grit sanding disc.

If you price out some new steel your going to really appreciate that free table top a lot more.

[rocketeir]

Your 1/2" plate should work fine. I always attach my work clamp to the workpiece whenever possible. In your case the tubing doesn't have much contact with the table in the first place. At least use a c clamp or vise-grip to clamp the tubing to the table.
If the surface is really pitted from rust you might want to work it over good with a hard grinding wheel and smooth out with a 50 grit sanding disc.

If you price out some new steel your going to really appreciate that free table top a lot more.

I have used a dewalt grinding wheel and it doesnt to a whole lot now that i got the rust off... but its still got a lot of pits.. i know there is different grit sand paper but is there different grit grinding wheels? i use the one that came with the dewalt grinder i just got

[wb5jhy]

I'm sure they have different grit wheels. 24 grit is what I see the most of around the shop. It's really agressive.
If you have gotten all the surface rust off then you should have no problems getting contact with the work lead.

[rocketeir]

i have the common grit im sure... i got all the rust off and i dont realy get great contact but as someone else said maby its cause not a lot of surface area with piping.i need to try some angle iron.

[Punisher]

an easy fix is to tack the grond to the table

[Richard]

maybe you could try to sand blast it.

[joe]

Think outside the box

The half inch thick top is nice so keep it in place as a good find. Attach one long or two shorter grounding leads with clamps to the table. Grind just the spot you attach the cables. Then down lower on a leg grind a clean spot for your welders grounding clamp. What you will get is a strong top, close at hand grounding clamps, and the ground clamp from your welder out of your way.