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View Full Version : Black coating on schd 40 steel pipe

bomberz1qr20
04-22-2004, 02:21 PM
Is this coating toxic when welded? Looks like a plastic type coating, just wonderding if it's dangerous.

Anyone?
arcdawg
04-22-2004, 02:24 PM
im not sure but it would be a good idea to run a grinder over the spot that you are going to weld.

dawg
enlpck
04-22-2004, 09:44 PM
Grind it before welding, or it will contaminate the weld. Otherwise, no more toxic than anything else you breathe when welding.
bomberz1qr20
04-23-2004, 01:26 PM
Originally posted by enlpck
Grind it before welding, or it will contaminate the weld. Otherwise, no more toxic than anything else you breathe when welding.

This was just for practice in class. I stuck some coupons in the lathe and "skinned" them to remove the coating.

The results were half-assed. Lots of stink and porous welds.

Next!
enlpck
04-23-2004, 02:13 PM
That may be the pipe, not the coating (the stink is a varnish and the paint used for the mill marks), or coolant, if you didn't do it dry. We machine end preps on coupons dry, light cut on the INSIDE, and light cut on the outside. Outside for cleanliness around weld, inside for concentricity of fit. Flap wheel for cleanup at time of fit.