Galvanized?

[jaybee]

I'm working with some old pipe that I initially thought to be black iron with at least 3 coats of paint but now I'm not sure that the bottom coat isn't actually galvanizing.  It doesn't have the characteristic crazed finish of galvanizing, but it's been in the weather.  The color is a slightly brownish gray.  It kind of powders when you hit it with a grinder.  How can I determine if this is in fact galvanizing and safely remove it if necessary?

[donsrods]

I'm not an expert in this, but here is a little I do know.

When you grind something that is galvanized, the grinder makes no sparks until you hit bare metal. The galvanizing will also load up grinding discs quickly.

While not extremely hazardous, grinding and especially welding galvanizing has some things to watch out for. You can get sick to your stomach from the fumes, and some say drinking milk helps the sickness.

You can remove galvanizing where you want to weld by grinding, or for larger areas you can sandblast.

Wear a respirator, and avoid the fumes.


What are you doing with this pipe, just out of curiousity??


Don

[jaybee]

Thanks for the advice, I'll grind with a dust mask just to be on the safe side.  I'm building a welding table from salvage pipe and a used table saw top.  The table top is made of aluminum, thinking of making a cover from steel sheet to protect it.  Construction is going pretty well.  Found a program online that makes templates for fishmouth cuts, it works like a charm.  My little torch has to be cranked way up to weld material of this thickness.  I'm learning rapidly that gas welding is very unforgiving of material that isn't perfectly clean.  Just when I think I've got a good weld going I'll hit a spot with a little rust, paint, or oil contamination and my bead looks like crap there.  I see the same thing when I walk away from a partially completed joint then come back the next day.  It's just harder to make that weld properly as opposed to a freshly ground part.