welding 'paintlock' sheet metal

The last time I bought sheet metal my choices were Galvanized and Paintlock. I am cutting small pieces and spot welding (electric resistance) them together. I chose the Paintlock after the salesman told me it would not interfere with spotwelding. He fibbed.... I've tried soaking in Acetone, sandblasting, wire-wheeling and an angle grinder with sanding disks. The angle grinder is the only one that worked worth a darn in removing this crap. I don't think it is a coating, but rather a surface treatment of some sort.

Does anyone know another way to make this stuff weldable?


Reply to
Roger Hull
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Apparently, Paintlock is galvanized with a surface treatment so paint will stick better. See link:

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Hydrochloric will remove it, but it'll rust shortly after unless you rinse and neutralize. Look for threads on rust removal. I've recently been getting black (uncoated) steel from the local sheet metal shop, any gauge I need.

I just got some powder coated latches I intend to weld on. the oxyacetylene torch reduced the coating to ash in short order.

Good luck,

Pete Keillor

Reply to
Peter T. Keillor III

Weird. I just made a pan for my washing machine when I relocated it. About

28" square with 4" sides. Bent at the right points, then welded the seams together. It is 22 ga, and it spot welded with my Lincoln 175SP+ easily by spotting. A little touch up with an electric wire brush, and then painted it.


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Galvannealed (which PaintLok is a type of, specifically ASTM A653 Coating A60) is very similar to Galvanized except it uses a zinc-iron alloy rather than just zinc. Both are per ASTM A653, with galvannealed being a coating designation of A or ZF and galvanized a G or Z designation.

Electro-Galvanized (ASTM A879) is another variant of corrosion resistant steel sheet.

Both Galvannelaed and Electro-Galvanized are readily formable and weldable with no need to remove the coating. Both accept paint well.

Normal Galvanized (ASTM A653 any coating G or Z) does not accept paint well.

Some commercial references:

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Reply to
Dan Harlan

I use a lot of paintlock for various purposes. I have never ever had a problem welding it. I use a Miller 180. I use various wire. As any good welder does, I cut coupons, and trial weld them. I have built a large assortment of items out of paint lock, and other than burn through, have not had a problem welding it.

The main thing is setting the heat setting, and using spot welding, rather than trying to run a line. Or for me, that is. A series of spots can be very attractive, looking like TIG, and very strong. I have none of the white hairy film like galvanized.

As I said, fitup, heat settings, and getting the sequence and timing of spot welding is the key to me. I do rosette weld in a lot of places where it is advantageous to have a nice tight fit for the paintlock to lay against the parent metal.

In rereading this, I see electric resistance welding. Might MIG serve your purposes better, perhaps drilling a rosette hole in one piece, hence giving you an almost flush finished weld on both sides. After a few practice runs, that is.


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