How much heat can Chome moly take?  Does it loose all it's tensile strength when turned ruby red?

When you heat CM to the melting point (welding) it isn't CM anymore. It needs to be re-heat treated.

imracin68j wrote on 12/09/11 at 6:15pm:

Not all.  It still has the strength of A-36, steel (not exactly, but close), but you will have lost the heat treated effect that makes it Chromoly ......  And, no the powder coating oven will not re-temper it back to Chromoly.
Next time, take the paint off with a sanding disc...........

imracin68j wrote on 12/09/11 at 11:14pm:

You have been missled ~~~~ a torch is "not the gold standard for removing powder coat".  It is a "quick and easy" process. But in your case "quick and easy" should not have been the most important part of the job.  If you are concerned that the material is to thin, and don't want to use a sanding disc, then a wire brush on a grinder will promptly send your powder coating to the floor.  Naval jelly will also take it off ~~~ just a little more messy.  Bottom line ---- a torch, in your situation, is acctually a last resort ~~~ as you have discovered.  Your biggest problem was the thickness of the material.  It took to much heat to burn the powder coat, and the material was to thin to handle it.  If the material had been alot thicker, you would have been ok.  Next time you get into something that might be a little out of your career field, you have my phone number, and you know I'll give ya' a hand ..........

PS -- If you were removing the powder coat because you needed to weld something there, I would not be to concerned.  Welding Chromoly destroys the heat treated state and it is no longer Chromoly where the weld is.  This is not a problem in your case becuase the weld is most likely to be greater in size than the thickness of the original material, and thus will be just as strong.

OLD SCHOOL#6 wrote on 12/10/11 at 8:47am:


so i take it that's the case also on a stockcar chassis built out or cro mo? it is only lost in the weld area correct?

I am bringing a piece of this powder coat and a wire wheel and will enjoy watching you send it to the ground.  lol.  It doesn't come off like paint.  It swirls and melts in more. The heat generated with the wire will get the metal hot in itself. I can ruby red metal with a grinding wheel easy. You really don't ruby red the metal with torch, you're just lightly burning the powder.  The powder coat absorbs most of the heat and flys off.  I called MB products and American Fab and they both said heat is how they remove it. I run .058 on sunnies kart which is on the thick side.  Some guys are running .035.  Even with .060 grinding even a little into it will make it very thin. I'm thinking the powder coat ovens help the chrome moly a little.

BTW, I'm not having any metal issues.  In fact I'm about to roll out one of my best creations to date. lol  Everything is good I was just wondering if heat weakened the tensile strength of Chome Moly.   Most karts are not using Chome Moly.

I think I'm going to do an experiment and really heat one piece of tubing up and let it cool and not the other and crack it with a sledge to see if it still holds up.

Here is a good thread on Chrome Moly welding and heat.
http://www.millerwelds.com/resources/communities/mboard/archive/index.php/t-1141...

As a sandblasting contractor, I got your powdercoat removal huckleberry.

I can cut your tubing in half with the 275 hp air compressor, and a little dirt
Lol