As part of the project I'm currently working on, we're stripping 55 and 60 years of paint off some Alco diesels. Because of location and facilities (the backs of our pick-up trucks-), we don't have air to needle scale or sandblast with, and we can't use chemicals. We have been using polycarbonate abrasive wheels with angle grinders, which seem to get the paint off much faster than cup style wire wheels, but the things don't last as long and are expensive!

Has anyone else had experience with these, and found a wholesale source for them? Harbor Freight has them for five dollars (item 94017) while they are roughly twice that price at Home Depot or Lowes. They work well, but I was going through one every twenty minutes or so this afternoon.

Have you looked at Liquid Nitrogen stripping, less dust, self powered, and fairly cheap.

Talk to your welding gas supplier, they sometimes have partial carboys on Friday, that will not make it to Monday that they will let go cheap.

-Hudson

Hi EDM!
What I use in my shop are the 3m green discs. They hold up better. Advance Auto sells 4 inch wheels in I think a 15 pack? Costs considerably less than buying individual discs. The harbor freight ones don't hold up as well and can end up costing you more.

To make them last longer:
-use a very high rpm grinder
-hold disc flat, you will get more jumping around at first but eventually you will see how much longer the outer fingers last
-if you start to shoot sparks you're using too much pressure!

Many dollars spent learning this!

You may be able to extend the life of the discs by usig a heat plate and scraper to remove the majority of the paint. There will be much less remaining to be ground off.

dave

The green discs are called Roloc. They come in several colors!

Is there something wrong with the old paint? Have you run a crosshatch and solvent test and did it fail? (use the solvent for your paint or your barrier coat if you're using one.)

If it's not coming off easily, that means it's not going to come off after you paint it. Best leave it on there for a couple of reasons. First, it's less work. Second, historic relevance: those layers of paint document the story of the unit. If you're not working in a shop I'm guessing you're not doing a top study of the paint forensics: layers, color truth, stenciling etc. You've seen some excellent work on this very forum, where people have spent days carefully peeling up layer by layer to reveal original stenciling. All the more reason to leave the paint in-place, so that when your organization does have those capabilities in the future, the paint is still there to study!

If roughness of the old paint offends, you might try fairing (e.g. Bondo, though I'd use West System) and a few quick sanding passes. Certainly easier than all that.

Thanks for the suggestions; we hadn't thought of liquid nitrogen before, and I'll look into the wheels from 3M tomorrow. As far as why we are stripping the paint, these units have been fully or partially repainted by various owners many times, there are places where the paint has failed, and some minor wreck repairs have been done. We feel that we will get better results if we go to bare metal and simply start over.

The green is 50 grit. The bristles are thicker and cut faster but still won't burn the metal.