Painting rims and aluminum cases

[DanM]

Hi- I'm restoring a 26 JD.

The cases need to be painted. Any advice on a good primer and prep for the aluminum ? Any different than the sheet metal?

On rims, is there any attempt on the spoke holes to prevent build up? I had a set of rims dome once that had terrible chipping around the spoke holes when the spokes were tightened. I'm wondering what technique should be applied here?

Thank you.

[Chris Haynes]

You must use zinc oxide paint on the cases. Regular paint will wash right off aluminum.

[PaintPro]

Paint for cases and rims

When painting older motorcases it's important to get them very clean first and then mask off any areas where you don't want paint. Once that's done I use what's called an etching primer. It makes a very tight bond with things like aluminum or galvinized surfaces. With the world going green zinc and chromates are being phased out of paints. Once the primer has dried I use a catalyzed acrylic enamel or urethane on the parts. I have done about 25 set of motor cases with no peeling problems reported. Any local auto paint store can help you with the selection of the proper products to use.

For clearing the holes on painted rims I used a straight sided reamer of the correct size held in a tap handle and just give it a twist or two in each spoke hole. This will remove the paint with enlarging the hole. measure your psoke nipple to get the correct size reamer. The second choice is a drill bit of the corret size again used with a tap handle so it can be carefully controlled. You can try masking the spoke holes with some kind of plug but more times than not you will cause a tear or chip in the paint when you go to remove it.

[DanM]

thanks!

Thanks Chris and PaintPro for your tips on the primer- and the idea of reaming the painted spoke holes!

I have Centauri acrylic enamel from Antique Cycle Supply. I was planning on adding a hardener.

[stevekleincustom]

Aluminum and Paint

The replies you got are correct. I have always cleaned the aluminum with an aluminum acid etch product that painters use on aluminum truck trailers, horse trailers etc.... Rinse clean thoroughly...then I use a zinc oxide primer. Quality paint properly mixed is the last step.

I am not an advocate of powdercoating on vintage machines although it is a wonderful product for rims. It is tough and chip resistant and will not cause problems with spoke nipples.

Steve Klein

[bobdo]

Dan M,
I've been using the Acrylic Enamel from Antique Cycle also. The primer I've used in the past was a PPG product called DP-90. It had lead in it so its not available anymore. It was replaced by DP-90LF which I'm using now. Of course the old stuff was better, but this is working out well on sheetmetal. I can't say about your cases, no experience there. The DP-90LF is an acid etch black primer. Hope this helps. Bob