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Tue Nov 23, 2021 1:14 pm

I have decided to 'let go' of the rust on the wheels of my 72 standard survivor, the only rust anywhere on the car. My auto restorer next door neighbor suggested powder coating for a durable finish. I dropped them off yesterday and was kindly informed that sometimes, on wheels that have the deep groove between the center and outer part, that latent 'oils'(?) may seep out during the baking process and cause bubbles at that seam. They said they would pre-heat to try to draw any out, clean it up, then powder and bake them.

Anybody have much experience like this vs painting?

I know the silver powder color won't be stock color but I'm not showing the car anywhere seriously and I'm sure they will look fine. At any rate, the tires, although looking unbelievably good, were probably 15 yrs old so I felt I had to get new ones on.... so while I was at it... good time to get the rims done.

Tue Nov 23, 2021 1:21 pm

When I had my wheels powder coated, they told me the paint would not go down into that crevice where the two pieces meet. Said it would rust, and told me to fill that crack with RTV. I did not, I bought some clear coat and laid the wheels down, and flowed a bunch of clear coat down into the crack. Then let it cure real good. Have not seen any rust.
I think they are correct, the static charge is not going to pull the paint dust in there. Capillary attraction might pull wet paint in there.

Tue Nov 23, 2021 2:32 pm

I had my stock steel rims powder-coated silver about 4 years ago, and since then have had some issues with little corrosion "tracks", spreading out from that joint areas you described above. These look kind of like little meandering "thread" lines, spreading under the powder coating. They're generally not all that big or noticeable though, unless you look pretty close-up.

Note that I often use my bug as a (mostly) "fair weather" commuter, but still occasionally end up in wet and/or dusty/salty conditions, which probably exacerbates the problem a bit.

In any case, would recommend that you consider somehow filling or sealing those seams, either before of after the powder coating process, to help prevent any issues like what I describe above...

Tue Nov 23, 2021 2:32 pm

Have the PC shop apply a coat of marine primer first. It has a good amount of zinc in it to help slow down rust from getting under the color coat. Adding a little clear coat where the inner and outer parts of the rims will help greatly there.

Tue Nov 23, 2021 5:04 pm

There is also a powder coat primer that they can apply first and bake on real good. Most powder coaters don't use the primer though, they just go straight to the final coat.

Tue Nov 23, 2021 6:31 pm

bomberbob wrote: When I had my wheels powder coated, they told me the paint would not go down into that crevice where the two pieces meet. Said it would rust, and told me to fill that crack with RTV. I did not, I bought some clear coat and laid the wheels down, and flowed a bunch of clear coat down into the crack. Then let it cure real good. Have not seen any rust.
I think they are correct, the static charge is not going to pull the paint dust in there. Capillary attraction might pull wet paint in there.

Thanks... Interesting... I wonder if this place I'm going has actually found the 'oil' or just suspect that's what it is, and maybe it's air bubbling up through the paint before it dries... they has some very convincing photos of the symptom at least. I will clear coat that seam in any case.

Tue Nov 23, 2021 6:32 pm

baldessariclan wrote: I had my stock steel rims powder-coated silver about 4 years ago, and since then have had some issues with little corrosion "tracks", spreading out from that joint areas you described above. These look kind of like little meandering "thread" lines, spreading under the powder coating. They're generally not all that big or noticeable though, unless you look pretty close-up.

Note that I often use my bug as a (mostly) "fair weather" commuter, but still occasionally end up in wet and/or dusty/salty conditions, which probably exacerbates the problem a bit.

In any case, would recommend that you consider somehow filling or sealing those seams, either before of after the powder coating process, to help prevent any issues like what I describe above...

Thanks! I'm not showing this car and the rest of it isn't perfect. Still, I'd like to 'get my money's worth' and can hope I don't see any more corrosion than what you are seeing. I noted in another response that I will clear coat that seam.

Tue Nov 23, 2021 6:34 pm

Eric&Barb wrote: Have the PC shop apply a coat of marine primer first. It has a good amount of zinc in it to help slow down rust from getting under the color coat. Adding a little clear coat where the inner and outer parts of the rims will help greatly there.

Thanks! I can check and see if they will do that primer and for how much more. will do the clear coat for sure.

Tue Nov 23, 2021 6:34 pm

I had my spare powder painted the same time and color as my alloys. 23 years later and it still looks new.

Tue Nov 23, 2021 7:18 pm

Lone Star Guy wrote: Eric&Barb wrote: Have the PC shop apply a coat of marine primer first. It has a good amount of zinc in it to help slow down rust from getting under the color coat. Adding a little clear coat where the inner and outer parts of the rims will help greatly there.

Thanks! I can check and see if they will do that primer and for how much more. will do the clear coat for sure.

If the folks at the PC shop look at you blankly, tell them to look the marine primer up. Our first set of PCed rims (before we found out about the marine primer) started to rust up on all the sharp edges due to the color coating went on so thinly. Rims were stored in a dry storage shed for about 2 months with new tires on them. From then on we got the marine primer done and never had such a rust problem on the rims again.

Marine primer also helps when the PC coating get cracked, chipped, scratched through to the steel. Very first rims we had painted, with normal wet paint at a body shop, ended up with rust all under the paint.... Could see veins of the rust running here and there under the paint. Have since found spray cans of a high zinc primer for non-PC painting from Gas Supply welding supply shops. The shop here does not carry it on the shelf, so we have to order it so they will get it in for us.

Wed Nov 24, 2021 3:22 pm

Eric&Barb wrote:

If the folks at the PC shop look at you blankly, tell them to look the marine primer up. Our first set of PCed rims (before we found out about the marine primer) started to rust up on all the sharp edges due to the color coating went on so thinly. Rims were stored in a dry storage shed for about 2 months with new tires on them. From then on we got the marine primer done and never had such a rust problem on the rims again.

Marine primer also helps when the PC coating get cracked, chipped, scratched through to the steel. Very first rims we had painted, with normal wet paint at a body shop, ended up with rust all under the paint.... Could see veins of the rust running here and there under the paint. Have since found spray cans of a high zinc primer for non-PC painting from Gas Supply welding supply shops. The shop here does not carry it on the shelf, so we have to order it so they will get it in for us.

Ok, quit teasing.....lol, what brand do you use?

Wed Nov 24, 2021 3:35 pm

Dan the workingstiff wrote:
Ok, quit teasing.....lol, what brand do you use?

It is the Air Gas stores Radnor brand. They carry two versions. One is a shiny aluminum finish and there is no zinc content amount listed, so do not buy that. The other is a matte finish and that has a listed 95% zinc content on the can. Anything with less than 85% zinc content is pretty much a waste of time and money according to Popular Mechanics Magazine back a few decades in the past.

Wed Nov 24, 2021 5:12 pm

Eric&Barb wrote: Dan the workingstiff wrote:
Ok, quit teasing.....lol, what brand do you use?

It is the Air Gas stores Radnor brand. They carry two versions. One is a shiny aluminum finish and there is no zinc content amount listed, so do not buy that. The other is a matte finish and that has a listed 95% zinc content on the can. Anything with less than 85% zinc content is pretty much a waste of time and money according to Popular Mechanics Magazine back a few decades in the past.

Thank you

Wed Nov 24, 2021 6:57 pm

Dan the workingstiff wrote: Thank you

Glad to help. Will warn you that the zinc metal pigment needs lots of shaking up often before spraying to avoid having it come out more like flocking. Personally pull out a can preferably the day before using. Every so often shake the can, then set it right side up or down alternating each time you shake it again. Have done this in as little as four hours without it flocking, but figure it better to normally do it the longer more leisurely routine.

Other thing we have found that when storing any spray paint cans, it is far better to do so with the cans on their sides. That way pigment does not get caught in the crevice inside the spray cans between the side of the cylinder and the domed bottom. The plastic shaker marble can not get into that crevice and so pigment like mud will just stay stuck into there. With the spray cans stored on the side the pigment falls out of the solution onto the inner side of the can where it is easily stirred up by the shaker marble. Plus noticed that the shaker ball starts clattering around when the can is first shaken up (after storing for even as short as just a week or two later) a lot faster this way.

Thu Nov 25, 2021 6:21 am

My FIL told mu eight year old son to shake the can til the marble stops rattling.

😄😄😄