DP90 Substitute for DOW-7 Mg Treatment

[Rick Iverson]

Gents;

Can DP90 epoxy primer be a reliable substitute for DOW-7 Process on my magnesium wheels?

I plan on truing the mounting surface a nanometer or so, filling in a few scratches, then finishing. Although I understand lightly repaired (read: scratches/road rash) with a compatible powder coat filler will not be detectable after the process, I am considering a flat black epoxy primer as an alternative. Thoughts?

[Rick Iverson]

Bump

[John LaRue]

I have used the DP90 on all of my mag wheels for years. They have taken the abuse and never have required repainting.

[billtebbutt]

Have used DP 90 on mag, alloy for many years. Always excellent results, no issues at all

best
bt

[Rick Iverson]

Gents;

Just to make sure, these wheels will be freshly milled on the back mounting flange to insure trueness (shiny Mg), then painted. Am I good to go?

[John LaRue]

I have had no issues with the Technomags when we machined them.

[Rick Iverson]

I have had no issues with the Technomags when we machined them.

You be the Man, Sir. Thank You. Stay safe

[stonebridge20]

Gents;

Must to make sure, these wheels will be freshly milled on the back mounting flange to insure trueness (shiny Mg), then painted. Am I good to go?

Centerlock or 4 bolt?

[John LaRue]

You be the Man, Sir. Thank You. Stay safe

Have them apply only a light coat to the mating surfaces to avoid issues.

[BrianT1]

Does DP 90 come in a rattle can??

[John Michial]

Rick,

Check out steel-it.com.

hope you are doing well,

Michial

[R. Pare]

Does DP 90 come in a rattle can??

Unless it is something new that they offer now ( and that is possible, as you can now get some 2-part epoxy paints that come in a rattle can that has a special way of keeping the hardener and the paint separated until you go to use it), then NO, since it is a 2-part epoxy.

[Rick Iverson]

Centerlock or 4 bolt?

Centerlock

[Rick Iverson]

Have them apply only a light coat to the mating surfaces to avoid issues.

John;

I lean towards the slightly semi-gloss black DP90 IL as a solid, economical, and fairly pleasing appearance as the choice of finish.

But I visited my powder coat shop this afternoon to check on some parts being processed, and had an epiphany: powder coating over Dow 7 is routine. Can I surmise it can be done over DP90 as well?

Reason: Color possibilities with powder coat is endless, and most certainly, the eye candy. Now I recognize the fundamental consideration is to protect the Mg from oxidation, and if DP90 works the same as DOW, why not?

Process:

1. Strip
2. As RP recommended, leave DOW on
3. Repair imperfections with a quality filler and sand smooth
4. DP90, LIGHT in the mounting flange
5. Powder coat, mounting flange masked

Thoughts?

[John LaRue]

I have no idea. I would guess that the DP90 will burn off in powder coating. You may want to consider how the mag will react to those temps as well. I don't powder coat anything any longer. It wasn't as durable and tends to hide cracks.

[stonebridge20]

Centerlock

I thought that if you machine the mating surface on a centerlock flat that they tend to loosen up. I thought that they need to be machined with a small cup shape if you will so that it acts somewhat like a Bellville washer when tightened?

I'd also not put any paint whatsoever on the mating surface.

[R. Pare]

They don't HAVE to be machined concave, but it does spread the loads better across the full face, which in turn reduces face wear and any possible loosening.

Dow 7 is a chemical conversion of the surface material, NOT a thick addition layer like a primer, so the temperatures of powder coating does not affect it, nor is there a possible issue with chemical incompatibility.

[tlracer]

Neither of the companies I use for powder coating likes doing magnesium because it can gas in the oven, causing the coating to lift.

Is there a reason not to have your wheels chromated? Not only does that give a good key for paint, but it will protect anywhere unpainted like the mating surface.

[Rick Iverson]

Is there a reason not to have your wheels chromated?

I cannot find anyone reasonably near to do the DOW 7 process. I live across the bay from Eglin AFB and Hurlburt AFB, and one hour to NAS Pensacola as well as Tyndall AFB, one would think this service would be readily available. But then again, I suck at math and computer research.

[EricP]

I have two Technos that came with my car that were powder coated. The rim/edges are chipping pretty bad where they are worked against for mounting tires. Rough handling? Probably. Poor prep? Maybe. I had some Revolutions for another car, aluminum, that were doing the same thing. Powder coating seems brittle for wheels to me. Not sure but it makes me pause on powder coating on wheels.

[stonebridge20]

The ladies in Indy will take care of you.

https://www.kecocoatings.com/liquid-coating/

[tlracer]

I cannot find anyone reasonably near to do the DOW 7 process.

Thanks for explaining, Rick, that's a good reason for not getting them chromated!

I assumed it would be easier than it is to find a local company. I'm lucky over here, as there's an excellent racecar specialist under an hour's drive from me. The nearest I could find to you is AM Metal Finishing in Orlando, so around 6 hours...