Red Oxide primer over DP74LF over acid dipped Mustang

C

craig429

Member
I am working on a 69 Mustang that the prior owner had acid dipped. The company that did the acid dipping had done a rinse process. As far as I know, they dipped and rinsed it correctly. The car had sat for around 6 months before DP74LF was applied. I helped the prior owner to sand and scotch bright the body before appling the DP74LF. It has been 2 1/2 years since it was primered with DP74LF. There has been metal replacement done and there will be some more that will be needed.

I would like to use SPI Red epoxy as I understand it is a closer match to the original Ford red oxid primer.

My question is, will there be problems with using SPI Red epoxy over scuffed/sanded DP74LF?

If there are any sand throughs in the DP74LF to bare metal, will that cause problems with the SPI epoxy being the metal was acid dipped?

Or am I best to stay with DP74LF since it is ok to use over acid dipped metal?

How well will the SPI red epoxy hold up on the bottom of the floor pan if it is not top coated (as Ford originally did with the red oxide primer)?
 
A couple of things:
If the body had not been washed like you were told the LF would be peeling in sheets by now as you ground areas, hit area with the air hose.
2nd, acids do self neutralise's with time and the time frame the acid sat and considering the dippers use a mild one anyways, I would guess by the time you sanded it, there was nothing there to cause a problem if it was not washed.
After four hours the lf can go over the SPI and visse a versa, no issue there, just treat the LF like you were re-coating the SPI, 180 and shoot.

Not coated?? Will hold up much better I can assure you.
 
Thanks Barry,
If I have sandthroughs to the acid dipped bare metal, do you see any issues shooting SPI Epoxy over the bare metal or should I shoot it first with DP? (Since DP epoxy is ok over acid preped metal)
 
Dp should not stick to metal any different then the spi, if an acid film is present it will come off just like filler will not harden at the metal.
The only reason people think ours is different is because we warn people so they call and get the right information about how to neutralize.
The main company's do not even recognize products they don't make.
Look at PPG acid for metal, if I recall you wash with water twice, just like the Duponts, we have many shops that use those systems under the SPI and like I told a guy yesterday, just follow the instructions to a tee.
 
The problem with acids is that guys have an aversion to washing them off with water, which is an ABSOLUTE MUST, but it just plain scares people to hit that fresh metal with water. Sounds like the vehicle was washed, so that's covered.

Now the remaining problem with a vehicle that has been acid dipped is that acid etched metal and possibly acid residue remain in the seams, and those can become what is called "corrosion hot spots," since they are difficult to coat with anything outside of full immersion (dipping).
 
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