Post Acid Dip Paint?

A

asutherl

I’m finishing up the fabrication on a gravel rally car and starting to plan my paint strategy. This is the first time that I’ll be painting an acid dipped (caustic soda) chassis from bare metal. The chassis was dipped 8 years ago and has been sitting in the warehouse ever since, with occasional fabrication, roll cage install etc. I am planning on re-dipping the chassis, to clean off the surface oxidation and grime and oil that’s built up over the 8 years of storage, and then start the painting process immediately to seal the car.

It’s a race car that see’s gravel roads, so durability is the primary concern, and looking good from 5 feet away!

My initial strategy:
  • A waterborne metal prep and cleaner (I’m not sure if this is a good idea after being dipped, I’m worried getting water into areas that I can’t dry)
  • Epoxy Primer 2-3 coats
  • Body work/filler
  • Primer/Sealer combo
  • Single Stage color coat (Avalanche Grey)

One challenge is that I rent a local paint booth, so I can’t camp out in it and need to time paint stages accordingly. There may be a time lag between shooting the epoxy and getting the primer sealer on.....is there a window?

Any input is appreciated.

Andrew

20180525_115952.jpg
 
I think SPI epoxy Is not recommended for application over a dipped body. Especially so if metal prep is applied.

Best to refer to the tech sheet....

Don
 
Caustic Soda and Acid are on opposite sides of the ph scale, and Caustic Soda is something that I wouldn't personally want any part of. You probably should check with who ever dipped it for you and see what they recommend.
 
Thanks for the feedback. I didn't see anything in the SPI Epoxy tech sheet about a dipped car, but I'll take another look. As part of the dip process, they wash and coat it with something....I will find out what that is. The initial response from the dipper was that I can apply epoxy directly.
 
They would have to coat it immediately to keep it from rusting. A couple decades ago I had an engine block cleaned with that process, and the guy that did the machine work complained about it rusting quickly after washing the metal shavings away. So I never tried it again.
 
asutherl said:
Thanks for the feedback. I didn't see anything in the SPI Epoxy tech sheet about a dipped car, but I'll take another look. As part of the dip process, they wash and coat it with something....I will find out what that is. The initial response from the dipper was that I can apply epoxy directly.
Click to expand...
My mistake. I was thinking acid dipped. Give Barry a call on the tech line.

Don
 
Here is what we do know, acids do self neutralize with time but what we don't know due to a lot of other factors is how log and when.
Dippers usually use a very diluted acid {if they do} and normally it will protect the car for about a week, so if driving it home and you get some rain it wont flash rust.
In your case you can do a simple test as lick you finger and touch a spot and see if flash rust in morning.
If it was me and I have advised this may times over the years as your case happens a lot.
Clean with 700 and dry, Da with 80 only the outer panels, won't take 5 mins, clean with 700 again, dry and let set 60 minutes and 2-3 good coats of epoxy.
 
Thanks all! First and foremost, I'll reach out to the dipper and get more details on the chemicals used to strip and then wash/seal it. Whatever the final chemical cocktail was, it's been very robust over the past 8 years. The only rusting has been where we've welded and on the cage, which was installed post dip.

update: I spoke with the dipper and they said that they dip using a proprietary blend that contains sodium hydroxide and other "stuff". After the stripping process, they high pressure wash the chassis and neutralize everything with a proprietary Phosphate coating. They claim that the metal is sealed and does not need an epoxy coat, you can do body work and paint directly on their surface.
 
Last edited by a moderator:
I appreciate all of the input! I'm most definitely coating it with Epoxy!!

I wish it was e-coat....but the only place I know that does that is back East / Midwest....no one on the West coast.
 
asutherl said:
I appreciate all of the input! I'm most definitely coating it with Epoxy!!

I wish it was e-coat....but the only place I know that does that is back East / Midwest....no one on the West coast.
Click to expand...
Done correctly Epoxy is far superior to e-coat. If you've ever intalled any door skins that were e-coated from an OEM ever noticed how it peels off as you are folding over the flange? Coat a door skin with epoxy and then install it the epoxy is still holding strong. I've done that a lot and never seen epoxy let go like E-coat. Also corrosion protection is far superior as well.
 
You must log in or register to reply here.
Back
Top