Just picked up my dipped parts.....getting ready for Primer.... ??

  • Thread starter Richard Jennings
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Richard Jennings

I just picked up my dipped front clip parts where they suggest to wash with warm water and Dawn soap. I believe I should sand the bare metal with 80 grit then clean with Dawn and water again, then do a final wipe with SPI 700 W&G before spraying SPI epoxy. I've sprayed SPI epoxy once when I blasted my '55 body. Thoughts ? I've never sprayed over "dipped" metal before.

Since epoxy spraying my '55 body, I've built a home hobby spray booth. Its 12'x24' insulated, drywall and floor sealed, 170 fc of LED lighting. I will pull heat into the booth through a 25"x75"x2" filter door and exit via a 18" louver fan that's 3 speed 1800/ 2000 / 2300 rpm, from my forced air Reznor furnace from my 30x48 shop.

My 30x48x10 hobby shop.....


Note from the dipper......


dipped parts....


Underside of '55 hood...


My home hobby booth with 3 speed exhaust fan and louver... I big upgrade from when I first started the hobby of painting and building cars from a dirt drive way, lol....


Home hobby both opposite end filter door...


Filter door....


 
"Thoughts ? I've never sprayed over "dipped" metal before."

It must have been the electrolysis stripping system and there will be no problems with it, just wash with Dawn soap as stated, but do it before sanding.
A couple things stand out to me, first is the anti flutter in the truck lid is gone now and has to be replaced. I've never had a trunk lid done because of that.
Also you might want to consider removing the cowl side panels from the firewall to repair rust issues. There will probably be holes in there that will allow water inside the car. It will also allow you to clean out all the garbage from your fresh air supply that comes in through the cowl grill below the windshield.
 
When I get dipped parts back I sprinkle baking soda on the parts and scrub with a scotchbright and water. Rinse really good,(powerwash in summer and hose in the winter) repeat, then wash with dawn and water twice, dry with squeege and compressed air, 80 grit the parts.
Then I use dawn and water and wash each part and rinse twice. Throughly dry each part asap. I do one part at a time as they will flash depending on what time of year.(humidity)

I haven't had any problems with this procedure. I double up each procedure just to be safe and it doesn't take much longer since everything is right there.
 
That is a good procedure for acid dipped parts, but if my guess is right, then it wasn't acid dipped and wouldn't require the neutralizing steps.
 
I use an acid dipper when the parts are really pitted. His instructions to me are they don't need washed with anything and his anti-rust is ready to be painted over. I don't buy that because the anti-rust spray he uses leaves a distinct film. I've tried to find out what he sprays them with for my own research but he hasn't given me that info yet. Crotchety fella.

10+ years ago I got my parts back and did the repairs and just prepsoled them. I had to repair one of the doors later and found the metal was completely flash rusted under the Dupont Variprime. I had to strip 4 doors and eat a lot of labor on that. I never liked Variprime but PPG went lead free and Valspar quit with their epoxy primer that I liked. This was about the time I found SPI and haven't looked back.

20 years ago when I was working for my Grandfather in law he used to get the dipped parts back and would Dupont Metal Prep them. Then we would drag them over to his wash bay and spray them with a very harsh whitewall cleaner he had and we would wash them good. We never had problems with that procedure either. Seems kinda pointless to metal prep them when they have already been dipped.
 
I washed with Dawn then scrubbed with a hand style wire brush as tge parts seem to have some pitting with black deposits or residue. They cleaned up great. I then used 80 grit on a DA. Followed by SPI 700 W and G. Let sit for an hour, then sprayed with SPI epoxy.
 
Maybe Richard will come back on and let us know what they used for stripping his parts, but the reason that I think it was electrolysis instead of acid is because of the instruction sheet they gave him which says their stripping system is not compatible with acid.

2015754b-9b15-4ec8-8c44-9ee9110ca263_zps7l3bwvsm.jpg
 
Sounds like he used HT-2 and all that does is change PH of the metal for a short time, If this is case, we have always said clean with 700 (only) sand with 80 DA and clean again with 700 and epoxy.
Lots of "ifs" here but this would be my best guess.
 
chevman said:
Maybe Richard will come back on and let us know what they used for stripping his parts, but the reason that I think it was electrolysis instead of acid is because of the instruction sheet they gave him which says their stripping system is not compatible with acid.

2015754b-9b15-4ec8-8c44-9ee9110ca263_zps7l3bwvsm.jpg
Click to expand...

Well, you either strip with acids or you strip with caustics. Caustic soda at 160 degrees with enough sodium gluconate to keep it from becoming a brick when it cools is a common strip process. Acids and caustics neutralize each other, but spraying an acid on a caustic film will make snot.
 
I'm not 100% sure of their process, however I was told by the owner its NOT acid. I stood right next to the tanks...its not a breath of any acid. Therefore it doesn't harm machined surfaces, like crank journals, cam bores or sheet metal parts for that matter. They dip aircraft engine cases in this stuff. Its almost like its a molasses dip process that guys do in their garage. the red tank is heated. teh yellow tank has DC voltage applied to it. The owner hoisted a huge pump casing from it ...said it was for a water treatment plant. Chevman...yes sir the link is the business. They are about 1 1/2 hours from me.


 
Another.... I cleaned with Dawn and warm water. Not satisfied, I then scrubbed with a hand held wire brush. This seemed to remove the blackish spoil from any pitted pore in the metal. Then washed with Dawn again and dried. Cleaned with SPI 700 and sat for an hour before I tacked and sprayed the SPI epoxy. I have my shop heated to 70* all day yesterday and throughout the night. This evening I turned the heat down to 60*. 24 hours after spraying I *think* the epoxy is cured to drop my temps ??
 
Wire brushes tend to smooth and polish metal, so you may want to test adhesion on any areas that saw intensive wire brush action. The lack of an 80 grit scratch would concern me greatly if there is no surface profile left by any other process (media blast or acid etch).
 
crashtech, I used a DA with 80 Grit after I cleaned the panels with a wire brush.

Barry or others ... Being I have a home shop and a day job to go, I run out of weekends pretty quick. Evenings are tough to get much spraying done. I keep my 30'x48' shop at 68-70* with a forced air 75k btu Reznor furnace. I preheat my booth with a 10,000 btu radiant heater until I'm ready to spray. The booth gets heat via the man door between it and the shop, nothing is ducted. After the exhaust fan has pulled the fumes out I start up the 10k radiant heater to raise the temps again to 70-75*. After the panels are dry, I place them in my big shop for better control of the temperature. I will NOT leave the radiant heater on when I'm not in my shop. The paint booth is then closed off. My question.... if its the following weekend before I can get back to painting, should I red scotchbrite the epoxy before I 2k prime the panels??









 
This SPI stuff is addicting. Chad is my "dealer".....although Kate is my supplier, lol. I suppose there are a lot worse habits :)
 
Its a nice set up, but you worry me with the electrical. Explosion proof fittings is just basically water pipe where you lock the boxes with locknuts in and out. Those house outlets, switches and cords are going to hammer you if god forbid you have an insurance claim. If you have a chance to upgrade, try to pick up some explosion proof fixtures.
 
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