i would clan it thoroughly with rubbing alcohol, then ue bull dog adhesion promoter(2-3 light coats,2-3 mins in between coats) then whatever finish you want to apply
What kind of prep work, and what kind of adhesion promoter should I use to paint me manifould?
Has it been on a motor and running before? If so I would clean it first with dawn and hot water, then wax & grease remover, then silicone remover, then put on the adhesion promoter. You'll get all kinds of fish eyes if you don't get it REALLY clean!
1) Start with 120-180 grit sandpaper and sand off all the pebble-like finish.
2) Go to 320-400 grit to remove previous grits scratches.
3) Now here's where you can make a choice. You can either keep going up in grits to 600, 800, 1000 to make the plastic smooth or you can stop at 320/400 depending on what type of primer you use. I don't like sanding that much so I use a high build primer. One good rattle can brand is Duplicolor High Build Primer/Filler. Get the gray, not the red oxide.
4) If you can't get that and have to use regular primer then continue with the finer grit papers up to 1000.
5) Now you will need to use an adhesion promoter since these pieces are plastic. I use a product called Bulldog and it is available in rattle cans. Spray 2-3 light coats waiting 2-3 minutes between coats. After last coat wait 10- 15 minutes before applying primer or the primer will "wrinkle".
6) Now start applying primer and make SURE the first coat is very light and only a dusting. You just want a misting to adhere to the Bulldog.
7) If using Duplicolor wait 15 min. between coats. Otherwise follow directions on can.
8) Continue now with slightly heavier coats up to about 3 coats.
9) Light dry over night and sand with 400 grit. Check progress and if smooth sand with 1000 grit and you're ready for basecoat. If not satisfied lay down some more primer and dry overnight again, etc.
10) When ready for base coat again first coat is only a slight misting. You're not looking for full coverage. Some primer should actually show through. Follow instructions on time between coats. 2nd coat a little heavier and 3rd coat should be enough for full coverage. If you are using a solid color, that is not metallic, you can wetsand the base coat with 1000 grit if you want, but if it looks good leave it alone.
11) Wait at least 20-30 minutes and then start applying clearcoat. Again, for rattle can stuff Duplicolor is good. Light misting for 1st coat followed by slightly heavier coats.
12) 4-5 coats of clear. Let dry for 2-3 DAYS!!
13) Now if you are planning on wetsanding and polishing you can do that at this time. I usually do not wetsand and polish since my painting skills are fairly adept. The key to not having to do this is to lay on the clear very lightly. Go with multiple light coats holding the can about 12 inches from the surface. Also try to do it in as clean environment as possible so you don't get dust in the finish.
Excellent write up with great results. Duplicolor is probably the best shake shake primer you will find. Though if you can find someone with a mini spray guy and air tank, you can get a much deeper gloss from a full automotive clear. I plan to repaint my intake black with blue "True Flames" so as to someone simulate air flow....
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