How smooth does primer have to be sanded prior to paint? I'm getting ready to spray the jambs and inside the trunk. Ive sanded the high build primer with 320 along the edges and a few inches into the panel. The area sanded feels smooth but as you can see in the pics there are "divets", would these show in the color coat? TIA.
You want to use a black guide coat and sand until it's all grey again. http://www.eastwood.com/kevins_korn...10/24/12+-+Kevins+Korner+Laser+Straight+Lines Auto body 101. Any black spray bomb will do - fog it on a bit heavier than the video shows.
More high-build primer and sanding. If you can see or feel it, it will show up in the color coat. 1951Streamliner and 53 COE are both giving good advice.
use flat black for the paint i use the cheap ones from walmart they work well high gloss black clogs up the sand papaer
Yep, sand it some more. I use a dry guide coat, just wipe on sand off, no spraying and no clogging at all. http://www.downwindmarine.com/3M-Dry-Guide-Coat-Kit-p-91001422.html Scotty
You can buy aerosol versions of this product (dry guide coat) that are about a 1/4 of the price of 3M and if you drop it on the floor your 50 dollars worth of powder is not all over the place.
I can sand it totally flat with 220 but it leaves sanding marks. Should these be resanded up to 400 or another coat of 2K over the 220?
It depends on how much primer is left after the 220 sand, probably best to put another coat over to play it safe, put a little more thinner in it and keep your passes wet to avoid putting more pock marks back in. 320 or 400 sand then good to go. Scotty
Keep in mind that "a little more thinner" means nothing to the OP. To Sting Ray: Yes those will show in final paint. As someone said, reprime with a high build primer and sand until completely smooth. I also like dry guide coat. It never lies. It shows everything. I start guide coating at the 220 stage and use it through 400 or 600 depending upon the car.
it depends on color but i never spray over anything more coarse than 500 grit, colors like silver 600 grit. you should continue using the guide coat between grits to be sure you have reached the finest grit scratches. and use a block wherever you can so you don't make finger grooves. oh and you should be finishing yer bodywork with at least 180 on a da. i finish with 320. then i prime dry block with 180 then 320 then da with 320 then i prime again and begin blocking with 320,then 400 then 500 then 600. then a sealer coat then basecoat and finally clear. i like to paint my cars with dark colors and they need to be straight! and also i sant the crap outa the clear starting with 1000 and all the way up to 2500 before polishing. good luck and don't rush. it's called body WORK not body fast.
i want to ad one more thing paint materials are expensive i know, but buy quality products and use urethane all the way through. trust me it will hold up better with a better shine too. i like to use ppg on my hot rod stuff. through out my carreer as a bodyman i have used a lot of different stuff in various forms like laquor and enamel.i have used sikkens, glaserit, sherwin williams,dupont, and a few more i care to forget but ppg is very user friendly especially for the hobbyist.the thinners and hardeners are simply numbered by temperature also like dt 870 for 70 degrees. keep it simple you will be happy if you do.
Keep sanding till they come out. Spray a guide coat on it to tell if its all gone. Depends on how much material you have on there you may need to re-prime it. If you use 320 dry paper that will be more than smooth enough for jambs if you shoot sealer first. If its the car exterior, 400 or smoother for a final sand. 400 is plenty smooth.
Just remember to get your bodywork straight.... theres a difference between sanding primer and sanding bodywork. Primer is a foundation for your Paint to grab on to, it doesnt really make anything "straight" and wont take out any "ripples" . Dry guide coat is nice because it cover the entire surface of the primer. Block it good, re prime, from there you can also take 500 on a DA with an interface pad and sand the primer until the guide coat is gone. Go to 3Mcollision.com for a video in Dry Primer Sanding.
I'll second the motion to final sand with the DA, though I'll use 600 grit. It's amazing what shows up in the dry guide coat when using 600 on a DA-you think the sanding with 400 gets rid of all the imperfections, until you re guide coat and DA it. It might be overkill, but with the cost of materials, why chance it?
Old me I agree 600 is good especially for metallics and new water based paint systems. One thing to remember when using an interface pad the abrasive scratch moves up a grade ie 500 leaves a 600 grade sand scratch
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