Ok, heres the deal, I think Im getting close to being ready for my top coat. Heres what Ive done: Epoxy primer Filler More Epoxy primer, followed by Hi fill Primer Blocked with 80, then 180. Just shot another coat of Hi fill primer, I think my cars straight enough for paint, but I need to know how fine a grit of sand paper to use. I was gonna go. 180, then 320. then ????????? Do I have to wet sand? Thanks
I'd go with at least 400 or finer, depending on your topcoat. Have you shot a guidecoat before block sanding ?? You say "I think it's ready" with a guide coat and some more blocking you will KNOW if it's ready.......
if you shot just one coat of primer, odds are your going to sand all of it off again, maybe should have put at least 2 or 3 coats. sand it with 320 first to see if goes thru, if not finish it with 500 and then a nice coat of sealer before paint. any body work that comes thru ( bondo or putty ) should be spot primed and resanded before sealer. good luck.
I use 400, sometimes go over it by hand with P-600. 360 can show sand scratches if you're not careful, such as where the edge of your paper leaves small 'gouges' in the primer. Like Abomb said, use a guide coat and run over it with a block to make sure you don't have any low spots, high spots, or sand scratches showing through. And yes, use water, lots of it, to make sure you keep the paper clean.
Yeah, When I say another coat of primer i mean 2 total. What Shoud I start with 180 and progress or go straight to something finer? Thanks for the help!!
If you are wet-blocking, you may want to use an additional 'step' between 180 and 320. 220-260 would be good, and I'd be using a long block to do the wet blocking. Guide coat should be used between each grit change. That lets you know when you have sanded out all of the previous grit scratches, and have smoothed out all of the undulations in the bodywork. If you are using catalysed urethane hi-build primer, you don't have to use a seal coat. You can, but I'd only do so if I had broken the surface of the primer and hit bondo. If you are doing that, you weren't ready/weren't straight in the first place, and you should get the blocking straight before moving up in grit. Avoid applying too much paint without blocking it back off. Keep your final paint job as thin as you can, without breaking through. Extra mil's of thickness only make a paint job easier to damage. Dan Stevens dba, Steelsmith
Im planning on only dry sanding if thats possible. I plan I guide coating between each blocking session.
Oh, and add a little Ivory dish-soap to your sanding bucket/water. It helps the sandpaper to glide across the paint. Don't use just ANY dish-soap! Some have lanolin in them. Lanolin is for 'nice hands', it leads to fisheyes in a paint-job! You want to read the dish-soap labels. Ivory used to be 99-44/100ths% pure! Times have changed and that may no longer be true either ... Dan Stevens dba, Steelsmith
When I do that it never fails that I get beads on the paper that gouges the surface and leads to more trouble. If you are affraid of too much water,, I use a spray bottle with a drip of soap (no lanolin/conditioners) and a whole roll of paper towells. Do a section at a time. No need to guidecoat that much.
I'm assuming you are painting in your garage? If that is the case, wet-blocking will help with the dust issue you will be facing. Dry-blocking will just add to the problem. However if you are carefull to blow everything off throughly before during and after masking, you can still do a decent job. After you are done with all of your block sanding at 320, I like to do a light recoat(last coat of primer) guide coat and DA using 400 grit. It gives a good final 'tooth'. You haven't said what top-coat you are using. Single stage, base-coat/clear-coat? Base coat/clear-coat likes a little finer grit for a final 'tooth'. Stopping at 400 may leave some fine sand scratches. I'd final block 'wet' at 600 for BC/CC. If you go with dry sanding, you go dry ... it's largely personal preference. Dan Stevens dba, Steelsmith
in my opinion, you gotta wet sand when approaching your final coat. you'll find it much easier....i actually enjoy sanding when it gets to that point.
one of the things I like to do is use different color primers (epoxy, high build, sealer) gives me a better idea of what's going on blocking.
wet sanding is the only way to go. your job will come out straighter and you'll be able to do it in half the time and half the material! you'll be clogging the paper every 2 passes. like said before, add a little soap to the water and have at it. it's really not that messy if you clean every panel after sanding, plus you will be much more satisfied with the final results!
A big question is ( sorry if I missed it ) what kind of paint are you putting on? Color? Single stage? Urethane or laquer? enamel? base clear? metallic? pearl? transparent yellow pearl base clear or single stage white? Huge differences on what you really need to do. And your technique on sanding makes a difference on what grit to finish in etc. have fun wil www.sakowskimotors.com
if you want to dry sand you just need to keep the paper clean. stop and blow all the buildup off once in a while. for what might not come off with that keep a clean new wire brush handy.
like everyone else said least of 400 if your going to seal after, but you can skip the seal stage if you want and sand it with 600 grit....as said ANY repair spots showing through primer need to be spot primered and feather edged....i would do 3 coats of primer block each coat on the final coat block to 400 seal and paint
Krylon. But I'm a loser. I'm a loser with a p.o.s. and krylon. Lets see pics. Its gonna be beautiful. unlike mine,with krylon.
Guide coat it, 320 wet, sealer, topcoat. If its a metallic go 400. Any finer and you lose a bit of the mechanical adhesion.
im gonna do a bc/cc proly a copper metallic with a flattened clear thanks for all the replies !! ill post pics when im done (if it ever stops raining)
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