sanding reassurance needed

[andyv]

I've sanded down my VW camper for a bottom half respray. I went to 400 grit before the primer which I've sanded to 800. Some areas are now almost gleaming whereas others are smooth to touch but still matt and if you look close up you can still see some very fine swirly scratches.

Will this look OK once the top coat is on? I aim to put on 6 coats of cellulose and polish up to 2500.

 

[steveo3002]

sounds a bit iffy

did you use a guide coat ? dust a light mist coat of matt black rattle can over it , sand until its all gone , needs to be uniform and smooth all over with no scratches other than the 800 marks ..which wont be scratches as such

 

[andyv]

Here may lie the problem. I started off using a 3M powder puff guide coat. It's just like dusting soot over everything and I've never used it before. I did one panel which is the one that came out really smooth but it made such a mess that I decided not to do the rest that way. I just sanded it without until it's smooth to the touch. I sanded wet so maybe that's why the powder puff was so messy.

However, the scratches I'm describing are only those from the 800 grit so maybe it'll be OK. I can only see them if I get really close up.

 

[steveo3002]

yeah that powder stuff is more for dry sanding ..wet sanding washes it off lol

a way to see how it might look with paint is wet it with a soaking wet spirit wipe rag and get down and look up into the light ...any wobbles /scratches that you see then will show in the paint

if in doubt sand it up a bit more, you cant sand big areas well with no guide coat ...prep is everything

 

[the snooper]

Are you sure the scratches are from the 800 ? They could be showing through the primer from the 400 never seen scratches from 800 that would affect any top coat if the scratches are that visible I would flat t and give a coat of filler primer

 

[steveo3002]

yeah 800 shouldnt really leave any noticable marks

 

[andyv]

I didn't notice scratches from sanding the previous coat but I wasn't looking. I think I'll dry sand a bit more, then paint just one panel. If that's OK then I know what to do. Otherwise back a step.

Thanks for the advice.