Originally Posted by mongocanfly (Post 8500926)

It's best to sand in a x pattern...not just one direction....but it's looking good

Originally Posted by MP&C (Post 8501159)

make sure your sanding block is a good 2x or more the length of the distance between high spots. When you sand side to side, you don't want the sanding block dropping in the low and cutting out the low. If it stays on top, it only cuts the highs.

Originally Posted by Foot Stomper (Post 8501629)

If you can block it flat with high build 2k urethane primer, there's no need for featherfill. Right?
If you can't block it flat with high build, then you have to put more high build on or go with featherfill...in which case you'll have to high build primer the featherfill because it's not meant to be painted because it's too hard to sand with finer grits and is too coarse and porous for paint.

Originally Posted by pwdcougar (Post 8501680)

Thanks. In another thread I was told I could sand the featherfill with 220 then 320 wet sand with 600 and do the base coat.

Originally Posted by nsb29 (Post 8501762)

I have worked at a shop that has won multiple awards including pebble beach for paint every one has there own opinion and what thay Like all high build primer‘s have talc in them some people say they don’t like the slick sand or feather feel because they are full of talc thay call it spray on Bondo hard to sand and you can’t paint over it or it has to be top coated non off this is true if you read the instructions I have used it for twenty years O shrinkage O Die-backs I am the one that said you can sand it down to 600 and I will stand behind it I see cars we panted 15/20 years ago that look like thay were panted yesterday I have not seen a spot putty that did not shrink and if you have used Bondo you’re urethane primer it’s not going to stop diebacks it works fine on straight stuff body shops use it it’s good for production it cost effective but this is my opinion and experience

Originally Posted by pwdcougar (Post 8501866)

I have a little bit of SPI 2K primer left. Can I just spray the low spots or should I get another gallon and do the entire roof?

Originally Posted by Foot Stomper (Post 8501976)

There's no harm in spot spraying primer if you do it right.
One such method is to spray three coats, the first being the smallest area, the second a little larger area, then a third a little larger area yet.

If you run out, you run out...then go buy more. There's no reason to spray the entire roof, unless you're selling primer. :lol:

Originally Posted by nsb29 (Post 8509956)

Only if you sand through to metal if that happens spot those places in with a reduced primer and then 600 The whole peas

Originally Posted by Foot Stomper (Post 8525211)

Epoxy only works on bare steel. You can overlap the 2k urethane in the adjacent areas with zero negative effects.

The next stage is tricky because if you high build and sand too much, you can burn through the epoxy again. If you do, and the panels is otherwise perfect, you can paint. A tiny area of unprimed epoxy is acceptable to some. If not to you, epoxy prime and paint wet on wet.