2 quick body prep questions

[N2ae86]

Ok, just about to prep the rest of the car body prior to paint and just got 2 quick questions.

Will high build primer fill sanding scratches created from 120 grit? Or should I step up to 240 to smooth out and then use the primer

I am using a grey scotch pad to key the paint work prior to paint - the first time I have done it to good paint work so slightly uncertain on what a properly keyed surface should look like. After scothcing away the panels still seem fairly shiney and smooth but looking down the panel have lots of very fine scratches in the existing paint. Is this a adequate key or does the surface need to be keyed more (possibly a harsher grade?)

Thanks all!

Cheers

James

 

[sprayerDrew]

Grey is toofine you need red and when done it should leave a dull surfface

 

[Chickenjohn]

You need to go up to 240 grit when DAing the car. I would go via 180 to get rid of the 120 scratches, then go up to 240.

You can then DA the sound paint with the 240 pad as well to get a good key on the paint all over. Don't forget to panel wipe and then tack rag!

 

[N2ae86]

Seriously - I do wonder about the paint shop I use - they said grey was what I needed for keying the paint, its not the first time they have told me BS, last time I use them! Good thing I checked, I knew the key didnt look enough!

So definatley red pads for keying good paint work (I wont be priming over the top, just applying paint directly over the old stuff). What are grey pads used for though?

Will also get some 240 to feather out the 120 grit sanding - its only on a few patches.

Cheers

James

 

[badersbus]

Red scotch pads are generally used when you are going to overprime the area. Grey are less aggressive , so mainly for use under top coat especially lacquer , so any flatting scratches will not show through.

 

[langy]

A lot of people don't know but a 240 grit on a DA equates to using a 400 grit by hand.

You need to go up to 240 grit when DAing the car. I would go via 180 to get rid of the 120 scratches, then go up to 240.

You can then DA the sound paint with the 240 pad as well to get a good key on the paint all over. Don't forget to panel wipe and then tack rag!

 

[oapt25]

Are they grey or dark grey?

http://oxfordhardware.co.uk/khxc/ccp0-prodshow/fabrication-supplies-scotch-brite-pads.html

According to this site grey is ultra fine and dark grey is coarse

 

[langy]

Ultra fine are light grey, or at least all mine are.

Are they grey or dark grey?

http://oxfordhardware.co.uk/khxc/ccp0-prodshow/fabrication-supplies-scotch-brite-pads.html

According to this site grey is ultra fine and dark grey is coarse