Guide coat for final sand before sealer?

A

Aaronj

Promoted Users
Just want to run my process by you guys to see if it makes sense and ask a few related questions.

Process:

Ive spray epoxy followed by 2k. 2k is sanded with 180 then 220 using guide coat.

Im planning on spraying one more coat of 2k to fill the 220 scratches and cover some exposed epoxy.

This final coat of 2k ill sand with 600 before applying reduced epoxy sealer>base>clear.

Questions:

Is it a good idea to used guide coat with 600 grit or is it a waste of time?

Would you go straight to 600 on the final 2k sand or step up from a lower grit?

If i have sanding scratches that show on the finished paint job (black) does wet sanding and buffing the clear remove them or are they still visible below the clear surface?

Thanks!
 
I don’t use 600 for solid colors. I’d probably use 320 followed by 400. Dry no wetsanding. Then reduced epoxy sealer.

I use dry guide coat for all grits.

Mandatory backyard hack disclaimer inserted here….

Don
 
dhutton01 said:
I don’t use 600 for solid colors. I’d probably use 320 followed by 400. Dry no wetsanding. Then reduced epoxy sealer.

I use dry guide coat for all grits.

Mandatory backyard hack disclaimer inserted here….

Don
Click to expand...
Does the dry guide coat sand out better than the spray can stuff?
 
Aaronj said:
Just want to run my process by you guys to see if it makes sense and ask a few related questions.

Process:

Ive spray epoxy followed by 2k. 2k is sanded with 180 then 220 using guide coat.

Im planning on spraying one more coat of 2k to fill the 220 scratches and cover some exposed epoxy.

This final coat of 2k ill sand with 600 before applying reduced epoxy sealer>base>clear.

Questions:

Is it a good idea to used guide coat with 600 grit or is it a waste of time?

Would you go straight to 600 on the final 2k sand or step up from a lower grit?

If i have sanding scratches that show on the finished paint job (black) does wet sanding and buffing the clear remove them or are they still visible below the clear surface?

Thanks!
Click to expand...
My opinion—guide coat on anything over 400 is a waste and it’s easy to see what you’ve sanded and what you haven’t. You’re not blocking at that grit.

If I’m doing a coat of sealer afterwards then I do 400 wet. Straight to 400.

Sand scratches—I find the clear to be pretty forgiving and you can bury a lot with it.
 
I realize the OP is painting a solid color but it’s worth stating here that sand scratches with a metallic base are going to show no how hard you try to bury them in clear…
 
I guess im trying to understand better how the scratches show. Is it unevenness in the top of the clear or can you see them through the clear in the base?
 
Lizer said:
My opinion—guide coat on anything over 400 is a waste and it’s easy to see what you’ve sanded and what you haven’t. You’re not blocking at that grit.

If I’m doing a coat of sealer afterwards then I do 400 wet. Straight to 400.

Sand scratches—I find the clear to be pretty forgiving and you can bury a lot with it.
Click to expand...
I have to disagree here Lizer.

When doing a final wet sand with 600, I found a couple of small areas where fine scratches were still present and needed to be gone over again.

This lead me to start using guide coat when cutting and buffing clear as well. This hood was completely wet sanded with 1000 grit. I applied guide coat before wet sanding with 1500 and to my surprise found some spots that needed attention. (the top one is from a smudge on the camera)
Hood P1500 with Guide coat.JPG


The dry guide coat is very inexpensive and being such a fine powder it gets into the smallest of scratches.
 
Aaronj said:
I guess im trying to understand better how the scratches show. Is it unevenness in the top of the clear or can you see them through the clear in the base?
Click to expand...
It’s because of the way the metallics orient on the scratch. As I said you are painting a solid color so not as much of a concern. But don’t assume you have license to leave deep scratches….

Don
 
You really have to work the dry guide coat onto the surface so it gets into every little scratch.Also need good eyes to see them.
 
Thanks everyone for the help. There is very minor body work to do on this car. I did all my blocking with 180 then went over that with 220. I figure one more coat of 2k over that should hide all those scratches. Ill probably start with 400 then move to 600 for my final sand. Basically just sanding out any orange peel there might be in the final coat of 2k.
 
'68 Coronet R/T said:
I have to disagree here Lizer.

When doing a final wet sand with 600, I found a couple of small areas where fine scratches were still present and needed to be gone over again.

This lead me to start using guide coat when cutting and buffing clear as well. This hood was completely wet sanded with 1000 grit. I applied guide coat before wet sanding with 1500 and to my surprise found some spots that needed attention. (the top one is from a smudge on the camera)
View attachment 32005

The dry guide coat is very inexpensive and being such a fine powder it gets into the smallest of scratches.
Click to expand...
Are you using a dry guide coat? That could be the difference as I just use cheap black spray paint and it might not be doing a sufficient enough job for this type of sanding.


Though for wet sanding, the method I use and find to be very effective is I'll squeegee the water off the panel so it's just damp on the surface, but there is still deeper 'shinier' water left behind in any scratches. I look at the panel at an angle and it really makes every scratch stand out. For some reason doing this in lower light makes the scratches stand out more too.
 
solid colors its totally unnecessary to go to 600g. i have done solids especially dark ones like black in as coarse as 220 grit. you cannot see the scratches after clear. finishing your primer in 320-400 is perfectly acceptable. metallics are another story. 600g for those
 
Jim C said:
solid colors its totally unnecessary to go to 600g. i have done solids especially dark ones like black in as coarse as 220 grit. you cannot see the scratches after clear. finishing your primer in 320-400 is perfectly acceptable. metallics are another story. 600g for those
Click to expand...
Thanks Jim. Thats good to know. I don't have much experience to back my decision making here. Ive just asked around and i get a mix of answers from what you said to guys saying that you need to go to 600 even on solids. I figured i would just error on the high side.
 
You must log in or register to reply here.
Back
Top