Revealing sand scratches? (and other stuff)


New Member
Howdy, first time poster here.
I'm in the middle of repainting the hood on my '69 GTO (long story, had an engine fire years ago that bubbled the paint and just now getting around to redoing it).

I painted the whole car myself about 10 years ago and it turned out really well, considering that it was my first ever paint job and I chose black (duh). I used all SPI materials then too.

Anyway, back to the current question: I got the damage repaired, blocked nice and flat, sanded it to 600, sealed with SPI Epoxy reduced 25%. It looked "mostly good" except for a couple places where I got the sealer on too heavy/moved to slow and got some orange peel. I let it sit over night (actually a couple days), and sanded those spots out with 600. It looked good to me, but when I started applying color I started to see some fine sanding scratches showing up that either I just missed or just couldn't see in the sealer (I'm 67). They were still visible after 3 coats of color so I decided it was time to stop, drop back and deal with them before going any farther and digging myself any deeper.

My current plan, unless someone can tell me this is a bad idea, is to go over the whole thing again with 600, then 1000, then go back to applying base coat. Sound ok?

Another alternative I guess would be to apply another coat of sealer and not sand it this time, instead start shooting base after the 6 hours recommended in 'perfect paint job'. I'm not sure if it's "ok" to shoot sealer over whatever base is left after I sand it. So that's another question I have.

I'd also like to know if there are any tricks I can use to see and make sure I've got all those tiny scratches out before I start spraying base again. They're really hard to see until I get color on it, and then of course it's too late.

Thanks in advance,


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Promoted Users
Your car is neat & while I could give my opinion after painting my car, but I'll leave that to the the very capable pros that give way better advise than me. I just had to say the P-51 looks great!


New Member
Thanks for the replies, and the kind words. I did go ahead with sanding the base and shot 5 coats of clear over that. It looks fine. I did get some nibs of course, and two spots where my gun leaked and created a 'blob' because apparently I didn't get the cup lid on tight enough, but I know how to deal with all that with the 'razor blade plane' trick. The attached photo shows how it looks right now, before dealing with those problems and before color sanding, cutting, buffing, etc.

I've got some ideas for building a 'convertible' booth in my shop that I'd like to run by folks. My plan is to copy more or less what these guys did for the walls:

...and make some sort of permanent ceiling to close off the top.

But for the air handling, I was thinking of doing this:
  • Run lengths of PVC "sewer pipe" along the top and inside of both side walls, with 3" holes in the side along their full length.
  • Create an input manifold/plenum at one end for input air.
  • Connect the input manifold/plenum to an air source - a "big enough" fan blowing through replaceable filters.
  • For exhaust, run more lengths of similarly perforated PVC pipe running along the bottoms sides of the walls and extending out underneath the overhead door of my shop bay. (I live way out in the country on 13+ acres, so I don't have to worry about the exhausted air bothering the neighbors, but I could also build some sort of filtered plenum for them to "empty" into. )
I'm thinking that might make a decent "more or less" downdraft booth? What I don't know at this point is if my idea for using the perforated PVC sewer pipe will be capable of moving enough air volume without creating a hurricane inside the booth. The enclosed volume will be approximately 22 feet long, 12 feet wide, 8 feet high for a total of about 2,112 ft.^3
The "input" PVC would be permanently mounted as would the air source and plenum (I've got a good spot "up high" on a nearby wall to mount the fan, filters, and plenum). The exhausts would be removable. Setting it up for use would be a simple matter of putting plastic sheet on the floor, dropping the walls (still thinking about how to close up the corners, but I've got some ideas) , setting up the exhausts, and turning on the air system. It'd all be up and out of the way when not being used.

I'd love to hear opinions, especially if you think the air system would work or not. It seems like the air velocity coming out of the holes in the pipes would be higher near the source and lowest at the 'other end' of the input PVC so I'm concerned about it making too much 'wind' inside.



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