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72scamptramp 02-07-2013 09:10 AM

Paint Questions
 
I painted my Plymouth a few months back with Single Stage Urethane. It ran pretty good. This is a resto I left it for a bit got tired of body work so i moved on for a bit. I plan to sand it back down. Ive done all the body work on this car but im not an experienced painter. I need to buy more paint and was thinking about going with a Urethane Basecoat system same color. Can i get away with just sanding the car back down and shoot the basecoat? Thanks!

33Willys77 02-07-2013 10:17 AM

You can get away with sanding the single stage and applying just clear or base/clear. BUT, if you sand through the color, you will need to apply primer over that area, otherwise, you risk having the paint lift.

72scamptramp 02-07-2013 10:27 AM

I had actually wanted to sand it all off back down to the primer. I was thinking of going with 400 to get the paint off then wet with 600 and paint.

jcclark 02-07-2013 02:49 PM

The less paint you paint over, the better.
You don't want to much film thickness

33Willys77 02-07-2013 07:11 PM

Sanding it all off with 400 will take 'forever'. Plus, it would be very hard to keep the bodywork straight doing that too. How many coats of paint are on it now? 3-4? If so, sanding it would take off a layer, then left with 2-3 - no need to take it all off. Block out the runs, sand it (wet or dry) and spray it with BC/CC. If you sand through, put a little primer on, sand it and then paint it. If the only thing wrong with the actual paint is the runs, why take it all off?

carolinacustoms 02-07-2013 08:46 PM

Why not try to sand out the runs before you plan on repainting the car? I'd rather have a run than a dry spot to fix any day. If you are careful you can prob sand them out and buffing will fix you up:thumbup:

demarques_191 02-08-2013 12:31 AM

make sure the runs are hard from the outside and the inside of the run so when u sand the run down... it wont crumble from still being soft in the underlayer.... you can also use a razor blade to shade it but shave only the run itself.. take your time... then when u get low enough you can take some 1200 sandpaper and flatten it out as well as removing any scratches from the razorblade..

swvalcon 02-08-2013 10:24 AM

I would try to sand out run frist. I start with 600 or 800 rapped on a peice of a paint mixing stick and when run is flat work up to 1500 from there.

69 widetrack 02-08-2013 10:49 AM

Before we start suggesting sanding out the runs and polishing we need to find out if it's a solid color single stage...if it's a metallic color...polishing after you sand out the runs is not possible.

If you prep the existing single stage paint using a block and 400 grit or 600 grit paper is fine...33Willys77 is correct with respect to taking a long time and keeping the car straight...if you don't use a block. If you know how to sand a car by way of properly using a block, the body work will stay straight. Also, if you sand through the SS color, (depending on what's underneath the Single Stage) and you don't spot prime, you could have lamination problems or ringing around the area you broke through...again...depending on what's underneath your single stage.

Hope this helps.

Ray

72scamptramp 02-08-2013 11:06 AM

Quote:

Originally Posted by 69 widetrack (Post 1644026)
Before we start suggesting sanding out the runs and polishing we need to find out if it's a solid color single stage...if it's a metallic color...polishing after you sand out the runs is not possible.

If you prep the existing single stage paint using a block and 400 grit or 600 grit paper is fine...33Willys77 is correct with respect to taking a long time and keeping the car straight...if you don't use a block. If you know how to sand a car by way of properly using a block, the body work will stay straight. Also, if you sand through the SS color, (depending on what's underneath the Single Stage) and you don't spot prime, you could have lamination problems or ringing around the area you broke through...again...depending on what's underneath your single stage.

Hope this helps.

Ray

Color is a solid color no flake. Whats underneith was epoxy primer as bottom layer followed by 2 coats of 2k Urethane high build primer. Filler work done then 3 more coats of 2k Urethane high build primer. Car was then blocked with 400 grit and shot with Single Stage Urethane. I will sand the car down to get runs out then block with 400 or 600 then go to a BC/CC system. After reading and some videos I have decided that it may be for forgiving for a beginner such as myself.

69 widetrack 02-08-2013 12:38 PM

Well you are right about base clear being forgiving...to a certain point...if it was a metallic color, base clear would without a doubt would be the product of choice...if you make a mistake or just want to do a quick de-nib, all you would need to do is let the base coat flash, sand the area that you want to repair and re-base and then clear...runs? Cut and polish them out. With Single Stage metallic's...that can't be done and you never get the same gloss in Single Stage as you would with base clear.

If your Single Stage paint is totally cured and you prep the car fine enough, you should be able to base right over top of the Single Stage, even if you have a few small burn throws. Your primer underneath your Single Stage is catalyzed, your Single Stage is catalyzed so the only way you should have a problem with adhesion or wringing is if it wasn't prepped fine enough (wringing) or the Single Stage wasn't cured (wringing and adhesion)...I'm sure I don't need to say this but...to keep the car straight...always use a block wherever possible when prepping a car for that mirror like finish.

Best of Luck.

Ray

33Willys77 02-08-2013 12:47 PM

Also, if you had issues the the single stage running and you are not at least a somewhat experienced painter, don't think that clearcoat will be easier. There are many times when you can not see your overlap and need to know what your gun is doing - all done with experience. Good luck and I hope it comes out good for you.

72scamptramp 02-08-2013 12:47 PM

Quote:

Originally Posted by 69 widetrack (Post 1644058)
Well you are right about base clear being forgiving...to a certain point...if it was a metallic color, base clear would without a doubt would be the product of choice...if you make a mistake or just want to do a quick de-nib, all you would need to do is let the base coat flash, sand the area that you want to repair and re-base and then clear...runs? Cut and polish them out. With Single Stage metallic's...that can't be done and you never get the same gloss in Single Stage as you would with base clear.

If your Single Stage paint is totally cured and you prep the car fine enough, you should be able to base right over top of the Single Stage, even if you have a few small burn throws. Your primer underneath your Single Stage is catalyzed, your Single Stage is catalyzed so the only way you should have a problem with adhesion or wringing is if it wasn't prepped fine enough (wringing) or the Single Stage wasn't cured (wringing and adhesion)...I'm sure I don't need to say this but...to keep the car straight...always use a block wherever possible when prepping a car for that mirror like finish.

Best of Luck.

Ray


Thanks Ray! I dont discount any info offered up. This is my first paint job. Its been several months since the car was sprayed with SS im sure its cured. The paint supplier also told me I could sand down the SS and go back over with BC/CC system.


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