Final grit before sealer

J

jwd

I plan on using reduced epoxy 1:1:1 as a sealer. What grit should I use for the final sanding of the primer before I seal and paint? The reason I ask is when I talked to Barry, I asked a ton of questions I believe he said "#320 to #600, wet or dry" but I could be mistaken. That seems like a very large range and I don't know what the scratch filling ability of the reduced epoxy would be. Any help is greatly appreciated.

Jim
 
Usually guys will sand to 400 for solid colors and 600 for metallics
 
Steves69LS3;21025 said:
Usually guys will sand to 400 for solid colors and 600 for metallics
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Thanks for the reply Steve. I plan on applying the base directly over the sealer. The grits you quoted are typically used for applying base over sanded substrate but what do I use on the primer if I'm going to seal it before the base?

Jim
 
What I stated above. It is recommended to apply your sealer an hour or two later (not sure of the time) go right into base/clear.

the sealer is going to be paper thin so it is going to act like base coat.
 
320 dry, seal it with your reduced epoxy, wait a few hours and shoot your base.
 
Thanks for the reply firebird. I talked to Barry again yesterday and that's exactly what he said to do. The reduced epoxy will fill the 320 scratches. I agree that going to 400 for solid and 600 for metallic is the accepted practice for the final sanding before going directly to base but I would think adding a coat of sealer would change that. For my own piece of mind, on this project, I'm going to 600 before the reduced epoxy. I have an extra trunk lid that I'm going to paint at the same time. I've divided it into 3 sections. One section finished in 320, 400 and 600. That will be my definitive answer on what I need to do on my next project. If I can reduce the time spent sanding, that will be great.

Jim
 
I reduce my epoxy 1:1:1. I dont feel it would fill a 320 scratch.

Maybe the reducing just the 20% would.
 
orangejuiced86;21319 said:
I reduce my epoxy 1:1:1. I dont feel it would fill a 320 scratch.

Maybe the reducing just the 20% would.
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Have you tried 1:1:1 over 320? When I talked to Barry, that's what we were talking about, 1:1:1 (ie: 50%). My test trunk lid will tell the real story. I'll post the results when/if the weather ever warms up in the Pacific Northwest. We're lucky to get up to 65° during the day.

Jim

P.S. Please don't anyone get the idea I'm arguing over right and wrong. Today's products are all new to me and I'm trying to prevent any mistakes by doing the research first. Trial and error is a very expensive way to learn. I haven't painted a car in many years. I used to paint Corvette's in the 70's and early 80's back when Dupont Acrylic Lacquer was $20 a gallon. Anyone remember those days?
 
You only need a thin coat for the sealer, what color is being sprayed?
 
Is there a reason you want to reduce it 50%? I understand you only want a thin layer, but why not reduce it 10-20% like orangejuiced said so it's thicker and then you won't have to worry about it not filling your 320 sand scratches. Then if you really want to be sure your scratches are gone, let your sealer dry over night and wet sand it the next day with 600.
 
82firebird;21336 said:
Is there a reason you want to reduce it 50%? I understand you only want a thin layer, but why not reduce it 10-20% like orangejuiced said so it's thicker and then you won't have to worry about it not filling your 320 sand scratches. Then if you really want to be sure your scratches are gone, let your sealer dry over night and wet sand it the next day with 600.
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I reduce my epoxy 1:1:1 to avoid texture which can cause issues in the base if its a mettalic base.
 
Years ago, I always used a dedicated sealer (Dupont Velvaseal) over 320 and never had a problem. I haven't used SPI epoxy as a sealer but the majority on this forum seem to prefer it reduced 50% so it lays perfectly flat. Many here (including Barry) say to sand to 320, seal it with reduced epoxy and go directly to base. Others say you have to go to 600 before or after the sealer. In your two posts (82firebird) on this thread, you've said to do it both ways. Confusing to say the least. That's why I'll go to 600 before the sealer but I'm experimenting on an extra trunk lid so I'll know the definitive answer.

Jim
 
There are a lot of people on here that spray 1:1:1 epoxy over 320 scratches and then base with solid colors. I just sprayed black 2 days ago this way and it worked great. The epoxy does not seem to fill the scratches all the way and neither does the base but you cant see a thing after just 1 coat of clear. I have to ask about reducing epoxy 50% which some say is equivalant to 1:1:1. I guess it would be 50% of the epoxy itself but 33.3% of the epoxy activator mix. Is that correct?
 
jwd;21348 said:
Years ago, I always used a dedicated sealer (Dupont Velvaseal) over 320 and never had a problem. I haven't used SPI epoxy as a sealer but the majority on this forum seem to prefer it reduced 50% so it lays perfectly flat. Many here (including Barry) say to sand to 320, seal it with reduced epoxy and go directly to base. Others say you have to go to 600 before or after the sealer. In your two posts (82firebird) on this thread, you've said to do it both ways. Confusing to say the least. That's why I'll go to 600 before the sealer but I'm experimenting on an extra trunk lid so I'll know the definitive answer.

Jim
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I sprayed a lot of velvaseal years ago under Centari. I bet Barry's 1K sealer he had was similar. Definately old technology but it sure was easy to lay down flat. With solid colors you won't see any scratches shooting over a 320 final sand but with FINE metalics I have seen them show up after full cure when shooting over 320 so I always take it another step to 600 and never any worries. Coarse metalics are also less critical. If you sand with 320 or 400, apply more guidecoat and sand to 600 the amount of time and effort needed is minimal. How thick the sealer coat of epoxy is applied is mostlikely the determining factor for people having different results-if that makes sense....
 
Thanks for the reply Bob. That makes perfect sense. The paint I'm using has a lot of fine metallics so I plan on going the safe route and sanding to 600.

Jim
 
strum456;21359 said:
There are a lot of people on here that spray 1:1:1 epoxy over 320 scratches and then base with solid colors. I just sprayed black 2 days ago this way and it worked great. The epoxy does not seem to fill the scratches all the way and neither does the base but you cant see a thing after just 1 coat of clear. I have to ask about reducing epoxy 50% which some say is equivalant to 1:1:1. I guess it would be 50% of the epoxy itself but 33.3% of the epoxy activator mix. Is that correct?
Click to expand...

It makes me think of the old saying---is the glass half empty or half full
If you mix 10 oz of epoxy and 10 oz of activator you have 20 oz of mixed product, and to add 50% reducer you would need 10 oz----1:1:1
But looking back on what you have, its 33.3% of each.
 
UPDATE: Boy, am I glad I took the body to #600. Today I sprayed 2 coats of epoxy reduced 20%. My extra trunk lid tells the story. Sand scratches are CLEARLY visible on the #320 and #400 sections. Only the #600 section came out nice. The epoxy laid out great and is very shiny so it shows EVERYTHING. Tomorrow I'll go over everything with #600 wet to get out a very small amount of texture and some dust nibs. Then on to the base. Thanks to all that gave me advice.

Jim
 
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