Help. I mixed and sprayed PPG DBU wrong

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danford1

I know this is an SPI forum. I use SPI products. A customer wanted me to repair a fender. It was painted with PPG DBU so that is what I'm using. The mix is 1 paint to 1 1/2 reducer. I had a brain fart and mixed 4oz paint and 2oz reducer and sprayed it on. It seemed thick when spraying but I didn't think much about it and just opened up the flow more.
Now I'm done and realized my blunder.
What does this mean? Is the paint just going to require longer to dry before clear coat or am I screwed?
It has been an hour. I haven't looked at it yet...

Danford1
 
Your fine, just let it set maybe over night, if you can before you clear. If you have an infrared, another choice is set lamp 3.5 feet away for 20 minutes and then when cool clear.
 
A foot-note to make you feel better, the reps are actually recommending on some colors not to reduce at all for either metallic control or for coverage of certain colors.
 
Barry;40107 said:
A foot-note to make you feel better, the reps are actually recommending on some colors not to reduce at all for either metallic control or for coverage of certain colors.
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Thanks Barry.
I can wait till tomorrow. I just looked at it and it seems fine. It looks shiny for base coat though.
I want to sand down the blend edge as it appears rough or dry sprayed...
I'll lightly sand the fresh base also then clear. I have SPI universal clear and some PPG DC3000 clear.
I was going to use the DC3000 as I only have 1/2 qt left.
I know the SPI is an excellent clear I'm just worried it would out shine the rest of the truck :)
More than likely the truck has PPG clear on it. It looks thin, wouldn't SPI look thicker if I used it? I'm clearing a fender for a 66 Chevy pick up, and wonder what it would look like when the fender is mounted to the truck and butted up against the door and hood.
Oh, this is a solid red color, no metallic or pearl...

Thanks
Danford1
 
Don't sand before clear. If you got dry spray, the reducer was too fast. If you sand, you have to put another coat or two over the sanding marks.
 
A lot of the higher end bases now dry with a slight gloss, its called "resin rich" and the question I get all the time, will it hurt adhesion, no usually does the opposite.
 
Truly wish I could just follow you around for a few weeks and pick your brain Barry. I love the technical information you share.
 
crashtech;40148 said:
Don't sand before clear. If you got dry spray, the reducer was too fast. If you sand, you have to put another coat or two over the sanding marks.
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I'm not trying to argue, I want to learn.
Why can't I wet sand with 1000 grit before clearing?
No matter how I blend it I'll have a roughish "over spray" area. I would think that roughish area would show through the clear before the 1000 grit scratches would.
What about a scotch brite instead of wet sanding?
This is a solid red color. It doesn't have any metallic particles in it.

I used Mid temp reducer but the garage temp was only about 60 degrees.

Thanks
Danford1
 
danford1;40155 said:
I'm not trying to argue, I want to learn.
Why can't I wet sand with 1000 grit before clearing?
No matter how I blend it I'll have a roughish "over spray" area. I would think that roughish area would show through the clear before the 1000 grit scratches would.
What about a scotch brite instead of wet sanding?
This is a solid red color. It doesn't have any metallic particles in it.

I used Mid temp reducer but the garage temp was only about 60 degrees.

Thanks
Danford1
Click to expand...

Clearing over pigments that have been disturbed by sanding is almost always a bad idea. On a solid you might get away with it, but it's not a sure bet. Tell you what, why don't you do a test panel and sand half before clearing to see how it looks. I would suggest doing this with every one that you want to sand before clearing. Eventually you will see one where there is a difference. If you don't like dry spray on blends, you need to do something called "wet bedding," where after you get 75% or so coverage on your repair, then use two spray guns, one to apply a medium coat of transparent basecoat to the blend area, then use your basecoat gun to finish covering the repair area and fan out your blend into the wet transparent "bed."
 
Also, from what I've read the finest you would want to clear over is 800 grit scratches, with most people recommending 600-800.
 
mitch_04;40178 said:
Also, from what I've read the finest you would want to clear over is 800 grit scratches, with most people recommending 600-800.
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Well, I wet sanded and cleared it yesterday, before I could read the replies here. I used 1000 grit wet and then cleared. The part looks great. I can't tell where the blend was but I'm only looking under flouresent lights. I'll have to look at it in the day light to see. The problem is today is overcast, no sun...

What is a transparent base coat? Is that a special product? I haven't heard of it...
I've heard of spraying straight reducer over the blend area before.

I'm heading out to wet sand the clear with 2000. I'll let that cure for a day them buff it up.

Danford1
 
danford1;40179 said:
What is a transparent base coat? Is that a special product? I haven't heard of it...
Click to expand...
I think they are referring to SPI Intercoat / Color Blender Clear, Product Number 2020-1.
 
I have heard of SPI Intercoat being used, but my recommendation for wet-bedding, since it involves wet-on-wet intermingling of the products, is to use the transparent basecoat that exactly matches the basecoat being used for the job. For DBU the product is DBU500. This can also be used to "lock down" the pigments and if sprayed over the color can generally be scuffed a bit with no risk of disturbing pigments.
 
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