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Painting with Polyurethane?

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Old 10-04-2006 | 12:46 PM
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Painting with Polyurethane?

Going to paint the truck this weekend. Cant stand to look a the peeling paint any longer. I have been doing body work for the last two weeks as I can get to it so hopefully it comes out looking good. I had a truck painted before with the same brand and color paint I am using this weekend and it orange peeled real bad. I am wondering if the seven coats we put on were too much or if that last coat was just too heavy? Talked to a budy/fellow painter, he said we should only use two coats but that seems really light to me. I know poly is alot more durable than base/clear or acrylic enamel, but is two coats enough? I want this to look good, but I know that once this poly is on, you cant color sand it without applying a clear coat (which I am trying to avoid). Any thoughts from you DIY painters? Thanks.
Old 10-04-2006 | 01:05 PM
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A friend of mine painted my CJ-7 (look at my picts). We used a poly. I painted all the parts 2 coats before assembly. Then another 2 coats after assembly. It all depends on the color of paint to howmany coats u use. Yellow is hard to paint, doesn't cover very well. We had orange peal also, but it came out when we wetsanded. I waited a couple weeks before wet sanding the paint. Came out great.
Old 10-04-2006 | 01:08 PM
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I tried wet sanding a small area of the other truck that was painted and then tried to buff it out to regain the gloss but it wouldnt come back. Im trying to avoid wet sanding and then having to buff out the whole truck because I am afraid it will require a clear coat to get the shine back into it.
Old 10-04-2006 | 01:14 PM
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Regardless of how the paint finishes, it will look better than the blue dandruff that my truck has now. Even with some orange peel, it will look ok from a distance. Im not looking for a show car paint job by any means, just dont wnat to see any more paint peeling or rust spots. I do however want to do the best job possible. DISLSMOKE, did you do anything special to bring the shine back into the paint after wet sanding?
Old 10-04-2006 | 02:31 PM
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Orange peel is caused from the paint drying too fast. If you use a slower reducer to slow the drying time it will give the paint a chance to flow out better.
We find the most important part of a paint job being the prep prior to painting .Often using 2-3 or even 4 coats of primer, sanding between each coat. Seldom ever use more than one tack coat and one wet coat of paint. It does vary however based on the quality of paint you use. Cheaper paints normally do not have the "body" a top quality paint does so cheaper paints could take more coats to cover.
We have our best luck with PPG paints.
Old 10-04-2006 | 03:21 PM
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herb: Seldom ever use more than one tack coat and one wet coat of paint
I dont mean to sound like a rookie, even though I am, but what I paint is aircraft. There is not a large amount of concern with cosmetics when painting airplanes as the purpose is solely corrosion control. Can you specify what you mean here? (the above quote) The poly white we normally use tends to cover well, just likes to orange peel. The brand is Deft, not sure what other kind of reducer I could use that is compatible. If there is no option but to use the kit as it is supplied, what other methods can I use to ensure the paint will flow out better? If I use less part B will that be sufficient to slow drying time or will it not allow the paint to cure properly at all?
Old 10-05-2006 | 05:16 AM
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From: Huffman, Tx.
Make sure you wipe the truck down with 3M Prep Sol before shooting any paint. I removes any residual silicone which imbeds itself into the metal pores (old wax jobs).

Don't ask me how I learned this invaluable tidbit of info.

Good luck and happy shooting!!

Gary
Old 10-05-2006 | 06:56 AM
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I intended on using toluene (sp?), supposedly a good grease residue/wax remover. Im priming tomorrow and shooting color on Saturday.
Old 10-05-2006 | 11:51 AM
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From: Hoosier
Originally Posted by scuzman00
Make sure you wipe the truck down with 3M Prep Sol before shooting any paint. I removes any residual silicone which imbeds itself into the metal pores (old wax jobs).
Add a "Fish Eye" preventer also will help with this. Get a slower reducer to prevent the orange peel. Two coats only. Should be a good looking job.
Old 10-05-2006 | 12:41 PM
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Originally Posted by Txwelder
DISLSMOKE, did you do anything special to bring the shine back into the paint after wet sanding?
All I did was bought 1 gallon of super suds (go to the paint store and ask for it) It's just a lubricant when you wetsand. Mix it up with water and use 800-1200 grit sand paper and a block. Lightly dull the paint (DON'T press hard). After wet sanding, I took a buffer and a good rubbing compound over the paint, to get the majority, then buff it by hand using the compound. Then wax, and buff the dullness out. Try it on the roof first. VERY TIME CONSUMING JOB. Check with the paint store before adding Smootie or fish eye remover to the poly. I wasted a gallon of yellow ($200) by mixing smoothie in with it.
Old 10-05-2006 | 03:09 PM
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Buy some Smoothy. It gomes in a small bottle with a eye dropper.

It lets the paint flow out/melt and prevents fish eye and orange peel
Old 10-06-2006 | 07:22 AM
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Im going to follow DISLSMOKE and not use the smoothie. Im mixing per the manufacturers instructions and hoping for the best. Im sure it will turn out fine once I get it all done. Im spraying primer this afternoon and hopefully color tomorrow. Thanks
Old 10-06-2006 | 06:33 PM
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Well orange peel is actually caused in part by a few factors, the least of which is drying time, the second is paint to thinner ratio, and the primary bad boy reason is air pressure. If air pressure is to low it basicly spatters onto the surface, Now that being said, all other factors need to be in line, its kinda a delicate dance.

Best way to do it if you have a shop, use a fan to pull overspry out, i use a old door with a fan mounted in it. But plastic or anything will work. Second is read the can, medium thinner is like from 75-90 degrees, As a rule of thumb the longer the paint stays wet, the better the job. If you start on the hood and go around the truck the paint needs to still be wet on hood when you get back to it, if not it will show.

If the paint says 4 parts to one, use that, its formulated to produce at that mix. The best check on viscocity is after stirring completly pull stick out, if you can't hear the paint drip its to thick. The reason i put viscocity check is, modern guns dont do well with thicker paints unless you crank air up and that causes other probs.

The poster that said two coats only, basicly meant, the first coat is for color, the second coat commonly thinned a bit more is put on as wet as possible, this makes for a nice shiney job. If your using a base/clear coat paint the paint plays no role in shine, its all the clear coats job to make it shine.

I use 3 coats paint and two of clear, anything over 5 ( unless its laquer ) is a waste of paint and the job wont look any better if as good. Last thing i can add is use clean stir sticks and a paint filter, change both often, and keep the gun moving at constant speed and at a constant distance from the surface.
Old 10-06-2006 | 08:17 PM
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Originally Posted by loch
Well orange peel is actually caused in part by a few factors, the least of which is drying time, the second is paint to thinner ratio, and the primary bad boy reason is air pressure. If air pressure is to low it basicly spatters onto the surface, Now that being said, all other factors need to be in line, its kinda a delicate dance.

Best way to do it if you have a shop, use a fan to pull overspry out, i use a old door with a fan mounted in it. But plastic or anything will work. Second is read the can, medium thinner is like from 75-90 degrees, As a rule of thumb the longer the paint stays wet, the better the job. If you start on the hood and go around the truck the paint needs to still be wet on hood when you get back to it, if not it will show.

If the paint says 4 parts to one, use that, its formulated to produce at that mix. The best check on viscocity is after stirring completly pull stick out, if you can't hear the paint drip its to thick. The reason i put viscocity check is, modern guns dont do well with thicker paints unless you crank air up and that causes other probs.

The poster that said two coats only, basicly meant, the first coat is for color, the second coat commonly thinned a bit more is put on as wet as possible, this makes for a nice shiney job. If your using a base/clear coat paint the paint plays no role in shine, its all the clear coats job to make it shine.

I use 3 coats paint and two of clear, anything over 5 ( unless its laquer ) is a waste of paint and the job wont look any better if as good. Last thing i can add is use clean stir sticks and a paint filter, change both often, and keep the gun moving at constant speed and at a constant distance from the surface.
I second this. I was thinking that you must have either had the paint too thick or not enough pressure to properly atomize the paint.
Old 10-07-2006 | 12:43 PM
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All you really needs is to shake a few minutes then apply an even coat:




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