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Paint Chemistry

B

Bill Blue

Platinum Level Sponsor
Back in June when I ordered my paint, we were having day after of 80 degree morning temperatures, climbing rapidly to the low 90's. So I ordered my paint with "85 and up" reducer and catalysts. Now, ready to paint, can't find a day when it gets significantly above 80. The forecast high temp is 83 on Friday.

Question: Should I paint with temps in the low 80's? I have a two part primer, base coat with a lot of metallic and clear coat. I figure the lower temperatures will extend flow time (increasing chances of runs), recoat time and probably time to final cure. Is that all? Are the changes dramatic? What impact will it have on the metallic pattern?

Getting antsy.
Bill
 
Jeff Scoville

Jeff Scoville

Donation Time
Using a "slow" reducer in any weather is possible and in many ways better.
Trying to use a "fast" reducer in warm weather is painters suicide.
The temps you are dealing with are well within range of not having a problem.
"Shoot to kill!"
Now if it gets down below 60f, you will start to see problems.
 
B

Bill Blue

Platinum Level Sponsor
Thanks Jeff. I already knew about using "cold" reducer in hot weather. Leads to a lot of sanding and a repaint. Am very surprised the "hot" reducer has that much temperature flexiblility. Now all I need is a somewhat low humidity.

Bill
 
sunalp

sunalp

Diamond Level Sponsor
Bill: Depending what type of paint you're using, the humidity factor isn't that much of a problem . I used a single stage urethane that didn't blush or fog even though it rained while I was painting the car! I was really surprised about that and asked the guy I bought the paint from and he concurred with me. Said that was a problem that's getting rarer with new technology paints. Just wait until the waterbased stuff comes around!
Cheers!
Steve
 
B

Bill Blue

Platinum Level Sponsor
sunalp said:
Bill: Depending what type of paint you're using, the humidity factor isn't that much of a problem . I used a single stage urethane that didn't blush or fog even though it rained while I was painting the car! I was really surprised about that and asked the guy I bought the paint from and he concurred with me. Said that was a problem that's getting rarer with new technology paints. Just wait until the waterbased stuff comes around!
Cheers!
Steve
Click to expand...

Now that is good news! I once painted a car with lacquer (about 20 years ago) on a humid morning and the color was unrecognizable. Guess I'll paint tomorrow. I figured that moisture in the air condensing in the paint would be a problem with anything that was not water based.

Bill
 
M

Mod_Squad!

Bronze Level Sponsor
You'll want to be careful that the air from your compressor to your paint gun is dry. Definitely purge the bottom of your compressor before you start. They always have water in them. Also, you can buy little inline dessicant filters that take the moisture out of the compressor air.
Good Luck!
Bryan
:)
 
Mark T

Mark T

Donation Time
Amen to that! I remember spending a whole weekend preparing my '68 Galaxie convertible so that a friend who owned a body shop could paint it for me. The car came out covered in little dimples with a little brown dot in the middle of them. I re-sanded the car and he re-sprayed it with the same results. When we took the paint back to the supplier the first thing he asked was if my buddy had blown the water out of his air tank! You'd think that a guy who sprayed cars for a living would have done that...
Bottom line, buy new paint, re-re-sand car, re-re-spray car and voila... no dimples!
 
C

Chuck Ingram

Donation Time
This is one of the reasons I like my HVLP.The turbine compressor puts out warm dry air.One almost needs to relearn spraying 101 when using this system at the start.Material transfer is like 80/85%.Very little overspray.
On the air I do have the moisture filters but they also need purged regulary as well as the tank.I do use the air quite often as usually a gun is sitting on the bench with a bit of laquer thinner in it.So you can see I can be a tad lazy
 
B

Bill Blue

Platinum Level Sponsor
I think I solved the atomization problem. Ended up thinning to the consistency of water. Went on very rapidly and leveled nicely. A couple of runs were definitely my fault. This is primer, going to have to be more careful with the base and top coat. Seems like I loose my depth of field, everything being the same color, I loose my reference point. Sort of like being in a white out. Getting in a hurry doesn't help at all.

Bill
 
britbeam

britbeam

Donation Time
Mark told us about the water in the air tank. I had a similar problem. I wiped with lac thinner and sprayed and got fish eye. After doing this twice and resanding a close exam of the lac thinner showed moisture in the can. Brand new but had water in it. Skiped the lac thinner and did a dry tack rag ,sprayed, bam beautiful Imron paint job no fish eye. So just another area to consider.
Dwain V6 Krazy
 
B

Bill Blue

Platinum Level Sponsor
Not yet, not even "in the camera". Finished last night at 9:00, this old man's ass was draggin', big time. Took a total of twelve hours with all the setting up I had to do. Maybe will get something on line Wednesday.

Bill
 
britbeam

britbeam

Donation Time
Just had a product update from JEGs on paint. Has anyone tried this?Its called Paint Shop Finish System by Duplicolor. It says paint shop is a ready- to- spray system,so no mixing or reducing is required and with no recoat window,additional coats can be applied anytime. Sold in 1 qt cans.Primer,color & clear. At $19.99 a qt. Sounds almost to good but I would be tempted to try it on a hardtop I need to paint. What do you think?
Dwain V6 Krazy
 
B

Bill Blue

Platinum Level Sponsor
I think the paint the Duplicolor is lacquer. Not the most lasting kind of paint, but as I've said before, these cars don't need the most durable paint, they spend 99% of their remaining life in a garage.

I used the Kirker urethane kit, $230 (including shipping) for everything needed to paint an Alpine. The two part primer was way to thick, had to thin much more than the instructions hinted. The two part color coat was great, applied very nicely using instructions on the can. The two part clear coat, once again, was too thick. Am going to have to sand and recoat with the product thinned about 20%. Might be due to the high temps we had while I applied it, Got a lot of orange peel. But so far, I think the kit is worth the money. If I only knew how to paint.

Bill
 
britbeam

britbeam

Donation Time
Hey Bill you should be praised for doing your own paint and orange peel is made to sand. I know a guy that paints show quality and before he sands , buffs ,polish it sure doesnt look to nice. I wet sanded with 1000 grit,then washed sanded with 1500, them 3m fine cutbuff compound,then 3m fine cut polishing compound, then Mothers carnuba. Shes not perfect but afterall shes driven.
I do think I will spend the $60.00 on the 3qt package of Duplicolor for my hardtop. Now if I could get up off butt and get busy naw still not enough time to finish before the Invasion. This other thing gets in the way called work.
Dwain V6 krazy
 
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