Found an interesting post with a concept I actually tried out. While I have shop heat I’ve always painted in warmer weather (due to venting as well as curing). So, I find this guy who said never (? maybe not “never”) use faster reducers. His reasoning:
Dries on the surface and holds reducers against your body work and underlayments which causes trouble. He claims only the surface dries faster - or more correctly at the correct rate. Now these days most guys are talking clear coats, and putting clear on pretty thick. Anyway, used the slower thinner at a 66 degree F shop temp. No problem. No runs and cure rate seems fine. The guy with the post seemed rational and sensible and his points seemed to work out. Your results… etc, etc.
I agree, faster thinners are for production shops. Personally I get a better gloss with slower thinners. But painting the car will take longer, but I am a hobbyist and don’t care it takes longer. I shoot mostly single stage on my collector cars. I have painted about 1 car every 2 years for the last 40 years. Here was my last paint job.
5 Likes
Beautiful job. How did you get that windscreen so darned clean? 
Phillip
2 Likes
I hope there’s an XK engine in there to qualify as Jag content 
On the opposite end of the spectrum I just used an HVLP turbine system to do a garage respray of my old pickup. Those things throw out very warm dry air, and when it started warming up here in Texas, I had to go to the slowest available reducer just to keep the paint from kicking off in the waiting gun while I mixed another batch of paint. Anyway, slow reducer works for me.
Hot rod satin black…a real bugger to get right, and virtually impossible to spot repair if you have a run. I had to repaint one of the doors for this reason.
Regardless of what you get anecdotally, follow manufacturers’ directions. They know their products best.
2 Likes
I’ve almost always used medium reducer and don’t shoot unless conditions are right. Prefer mild, windy days. Like Bill my default is single stage, mostly because it’s the only way I know how to pull off a show finish in a home workshop as the inevitable bit of dust that settles onto the paint while it’s setting up gets sanded off along with any orange peel before polishing to a high shine. Unlike Bill, the days of doing a paint job every couple of years are behind me. My previous major paint job was five years ago and I’m a couple weeks away from beginning paint prep on my current, which will be my final, total restoration.
2 Likes
I shoot DuPont or Glasurit. I do my metal work in the summer when it’s warm and dry. Each time I’m ready to shoot, it’s cooling off herr in the NW. DuPont series of reducers are very versatile, and can be mixed to fine tune to temperature.
If I shot a slow reducer at 66 degrees, most of my clear would be hanging from the bottom of my car.
I like medium, but I’ll shoot it hotter, and lay it on fat like glass.
Any of you use body schutz in your wheelwells and underside? I used this stuff on my E and it’s holding up really well. Paintable.
It’s available only in the “no-cleanup” format that requires the 3M special gun and nozzles but I used it with my cheap shutz siphon gun and it went on well.
Yes, agreed. I do follow the “use the same product line” (despite the crazy cost of ppg) and read all the sheets carefully. All guns, temperatures, humidity and ratio of reducer can vary slightly or even greatly. Individual experimentation can fine tune a job. What I did wasn’t far off the ppg advice - I really just went one type above what they would advise.
In the past ppg had one “slow” reducer - the one I still use. They now (apparently) have 2 more even slower and maybe 3 faster. I’d guess if I used their absolute slowest the paint would have run at 66 F. Based on their data sheets they use 70 F as the mean and standard temp. they base most dry times, etc.
With ppg you can also mix reducers, but this contradicts with sensible advice not to ‘go off the reservation’ .
The 3M gun doesn’t fit UPol. I saved my 3M can and transferred the product. The 3M shutz was dried out in the can, despite coming from the local high end ppg store! They took it back, of course, but it makes me think the packaging may not be ideal or something very critical about the shelf life. I’m very happy with 3M - a real ‘fan boy’, but did go with the Upol on the shutz. There were so many 3 M options sometimes they scare me away with confusion.
Used it, 30 years ago, with a docket gun… worked well.
What he said! 
…
Generally, the best, glossiest finish is shot just shy of runs.
Easy on horizontal panels, not so much on the verticals.
Also, lots of “uplight:” I fabbed up covered neon fixtures, mounted around the car, at floor level, mounted on rhe booth’s walls.
Id spray the covers with Pam, a day before shooting (made it easier to clean off overspray), ensure the floor was wet, and ran a chain over a suspension part, making sure it was lying on the wet floor.
1 Like
To be fair, so much of this depends on how fast you run your gun, how high you turn out the volume, hand speed, car temp, and material temp. I learned to put my materials in a large bucket of very hot water for a couple hours, and also to roast the shop and car for a couple hours before turning off the heat and shooting. I can lay it on a lot fatter this way, and use a slower reducer than air temp would otherwise allow.
2 Likes
I knew my post would elicit many opinions on painting in general, all useful. Most posts bring out interesting experience and methods. I just wanted to put a bug in peoples minds about reducer selection. The manufacturers and experienced guys have their methods - just thought a little review of our old ideas is helpful at times.
One major issue I hinted at, but didn’t emphasize, is I’m using single stage to color urethane. Clear isn’t the same. which is what most guys use now. For instance, a run with single stage is a worse issue than with clear. Some high end shops put so much clear on it’s scary. With some single stage colors sanding a run will slightly change the color, in addition to being harder to do in practice vis vis clear.
I’ll almost never again use single stage. Did some panel repair on our old '62 TBird with base/clear and it was a breeze compared to trying that with single stage. Moving on to the new ways (still shaky on my smart phone…).
1 Like
I haven’t had an issue with PPG Concept single stage with achieving invisible spot repairs.
Great thread, btw. 
1 Like
Windex makes it disappear
How did you spray this under the wheel well without it coming out the top of the fender through the gap where the chrome bead trim goes?