[oldguy829]

This week my 15 year old painted the hood on my 41 Pontiac. [Its a driver not a show car. The original paint is poor but the hood was a mess, so we decided to redo it for now and put off a full blown resoration till later. It also seemed like a good practice run for painting his car in a few months]
The body work, primer went well and the base coat looked great. [Dupont BC/CC ] It was 101 degrees outside and nearly that in the shop. When he sprayed the clear coat he had a bit of trouble. Seemed to be drying in the air and looked a little like it would orange peel, so he adjusted some and started laying down a nice smooth wet coat. Then it started sagging.
1. should we have tried to do something when the paint was wet? [we didn't]
2. Some of the sags sanded out this morning and I could probably polish it out, but we broke through to the BC in a couple of small areas, so I think we will reshoot the entire hood. Should I just wetsand the entire hood with 500 grit and shoot it?
3. Any tips to avoid a repeat? If he had continued as he started (a little dry, a little orange peel) would that have been better and just sand/polish it out?
4. This morning there appears to be splotching in the BC. It has some metallic in it and kind of looks like the metallic "bunched up" in places. Did not look like that before the CC. Can the CC cause the mettalic to move, or was this an error in application. Again, how do you prevent it.
I don't expect this to come out perfect (wouldn't go with the rest of the paint job if it did) but we would like to learn from this. Any help is appreciated.

[kenseth17]

I know the feeling, I painted in really hot temps recently, not quite that hot, but close inside my garage which is always hotter.
To answer your questions here are my opinions
1] No not neccessarily. Sometimes you can take a piece of two inch masking tape and make it into a circle and gently roll the sticky side on the run and pull excess clear off. Then shoot another coat of clear when it has time to set up a bit. If you are successfull, it may only need very little blocksanding to get rid of. You can also make more of a mess and end up being worst off if you are not carefull. Barry K posted a trick he saw awhile back where guys were using a pinstriping brush dipped in thinner and pulling the run off. A few of us, even though we all know none of us ever gets a run, will continue dumping clear more clear on the run if it is near the bottom and run it right off the panel, wipe the icecycles of clear hanging off the bottom. Again you can end up with more of a mess doing this. If the run is small, I will normally just leave it be and try to add more clear for blocking it out after its painted. I learned its often best just to walk away and leave it be. If you got a huge arse hanger or curtains and it leaves a bunch of drips with a big drop of clear at the end of each one, then i guess you don't have a lot to lose messing with it during cleacoat application, at least knocking down the big drips and balls. When you have a big one that leaves a bunch of tiny trails of drips they can be the toughest to sand out and not cut through or see a ghost of it.
2) I'd use 800 except where it needs courser, like getting out the run, or unless it warrents using 500 due to some pretty bad orange peel. You could chance cutting through in several places to base if you don't have enough clear on, meaning more base is needed, unless you planned on rebasing the whole thing again anyways. I woud rather have a small run or two and orange peel free then it too dry and full of orange peel. Small dry areas seem to buff okay, but if its pretty dry, even after buffing it can still look a little dry looking, just not the mirror finish we strive for.
3) I am taking it he doesn't have a lot of gun experience, but good gun control and ability to adjust will come with more practice. I like to spray my first coat of clear on not overly wet. Everyone has different ways of painting. I feel the first coat medium wet has less chance of moving metallic in the base and gives then following coats of clear something better to stick to. Just about everyone gets a few runs now and then. Lots of light with no shadows helps to read how the clear is flowing. Thats something I don't have at home I really need. Allow enough flash time between coats but short enough that the next coat of clear will flow out easily over the other one. They generally say when you touch a piece of you masking paper near where a panel is, when it feels tacky but not wet
4) Yes, see prior answer about painting first coat medium wet. Leave plenty of time between base and clear, since unless you are a production shop, shouldn't be in a big rush. Better lines of base dry quicker then cheaper lines, and if the base is activated it will help somewhat with that. Many people add a capfull of their clear activator to a quart of mixed clear if their base isn't activated.
Hmm, I don't claim to be an expert by any means, but I've had enough experience with runs. I use to have a real problem when painting white. Run it just about every time.

[302 Z28]

When the clear is going on smooth it is very easy to apply too much, especially for a novice....ask me how I know this . You make a pass and then see what looks like a dry spot and you hit it again....run. Leave that dry spot and cover it on the next coat. It is far better to build up multiple coats, upwards of four to achieve sufficient thickness rather than hog it on in one or two coats.

Vince

[student blake]

i always sag when i get to close... oops

[fiddy-two]

Thin down the clear. Here in Oklahoma, we commonly paint in 105+ temperatures, and the best way I've found to counter the heat is reduction. Prior to clear, make sure you guys are letting the basecoat flash, and widen the pattern with about 20% more reducer, also. Too little reducer will skin over the base, trapping in the solvent that causes mottling later. The slow reducers used in high temps need a little more time to evaporate the tail solvents. When you clear, use a reducer in the clear to thin it down enough so that you aren't having to pour on the clear to produce smoothness of finish, since thicker globs of clear will require a heavier application to get rid of the peel. Also, less pressure is required to spray. You may need an extra coat to get a good build, but it's better than a re-doo. Also, if you get a run, don't be scared to break out the rough paper. When I get a run, I'll take a sharpie and scribble over the run. Then take a 6" foam waffle block (stick-it) with some 400 grit to knock off the high spots. Take it slow, and don't sand like it's primer or something. Use your fingers to hold the block slightly off the surface, letting the waffled surface of the pad cut off the peaks of the run. Work with progressively finer paper until the sharpie marks are removed. It takes some practice, but if you ain't gettin' runs, you ain't tryin hard enough!

[colormecrazy]

Sounds like a few things to me. The heat probably had some to do with it. But most of it sounds like we need a little practice. As for the sags, that's Ok don't worry. Pay close attention to the distance away from the panel. Remember, distance, pressure, overlap, and speed. Stay consistent. As for the modeling (bunching metallics), try what's called an orientation coat. On the last coat of base (after you've got full coverage), try turning the pressure down about 10 lbs. holding the gun at about a 45 degree angle, back off the panel a few more inches, start at the middle from either side and lay an almost wet coat. Go for a kind of even satin look. I know this sounds crazy but I do it almost every day. Once you get the hang of it and dial in it's a sure fire way to lay even metallics. Granted maybe not the first time. But modeling rarely shows before you clear, so it's tuff sometimes to get it just right. Good Luck!!
Warning!! more reducer may not be advisable! It's hot in Texas too, and I don't over reduce.
ps Please encourage your 15 year old to use his head and stay in school!
The glamorous life of a painter ain't what it's cracked up to be!

[fiddy-two]

Colormecrazy, I'd like to know what paint you are using, since we have changed to DuPont after trouble-free years of PPG. It's been quite an adjutment, to say the least! This is simply how Iv'e adjusted.

[302 Z28]

A few weeks ago I toured the Corvette factory in Bowling Green. The tour guide made a point of telling us they use DuPont paint. You should have seen the orange peal on those brand new Vette panels and bodies, it was atrocious. At the end of our tour we were asked to evaluate the tour. I thought it was outstanding and I let them know, but I also let them know about the orange peal. The tour guide acted like it wasn't the first time she had heard it. She did say that the Vette factory has a new paint manager, so maybe improvements are forthcoming.

Vince

[colormecrazy]

Originally Posted by fiddy-two

Colormecrazy, I'd like to know what paint you are using, since we have changed to DuPont after trouble-free years of PPG. It's been quite an adjutment, to say the least! This is simply how Iv'e adjusted.

Well, currently I'm using PPG. But that's not my choice. I'm a European style painter. If that makes sense to ya. I prefer Sikkens, they had some delam problems in the early 90's, but they have come out with several new clears over the years that have really improved. I definitely do not like Dupont. there base system is for the birds. PPG's clear is inferior in my opinion. I know a lot of guys will say "my car has PPG clear on it and it looks great" but in my opinion it shrinks to tight and tends to loose it's gloss, with out being babied. If you are using Dupont in a shop tell your jobber you'd like to see Spiez Hecker's 8030 clear. That stuff is awesome.

ps Didn't mean to be rood about the over reduction. I just like to stick to the books on mixing. I'm a great painter but, not a chemist.