Painter types..I have a bc/cc question for ya..........

[Root]

We are spraying a friends truck soon and a while back I had talked to the PPG reps at one of the shows.

They told me that one of the ways the higher end shops were getting the really good and flat paint jobs was to spray one coat of clear...medium to heavy, then let it dry, color sand with 400 grit then spray the last 2 coats, colorsand ...buff.

My question is: with temps averages from 85-high 90's and hhumidity around 50%, how long will I have to let it stand after the first coat before colorsanding? How long will it remain green? 24 hours?

This will be Deltron 2000 and the clear will be something compatible...he's unsure what he is going to buy yet.

Thanks in advance.
Root

[purplepickup]

I'm not a professional painter but have painted a couple pretty smooth paintjobs (not the one on my truck :? ).  I thought before I replied I'd check to see what advise you got on the HAMB.  There's not much to add.   The smoother everything is from the primer on up, the smoother the finish will be.  Guide coating everything is good advise.  Like Hatch said, I'd check to see what the recoat window is with whatever clear you use.  If there is any doubt about it I would clear a test panel at the same time you paint the clear the truck.  Then when you're ready to spray the final clear you can put a good wet coat on your test panel to see if it lifts.  

I see Roadstar answered too and since he is a professional painter, whatever advise he gives is probably right on.

I basically replied to put this back to the top to see if we'd get any more tips on getting a flat like glass paintjob.

[1FATGMC]

We are spraying a friends truck soon and a while back I had talked to the PPG reps at one of the shows.

They told me that one of the ways the higher end shops were getting the really good and flat paint jobs was to spray one coat of clear...medium to heavy, then let it dry, color sand with 400 grit then spray the last 2 coats, colorsand ...buff.

My question is: with temps averages from 85-high 90's and hhumidity around 50%, how long will I have to let it stand after the first coat before colorsanding? How long will it remain green? 24 hours?

This will be Deltron 2000 and the clear will be something compatible...he's unsure what he is going to buy yet.

Thanks in advance.
Root

This method does work real well, but I would disagree with them on the "one coat".  I would spray a minimum of 2 and if you aren't a real experienced painter, like me, I would spray 3.

The reason I say this is if while sanding the clear with the 400 you break through any place you will have to touch that area in with base again and re-clear it.  With the 2 to 3 coats you can get more aggressive with the sanding and it will go much faster.  Still be very careful near any edges.

I sand with 400 wet on one of the small "hard" rubber blocks for most of it.  Use water, with a touch of soap in it, while you are sanding.  I get a big sponge and keep filling it and pressing it above where I'm sanding to keep water constantly on the sanding process.

As you sand an area use a squeege and paper towells to take the water off and dry the area so you can see when it is flat, and all orange peel is gone.  As you sand it will get dull with specks of glossy looking paint all over.  That is the bottom of the pits of the orange peel.  Keep sanding until the glossy specs are gone and you are done.

Now remask and paint on more clear.  You will find you have a very flat surface that you might not even need to color sand.

I think the reason this works is when we put the clear on we see the orange peel, but the orange peel is also forming anytime you paint, so the sealer creates some and so does the base.  It just isn't evident until the clear goes on and then the clear adds more orange peel.

Sorry if you didn't need all the additional information.

c ya, Sum

My Paint/Bodywork Info

[1FATGMC]

I'd check to see what the recoat window is with whatever clear you use.  

I don't think the recoat window will be in effect here as you are sanding the surface and now will have a mechanical bite between the old and new clear and not a chemical one.

When I wrecked my truck on one side of the front tilt I repaired that section, sanded the whole front (all the clear) with 400, then shot the base on the repaired section, blended the repaired flames into the old flames and then cleared the whole front.  I also did this later on one back fender and bed side.

Usually when you repair base/clear you just have to re-clear that whole panel, so you are clearing over some new base in the repaird area and old clear for the rest of the panel.

Now I'm not a professional painter so I would follow the recommendations of the paint manufacture if you have any doubts.  I used Dupont clear for the above.

c ya, Sum

[purplepickup]

I'd check to see what the recoat window is with whatever clear you use.  

I don't think the recoat window will be in effect here as you are sanding the surface and now will have a mechanical bite between the old and new clear and not a chemical one...

You're probably right.  My experience is pretty limited and paints are getting more sophisticated all the time.  Much of my experience is before catalyzed paints.  I don't know why, but even with catalyzed paints I had one job wrinkle in a spot when I sprayed a wet final coat over a freshly(one day) painted and sanded surface below.  I've also noticed that if coats are too thick and/or too soon recoated, I get solvent pop.  That doesn't really pertain to what Root asked about tho.  It wouldn't have happened if I'd have known what I was doing and wasn't so impatient.    

One other thing I've experienced is that, even tho 2 part primers and paints aren't supposed to shrink, they do....especially if all the coats were piled on in a short period of time.  For that reason if I was going for a perfectly flat paintjob, I would let the first coats cure for quite a while before wet sanding and recoating.

With all that said, I'm going to hurry back out to the shop and spray a coat of 2K primer on some parts of my truck so I can sand and paint tomorrow.  See what I mean about being impatient ....recoat window?....what's that?  ......gotta be ready to hit the road in 4 days.

[Root]

I'd check to see what the recoat window is with whatever clear you use.  

I don't think the recoat window will be in effect here as you are sanding the surface and now will have a mechanical bite between the old and new clear and not a chemical one...

You're probably right.  My experience is pretty limited and paints are getting more sophisticated all the time.  Much of my experience is before catalyzed paints.  I don't know why, but even with catalyzed paints I had one job wrinkle in a spot when I sprayed a wet final coat over a freshly(one day) painted and sanded surface below.  I've also noticed that if coats are too thick and/or too soon recoated, I get solvent pop.  That doesn't really pertain to what Root asked about tho.  It wouldn't have happened if I'd have known what I was doing and wasn't so impatient.    

One other thing I've experienced is that, even tho 2 part primers and paints aren't supposed to shrink, they do....especially if all the coats were piled on in a short period of time.  For that reason if I was going for a perfectly flat paintjob, I would let the first coats cure for quite a while before wet sanding and recoating.

With all that said, I'm going to hurry back out to the shop and spray a coat of 2K primer on some parts of my truck so I can sand and paint tomorrow.  See what I mean about being impatient ....recoat window?....what's that?  ......gotta be ready to hit the road in 4 days.

Thanks for the info. I am closely monitoring both boards and forwarding the info to my buddy. He can read all this and decide what will work best for him.


Thanks again

Root

[jakesbackyard]

I would also apply more than one coat on the first application. And three would be great. You may want to use 600 versus 400 to cut the clear that first time. You are really only smoothing out the orange peel and any dirt nibs. That's all they use at the PPG schools. Even 800! They (PPG) call that second application of clear a "flow coat" and it works great for custom paint applications.

About the only time problem you may run into would be reclearing the sanded clearcoat too soon. It should have no problem sticking to the 400 to 800 scratches, but if applied too soon - like in a few hours - you may have a blow up. I would say let it air out in good old outdoor air for at least 24 hours after sanding to let that new surface cure out. When you sand that clear you are opening up a new surface that is not cured completely and it now needs to cure out before recoating. If not allowed to cure you may have recoat lifting or at the least it will die back considerably.

Remember - you can get all kinds of information on PPG products by going to ppg.com.

Good luck.

[Root]

I would also apply more than one coat on the first application. And three would be great. You may want to use 600 versus 400 to cut the clear that first time. You are really only smoothing out the orange peel and any dirt nibs. That's all they use at the PPG schools. Even 800! They (PPG) call that second application of clear a "flow coat" and it works great for custom paint applications.

About the only time problem you may run into would be reclearing the sanded clearcoat too soon. It should have no problem sticking to the 400 to 800 scratches, but if applied too soon - like in a few hours - you may have a blow up. I would say let it air out in good old outdoor air for at least 24 hours after sanding to let that new surface cure out. When you sand that clear you are opening up a new surface that is not cured completely and it now needs to cure out before recoating. If not allowed to cure you may have recoat lifting or at the least it will die back considerably.

Remember - you can get all kinds of information on PPG products by going to ppg.com.

Good luck.

Flow coat...yeah that's the term I was looking for. I remember that now. Thanks