PPG DCU2021 Clear, how many coats?

[chopperroxie]

Hey guys, so I'm getting ready to shoot my 1966 Chevelle on Saturday. I'm using PPG DBC base and DCU2021 Clear. DT885 slow reducer since it's going to be 80 deg and i'm shooting in a downdraft booth.

I was going to shooting 3 coats of base and then 5 coats of clear, since I'll be doing some pretty aggressive color sanding.

I was talking to the PPG rep today and he recommended I do 2 coats of clear, DA with 1000 grit when dry, and then do 2 more coats on top of that.

What's everyone opinion about that. I've never done that before so I'm not sure I'm comfortable with it, but if it makes that big a difference, which he said it would, I'll try it.

Thanks

Corey

[MidnightOilJK]

2021 is my clear of choice,

I would put 1 coat, wait appropriate flash time,

second coat followed by a drop coat.

cut with 800 then 3 more coats,

easier to cut for buffing, your edges will have minimum "Meniscus"

i spray with a SATA 5500 RP 1.2 31psi

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[Phil V]

I would follow the PPG rep advice with two coats of clear. Cut with 100 or 1200 grit then do ONE flow coat.

NO car needs 5 coats of clear.

Why do you see yourself doing some "aggressive" sanding of the clear ?

I would switch to mid temp reducer also. Less chance of serious runs and it will still flow out fine. I never use slow reducer, I don't care how hot it is. In fact if it's 90 or above in the paint booth then I'm not painting anyway (too hot for me to paint). With all the paint gear and breathing gear on you would be sweating like a pig and maybe develop a heat stroke.

[chopperroxie]

Thanks for the reply guys. I think I will go with what the rep suggested. Makes alot of sense.

[baubau]

Please don't do 5 coats of clear at once, you will fuck it up, anyone would, too much product, gas bubbles underneath, urethane wave...

Remember that paint rep always wants to sell more product.
Shoot 2 coats of clear, let it flash for 10, 15 minutes and then lay another and see how it is..

Maybe you just need some slight buffing polishing and away you go...

After this cures, try this...minimal aggressive sanding with 2000 grit dry sandpaper on DA with some backing spinge, high quality paper like 3M or Sunmight, you will see orange peel being removed but not all of it, then make a jusdgement call and polish and see how it looks...you will still have 2 1/2 coats on..

Sanding clear coat to do a flow cost will produce flat like glass finishes.....it takes a lot of work and material..

[bmarler]

what the rep recommended is pretty standard for people trying to get that perfectly flat, show car finish. but you're in a nice downdraft booth, presumably know what you're doing, flow coating might not be necessary.
baubau is right about urethane wave and other issues if you try to stack too much on. phil is correct when he says no car needs 5 coats of clear. that's way over the recommended film thickness, no matter how much you intend to sand off.
putting on too much is simply creating the problem you're planning on sanding to correct.
i like baubau's suggestion of looking at it after two coats. if it looks great with just a little peel, add the third so you have some build to work with to level the surface. after you cut off the peel you'll be about right for film thickness.
if after two coats you don't like how it's going, then cut and flow coat.

[Ronf]

I have been using DCU2021 since it hit the market and never have I applied 5 coats. Most of my work is on high end cars that require a show quality finish. Baubau, PhilV and bmarler have it dead on. If your not the best applicator you "may" need to flow coat it with 1 coat only after sanding with 1000. My typical shot is to hit it with 1 tack coat, 1 medium coat and 1 heavy coat just prior to product break. I wet sand after 4-5 days starting with 1500, followed by 2500, 3000 Trizact and end with 5000 Trizact. Buff this out with Mystic 11048. Makes for a show quality finish. Only on a couple of occasions have I had to flow coat a project (due to debris and color) after using this system as there is plenty of build with 3 coats to wet sand to an ultra flat surface. However, you have to take into consideration the prep work it took to get it ready for paint, i.e. Surface has been worked to a dead on flat panel, high build primer such as Optex 4:1 was applied several times and sanded out to 600g, etc.. To me paint application is the easiest part of the restore process, getting it to the point of being ready for paint is where the work takes place to get that show quality finish as you can't expect your paint and CC to level a surface that is ill prepared from the body work.

[bmarler]

I have been using DCU2021 since it hit the market and never have I applied 5 coats. Most of my work is on high end cars that require a show quality finish. Baubau, PhilV and bmarler have it dead on. If your not the best applicator you "may" need to flow coat it with 1 coat only after sanding with 1000. My typical shot is to hit it with 1 tack coat, 1 medium coat and 1 heavy coat just prior to product break. I wet sand after 4-5 days starting with 1500, followed by 2500, 3000 Trizact and end with 5000 Trizact. Buff this out with Mystic 11048. Makes for a show quality finish. Only on a couple of occasions have I had to flow coat a project (due to debris and color) after using this system as there is plenty of build with 3 coats to wet sand to an ultra flat surface. However, you have to take into consideration the prep work it took to get it ready for paint, i.e. Surface has been worked to a dead on flat panel, high build primer such as Optex 4:1 was applied several times and sanded out to 600g, etc.. To me paint application is the easiest part of the restore process, getting it to the point of being ready for paint is where the work takes place to get that show quality finish as you can't expect your paint and CC to level a surface that is ill prepared from the body work.

i was hoping you might chime in on this seeing how this clear is your go-to. we don't know what the OP is starting with in regards to panel prep, but i assume it's pretty well prepared. i'm hoping he'll post his results when completed.

[PaintEmIfYouGotEm]

I don't have near the experience that some of the above posters have, so my advice isn't on their level.. but for what it's worth, they're absolutely right about the negative consequences of spraying too many coats of clear. One of the things I've learned from experience over the years is that having too much sprayed material of any kind on a vehicle is a recipe for chips, cracking and peeling paint failures. When I was less experienced I used to think along the same lines as many others with limited experience - "more clear means more depth and room to wetsand and polish". Eventually I learned from others and from experience that following the tech sheets to the letter and improving my own skills and methods got me amazing results, both in terms of appearance and durability. I also invested in a paint depth meter, which allowed me to do my own tests on what I was spraying to see for myself that I was being overly paranoid about how much material I was actually taking off when sanding and polishing. Plus, when I got better and better and learned how to spray clear with far less orange peel out of the gun, that further reduced the amount of material I had to remove to get the surface properly flat. I learned that dumping on large quantities of clear and removing tons of material to get it flat is not the right way to achieve a great finish.

One of my goals any time I paint a vehicle is to minimize the amount of sprayed materials of any kind I have on the car. That includes primer, base, etc.. I only spray the minimum to achieve coverage with primers and base, then no more than three coats of clear, regardless of what clear I'm using, usually a mist-light coat, a medium coat and a medium-heavy coat. The only time in recent years where I ever had to go back and add more clear was when a damn bug somehow got in and decided to walk around on a panel just after spraying the third coat. But as a matter of course, I go in with the idea that I'm going to spray three coats of clear and that's it.

[Phil V]

I don't have near the experience that some of the above posters have, so my advice isn't on their level.. but for what it's worth, they're absolutely right about the negative consequences of spraying too many coats of clear. One of the things I've learned from experience over the years is that having too much sprayed material of any kind on a vehicle is a recipe for chips, cracking and peeling paint failures. When I was less experienced I used to think along the same lines as many others with limited experience - "more clear means more depth and room to wetsand and polish". Eventually I learned from others and from experience that following the tech sheets to the letter and improving my own skills and methods got me amazing results, both in terms of appearance and durability. I also invested in a paint depth meter, which allowed me to do my own tests on what I was spraying to see for myself that I was being overly paranoid about how much material I was actually taking off when sanding and polishing. Plus, when I got better and better and learned how to spray clear with far less orange peel out of the gun, that further reduced the amount of material I had to remove to get the surface properly flat. I learned that dumping on large quantities of clear and removing tons of material to get it flat is not the right way to achieve a great finish.

One of my goals any time I paint a vehicle is to minimize the amount of sprayed materials of any kind I have on the car. That includes primer, base, etc.. I only spray the minimum to achieve coverage with primers and base, then no more than three coats of clear, regardless of what clear I'm using, usually a mist-light coat, a medium coat and a medium-heavy coat. The only time in recent years where I ever had to go back and add more clear was when a damn bug somehow got in and decided to walk around on a panel just after spraying the third coat. But as a matter of course, I go in with the idea that I'm going to spray three coats of clear and that's it.

Bugs in clear coat. LOL ! One time I had just finished up a BC/CC paint application . And a June Bug came out of nowhere and landed on the roof. Walked around before it croaked and made a mess. I've had moths screw up otherwise good paintjobs, they can cause a real mess. One of the downsides of not always painting in a paint booth.

[PaintEmIfYouGotEm]

Bugs in clear coat. LOL ! One time I had just finished up a BC/CC paint application . And a June Bug came out of nowhere and landed on the roof. Walked around before it croaked and made a mess. I've had moths screw up otherwise good paintjobs, they can cause a real mess. One of the downsides of not always painting in a paint booth.

Indeed. I suspect the bug that got me that one time followed me into the booth. After that I installed bug attractant lights high up in the far corners, as well as in my short entryway into the booth, and I hang those sticky strips by the lights in the entryway. I was actually surprised afterward just how many tiny little guys I would catch on them. I installed some attractant lights just outside the booth walk-in door as well. But thankfully I have not had any substantial issues since then. Occasionally I do get a little gnat or something that falls in, but I keep tweezers and picks handy to get them out if they haven't sunk in. If they leave a noticeable depression or trail I will drip a drop or two of clear in that spot and sand it down later. That seems to work well for me. Thankfully we don't have a ton of flying bugs in northern Nevada, so it's not that big a deal here usually.

[chopperroxie]

Well the painting of the 66 Chevelle did not go as planned this past weekend. I sprayed 1 coat of sealer and things looked good. I then followed it up with a coat of the Mariana Blue basecoat and omg that's when the scratches started to appear. I tried to fix it with 600 grit and then followed by 1000 but there were too many. I decided to stop and trailer it back to my shop, as I only had the paint booth for that day and I didn't want to rush it.

My prep was Evercoat superbuild 4:1 with I think 3 rounds, finishing with 220, 400 with guide coat, and 600 to finish. I'm pretty confident on the smoothness of everything. It was recommended to me to put 5 coats on but after reading all the comments, when I go back to finish this, I'll do as you guys recommended. Check after coat 1 and 2 of clear and decide from there. It's a really good paint booth and I don't expect there to be any problems.

Thanks so much for all the help guys, I really appreciate it.

Corey

[bmarler]

Well the painting of the 66 Chevelle did not go as planned this past weekend. I sprayed 1 coat of sealer and things looked good. I then followed it up with a coat of the Mariana Blue basecoat and omg that's when the scratches started to appear. I tried to fix it with 600 grit and then followed by 1000 but there were too many. I decided to stop and trailer it back to my shop, as I only had the paint booth for that day and I didn't want to rush it.

My prep was Evercoat superbuild 4:1 with I think 3 rounds, finishing with 220, 400 with guide coat, and 600 to finish. I'm pretty confident on the smoothness of everything. It was recommended to me to put 5 coats on but after reading all the comments, when I go back to finish this, I'll do as you guys recommended. Check after coat 1 and 2 of clear and decide from there. It's a really good paint booth and I don't expect there to be any problems.

Thanks so much for all the help guys, I really appreciate it.

Corey

smart decision to stop and regroup. what were the scratch marks like? you did 400 with guide coat, scratch marks should have been eliminated there. did you do the 600 wet? i probably would have guide coated that too, just lightly. did you remember to soak the paper first? dry paper can make scratches as the edges are sharp. soaking overnight will softens the edges of the paper and reduce any tendency to scratch. pilling on the paper will make marks too, another good reason to wet sand.
scratch marks should have shown in the sealer, maybe you just didn't see them. base will really bring them out, especially if the first coat is fairly light. i don't get concerned if they're just those micro-scratches, they'll cover. but deeper ones won't.
what sealer did you use?

[chopperroxie]

smart decision to stop and regroup. what were the scratch marks like? you did 400 with guide coat, scratch marks should have been eliminated there. did you do the 600 wet? i probably would have guide coated that too, just lightly. did you remember to soak the paper first? dry paper can make scratches as the edges are sharp. soaking overnight will softens the edges of the paper and reduce any tendency to scratch. pilling on the paper will make marks too, another good reason to wet sand.
scratch marks should have shown in the sealer, maybe you just didn't see them. base will really bring them out, especially if the first coat is fairly light. i don't get concerned if they're just those micro-scratches, they'll cover. but deeper ones won't.
what sealer did you use?

Some of the scratches were pretty deep, most were at or around the bottom body line and down lower. I'm thinking I just wasn't careful enough going around and making sure all were gone. I didn't do wet sanding at all because I was told not to if you use a polyester primer since it might absorb it. Is that true?

The sealer I used was PPG DAS3025, the medium gray.

My plan now is the wet sand the basecoat with 600 and try to get the scratches out, I'm assuming I'll break into the sealer and polyester primer? Do I need to apply sealer then base to these spots? I guess I can use the basecoat as a really expensive guide coat to see how my progress is going?

[Phil V]

smart decision to stop and regroup. what were the scratch marks like? you did 400 with guide coat, scratch marks should have been eliminated there. did you do the 600 wet? i probably would have guide coated that too, just lightly. did you remember to soak the paper first? dry paper can make scratches as the edges are sharp. soaking overnight will softens the edges of the paper and reduce any tendency to scratch. pilling on the paper will make marks too, another good reason to wet sand.
scratch marks should have shown in the sealer, maybe you just didn't see them. base will really bring them out, especially if the first coat is fairly light. i don't get concerned if they're just those micro-scratches, they'll cover. but deeper ones won't.
what sealer did you use?

I agree. Smart decision to stop and regroup. Most people would have just pushed through (with negative results).

I also agree that the scratch marks shouldn't have been there given the prep work that was done.