Clear Acrylic Urethane over Acrylic Enamel?
My son's Grandfather took him to the paint store and came back with a very nice looking Acrylic Enamel metallic paint to paint his truck with. He got it because it was cheaper than the Urethane paints. I (his Dad) am worried because I think he should have bought the Urethane base coat/clear coat paints. The paint is by BASF Limco and he bought some Super Wet Look hardener for it, too. I can't take it back now that it is mixed. I have two questions..... 1 - Can this paint be clear coated with an Acrylic Urethane (the paint store guy says it can but he wants to sell the stuff)? 2 - Would it help the paint last longer by spraying the clear Urethane over the Acrylic Enamel?
Yes and yes!!!
I talked to a paint chemist, who is the owner of a paint mfg co.
about this very thing.
He told me you could clear right over the enamel with clear urethane
as long as the enamel used a hardener, like you're doing.
He said it was better and safer to let the enamel cure longer first,
about 24 hrs was best, enamel cures slower and you want to let
most of the solvents escape. (The clear sets up quicker, and seals it.)
And he also told me you don't need to scuff it beforehand
as long as it's kept clean.
I used urethane as a base on my last car and did it the very same way.
My urethane specs said to clear within 24 hrs so I split the difference.
I applied my color on a Friday afternoon, then cleared it Saturday morning
early before the bugs and dirt got bad, which was about 12 to 14 hrs later.
I like it better than basecoat, the colors are more intense, and it's
much stronger than basecoat. Cheaper too.
The key is to use hardener in the Acrylic Enamel. As long as you do that, and wait 12 hours or so you should be able to use AU clear over it without issue. However there is a recoat window issue here that you really need to be careful about. Shoot the clear too soon and the AE will wrinkle (complete disaster) wait too long and the clear will not be able to bond to the too far along catalyzed AE underneath it without scuffing.
While I agree you can put Urethane clear over Acrylic enamel the BASF Limco enamel is some cheap stuff and has a tendacy to wrinkle and mottle, very bad with metallics and can cause light and dark spots. It does cover well and is very thick but needs to be applied in thin coats and alllow plenty of time for it to cure otherwise it WILL wrinkle and mottle and have you wishing you had bought another paint or left it alone !
I speak from experiece as I have used the Limco line and have used their whole line and even their basecoats are Acyrlic enamel like and very thick. I have used the cheap AE enamel on farm equipment and toolboxes and for those things it works OK. I have used the SS Urethane on work trucks and for that it works OK. I have used the Limco 4 basecoat on cheaper "newer" cars and it NEVER matches with a metallic even with blending and is only good for doing say a "nice" work truck.........Their Limco 4000 clear is actually pretty good for the money for a work truck but it has a tendacy to shrink regardless of what you do with it so 3-4 coats are a minimum with LC4000 clear.
I don't know what kind of truck your son is going to be painting but if it is important to him or you use a different paint line for your basecoat, or just move up to the BASF Diamont RM line which is really good paint but of course costs more.....................best of luck with your project
Just wanted to say thanks for the input on my question. Unfortunately, I am a bit too late as he has already bought the paint and clear. Oh well, we will see how it holds up. So far the interior and inner fenders and wheel wells look very good but that is as far as we have gotten.
as a BASF rep the answer is yes and no . you can clear coat over acrylic enamel but no not for 24 hours and then and only then if you wet sand it 1st with a untra fine sand paper . if you do so with a metallic color you will sand off some of the metallics . metallics flot to the top when the color is still wet . i have at times let the color coat dry for about 10 to 12 hours and then with out sanding sprated 2 coats of clear but BASF does not want you to do this .
If it were mine...
I just would NOT do it. Too many variables involved unless your Grandfather was like one of the pros on this site. Unless the paint is red, the cost of base coat would not have costed much more than the AE.
Originally Posted by JimMcRae
I just don't like the mis match of products as it goes against the norm. Will it look good? Probably yes. Will it last? Probably not. Good luck. Henry
Jim, What would be a really good idea is for you to do a couple spray out test panels. Take a couple metal panels say about a foot square and spray those test panels with the acrylic enamel. Let one panel sit for 12 hours and the other panel for 24 hours. Take a rag or a paper towel with some acrylic urethane reducer (which you will most likely need for the clear anyway) and swipe the reducer rag across a corner of the first test panel at 12 hours. If a little bit of the paint transfers from the panel to the reducer rag then the paint is not too dry and will not require any sanding/scuffing. At that point spray on your first coat of urethane clearcoat. Spray a medium coat of clear on the first coat wait 20 minutes and spray on the medium coat for the second clear coat. ( A medium coat is one that is not real dry and not real wet, too dry and you'll end up with orange peel. Too wet and it stands a better chance of eating into the acrylic enamel, and cause it to lift.) If the paint does not lift and it flows out smooth then the first part of your test is done.
Wait 24 hours on the second panel and do the reducer rag swipe test again. If that reducer does not cause some paint to transfer from the panel to the rag and the reducer rag does not eat into that acrylic enamel causing the surface to permanently dull out then the acrylic enamel is to hard/cured and its not a good idea to spray urethane clear over it without scuffing the acrylic enamel first. In the case of the latter the problem "could" be that the urethane clear will not adhere to the acrylic enamel and the clear "could" chip and peel easy.
I personally think you should be fine spraying urethane clearcoat over the hardener added acrylic enamel. BUT like Henry stated it is NOT without
risk. Things could turn to sh*t real quick. One of the things I learned in 40 years of painting cars for a living is that paint doesn't always do what its supposed to do and mixing and matching can cause unpredictable results. Needless to say its always best to buy the highest quality (read that as expensive) paint materials available. But in real life it don't work that way. It makes absolutely no sense to put $2,000 worth of paint/materials into a thousand dollar work cummuter car.
If the urethane over the acrylic enamel doesn't react negatively right away then you should be good to go and the longevity of the paint should not be seriously compromised (it'll stay shiny and look good for a long time).
Bottom line ------ You should be fine but its a good idea to do those test panels before you spray your truck.
This old thread prob don't matter as much anymore but I would scuff the CURED AE with 1000 then go 2-3 coats clear depending on the clear.
I know you purist are going to go nuts but I used plain old PPG gloss oil base enamel on the bumpers on my F100 and cleared over it ,no problems.
Why did you do it that way instead of using base/clear?
Originally Posted by mkrog1
Because I had the paint.I matched Fords Wilmington white.
Originally Posted by Len