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-   -   Extremely hard clearcoat???? (http://www.hotrodders.com/forum/extremely-hard-clearcoat-183129.html)

427blownvette 08-22-2010 12:13 AM

Extremely hard clearcoat????
 
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I am new to painting and ran into some issues.

I decide to paint my 81 corvette. I molded the front bumper smooth, installed a lambourgini door kit, high rise rear bumper and fixed all the spidercracks and blemishes.

I used a 2k high build primer/sealer and put on 3 good coats, blocked sanded with 220, 400 and 800.
Sprayed on 3 coats of Black basecoat and everything looks great, paint is already shining and no problems.
I waited the 45 minutes as directed by my tech sheet to begin clearing.

I had to mix my clear in 2 different containers, the first batch of clear was mixed exactly as the tech sheet recommended in a 2:1 ratio. I was able to lay on 2 heavy coats of clear before having to mix my last batch.

When I mixed the last batch it was 3am and I guess I wasnt paying attention. Instead of mixing the clear with the hardener I grabber bug and wax remover and used that!!! Which means my last coat of clear had ZERO hardener in it. The clear was now mixed 2:1/2 wax remover. (I didnt find this out until early next morning.)
I sprayed on the last heavy coat of clear and called it a night. Early the next morning (7 hours cure time) I went to my garage and discovered my mistake. I went over to the car and amazingly the clearcoat was hard.

I decided to try to wetsand and buff an extra hood I sprayed along with the car, so it is like my test piece to work on. I started with 1200 wet and after an hour and a half barely did anything to the light orangepeel, stepped it down to 800wet and same thing. Finally 400wet cuts it down and works good. Still takes alot of sanding with the 400 to make it smooth though. Stepped back up to 800, 1200, 1500 and finally 2000. The hood is ready to buff with medium compound. I didnt sand through anywhere, all edges are good and I am shocked.

Why is my clear coat so extremely hard to sand? Considering the last coat of clear had ZERO hardener in it.

I was scared that my sand paper would cake up with clear, or I would have to strip the entire car down, but I dont think this is the case.

Any help would be appreciated! At the rate I am going it will take me 3 weeks to wetsand and buff the car

.****This car is not a show car, I am not worried about light sand scratches, faint orangpeel or other tiny blemishes****

302 Z28 08-22-2010 07:16 AM

What brand of clear did you use, so we can try and draw a conclusion? The last mixture of clear and W&G remover was probably catalyzed by the previous coats of still wet clear.

Vince

427blownvette 08-22-2010 07:31 AM

I used PPG shopline brand.
Cleracoat#jc661
Hardener#jh6670

I realize that the clear I sprayed on the car last had to mix with some of the first 2 coats of clear. Otherwise it would not have gotten hard and settup.

But why so rock hard that I have to use 400 grit to cut it.

shine 08-22-2010 07:59 AM

wax and grease remover in clear makes jelly. mix some together and see what happens. dont see any way this could have happened and still cured. but then i dont use shopline.

lukeembry 08-22-2010 10:13 AM

yor clear may feel dry but it is still wet thats why it is so hard to sand, i know it sounds crazy but put it in the sun and heat for a day or 2 and try sond 1000 grit with soap and water and see what happens. seen this happen before.

shine 08-22-2010 10:23 AM

if there's no hardener in the clear then it has to come off. urethane will not cure from sunlight .

lukeembry 08-22-2010 10:39 AM

the last coat of clear was melted into the 2 coats before so there is no clear unactivated on the panels, it will dry, 3 coats of clear becomes one build of clear when dry not 3 different sheets because it will all melt together. not enough activator is much better than to much activator, give it a good day in the sun and try some 1000 grit if still to hard to sand cut with 500grit and add 2 more coats of clear. all that can happen is some die back in the clear in the next month or 2 but you can run a buffer over it and solve that problem anyways.

427blownvette 08-22-2010 12:21 PM

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Thanks for all the advice, I talked to my friend who has worked in a bodyshop for the last 30 some years. lukeembry is correct and my friend told me the same thing. All 3 coats do blend together, that is why you can never just remove 1 coat of clear, base primer etc.

It is not a good way to put clear on, but it will work.

I went out in my garage today and figured I would try to wetsand some. Presto once again lukeembry was correct, it is now alot easier to sand! I guess the recommended 6-7hour cure time was messed up by me not adding hardener to the last coat of clear.


So now I have another question. I have half the car wetsanded with 1000grit, I have noticed 2 spots that I am not happy with. How can I fix them? Do I have to paint the entire fender, or can I tape off the section paint and clear it, then wetsand blend it to the car?

Thanks for all the help so far.

lukeembry 08-22-2010 12:33 PM

paint just the spot of repar with it being black that is very easy, but for the correct repair you must clear caot the entire panel. if you sand through the clear be very careful putting base over it slow and very little amounts so it won't wrinke up.

crashtech 08-22-2010 01:31 PM

Amazing.

There is no way to trust that material to hold up over time. If you don't sand that last coat of clear way down (I'd say ALL the clear has to come off, since there's no perfect way to sand off one coat) there will be regrets later, you can count on it.

427blownvette 08-22-2010 01:39 PM

Not really worried how the car will hold up over time. I dont take care of my vehicles to be honest. Lucky if I wash them twice a year. I stand on them when I need a ladder, put stuff on them if I need storage and use a shovel to clean them off in the winter.

Between all the abuse I do to them I will take my chances.

Besides I really trust my painter friend, this is his living, If he said it will be ok, I trust him.

lukeembry also answered 2 of my questions and was right on the money with his answers. Thanks for your input, but I will go with it and see.

shine 08-22-2010 02:50 PM

we need a moderator to delete this bs thread.

427blownvette 08-22-2010 03:00 PM

Why is this thread bs? I have listened to everyones advice, some say the clear is good and others say dont trust it. I thanked everyone for their help multiple times and decided to go with the clear that was sprayed.

I must be missing something.......

As i stated in my very first post *** this is a show car, I am not worried about light sand scrathes, orangepeel or minor blemishes***

Just because I dont take care of my vehicles is no reason to say the post should be deleted. I am just being honest.

shine 08-22-2010 03:17 PM

because i am a professional painter and know this is bull**** . it serves no purpose what so ever. an uncatalyzed coat of clear is not going to majically draw hardener from the coat before. you may bake the solvents from it but it will never do the conversion. period. it is a chemical reaction.

427blownvette 08-22-2010 03:27 PM

I am sorry you feel that way, but its the truth. How else am I wetsanding the car? I can only do it if it hardened.

I live in Hegins PA 17938, if any lives in Pa and wants to stop by and take a look feel free. This thread is not bs, I have better things to do with my time.


Just because you dont think the answers are right dont make a thread bs. We are all on here and learning new tips and tricks every day.

Please stop being rude, it is not benificial to this post. Thanks for all your input and have a nice day.


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