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-   -   Not enough base under clear coat! (http://www.hotrodders.com/forum/not-enough-base-under-clear-coat-128667.html)

shad9876 11-21-2007 10:08 PM

Not enough base under clear coat!
 
I painted my frame last week in Nason base/clear urethane. It turned out very nice, except I noticed a few spots on the underside that did not get enough base!
Can I just scuff and re-shoot the base and then clear again?

If it helps, here is what I used.
Nason ful-base black (mixed 1:1 w/ful-base reducer 441-22)
Nason Select Clear 497-00 (mixed 3:1 w/ activator 483-79)
[IMG]http://i219.photobucket.com/albums/c...s/DSCF1777.jpg[/IMG]

The frame is a frame that I built for my '57 Belair. It is setup for an LS1 motor and corvette C4 front and rear suspension.

MARTINSR 11-21-2007 11:32 PM

Sure, all you need to do is scuff it with a gray scuff pad and reshoot the color and clear. If you find that the clear is thin (it may be, being the base was shot thin) then be careful and don't shoot the color or clear too wet. In other words be sure that the metal is not cold, don't use too "cold" of a reducer, don't apply it too wet, all the things you need to keep the paint flashing relatively quick. If you don't do this the solvents in the paint or clear that you are applying can get thru and under the thin clear that you have applied and lift it.

By the way, don't feel bad. Painting something like that frame is taxing even for a seasoned pro. To get in and out of all the nooks and crannies and get all the sides and what not, it is pretty tough so don't beat your self up.

One thing you may want to think about is to turn it over now and shoot the bottom from the top. If you think about it, THAT is how it is going to be seen. When it is under the car, all that you are looking at now will never be seen again! So if you turn the frame over and paint it real nice, even if the top side has some dry spots, it will never be seen. But painting the what WILL be seen will be much easier and you can really make it look nice.

Brian

shad9876 11-22-2007 01:00 AM

thanks for the info! temperature is another issue that I have right now. the weather has just shifted with a cold front. When i bought my paint and supplies and painted the first time, the temperature was about 70-80 degrees and now i'm looking at fifties and sixties. will this affect the reducers and or activators that i use? I currently have high-temp activator and slow reducer.

milo 11-22-2007 03:22 AM

Another thought I was having would be to mask off the areas that are ok from the next rounds overspray.
Might even be a good idea to do sections at a time and then mask them off and do another etc .if you have the time...

Looking good in the pic for sure :thumbup:

kenseth17 11-22-2007 04:21 AM

I agree with milo, if there is an area that is convienient to mask off for a blend or if you feel you can just paint the bottom, I'd do a blend if you feel you can get a good looking repair, and save on paint and effort. Being under the car, really not going to be exposed to uv. I painted a motorcycle frame once and even though fairly small, don't want to go through that any time soon, all the areas and nooks and crannys to hit. Also had to seal a semi frame and seal and paint a trailer frame that had been blasted inside of the rails in the past at jobs, wasn't having a ball on either of em, I can feel your pain and understand how a spot could be missed.

cboy 11-22-2007 07:17 AM

Quote:

Originally Posted by MARTINSR
If you don't do this the solvents in the paint or clear that you are applying can get thru and under the thin clear that you have applied and lift it.

Could one also shoot a few more coats of clear on the areas that might be thin and THEN scuff? I've heard some horror stories about reshooting base over thin or "sanded through" clear and the lifting/wrinkling that can occur.

[Edited after re-thinking] I suppose this option is out if the "window" has closed and the clear is too dry. Wouldn't the clear then have to be scuffed just to shoot more clear...which puts you right back in the same predicament.

MARTINSR 11-22-2007 08:00 AM

Whether it's clear or color you still need to "baby" it over thin clear. As far as the temp reducers and hardeners, darn tootin that will make a difference. You really should have the faster reducers and hardeners. HOWEVER, and this is a big HOWEVER, those slower reducers and hardeners are the best ones even in the colder weather for doing something like this frame. It's hard to keep from getting dry spots on something like this. If you have a little "wetter" reducer and hardener (slower flashing/activating) you can keep it wet over the whole thing until you are done shooting.

But IF and I am not saying you do for sure have thin spots in the clear, just a guestimate, you would want the faster flashing solvents so they don't soak in and lift.

Listen, if you can get the thing warm, and then just don't bomb it on, you should be ok. Did you see the propane heater discussion a while ago?

Brian

speedydeedy 11-22-2007 08:19 AM

Looks great!! :thumbup:

t66turbocobra 11-23-2007 12:09 AM

scuff it, base it in area of interest, clear it

shad9876 11-23-2007 08:35 AM

Quote:

Whether it's clear or color you still need to "baby" it over thin clear. As far as the temp reducers and hardeners, darn tootin that will make a difference. You really should have the faster reducers and hardeners. HOWEVER, and this is a big HOWEVER, those slower reducers and hardeners are the best ones even in the colder weather for doing something like this frame. It's hard to keep from getting dry spots on something like this. If you have a little "wetter" reducer and hardener (slower flashing/activating) you can keep it wet over the whole thing until you are done shooting
Yeah, I'm sure there are some thin areas of clear. Part of the problem for me with all of the nooks and crannies is that some areas would get quite a bit of paint while others would get very little. I kind of had to meet in the middle on some areas and go with a slightly heavy area with a slightly thinner areas next to it(the harder to get areas)...otherwise I could tell that if I kept trying to push more paint, runs and sags would be inevitable.

Would it help to dust on a a couple light coats of base over the areas that have thin clear? If I did this could I then follow this with a slightly wetter coat? also, will I be able to lay the clear down wet enough so as to avoid dry spots while at the same time not causing solvent problems?

It is going to be very difficult to keep the frame warm for very long. I could get it warm, but when I start painting I've got to open the shop door at least a few feet to vent it out with the fans.

I'm pretty sure that I will need to go with the faster reducer and hardener.

t66turbocobra 11-23-2007 09:08 AM

The best way to get tight areas. is to start of with those area first then go back and spray the entire piece as if there was no tight areas. That way, the tight areas are already coated and now u just have to worry about the visible area. When it come to using the gun in tight areas. Turn the air pressure down and adjust the fan pattern as needed. This will provide a even coat over the entire peice.

shad9876 11-23-2007 09:58 AM

very good technique.

Would a sealer help me in this situation? Could I reseal the entire frame and then shoot over the sealer or would this only create more problems with solvents getting trapped under the sealer?

How long will it take for the finish to cure sufficiently so that the new paint won't be able to penetrate the existing paint?

t66turbocobra 11-23-2007 12:58 PM

Quote:

Originally Posted by shad9876
very good technique.

Would a sealer help me in this situation? Could I reseal the entire frame and then shoot over the sealer or would this only create more problems with solvents getting trapped under the sealer?

How long will it take for the finish to cure sufficiently so that the new paint won't be able to penetrate the existing paint?

It doesnt matter if u seal the frame or not. The amount of paint that gets in the tight areas depend on the painter.
Once the clear has set and hardened; you can repaint the part. The time it takes to dry depends on the air temp and the hardener. Also if ur in a garage or booth

shad9876 11-23-2007 02:28 PM

i was also told by a paint shop rep that i should have used a catalyst in the base. he says that this would have allowed me to simply scuff and reshoot without worrying about solvent pop. When i repaint, should i use a catalyst?

t66turbocobra 11-23-2007 02:36 PM

Quote:

Originally Posted by shad9876
i was also told by a paint shop rep that i should have used a catalyst in the base. he says that this would have allowed me to simply scuff and reshoot without worrying about solvent pop. When i repaint, should i use a catalyst?

Yes he is right. U defiantly want to use a reducer with the base coast. Make sure u choose the right reducer for the temp u will be sparying in. It sould be mixed to a 1:1 mixture. Simply use a mixing cup for this. Plus your paint will go a longer way.


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