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Topic Review (Newest First)
11-27-2007 06:35 AM
Irelands child I do have a cheapy HF airbrush that for whatever reason does a very nice job - actually better then the expensive Binks that I had years ago. I have used it on touching up small sand thrus on an edge very sucessfully as late as 4:30PM yesterday. It sure beats warming up the big Iwata LPH 400 for a 1" burn thru!!!

Dave
11-26-2007 10:54 PM
mattcorby to add to the great advice, if you have an airbrush, keep it at hand. i have an iwata hp-c gravity fed airbrush that will spray eurethane basecoats at 5 PSI! its the lower pressure that lets it get into ANYTHING.

just remember if you're going to use an airbrush in conjunction with a spraygun to be careful not to give yourself dryspots switching them around.
11-25-2007 08:13 PM
shad9876 Good, not a big fan of isocyanates myself.
11-24-2007 05:52 PM
Irelands child
Quote:
Originally Posted by shad9876
were you mixing the dupont bc with 1:1 base and reducer, or did you also use a catalyst(activator)?
Strictly the BC with the 7175S mid temp reducer according to the DuPont instruction. The Chroma Premier activator 1230S is optional and adds an isocyanate to the mix - which I didn't want.

Dave
11-24-2007 04:48 PM
shad9876 were you mixing the dupont bc with 1:1 base and reducer, or did you also use a catalyst(activator)?
11-24-2007 04:31 PM
Irelands child I've become an "expert" doing my car with thin spots. I just painted the AVATAR car and most of it turned out pretty good, or so I thought. The clear on the back of both rear quarters was a little too thin for a good cut and buff so I decided to reclear - so I sanded with 800. I stood back and decided that the shadows were not my imagination. I reshot the DuPont BC (3 coats back to back after flashing) over the SPI clear, MUCH BETTER. I then hammered on 4 coats of SPI clear - even better yet. The temp was 55/60*, I used mid temp reducer for both the BC and CC. BUT after dropping one of my splash shields and gouging the paint, found that if you try to re base the feathered out paint ding without having any clear, you will very probably raise the first BC layer. Then it turns ugly - and you start with 2K after sanding the raised paint. A real PITA and time eater.

There is probably nothing nastier to paint then a frame - which is one of the reasons I had mine powder coated after originally painting it with Centari - no thin spots now!!!

Dave
11-24-2007 01:00 PM
kenseth17 Yeah, like the other guys said, if your clear is thin or non existant, then likely will have some lifting occur when you reapply. Back when I did the motorcycle frame, had some white specks in it and missed some spots and wasn't happy, so I repainted the thing. I had few spots that lifted, and had to mess around sanding em flat and getting base to lay over the area. Of course didn't help it was a cheap omni base that was unactivated.
If you can avoid using a fast reducer at all I would, even though it may be over some thin areas. Black is slow and afraid you will trap solvents, plus on something like a frame you need time to hit areas and avoid dry areas. If you get lifting when you start laying your base, maybe best just sand and hit those areas with some epoxy and leave it sit awhile, knock epoxy flat and continue. All this, as well as your struggle with temps, is also a reason to avoid repainting the entire frame if possible. A heat lamp may possibly help, but with thin areas solvent is gonna want to get under the edge and lift. But the lamp could help warm the area you will be painting (kinda hard to warm entire thing without having several lamps or heating the paint area) and also help speed up repair time in the event of an area lifting.
11-24-2007 10:35 AM
shad9876 would a paint heat lamp help out?
11-23-2007 03:49 PM
shad9876 i did use a reducer, but I was told that i could also add an additional component, a catalyst. so instead of mixing 1:1, base and reducer, a catalyst is added to the equation for a 1:1:1/16.
11-23-2007 03:36 PM
t66turbocobra
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.
11-23-2007 03:28 PM
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?
11-23-2007 01:58 PM
t66turbocobra
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
11-23-2007 10:58 AM
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?
11-23-2007 10:08 AM
t66turbocobra 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.
11-23-2007 09:35 AM
shad9876
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.
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