Bad base job on motorhome

I

inspectorbob

I've been working on a motorhome in batches for a while now, as I don't have the time or energy to do the whole thing at once. The first few shoots came out great, using SPI epoxy, and Production Clear with Chromabase. The last shoot was a disaster. I think I rushed it, and built the base too quick, as the base looks puckered almost all over. It's not like orange peel, but looks more like putting lacquer over enamel, but with a very light texture. In fact, you have to look pretty close to even see it. No way was I going to clear it, though, as it has to be re-done.

I had to take a couple of months off for health reasons, and the section still sits with uncleared base. The base adhesion looks pretty sound, but how far down do I need to take it before new epoxy and re-base? Do I need to take all the old base off, or just sand it smooth?
 
With Chromabase per the tech sheets you shouldn't sand it except for light denibbing, sorry to say it but all the base needs to be removed before you seal and paint again.

Chromabase is a different animal, most basecoats you can simply sand any defects out and apply another coat or two and your clear and not have to worry but with Chromabase if you do that there will be adhesion problems at the sanded level. I worked in a DuPont shop back in the 90's and had some strange delamination problems, it only happened on the high end jobs I did, the rep and the paint sales guy couldn't figure out what the problem was but years later I figured it out after talking with another rep- the only time I had delam problems was when the base was sanded between applications and I did this only on high end work, caddy's, bmw's, street rods... frustrating. Ideally a painter would never need to sand the basecoat to remove texture, dirt, runs... but if you do need to sand it better be a base that can be sanded.
If you use Chromabase per the tech sheet (don't sand it) it will work fine.
 
Same thing with sherwin williams ultra 7000......don't sand that either. Learned that the hard way.
 
I know you are not suppose to sand and re-shoot the base but do you mean it still all needs to come off even if I am going to reshoot epoxy over it?
 
Check with Barry but I think all of the base needs to come off regardless of what is being sprayed over it. Is this a nice motorhome and you want the paintjob to last?
 
Doesn't look real nice now, but I hope to get it there someday! I thought I recall a thread somewhere here where sanding CB was discussed and Barry had some comments, but I can't find it now.
 
You must log in or register to reply here.
Back
Top