Rainbow look under base before clear?

CK-2

Promoted Users
I’m having a time with a truck bed I’m spraying. Sprayed some intercoat clear over sanded clear to give a smooth bed for new base I was spotting in. Had some problems, then sealed with dplf 90 and let set overnight. Sprayed two coats of base and everything looked good. Pulled out in the sun and here’s the rainbow look coming through the base.
I can spray wax and grease remover on it to give it a clearer look and the rainbow look goes away. When the W&G remover dries the rainbow under the base is back. What’s going on and what should I do?
 

Attachments

  • 870F3434-713A-440B-8349-836166132036.jpeg
    870F3434-713A-440B-8349-836166132036.jpeg
    59.4 KB · Views: 316
Last edited:
Need some specifics. What brand of basecoat? What brand of intercoat? What does it look like inside? Being that I never pull something out in the sun to look at it (in basecoat) I can't be absolute, but my gut tells me that it is simply the way the base itself reflects the sunlight. Maybe someone else can add more.

I did notice that you don't have a very good blend in that pic. Might just be the picture, but it looks like it ends fairly abruptly. If you clear it you may end up seeing the blend area especially if there is any difference in color. If it was me I'd shoot a couple more coats and get the transition better.

FWIW in the future a situation like that absolutely zero need to spray intercoat on it before base. Especially black. If you have some intercoat left mix it 1:1 with your RTS (ready to spray) basecoat and shoot 1-2 more coats concentrating on softening the start stop areas. First coat extend a little farther out past the orginal end point. 2nd coat extend a little farther out past your 1st coat. You can add more intercoat to the what you have in the gun for the 2nd coat to help it further.
 
Last edited:
Little more info. I had the whole bed finished but noticed a dent that I hadn’t seen before. The bed was red and I scuffed, sealed with black sealer,then black Wanda base then cleared. That’s when I noticed the dent that I couldn’t live with.
So I fixed the dent and that’s when the trouble started. The rainbow look is where the SPI intercoat is. I went ahead this evening and sprayed two coats of reduced SPI epoxy over the whole area. I’m hoping that locks it all down. Tomorrow I’ll try the base again
I couldn’t see the sheen at all in the booth but rolled it out just to make sure. I normally don’t pull stuff outside either but I’ve been fighting this for two days so I wanted to see it outside too.
I’ve learned my lesson about not needing the intercoat in this situation. Just thought it might help with scratches under my black base. Rookie mistake. I didn’t really think about the blend showing where I was using a solid color going right back over two week old paint out of the same can. Am I wrong about that?
Thanks for the help.
 
By the way I’m not a big fan of this Wanda base. I’ve always used PPG’s DBC or shopline. Used Nason and Chromabas a few times. But the price keeps going up and up. So I thought I’d give the Wanda a try on this project. I’m tempted to go buy some black shopline and finish this bed with it. Do you think I’d have color match problems on solid black changing brands mid job?
 
I wouldn't change it mid job no. Plus Wanda is a much better base than Shopline. Shopline is just Omni repackaged. More I think about it I'm sure that reflection you saw was normal. Just the way the intercoat reflects the sunlight.

I didn’t really think about the blend showing where I was using a solid color going right back over two week old paint out of the same can. Am I wrong about that?

You would have been ok color wise, I was assuming you were going over an existing finish. But if the start stop areas are abrupt enough you can still see them. That was my concern. If you have enough just do the entire side. Two wet coats should do it.
 
Will the SPI intercoat mix ok with Wanda if I decide to feather out the blends some.? It’s going to be close on having enough base.
 
If you need to SPI Intercoat will intermix fine. Just take your RTS(ready to spray) base and mix it with the Intercoat. If you are trying to extend the base, do your first coat full full strength over the repair/epoxied area. Next coat mix it 1:1 or less if you have more base and cover the entire side. Or you could mix it 2:1 (2 parts RTS base 1 part Intercoat) and shoot 2 coats over the whole side.
 
When you talk about the intercoat you are referring to mixed intercoat 1:1 with reducer? Then add that to my base at the ratio I choose to extend my base?
 
Reduce your intercoat 1:1. Only use a high grade urethane reducer preferably SPI. Then mix the reduced intercoat with your ready to spray basecoat. I would get coverage on the repaired area using just base if at all possible. If you have enough, do your first coat with base only. Nice medium wet coat. Then reduce your RTS base with RTS intercoat and do a second coat. 1:1 would be good.
 
the rainbow thing is fine. base will tend to do that that when its right on the edge of blushing OR when you shoot it really wet like clearcoat so it flows out and leaves a slick finish like you have in the pic. if its a cool and really humid day then go thin coats and allow more flash time. with that said though, there was nothing wrong with the base you had down. you can just clear it. wanda is a very good base.
 
base isnt supposed to be sprayed really wet. it should not flow out like clearcoat does. just medium coats. base will generally dry to a matte finish
 
Should I not lay the base down as wet/slick?
Everyone's idea of wet/slick is different. IMO one of the most common mistakes painters make is applying the base too heavy, trying to get coverage too quick. It can cause a multitude of problems now and down the road. I apply my base wet enough to be slick, but not heavy, if that makes sense, and don't worry about coverage the first coat, especially.
 
Update. Let the spi epoxy I sprayed yesterday set overnight, put a few coats of base on this afternoon and the rainbow is back. Didn’t see it in the first two thin coats I sprayed. But when I put the third coat on a little wetter to make sure I had good coverage it came back. First coat was very light withstand lot of epoxy still showing. Second coat covered better but still some light spots. Third coat covered but rainbow look came back after it flashed.

Think I’m just going to clear it and hope for the best.
 
Let us know after clear. I think Jim C may have hit on the blushing thing. altho not normal this time of year and with the modern base coats BUT I have a Toyota dark hunter green color that did the same thing even on test panel. Used another base and no problems. Sprayed this left over base again to test last night after reading your post and again blushing . Moisture in base???????? Just guesting Oh a paint store mix
 
Back
Top