t5montecarlo said:GM used water-based paint in the '80s. The SPID on my 1986 MCSS says something like water dispersed paint.
that's messed up!you might be able to get away with that today with how far sealers have come in the past ten years!i'm told that i don't have to skuff the e-coat on the undersides but for me that mechnical adhesion(sanding) helps me sleep at night! [-o<shaggydjlg said:my ppg reps and i just had that dicussion what actually happened is the factories tried to keep costs down because paint prices were on the rise so what they did is skip a few steps.First the grey that u see under the peeling paint was not primer nor was it sealer it was the E-coat factories sprayed right over it without sanding it or sealing it. if they would have sealed it the sealer wouldve stuck to it..The reps explained it this way to me...sand and seal it.When u paint and the paint drys it grows (fingers) and they dig in the sealer to hold it there the E-coat is hard and the paint will not penetrate it as good as the sealer does. Second they sprayed really thin paint over it.If you peeled it u can actually see through it ..Hence the uvs goes right through to the e-coat causing the paint to blister or peel. On my 90 dakota it was repainted so u cant tell but on the 94 i just bought all the silver is peeling and the green is not reason being there is more paint where it is green (they painted them all silver first then the 2nd tone over that)and the uvs are not going through the paint to make it peel so it has nothing to do with it being water base paint.It was a matter of prepping and being skimmpy on the paint.
shaggydjlg said:My shop decided that we may not use the dryer and we will let it air dry it takes a bit longer but right now we dont see a need for it because we paint alot of panels at one time.And it is still dries faster then solvent.
if nothing else,i've found that it's worth the time/effort to do as many spray out cards as needed and keep them on file for future use,it's a pain when their's ten variants but worth it if the chips from the jobber aren't working out for ya.tell the writer in the office to start including time for these let down cards to aid the color matching when they write the job.it works out in the end because you do them everytime you run into a color you havn't done yet but STILL write/get paid for it everytime.we've been using whats called a sun gun.its a light made by 3m that produces sun-like brightness if the sun isn't outside for comparsion.i also find that before trying to match i will compound an adjecent area even by hand to get a better look @it.that control coat in the end is where it's at,you sound like your far enough away with the increased pressure too.i could see the mottling with the mettalics but not with the solids.i know its a stupid ? because the h2o covers better/faster than the solvent but are you putting enough material on?could it be the sealer showing through?one thing i've had to change from mixxing the solvent was to use a rubber mixing paddle vs the old wooden stick so your sure to get all the metallics from the sides of the cup.are you using envirobase or what?shaggydjlg said:Ive been gone for too long yes melloelky ive been told the same thing and i do sleep better at night also because i sand the E-coat before spraying.Ive sprayed a lot of cars with this water base and some turn out great and others.... mostly the light colors and black metallics seem to get the mottling effect going on.We tried a lot of diffent things and so far on some colors we really hate it.We learned by turning the air pressure up and holding gun farther away (about 2 foot) on the control coat it seems to help a lot.We have also noticed that a lot of there paint chips dont match the color of car.Hows the colors and painting for u going??