Jim C;37578 said:
sorry if that was confusing. i was agreeing that its a different animal than omni and that he always shoots epoxy before base. i just let the epoxy flash dull. 5-10 min if your doing a single thin coat is all thats necessary. the spi urethane sealer is good stuff but i just prefer the epoxy because the adhesion of epoxy is just so much better than urethanes. i dont think the epoxy over you filler work is a cure to your issue. it may help and there is nothing wrong with doing it but in the probably 13 years i have been using spi i have done more jobs that i can count without shrinkage issues and without putting epoxy over my filler. an hour for the base to flash in cooler or cold weather before clear is your problem right there. in a cool shop without a baking booth you can run a purge cycle on there is no way all the solvent you just soaked the primer with is out in that amt of time. the base may feel dry but there is still solvent in the paint film. in the winter with a cool shop and its just air drying then overnight dry before clear. in the summer when its warm base first thing in the morning and clear at the end of the day. this may not be the most productive but it the best way to do a paintjob where you know in 10 years it will look just as good as the day you did it. only way around it is a quick bake cycle after the base is applied.
alright, copy that. 1 light coat of epoxy and let it flash off before base. Only other question I have is are you applying 2k urethane sealer over top of that ? Only reason I ask is because of coverage issues. When I have a brand new black plastic bumper and I'm spraying it say solar yellow, I'm going to make certain that I completely cover it with sealer before laying base so that I'm not trying to complete coverage with my base that may or may not be like freaking water. I did a front end clamshell of a lotus a while back ( it wasn't black plastic though, it was fiberglass and I had primed it white), and if I had not made complete coverage with my tinted sealer( I added some yellow to the sealer)there is no way that I would have been able to make complete coverage because this yellow is literally like water, it barely has any pigment at all. Its almost all binder and balancer. If I hadn't have made complete coverage with my sealer I would have been left putting 9 coats of yellow on or something crazy.
As far as flash off times, is that 6+ hour window ( I'm just guestimating from the base in morning, clear at end of day comment) SPI specific or just a rule you follow in general ? I only ask because like I've mentioned multiple times in this thread, I've used DuPont for so long and I have never waited that long to apply clear and have never ran across this severity of soak up issue before. I would like to get all the details hammered out so I can make sure I don't have to deal with this in the future and/or have to sand and buff or respray anything ever again and lose money.
Now that I see your website, my local jobber actually told me to look you up, we were talking and he knows the kind of work I put out and mentioned you do a lot of resto's and show cars like I do, I will take all of your input and stand by it. I like the spi products, I just want to be able to get it correct so I'm not having to go back and redo things. It is a new product to me and I'm relaying most of what I do, to how I used to do it with chromabase. I know its a learning process so I'm looking for the best ways to go.
Bob Hollinshead;37585 said:
Solvent soak up- I did a singlestage job last fall, PPG DCC, all the parts were shot with three coats and allowed to cure a month, I had used epoxy for the sealer, sanded the exterior with 320 dry followed by a light 600 sand and shot three more coats of DCC. I had ran out of SPI reducer and picked up some 885 Matrix for round 2-this was a big mistake. That solvent was so harsh it swelled up everything-it went deep and showed mapping. The only choice I had was to sand it to open the surface up and wait it out till full cure then sand and buff. It has been fine since but what a pain in the ass! I will never use matrix reducer again-maybe it was a bad batch of reducer but wth? Lesonal reducer also seems really harsh and people often complain about frying and mapping on repairs with it. I'll stick with SPI reducer from now on or use only PPG if I'm in a pinch. As Jim pointed out the primer always gets blamed for shrinkage and mapping but there is often other causes.
Yea that stuff is so garbage, I laugh at some of these shops I see on tv that are using matrix, it is terrible stuff, I used it once as well and the base just did not lay down right, it came out sort of chunky and turned me off immediately. I have only used SPI reducers for the last 8 months in everything I have done. I really like the reducers. I really like everything I have used from SPI so far minus my experience with the soak up issues, I just want to figure it out so I can move ahead and when something is done, not have to worry about it.