Clearcoat Sinkage
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Hi,
im new on here, stumbled on while trying to find an answer to my problem. We’re using the Standox (Standohyd) Waterbased paint scheme, and once the item has been baked, the clear coats appears to have sank ?.
Base coat looks nice and flat before the clear goes on, and prior to baking, the panel looks great, but once its baked it sinks. Even tried leaving it overnight to dry naturally without heat nd is still the same. Only thing is, it tends to happen more on new panels and is much worse on Silver’s. But once its cut with 1500, then 3000 and buffed, its fine! :blink:Thanks,
ScottAre you sure it is the clear shrinking, not the undercoats? Can you see the sand scratches? What grit(s) are you finishing with? How much clear (film build) are you applying?
Are you using any 1K products?
are you letting the water base dry enough before clearing
Well, an example, We get a new door and buff the electrocoat with 320 and 320 round the edges by hand. Wipe with Standox silicon remover and then a final wipe with Standox cleaner (panel clean) , then a light coat of etch primer, then a full coat of wet on wet primer, flash off for 5 – 10 mins, then a full coat of base and let it flash off, then another full coat and let it flash off and then a drop coat. Mix up clear and give it a full wet coat, and let it tack off for 10 – 15 mins and then give it another full wet coat. The panel looks fine before baking but once the panel cools after baking, it sinks!. We bake at 70 degrees for 25 Minutes.
Thanks,
Scottand do you see the same thing with out the primer , …. for instance if clearing over just base or sanded clear coat?
I see little die back on clear coat over sanded clear , some on things that are just based and cleared , and more pinch on things that are epoxy primed, based and cleared. :kofee
I suspect the epoxy primer :whistle:
Aren’t you suppose to spray Standohyd back to back coats with no flash in between?
With Cromax if you spray any additional coats after your initial 1.5 coats it will die back on you. Try spraying it with a light pass, a medium pass and a control coat back to back. let dry and clear if it looks good and covered.
again i am not a production guy nor am i using water but that all seems extremely fast to me. maybe i am still in solvent mode i’m not sure but 5-10 minutes flash between coats…you gotta be trapping some sort of solvents there. shrinkage is from one thing, trapped solvents coming out of the paint film. etch primer doesn’t help since its a 1k product and sucks up solvents from anything you put over it.
Kinda wondering why you would put etch over e-coat as well
I was looking at some Martin Manure Etch P-Sheets the other day. And I saw that E-coat was one of the listed substrates.
And I thought the same thing: What’s the point? :huh:But I guess it applies the same as to using it over Fillers.
Nobody is going to waste all their etch covering all their filler work, (Although with the Cost of Etch I’m sure they’d like you to.)
But I think it’s entirely just listed so that you can spot in burn through’s, and not have to worry about being extremely careful around the surrounding coatings.Although I do think that many people mis-read these P-sheets and try to put the stuff on like epoxy.
Which in the end just ends up costing them a lot of coin.[quote=”Scott_Thomson” post=17286]Hi,
im new on here, stumbled on while trying to find an answer to my problem. We’re using the Standox (Standohyd) Waterbased paint scheme, and once the item has been baked, the clear coats appears to have sank ?.
Base coat looks nice and flat before the clear goes on, and prior to baking, the panel looks great, but once its baked it sinks. Even tried leaving it overnight to dry naturally without heat nd is still the same. Only thing is, it tends to happen more on new panels and is much worse on Silver’s. But once its cut with 1500, then 3000 and buffed, its fine! :blink:Thanks,
Scott[/quote]
what kinda gun set up ya using tip size an brand of gun??We hardly ever use the etch, also it cant be anything to do with it if it was, wev tried it with and without and it made no difference. We’ve got a DeVilbiss GTi W for base, and a GTi W for clear, both with 1.4 fluid tips.
Thanks,
Scott[quote=”RatStang” post=17340]I was looking at some Martin Manure Etch P-Sheets the other day. And I saw that E-coat was one of the listed substrates.
And I thought the same thing: What’s the point? :huh:But I guess it applies the same as to using it over Fillers.
Nobody is going to waste all their etch covering all their filler work, (Although with the Cost of Etch I’m sure they’d like you to.)
But I think it’s entirely just listed so that you can spot in burn through’s, and not have to worry about being extremely careful around the surrounding coatings.Although I do think that many people mis-read these P-sheets and try to put the stuff on like epoxy.
Which in the end just ends up costing them a lot of coin.[/quote]I think the idea is that if you have burn throughs in the E-Coat, you can etch the bare metal prior to sealing (if your sealer isn’t DTM). So some etch does go over the E-Coat.
So did we figure out if its dieback or sandscatch sinking? I’m curious about the wet on wet primer with only 5 minutes flash, I’m not familiar with standox but know in my line the fastest one is 15 before topcoating, if you try and cheat it usualy results in dieback.
I dont know about the rest of the ppl in the thread but i’m not sure where its sinking exactly, do you see all the sandscratches from when you sanded the panel? are you over-reducing the primer?
[quote=”jimmo” post=17395]So did we figure out if its dieback or sandscatch sinking? I’m curious about the wet on wet primer with only 5 minutes flash, I’m not familiar with standox but know in my line the fastest one is 15 before topcoating, if you try and cheat it usualy results in dieback.
I dont know about the rest of the ppl in the thread but i’m not sure where its sinking exactly, do you see all the sandscratches from when you sanded the panel? are you over-reducing the primer?[/quote]
I agree, 15 minutes is typically the minimum for urethane sealer, and flash is usually doubled if you apply a 2nd coat.
Hi
what hardener are you using in the clear if it is very fast one you will get a slight drop in the gloss.
This may be even more apparent if you are extending the bake i.e. check it is not a 15-20 min bake hardener.
Are you adding any reducer to the clearcoat mix, if using a fast hardener it may be the reducer that is causing the gloss drop. as sometimes the mix is different with different hardeners within the range.
If none of the above try extending the gap between wet and wet and base.
That clear is either dropping down through the product or is getting to much heat too quick
After reading your post again you mention not baking so i suppose that rules that out hmmm.
Silvers usually have a heaviest pigment in them i.e. course aluminium etc, witch leads me to think the base is not dry enough, and your clear is sinking into your base.
Experiment next time you have some base left over use it on an old panel , and just leave it sitting in base
clear it with your next job and compare the two panels the one you just painted and the well cured base on the scrap panel
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