What cause solvent pop?
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Is there anyone here had solvent pop before. we witched a new fast clear recently and always get solvent pop on hood.can anyone share some experience or tips to get away of that? And what is causing solvent pop? Thx
cheap fast clears tend to do that even after applying the first coat. if its doing it on the first coat you can reduce it a little if theres room for that on the tech sheet, to slow it down a little. if its doing after your subsequent coats then your not giving it enough flash time.
R u talking about the flash time between coats or flash off before bake?
i was referring to the flash time between coats. are you baking it? does the solvent pop happen all over the hood? or only where you over lap in the midddle? if its happening only on hoods or horizontal surfaces and all over maybe your applying it too heavy?
They are all over the hood . I did the 2nd clear with 5mins flash, and 5mins flash off before bake.it could be a little bit too wet because I put one more midium wet coat clear after 2nd coat(it don’t looks enough thickness)
The speed clears tend to be thinner, if your going to put a third coat on it I would wait until it stops stringing before you put that last coat on. Then give it a little more time than the tech sheet says before you bake it.
Chuck
I think that’s the problem I put the third coat right after second,wait until no stringing? It’s goons be more than 10mins.will that skin over?
There is some good advice here.
Can you get by without baking? Try doing one and bake it right away after your last coat of clear. Sometimes they will skin over while flashing before bake, then the high heat just boils the trapped solvent.
Some booths take quite a while to get the panel temp up high enough on the bake cycle, giving the clear even more time to skin over, so the flash before bake can be sorta a waste. Every booth is different, but its worth looking into.
Solvent pop is too much too soon, pounding on solvent rich material will trap solvents and cause them to pop.
i avoid thinners in HS clears and i also avoid the temptation to whack a third coat on if it isnt needed ,if you thought you hadnt got enough on the bonnet then what made you feel there was enough on the sides becouse a bonnet is usualy where we all tend to flood it on ,as for flash tmes it depends on temp and airflow ,five minutes sounds a bit ambitiuos to me ,i rely more on what the product is telling me than my watch 😉
I sanded the hood and polish today,and find out the pop is really on the top,not so deep.so is it flash too long before bake? I don’t put reducer in clear.
Could be a number of things, doubt if it is to long a flash off
could be
Excessive film thickness. Insufficient drying time between coats
Drying cycle was started too soon after application.
Baking temperature too high.
Over the years i have found if there is solvent pop in the booth it is usually down to to much material on the panel and to much heat.
Think about it this way where is solvent pop usually found ? hood, roof, decklid. all the flat panels where the application is much heavier.
Sometimes guys that spray at lower pressures are susceptible to solvent pop as they paint much slower and generally use more material, this most evident when using H.S. products.
I would put money on your first coat skinning over before solvent can gas out,then hammering on a second coat will make it worse.In a down draft booth you should never use a speed clear or the fastest mix possible on a horizontal surface,it will always bite you in the ass with solvent pop or dieback.Not many painters realize this but I find it easier to slow down my hardeners and reducers in order to “speed up”For example if I do a side or a front end I will always use slow everything and maybe a bit of accelerator to speed up recoat times.A slower mix will result in a wetter thinner coat that will flash/cure faster than a turbo mix.If I bake it I can move it in 35 mins or if Im in a hurry I can unmask and move in 20 mins of air dry with the booth running.Maybe give it a try…..
Also with some speed clears you are better off doing 2 medium wet coats back to back with no flash time,this will eliminate the risk of your clear skinning over…..but you have to be careful :stoned
thanks for sharing! I will have a try tomorrow cuz I have one front end to do. Hope everything goes right.
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