For you automotive painters...

[Idea Design]

I had a guy call me and ask for some paint mask to be cut for an airbrush design he was doing on a bike tank some time back. I cut the mask and he painted and everyone was tickled pink.

The a friend of mine who is an automotive painter called wondering the same thing. Could I cut some paint mask for him to use in an intricate design he was doing. I said sure can, then I cut everything and sent it off to him.

Fast forward through the weekend and he calls me to ask if there was a mix-up in the vinyl I used to cut his masks. I told him they were all cut from the same roll (20" spray mask from SW) and he told me a story about paint reducer not being able to get along with the paint mask.

He had sprayed a candy coat that was fully cured, applied the first mask, painted, then applied the second mask, and applied a full "wet coat" and after about 20 or 30 seconds, it's like a horrid chemical reaction occurred and the vinyl began to wrinkle and shrink right there under the paint.

Do any of you painter guys know what may have happened here? He pulled some of the weeded material out of the can and put it on the floor and simply poured some reducer on it. Again, 20 or 30 seconds later, it shriveled up like it was being held above a fire.

Is there anything I can offer up as a solution to this problem? It seems as if only the "wet coat" as he referred, is what's causing this. He believes that if he does more of a dry coat, the problem doesn't show itself. I know nothing of automotive paint, so I'm swinging blind. It makes me nervous to possess a roll of "spray mask" that may very well ruin a high dollar paint project.

Thanks, I know there's a couple of dedicated painters out there and I'm counting on you.

 

[Vicg]

Ive been using the vinyl spray mask that Beacon graphics has , we use it for stencils with a pretty harsh epoxy spray ink without problem. if you dont want to buy a large ammount message me i can send you a piece to test i have about 300 yards 15" wide in stock.
Vic

 

[Pat Whatley]

I cut paint mask all the time for a custom paint shop around the corner and they've never mentioned a problem. I'd be interested in what caused it....might come in handy for stripping vinyl one day.

 

[Jillbeans]

I cut Oramask all the time for my pinstriper buddy down the street (uses HOK) and sometimes for my son's boss at the auto body.
The only time I have ever had mask crinkle was when I used Avery for the HOK guy.
I never tried the white Gerber mask for automotive use, but I hate it for a paint mask as it is too thick and brittle for my liking.
It may be best, if a supplier can send you a few free samples, to give them to the guy to test his paint with.
Love....Jill

 

[907customs]

I had a problem with the yellow stencil film from SW also. Cut stencil for a Harley gas tank, the customer said it basically melted, ruined the whole paint job. I've been scared to use it ever since.

 

[Vicg]

oops my last message looks funny i ment to say if you want a sample of what we use ill gladly throw some in the USPS mail for you free to try out , if it works then beacon has the stuff we use.
Vic

 

[OldPaint]

you gota watch these "body shop painters"..........and YOU need to ask what paint system they are gona use with the mask.
HOK..........has some high voc reducers, so it is important you know which MASKS will not react to these chemicals.
2 STAGE PAINTS(base/clear) from most other paint companies...DUPONT/SHERWIN-WILLIAMS/BASF/SEIKO etc. are usually the same basic chemicals and wont destroy most mask.
SINGLE STAGE(paint&clear 1 coat) some of the hardners will mess with mask.
ive used ORACAL MASK, with single stage & 2 stage, and never had a problem.
now i have never hit the mask with the CLEAR.... so it might have some reaction to it.
but most of the time when the paint guy uses CLEAR, there is no masks.
what they use for REDUCERS in the paint is usually the culprit. the hotter the reducer the more chance of it wrinkling.
MEK(menthol Ethel ketone) is the worst, will eat anything it gets put on.
ACETONE .....is next.
LACQUER REDUCERS
ACRYLIC ENAMEL REDUCERS
TURPS & MINERAL SPIRITS being the least harmful.
find out what he used for a reducer, check with manafacture of mask to find out how reducer resistant their mask is.

 

[Idea Design]

Thanks for all the replies and just FYI, this was some non-identified blank backer white mask that I got from SW.

He is, in fact, using the House of Kolor system, I know that for sure. It seems as thought the HOK reducer may be the culprit here.

Why would only start to "flash" after a certain time under the chemical pressure of the reducer instead of right away? Why is the chemical reaction not immediate?

I wonder if the suppliers of the mask would know the answers to these questions or is it something that needs taken up with the paint system manufacturers?

 

[OldPaint]

to make it simple, the VOC's in the reducer are what do the the damage. the LIQUID suspends these chemicals till they are in contact with the mask. now the reducer, liquid, is a fast evaporation chemical, this in turn causes the molecules of the mask to "pop" and the reducer takes the air out the molecules as it evaporates.
GOT IT?hehehehehehehhe

 

[knucklehead]

As a painter, I can tell you all paint mask are not created equal. Some are not "solvent proof", your airbrush buddy might have been using waterbased paints, with a lot are these days. Then your other buddy shooting solvent based material, fried the mask.

Just what is menthol ethel ketone?

 

[Gino]

Methyl Ethyl Ketone M.E.K.

That's some wicked stuff. That will melt anything down within seconds. If you know what you're doing, you can use it as a cleaner. We keep it around for those hard to remove adhesives, but I'd never suggest to anyone here using that doesn't know exactly how to use it.

 

[visualeyez]

Used MEK on vehicles without a resprorator multiple times not knowing what I was doing. Even got MEK in my eye one time. Stuff is harsh but works great.

 

[andy]

House of colour is a two pack system

The base, colour coats are thinned with a matched 2 pack thinner. The final clear coat is mixed with a thinner/ hardener.

If the mask is reacting with the basecoat then your painter is simply laying the paint on too thick....you need to work with a series of light coats which are allowed to flash off before re coating. This is the best way to build up body in the paint.

Dumping a thick, wet coat of mixed base coat onto a vinyl mask is equivalent to dumping the vinyl in a bath of thinners. With thin coats there is time for the small volume of thinners to evaporate off.... with big thick coats the thinners sits in the paint MUCH longer... this gives it time to attack the vinyl.

If you take a rag and dip it in two pack thinners you can quickly wipe over most vinyl without damage... if you leave the same rag which has been soaked in thinners on the surface of the vinyl for a minute or two it WILL melt the vinyl.

If it's the clear coat that's causing problems then it's probably a reaction with the hardener which you must add to a two pack lacquer in order for it to cure properly. What a lot of paint shops do is dump in an added accelerator. Most two pack clear lacquers take up to 16 hours to fully cure... the accelerator reduces this drying time by quite a lot.... BUT... these accelerators can cause weird reactions if you dump too much into the mix.

The first thing you need to find out is what part of the two pack process is causing the problem... if it's the base coat then switching to several thin coats will do the trick. If it's the clear coat then you might have to try a different brand or switch to a single pack lacquer which you thin with normal two pack thinners... there is no hardening agent.

MEK shouldn't be an issue.... it's way too aggressive for most modern paints, the ONLY thing we use MEK for is an alternative to peroxide when mixing up fibre glass resin.

 

[Jillbeans]

Just what is menthol ethel ketone?

It's the fresh minty one!