Masking Off Problems

[RavenAus]

Hey all, had a little issue today while experimenting with the airbrush. Well, 2 issues really. The big one though was at the end. I masked off the area I wanted to finish with masking tape, pressed the edges down firmly to get a good seal, but after spraying the finish on and taking the tape off I found quite a few areas of leakage, as you can see in the picture. So the first question is, what do you use for masking off? I was using regular white masking tape, is there something better I can use that won't leave behind any residue to prevent later dyework?

Second point, as I'm sure you can see, is that I'm getting a fair bit of leakage under the stencil. This one was a metal stencil and looked to be good and flat against the leather but even so there's leaks and spots where there shouldn't be. I am sure some of this is due to my really cheap single action airbrush but even so, I'm getting this a lot. What pressure do you guys run your airbrushes at? I bought a regulator to control mine as the compressor didn't have a very good one and (from what I recall, I have to convert the reading to psi to understand my gauge) I run it at around 15-20 psi. The airbrush is a suction model I use for all dye applications these days - no more uneven finishes! - but stencils I'm having problems with. Do you use anything like a spray mount on them to keep them in place, or just hold them there? Any other tips for a newbie airbrusher?

Many thanks

Raven

ps: I'm in Queensland, Australia and the dyes and finish I'm using come from here - http://www.leatherfinishingproducts.com.au/index.php/cobblestone/ - Cobblestone dyes. Fantastic product, much easier to use than the Eco-flo and dilute with spirits or water.

Edited April 19, 2014 by RavenAus

[Tree Reaper]

What kind of metal is the stencil?

You might be able to use earth magnets on the back side.

You could cut out the shape of the butterfly in thin wood and clamp it over the stencil.

If it's bleeding you might have to seal it, paint and then reseal or use several lighter coats.

I'm using green masking tape but I wouldn't stick it to the grain side of the leather.

[RavenAus]

I think that stencil is stainless, so the magnets would work on that, but most of mine are plastic so I still need another method for them. You don't mask off on the grain side then?

[Tree Reaper]

I wouldn't want to put tape on the grain side and risk damage from the glue on the tape.

You would have to go over where the tape was with denatured alcohol after or seal it before placing the tape.

You could cut a hole in card stock, tape or glue the card stock on top of the stencil and secure the card stock with tape outside of the leather then use weights close to the edge of the stencil when painting.

[RavenAus]

Whichever way I go about it I'm still going to want to mask off part of the design while I apply finish to another though. The stencil lifting etc is the minor issue, it's the bleeding of the finish into the masked area that's the big issue for me. If I finish the outside I'm going to want to prevent the detail area from being sprayed which would require masking, and if I do it like I have this time I want to stop the finish from going onto the outer area as I've not dyed that yet. The only way I can see of doing that is not to spray the finish on but use a brush instead, and I'd really prefer to use the airbrush.

[Northmount]

Frog tape is what painters use for masking. Works much better, can get a crisp line. Something in the tape reacts with the moisture (if I remember correctly) to provide a better seal. It's about 4x the price of masking or green tape. The green and blue tapes are supposed to be easier to remove than masking tape, without pulling paint or paper with them. That is their selling point, not good masking.

And yes, make sure no residue is left behind.

When spray painting with a stencil, use very light coats so there is no liquid buildup on the edge of the stencil. Needs to dry at least to very tacky or dry state before the next coat. Brush painting with a stencil uses very thick paint. So when you compare the application, you can see that any liquid buildup will run between the stencil and the article you are painting due to capillary action.

Tom

[Tree Reaper]

Tom;

I've used Frog tape on leather and it doesn't adhere well, it may work well for painting trim in a house but I wouldn't recommend it for leather work.

[papaw]

You can use magnets on both side of your plastic stencils, and how about useing latex mask over areas you don't wish to cover.

[RavenAus]

2 people have recommended latex mask to me, I always thought that would harm the leather? I've not used it before, how hard is it to use, and to remove after?

[howie696]

Look at this thread

http://leatherworker.net/forum/index.php?showtopic=11101&hl=%2Blatex+%2Bmask

looks great