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

[JLSleather]

As Kate points out in that other thread, the liquid can actually leave a residue on the leather. Depending on the tannage, the amount and length of time, this can also cause permanent discoloration (defeating the purpose of the mask).

We use some mylar stencils, though if we stencil we generally cut our own. Bristol board works about as well as anything - available in about any print shop for pennies (or pence, or quid...).

No adhesive at all as a rule ...and your single-action airbrush is not the problem. I've seen some STUNNING art done with single-action brushes.

The pressure will depend on the dye you're using and the brush you have. My Paasche sprays Fiebing's dyes at anywhere 15 - 35 psi, depending on the look I want. Normally around 20.

[Tree Reaper]

I believe the problem to be the bleeding which is bound to happen with penetrating dye.

The only sure cure I'm aware of is a sealing process on the entire surface to prevent the bleeding.

Careful hand brushing will work.

Spraying several very light coats may work or switching over to a water based dye that won't penetrate.

[JLSleather]

This was done with a waxy stencil paper, should be able to find online or in any hobby store. No sticky. No liquid. No bleed. Just have to use a VERY sharp knife to cut the shapes (burrs = bleed).

Edited April 21, 2014 by JLSleather

[RavenAus]

Hmm the sealer doesn't actually seal. So the whole point of doing that area in the first place was made pointless. I did mask it just in case but the dye still got under the tape, same as before, and went straight through the 3 times coated surface. Why would a company sell something in their range branded as 'Leather sealer' when it still leaves a porous surface? I can see it labeled as a finish but not when it says on the packaging it's a sealer. :/ Need to find a decent resist to spirit-based dyes now.

[cem]

RavenAus if you try the latex mask get the Winsor Newton latex masking fluid from an art store the general stuff used for making casting moulds here has a high ammonia content and turns the leather grey ok on stuff that will have a dark background but not on natural or light coloured dyes as the grey doesn't come out.

[Tree Reaper]

How does the latex prevent the dye from bleeding over and then up from the side?

[OdinUK]

I use liquid latex without problems.

[Tree Reaper]

I use liquid latex without problems.

With penetrating dyes?

[OdinUK]

Yes, but the dyes are airbrushed on. When I first started experimenting I did notice a slight change in shade where the latex had been, so now I apply the latex to the whole area being masked so that if there is a change in shade it will be uniform over the whole area. I just paint the liquid latex on with a brush, a small one for small detail or near edges and a larger one for the bigger areas.

[impulse]

Hi Raven. As A fellow Aussie, it may be useful to know that brushable latex is available from Adelaide Moulding and Casting - amcsupplies.com.au.............i would paint a little of this around the edges of your stencil, press onto the leather then clean away any oosings with a cloth dipped in soapy water. This provides a good seal, as long as you spray LIGHT coats of dye. Hope this helps.

Cheers, Lois

[Tina]

I use Winsor Newtons yellow masking fluid without any problems (2 layers). I use it with both airbrush and hand coloring and it does not change the color of my hides at all.

[RavenAus]

Excellent, thank you all It's really been bugging me. I'm still trying to get an answer from the dye company as to what they recommend as a resist to their dyes. 3 coats of their own sealer and the dye went straight through. I will definitely look into the latex