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Jennings Heilig

Vinyl mask question for you guys...

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So I've got Oramask 810 masking vinyl here that works great in the Silhouette cutter.  I've never used masks myself, so this is new territory for me.  For a design that's a single color (for example an F6F white star & bar), it seems simple enough to paint the model white, peel off the individual bars and the star and align them on the model before spraying it blue.  But for something that requires alignment like a three digit number on the fuselage, I see other mask makers providing the numbers in the correct alignment along with a rectangular cut around them.  

 

For the latter, I assume you need some kind of transfer tape to put over the mask before you peel it off the backing, in order to maintain the alignment of all the pieces, correct?  Do you guys buy your own low tack transfer tape to do that?  If not, what's your method?

 

Thanks!

J

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I use a clear film for transfer, I believe its called frisket film. I de tack it a little by sticking it a couple of times to my shirt first then use it to transfer the whole mask to the model, remove the transfer film and then whatever part of the mask won't be requiring the paint job. Usually cut a square of it just a little larger than the mask that needs to be moved. Dont cut your masks in the silhouette until you're about ready to use them, I find theres more often than not a little shrinkage in the film once cut, in that the part inside the cut pulls away a fraction from the material outside the cut. The gap widens over time, we're not taking a Grand Canyon sized void but a small one that really only causes issues on multi part masks requiring painting in various colours leading to bleed through in some cases. For instance, I tend to prime my model, paint the national markings and what not. Cover them back up with the masks, seal them down nice and tight then paint the camouflage scheme over the top. I did this mostly due to at the time I was using Mr Colour paints and covering a dark colour with something like the White for an RAF roundel id get some build up and raised edges from the number of coats required to cover the darker bases colour. I find this not so vital now I'm using MRP paints with their thinness and great coverage. So anyway, having left the Roundel masks on the kit for a week or 3 whilst life got in the way between painting sessions I'd found that initially despite all 3 circles butting nicely to each other with no gaps by the time came to complete I had gaps between all 3 circles of the wing roundels and all the circles on the fuselage which if I hadn't noticed them id have ended with hairlines of the Green and Grey top colours within my roundels. In this case i just used masking fluid to kill the gaps. Meant I couldn't re use the masks but now I have a plotter its not an issue to cut more.

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Posted (edited)

I'm asking because we're probably going to launch into providing masks plus decals in the fündekals package for certain projects.  I wonder if sealing a mask inside a zip bag will prevent the shrinkage?  Anyone tried that?  Obviously we'll have to cut the masks well ahead of when they're going to be used.

 

J

Edited by Jennings Heilig

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Indeed, as ade mentioned, frisket film is what I use too. Some use cust to fit sections of Oramask or whatever mask material they are using, but I have found them very unhandy to work with as they are not fully translucent, and it's super hard to see where you are placing things.

You can get frisket film even at the local Hobby Lobby, and of course Amazon and what not. It's nice as it's generally very clear, and you can easily see where you are placing your mask. Plus it allows you to cut a section big enough to transfer the while mask all at once, then weed out as necessary from there.

I've found especially so with things like Brit roundels that make concentric alignment and alignment of many multiple mask components critical. Much easier to transfer the entire mask over all in one go as it keeps the positive and negative parts of the mask in the same relationship to each other as they were cut with.

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Regarding the shrinkage of Oramask 810: I remembered that Bob Booth (Bob's Buckles) had stated that he used Artool Ultra Mask.  I PM'd him to ask about shrinkage with that product.  He replied that he had experience with both Oramask 810 and Ultra Mask, and the Ultra Mask had much less shrinkage.  Of course the Ultra Mask is more expensive as it's an Iwata product (or at least distributed by Iwata in the US).  I'm just throwing this out there so you know that there are alternatives to Oramask.  You would still need to use some transfer tape for the multi-part/multi-stage masks.  Also, I have only been using my Silhouette for a very short time and have very limited experience with Oramask 810 and the Tamiya sheets.  I have not personally used Ultra Mask yet.

 

Bill

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I've found you can minimize and nearly eliminate the Oramask 810 shrinkage issue by 

1 - like ade mentioned, dont cut your masks until the 11th hour - yes, not possible or nearly impossible if cutting for a set.

2 - keeping the Oramask both uncut and cut masks in as cool and dry a spot as possible. I found heat really exassorbates the shrinkage issue.

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2 hours ago, Out2gtcha said:

2 - keeping the Oramask both uncut and cut masks in as cool and dry a spot as possible. I found heat really exassorbates the shrinkage issue.

 

Thanks for all the info guys.  Keeping stuff dry is not a problem (at ALL) here in dry-as-a-taco-chip southern Arizona.  If anything, we have too little moisture in the air (right now the relative humidity is about 8%).  The Oramask I have on hand is a couple of years old, and it's been in my office the whole time.  I'd think if it were going to shrink, it would have already done all the shrinking it's likely to do.


I'll look into the Iwata stuff.

 

Appreciate the help!

J

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The Maketar and Montex masks I have from before I got my Silhouette cutter all came in the sealable bags and all have shrinkage. Again we’re talking hairlines not canyons but it does mean care and some consideration needs to be taken when using them and the method of application for painting. As I use them as both positive and negative masks a good seal is required to prevent bleed through. If I’ve painted markings before the camo coat I usually then place the masks over the markings to protect them and seal any gaps with masking fluid then shoot a coat of gloss coat over the masks to seal the edges, this further reduces the chances of bleed through or having paint run under the masks.  I think the shrinking has something to do with the tension the sheet is kept under when rolled up and in one piece, obviously when cut that tension is lost in places so you get some pull back from the mass of the roll. I don’t think there’s really any way to stop it. 

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9 hours ago, Jennings Heilig said:

  I'd think if it were going to shrink, it would have already done all the shrinking it's likely to do.

 

Heat is really only a huge issue for masks that are already cut. The noticable shrinkage that can render a mask unusable really only happens in between the negative and positive parts of a cut mask.

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I suspect the shrinking has something to do with tension in the material itself, rather than external conditions - though these could play a role, too.

 

Kev

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39 minutes ago, LSP_Kevin said:

I suspect the shrinking has something to do with tension in the material itself, rather than external conditions - though these could play a role, too.

 

 

It most definitely does. The process is slow enough in cool dry temps that I've been able to cut masks 24 - 48 hours before laying  them, but it took less than 6 hours for the mask set to become unusable in a hotter condition.

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36 minutes ago, Out2gtcha said:

It most definitely does. The process is slow enough in cool dry temps that I've been able to cut masks 24 - 48 hours before laying  them, but it took less than 6 hours for the mask set to become unusable in a hotter condition.

 

So how are companies like Maketar and the half dozen others who are selling all kinds of masks doing it??  They don't shrink, and they're certainly a lot more than 48 hours old, and they're subject to all the vagaries of temperature and humidity that happen in shipping from all over the world to addresses all over the world.

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Well honestly I'm not sure. The only experience I have with pre-made mask sets are from all my Ade Astra (now out of business) mask sets which are shrunk, and with the set that came with my Extra 330 SC from lcaerodesign, of which they had to send an extra set in order for me to finish. The intricate patterns for the fuselage were shrunk away from the background and they had to send a 2nd set.

 

It could also be that the 8x11 sheets I cut off the mega-roll of Oramask 810 I purchased has a higher pre-shrunk tension in it, but I cant imagine it would be sold in bulk any other way.

 

I can only share my personal experiences with Oramsk 810. I do actually love the product for making and spraying paint masks.

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Many mask vendors are using the yellow kabuki material rather than vinyl, and others may be using something other than Oramask. The sheet I received with the Aeropoxy Yak-3 certainly had signs of shrinkage. I'll have to check some of my other sets, and perhaps see if there's anything to indicate a reason for any differences in that regard.

 

Kev

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