Using vacuum to form a mask

[TomBanwell]

Here is a teaser photo for Leatheroo showing the results of my tests today with using a vacuum to pull leather down over a face form. I am quite pleased with the results. I will follow up in a few days with details and diagrams. After I took the photo I noticed the wrinkles on the bottom of the chin, and I removed them. This is so simple to do, once you have the equipment. I look forward to sharing with you all.

[Beaverslayer]

So I seem to have started something with the "teaser" pics......note to self....stop it!

Banwell, you've really peaked my curiousity here, we are going to have to see just how you did that...PLEASE I see endless possibilities with this.

Ken

[leatheroo]

oh oh oh oh...more more more....i bet you did this in minutes and it took me hours...i too had the chin folds

[zman7458]

I'm just guessing here, but I would imagine those space saver vacuum bags would do the trick. since they are already set up to accept a standard vacuum hose. I'm curious tho Tom, did you make a negative form from your positive to put on top of the leather before you put it in the bag, or is thet just from the positive and just plastic bag (hense the chin wrinkles)on top?

Edited April 10, 2008 by zman7458

[cem]

Please more pics of this especially the edges of the mask, I've done vacuforming with styrene before and would love to try it with leather. This would definately come in handy with a project I'm working on at the moment and probably save me a heap of time.

Cheers,

Clair

[TomBanwell]

Forming a full face mask using a vacuum

Let me first say that the following information is based on a single attempt to create this mask, as a response to Leatheroo's request for help with it. While I have years of experience working with leather and with vacuums, I had never done much using the two together. Hopefully my results and report will provide a starting point for others to experiment.

The Equipment

The ease of pulling leather down over the face form was accomplished by using a strong vacuum rather than the pulling and pushing normally associated with wet-forming leather. The overall system consists of a vacuum pump with an on/off switch, connected to a rubber hose connected to an open/closed valve, connected to a galvanized pipe with an open end. With the pump turned on, a vacuum will be pulling air into the pipe. The valve is used to control how strong the vacuum is--anywhere from full vacuum to zero vacuum.

The face form itself has a smaller (½") galvanized pipe about 6" long attached to it by means of a floor flange, into which the pipe is threaded. This shorter pipe is placed inside the larger pipe coming from the pump. By placing a plastic bag over the form and holding it tightly against the larger pipe a seal is created, and by turning on the pump the air will be quickly sucked out of the plastic bag, pressing it tightly against the face form.

Which vacuum pump you use is critical for success. Vacuum pumps come in many different sizes and strengths. The important specification is how strong a vacuum it pulls. In the U.S. this is measured in inches of mercury. The pump should pull at least 28"Hg to be effective. Household vacuum cleaners aren't strong enough to be used for this purpose. At the other extreme are high vacuum pumps measured in microns and used in industry and medicine. These are pricey and not necessary. In between are pumps used for removing freon from refrigerators (and many other purposes) and this is the right sized pump for our purpose.

One such pump available on ebay is the Robinair model 15600, which is ½ hp and draws about 29"Hg at 6 cubic ft per minute. The CFM measurement isn't important for this procedure since there is no rush to pull the leather down.

The Material

As anyone who has tried to force a flat piece of leather into a three dimensional shape knows, there is a lot of resistance in the material. What is required is a leather that becomes very pliable and stretchy when it is wet, and will retain it's shape when dried. It seems obvious that the thinner the leather, the more readily it will conform to the face form. While we might assume that leather needs to be vegetable tanned in order to absorb water, in fact I used garment lambskin, which I assume is chrome tanned. It does absorb water from the flesh side, though apparently not from the topgrain side. I purchased this leather years ago from The Hide House in Napa, California, and it measures about .04" or .8mm thick.

When saturated with water it becomes almost gooey on the flesh side. I haven't tried the 1mm (2/3 oz) veggie tanned leather that Leatheroo used, so can't say how it would behave. I suspect that cowhide is not as flexible as lambskin, and so may not perform as well.

The Technique

I cut a circle of the lambskin about 18" in diameter, enough so that it would drape over the form and all cut edges could be gathered together against the pipe. I soaked it in lukewarm water, rubbing the flesh side against itself under the running water to force it to absorb it. Once saturated I squeezed it to rid it of excess water, then draped it over the form (I should have waited a few hours to get it dryer, but I was too anxious to be that patient). I then gathered up all the edges below the form against the pipe, and pulled down hard enough to smooth most of the leather out. Using black vinyl electrical tape, I wrapped around the leather where I was holding it to seal it against the pipe, and went round and round, overlapping the tape as I worked downward until all of the leather was covered.

It is important that there be no air leaks anywhere in the system, and so covering the leather all the way down the pipe is part of this. For a face mask, the top near the forehead is going to be cut off there, and on the chin it will wrap only a short way otherwise it would poke the throat. The sides are where the leather must extend the furthest, so I insured as I pulled it that the sides were smooth, and all wrinkles went to the top and bottom.

At this point I tested it and turned on the vacuum pump. Immediately the leather was sucked against the form, with wrinkles showing up in various places. I knew I could work those out. My bigger concern was that the leather was bridging several parts of the face: Across the eyes, around the nostrils, and between the lips. What was happening was that the leather was being sealed against the form by the vacuum leaving air in those pockets. I knew that the way to resolve this was to direct the vacuum directly to those areas, so I removed the mounting pipe and floor flange and drilled six small holes from the face to the back of the form. Two holes each in the inside corners of the eyes, the nostrils, and the corners of the mouth.

I reassembled everything and this time the lambskin all pulled down nicely into every crevice of the face. I did need to work out some of the wrinkles, which was quite easy to do. I could reduce the vacuum as needed by adjusting the valve, in order to move the leather around to where I needed it. Once I vacuumed it the second time I spent less than a minute easing the wrinkles out of the chin. I used a heat gun set on low to speed up the drying, as the pump isn't designed to run for hours at a time. You can't turn the pump off until the leather has completely dried or you will lose some of your shape.

It would probably be a good idea to seal the mask while on the form, but I did nothing more to it. The finished mask is delicate in that it is easily deformed, so if you were to make it to actually wear I feel it would need either some reinforcement, or be made out of cowhide which would be stiffer.

[leatheroo]

tom, thankyou for going to all this trouble, it would be interesting to see if it works with the veg tan but i feel it should. this method could be used for lots of projects...the ideas are coming quick and fast

you are my hero

another example of the great and generous people on this forum

[Beaverslayer]

Tom, EXCELENT instructions. Thank you so much for taking the time and effort to put this together, this is why this forum is the BEST you will find anywhere.

I would never have thought that you could form Lambskin in this way and have it hold, very neat.

Ken

[TomBanwell]

I have ordered a side of 2/3 oz veggie cow and I'll give 'er a try. This is a better weight for making masks in general I suspect. Glad to help out.

[cem]

Thankyou for the thorough explanantion Tom, I thought it would have something to do with a vacuum pump. I would love to get one but need other things first but it's definately something I want to try in the future.

Cheers,

Clair

[zman7458]

Hey now, theres a novel approach! I would never have thought you could get enough suction on a porous material like leather to do that without something to contain the negative air preasure. great how-to Tom, you da man.

[TomBanwell]

I would never have thought you could get enough suction on a porous material like leather to do that without something to contain the negative air preasure.

I also was surprised to find that the leather alone held air. I had assumed I would have to cover it with a sheet of plastic to contain the vacuum, which would have made it much tougher to slide the leather around to eliminate wrinkles. Can't wait to see if cowhide behaves the same way.

[TomBanwell]

Here is a picture of the other set-up I referred to earlier. It is a flat-bed vacuum former, designed for making foot orthotics, but would work well with masks as well. The table has a series of small holes in it through which the vacuum pulls air. The top lowers down over the table, and after the edges seal, the natural rubber bladder (tan colored) is pulled down around your form.

If your leather isn't airtight (for instance, if you've sewn more than one piece together), you will need the bladder or something similar to contain the vacuum. This method makes it harder to work out the wrinkles, but does save on how much leather is wasted.

[MadTailor]

That is great wrire up. Thanks

[TomBanwell]

I received my 2/3 oz veggy cowhide today, and proceede to try the same vacuum technique that worked with the lambskin. It is much less stretchy, and thicker, and didn't work well. I discovered a hole in the piece I had prepared which made fully testing it impossible without starting over again, but from how it was going I am skeptical that it's going to work.

[leatheroo]

thanks for all you efforts with this project, it is much appreciated.

[TomBanwell]

I tried the same face form I used before on my flatbed vacuum former. This setup uses a sheet of natural rubber to maintain the vacuum seal, so you can use a much smaller piece of leather for the mask. On the downside is that you can't directly work the leather to eliminate wrinkles. Unlike a plastic bag, the natural rubber lays quite smooth against the form, due to it's ability to stretch quite a bit.

[leatheroo]

this looks like a great result, is this the veg tanned leather? if so any wrinkles left could be smoothed out with a modeling tool after the vacuum process. i find with the veg once it is stretched it says there. the picture above would make a great wall hanging, i can just see it hanging in a frame!! thanks again for all the work you have put into this process.

can we see a close up of the face?

Edited April 18, 2008 by leatheroo

[TomBanwell]

this looks like a great result, is this the veg tanned leather? if so any wrinkles left could be smoothed out with a modeling tool after the vacuum process. i find with the veg once it is stretched it says there. the picture above would make a great wall hanging, i can just see it hanging in a frame!! thanks again for all the work you have put into this process.

can we see a close up of the face?

Sorry to disappoint you, Caroline, but there was no leather involved. I was just testing to see how well the rubber bladder would pull down around the face form. I am going to give some veggie tanned leather a go with this setup, and I'll let you know the results.

[Cyrex]

Awesome stuff. Very cool!

[fishguy]

So what ever happened to this project? Did the 2/3 ounce leather work?

[TomBanwell]

No, the veg tan leather didn't stretch enough. Lambskin was far better.

[Cthomas1998]

Tom, I realize this is an old post, but I'm really wanting to make a vacuum setup like yours. Can you tell me what thickness the natural rubber is, and a good source to purchase a piece?

Thanks,

Chris

[TomBanwell]

Tom, I realize this is an old post, but I'm really wanting to make a vacuum setup like yours. Can you tell me what thickness the natural rubber is, and a good source to purchase a piece?

Thanks,

Chris

Hi Chris,

I haven't been on the forum for awhile. I don't remember where I got that rubber. The thickness is about 1/8".

[Cthomas1998]

Thank you Tom ! I appreciate it.