Mold box membrane

[Red Cent]

I am starting to build a vacuum mold box. Construction is rather straight forward but I need info on the membrane. I believe there is stuff that works well so I thought I would ask the experienced people before I bought any.

I will be doing concealed carry and some of them will be the hybrid holster consisting of some kydex/plastic. I need something thin enough to give me some decent detail and strong enough to take the HD shop vac.

Opinions anyone?

[Dwight]

Go to Joann Fabrics, . . . look at their clear vinyl, . . . that is what mine is made out of, . . 

I'll see if I can get some dimensions, . . . etc for you.

But if you are doing kydex, . . . you DO NOT need a vac box, . . . just get it droopy hot, . . . lay it on the gun, . . . drop a cold wet wash cloth on the kydex, . . . it's molded.  Trim and go..................

May God bless,

Dwight

Edited May 31, 2016 by Dwight

[Dwight]

Red, . . . the material itself is .0012 thick, . . . I contact cemented a strip about 2 inches wide all the way around the 18 by 26 bag.

The seal is made by two pieces of plastic pipe, . . . one has the bag wrapped around it, . . . the outside part is slotted to slide over the bag and the inside piece, . . . makes a good seal.

I use the little white cutting board behind flat backed holsters, . . . keeping them from getting folded up.

This has always served me well.  In fact, I made a reverse fold (sewing goes down the sight track) holster for a 1911, . . . made the mistake of shoving the gun down into the holster when it dried, . . . thought for a few minutes I would cut the thing off.  It was one of the first ones I did, . . . made a believer out of me.

May God bless,

Dwight

[chiefjason]

Go here and look.  This membrane is what I use.  Don't really use it for leather though.  Not cheap, but if you take care of them they last a long time.  I've been using the current one for several months.  

 

http://www.ifithermoplastics.com/products/hd-industrial-design

[Red Cent]

Hey Dwight, made me a kydex press a few years back. Use a heat gun if I need to touch things up. Press is a little of a pain. I use a food vacuum bagger at the present. Can't keep the wrinkles from the plastic out of my leather and spend time rubbing them out. Does a decent job. Recently bought a 20 ton shop press that is great at punching leather. Be putting air over hydraulic on it soon. Could take care of the kydex and mold problem.

Dwight, do you have a vacuum box?

The mold box intrigues me. One could make ten mag pouches or five holsters or whatever, all at one time with a reasonable size box.

Chief, do you have a vacuum box?

[Dwight]

No, . . . no vacuum box, . . . got a vacuum bag, . . . and it works wonderfully.  Sometimes it works too good.

I'm a "one at a time" guy, . . . prefer that to production, . . . did production in the factory for 30 years, . . . done with it.

Pitch the food bagger, . . . it's made for food, . . . not for leather.  See the other posts above, . . . no wrinkles, . . . no problems, . . . just a really good mold every time.

Takes a bit of "thinking" sometimes to get it to come out the way you want it to, . . . but all in all I prefer it over a press, . . . actually dismantled my leather press, . . . sold some of the stuff off it, . . . never use one again.

May God bless,

Dwight

[Ken G]

I use a high temperature silicone membrane from McMaster-Carr. The item I ordered was 8632k51 which appears to have been discontinued. The new number with the closest description is 1460N31. It is 1/32" 40A durometer with a 500 degree max temperature rating.

I use it to mold kydex shells for hybrid holsters and have used it to mold some leather also. I originally used a shop vac but get much better results with a rotary vane vacuum pump.

[Red Cent]

aaaaaah, gettin' there. I would suppose the rotary vane pump has some serious power over the shop vac. I was surprised at the reasonable prices also. Ken, did you build a box? And thank you very much for the info.

Dwight ol' boy, you are regressing.  Actually the food vacuum does a good job. Small area and the wrinkles are the problems. Difficult to get gun and wet leather in that little bag. The ability to have a large area to lay the mold gun down, lay leather on it, drop a frame with the membrane attached and not have to mess with it sounds good. Now the valves and hoses. I am getting a few requests for mag holders an hybrid holsters that I have turned down.

[klaykrusher]

Red Cent, here a couple links I found as I am interested in this also, although I will probably go Dwight's route. Didn't really compare items so not sure if pricing/quality is reasonable or not.

Amazon

Blugunstore

Thermapress

HD Design - Sells by the foot

And a video of Particle using his vacuum bag similar to what Dwight explained.  (Ifin you haven't seen this already)

Particle's Leather Vacuum Press

 

Forgot to ask:  What are folks recommending for the pump?

Edited June 1, 2016 by klaykrusher
edit

[Dwight]

For the pump, . . . this is what I use...........http://www.harborfreight.com/25-cfm-vacuum-pump-98076.html

May God bless,

Dwight

[JMWendt]

I've had excellent results with a vacuum kit I picked up from VeneerSupplies.com.  If you already have an air compressor, this system works really well and can be built at home in an hour or so.

http://www.veneersupplies.com/products/Project-V2-Auto-Cycling-Venturi-Vacuum-Press-Kit.html

They also have a variety of both vinyl and poly bags for use with vacuum systems.  Might be what you need. 

This system works much better than a shop-vac at drawing a vacuum.  Makes some tight holsters.  Has improved my work.

[Ken G]

Yes I built a box type vacuum former a couple of years ago out of some scrap materials I had at the house. It uses a 12" x 12" membrane so the overall dimensions are slightly larger. The basic box was built of 2 x 4 scraps with plywood top and bottom. I drilled holes in the top on a 1" grid. I sealed most of it with some two part boat building epoxy that I had on hand. I still have some air leaks around the gasket on the lid frame but I leave the pump running so it does not create any problems. I have been meaning to build a couple more with a better design and larger membrane area but haven't found the time.

 

I use a rebuilt Gast vacuum pump (model 1023-318Q-G274X) that I bought from a guy in Michigan who used to sell on ebay. I can't find him on there now but I do have his email address. Not sure if he still rebuilds them or not. It is a 1/2 hp pump which pulls about 10 cfm so it pulls down fast. The Harbor Freight pumps work fine but put them in the other room because I hear they blow out an oil mist from the exhaust port.

 

I mostly use it for hybrid kydex IWB shells but I have also used it for molding some leather dip can holsters and a knife sheath.

[Ken G]

The duct tape was actually an attempt to patch a hole in the membrane. It worked for a short while. I think this was the first prototype dip can holder I made with the vacuum formed leather.

[chiefjason]

Yeah, I just bought one of the smaller ones from Index Fasteners.  Looked at building one, but my skill level is a bit lacking in that category.  It was not cheap but I really like it.  Works great on kydex.  I tried it for leather but I use 8-9 oz and just did not like the results.  Plus introducing water into the vacuum pump means you have to change the oil more often.  

[Ken G]

I think I used 5-6 oz on that part of the dip can holder. I was concerned about the moisture also so I sort of towel dried the leather before molding. If I continue to do it I may put a moisture trap for an air compressor in between the box and the pump, figure that can't hur

With heavier leather you may need to help with some hand molding thru the membrane then let the press suck down for a minute or two to "set" the mold. The 1/32" membrane gives better definition with kydex but a 1/16" membrane may be more durable for leather with some hand work.

[Red Cent]

The food vacuum gives me decent definition. I carry some of it a little farther. I do not spend a lot of time getting detailed definition.

I still think the simplicity (other than construction) of the box works. I may not be satisfied but I want to put one together. Need to do some research on controls.

[stu925]

On 5/31/2016 at 8:29 PM, Dwight said:

No, . . . no vacuum box, . . . got a vacuum bag, . . . and it works wonderfully.  Sometimes it works too good.

I'm a "one at a time" guy, . . . prefer that to production, . . . did production in the factory for 30 years, . . . done with it.

Pitch the food bagger, . . . it's made for food, . . . not for leather.  See the other posts above, . . . no wrinkles, . . . no problems, . . . just a really good mold every time.

Takes a bit of "thinking" sometimes to get it to come out the way you want it to, . . . but all in all I prefer it over a press, . . . actually dismantled my leather press, . . . sold some of the stuff off it, . . . never use one again.

May God bless,

Dwight

Does your system hold vacuum or does the pump run the whole time you're forming?  Seems to me a lot of the vacuum forming systems are very complicated but most are designed for veneering wood where it would need to hold vacuum for a significant amount of time.  I'm thinking I could get away with just the pump and a bag and some connection hardware, at least to start with.

Stu

[Dwight]

3 hours ago, stu925 said:

Does your system hold vacuum or does the pump run the whole time you're forming?  Seems to me a lot of the vacuum forming systems are very complicated but most are designed for veneering wood where it would need to hold vacuum for a significant amount of time.  I'm thinking I could get away with just the pump and a bag and some connection hardware, at least to start with.

Stu

That's exactly what I do Stu, . . . put it in the bag, turn on the pump, . . . pull it down, . . . do the molding with it still on, . . . works really good for me.

I pulled a holster down for a 1911, . . . when it dried, . . . shoved the gun in it, . . . for a while I seriously considered cutting the gun out.  Finally worked it free.

I had a press, . . . it worked, . . . but with the upsurge in plastic fantastic firearms, . . . I knew it was just a matter of time until something "gave" under the pressure.

That is when I went to the bag, . . . it is my "way" so to speak.

May God bless,

Dwight

[particle]

Stu - I use a system like you're talking about. Cheap vacuum pump, then a veneering bag and pump hardware kit for the hose fittings, etc.

[dikman]

I built a vacuum system some time ago to stabilize wooden knife handles - never used it! The pump was made from a stand-alone single cylinder compressor head, belt driven from an old motor. I modified the input to the compressor head so that I could couple an air hose to it so it became a vacuum pump. It can pull 28" of mercury, which is the max vacuum I can get for my elevation. For the tank I used a 20 lb. propane tank, cut in half and welded a ring around the rim to fit a rubber seal. The top connection was adapted to fit a vacuum gauge and release valve and a nut was welded on the bottom half to fit the evacuation hose and a valve to close it off. I also made a wooden plate to fit in the bottom half so that I could use it for vac-forming, but haven't had a need for it yet.

I suppose I might find a use for it one day.....

[stu925]

6 hours ago, Dwight said:

That's exactly what I do Stu, . . . put it in the bag, turn on the pump, . . . pull it down, . . . do the molding with it still on, . . . works really good for me.

I pulled a holster down for a 1911, . . . when it dried, . . . shoved the gun in it, . . . for a while I seriously considered cutting the gun out.  Finally worked it free.

I had a press, . . . it worked, . . . but with the upsurge in plastic fantastic firearms, . . . I knew it was just a matter of time until something "gave" under the pressure.

That is when I went to the bag, . . . it is my "way" so to speak.

May God bless,

Dwight

 

5 hours ago, particle said:

Stu - I use a system like you're talking about. Cheap vacuum pump, then a veneering bag and pump hardware kit for the hose fittings, etc.

Thanks for the info guys, up until now I've been doing all my wet forming by hand.  Generally I don't mind but I'd like to get a bit more definition in my holsters and have been admiring the definition achieved with the vacuum forming methods.  Seems like most of the fittings are nothing but air compressor type fittings, that gives me a good place to start looking for them.  First I have to get my office/leather shop moved to the bigger room in the house then I'll start building the vacuum bag press.

Stu

[dikman]

Yep, forgot to mention that I mostly used air fittings/valves/hose and assorted brass plumbing fittings.