About Vacuum Forming

[Dwight]

There have been a few threads in the past little while about molding and forming.

I started out doing the thumbs, fingers, dowels, etc, . . . made me tired.

Went to a press, . . . worked great, . . . got scared that some day I would crunch someone's plastic fantastic shooter upper.

Researched vacuum forming, . . . with a little help from a carpenter / cabinet / window / door maker buddy.

This is the system I now use, . . . just thought I would share.

It starts out with the 3 basic tools needed: a vacuum pump, . . . a bag, . . . and a way to seal the bag.

The pump came from Harbor Freight, . . . $100 more or less, . . . it is the cheaper of the two they sell.

The bag is a piece of clear vinyl from JoAnns, . . . doubled over, . . . 2 inches of the edges stuck together with Weldwood.

The seal is two pieces of PVC plastic, . . . 1/2 inch and 3/4 inch, . . . cut the groove in the 3/4 with a table saw and a lot of care.

[Dwight]

To use the vacuum bag, . . . cut out your pattern (vac 6 picture)

Prepare your firearm properly, in this case I had to make sure the sight channel would be made, by taping a dowel onto the top of the revolver. Don't forget to do this !!!

WET the leather, . . . like REALLY wet, . . . almost sopping, sloppy wet, . . . wrap it around the firearm in it's general final position. You do not have to be perfect with this part, . . . but the better you are, . . . the better the end product. I'll usually lay it down and thumb in a couple places to help keep it from moving.

[Dwight]

Next slip the gun & holster into the bag, . . . seal the bag, . . . turn on the pump.

It only takes a few seconds usually. I'll also turn the pump on & off, . . . on & off, . . . carefully re-positioning anything that needs to be moved, . . . and allowing the bag to re-position itself. I usually hit it at least 3 times, . . . and sometimes even do a little thumb action to assist.

If you look real close, you will see a small cutting board under the holster, . . . I use that if I want the back to be pretty flat. If you don't use it, . . . it'll form the back to the weapon real close too.

The last picture is just to note that I was using 8 oz leather for this holster.

And of course, vac 11 picture is of the finished product. My customer was very well pleased, . . . his wife was estatic.

Anyway, . . . that's how I do it, . . . hope some of you can benefit from this.

May God bless,

Dwight

[Jeff L]

Nice tutorial Dwight...Thanks for sharing... That came out beautiful. How did you stitch that?

[hestes]

Thank you!! That was very helpful!

[Dwight]

Nice tutorial Dwight...Thanks for sharing... That came out beautiful. How did you stitch that?

Tippmann Boss, . . . 346 thread top and bottom.

May God bless,

Dwight

[olds cool]

Great posts Dwight. I think I missed what you are using for the nipple on the bag.

[Dwight]

The nipple comes from

http://www.veneersupplies.com/products/Valve-Stem-Assembly.html

If I remember correctly, . . . about $15.

You can see it in a couple of the pictures, . . . round, shiney thing, left side of the bag.

May God bless,

Dwight

[malabar]

Dwight,

I'm currently using a vacuum-sealer to to do the same job, but I'm looking for something that has a bit more "oomph." Have been pondering doing the press. Since you've tried both methods, how do you compare the degree of detail you get with each?

thanks for the guidance

tk

[Dwight]

Hands down on the vacuum forming for detail.

First holster I did with it was a Rhodesian pattern for a 1911, . . . 7/8 oz leather if I remember correctly.

Formed everything, . . . pulled it out of the bag, . . . gently slipped model out, . . . let it dry.

Had to force the model in the next day, . . . then I thought I was going to have to get a scalpel to get my model out.

Vacuum forming is seriously better in my estimation, . . .

May God bless,

Dwight

[particle]

Dwight - I have the same pump as you. Does yours hold suction after you turn off the pump? Mine doesn't, and I'm not sure if it's supposed to, or if I have a fault in the system.

[Feraud]

Movie making prop houses use vacuum forming to make multiple identical pieces for use in films. It's great to see the idea adapted for holsters! Very creative.

[Dwight]

Dwight - I have the same pump as you. Does yours hold suction after you turn off the pump? Mine doesn't, and I'm not sure if it's supposed to, or if I have a fault in the system.

No, . . . you would have to put a little reed valve or something in the line to get it to do that. When we used them in A/C, we used the valves on the pressure gauges to hold the vacuum in the system.

I'm sure someone makes one that does have an internal valve, . . . but from what I can see, . . . our's does not.

And for me, . . . that's OK, . . . as I don't need it to linger. I need that hoslter out of the bag and on to other things.

May God bless,

Dwight

[Denster]

Mine will hold 18mmhg for at least 10 minutes. Just have to make sure all of the seals on your connections are good and there are no pinholes in the bag. I found that it was worth the money to purchase the heavy poly bag from veneer supply as it is more flexible than the vynel one I started with. Difference between night and day and very tough I've done more than 3000 holsters and it still going strong. It also helps to clamp the edges of the bag to a flat surface as it keeps the bag flat as it pulls down around the gun and holster without bunching up.

[Denster]

One other thing. With all due respect to Dwight. It is not necessary or to my mind a good idea to get the holster sloppy wet. I give the holster a quick dunk in warm water maybe two to three seconds max then let it set till the color starts to return and insert the gun. As Dwight said it helps to get the leather going in the right direction with your thumbs before you put it in the bag. With the poly bag I can bone the details right through the bag.

[supercub]

I have pretty much the same system and it works well. I find I'm running low on the pump oil. Does anybody have a good source for the "High Vacuum Oil" for the pump? I don't find it at Harbor Freight (where I got the pump). Is there an automotive equivalent?

[particle]

Supercub - I think I just ended up ordering some online, but may have bought some from Oreilly's - can't remember....

Here is my pump setup. I built a little table that has a wood skirt to raise it up off the table. That gives me room to clamp the bag to the top.

Here is how I clamp mine.

Here is my pump with all the fittings. Maybe I don't have the fittings connected properly - I thought the red lever was supposed to close the system and keep it under vacuum when I shot off the pump, but it has no effect on the system at all. I'd love it if someone could point out my problem, if there is one.

Here is the platen I made. Ignore the string - I don't use it anymore. I just butt my dummy gun up to the platen - that allows enough air gaps to keep sucking air out of the bag.

Here's another view of the work surface I built (view from the back side):

[supercub]

I'll check out O'Reilly's for the oil - thanks. I pretty much copied your set up when I put my unit together. I'm using the vinyl bags right now, but will likely switch to the poly bags if demand increases. The vinyl works, and is relatively inexpensive, but I can see how a more flexible poly bag would create a little tighter line on the wet leather.

I started using food saver vacuum sealers and bags 20+ years ago when I made lots of knife sheaths. I used them on holsters as well, and they worked okay. The current set up with a higher volume pump is lots better - not to mention not having to buy lots of freezer bags.

One trick I used with the freezer bags to preserve the mold lines, was to put the sealed bag (with holster and mold) into a freezer and let the leather freeze solid. When It was frozen, I'd remove the holster from the bag and put it back into the freezer to "freeze dry". When it was almost normal color, I'd pull it out and let it air dry. Of course you need a frost free freezer to evaporate the ice. This kept soaked or wet leather formed to the mold so that it didn't "relax" and loose the mold definition. If you use quality leather and properly wet it so that it isn't too soggy, this process isn't necessary. It did work for old dried out leather that needed some help. It worked especially well for leather parts like molded box fronts or the face of flat back holsters that were not yet attached to a back.

Edited July 25, 2013 by supercub

[shtoink]

Here is my pump with all the fittings. Maybe I don't have the fittings connected properly - I thought the red lever was supposed to close the system and keep it under vacuum when I shot off the pump, but it has no effect on the system at all. I'd love it if someone could point out my problem, if there is one.

The four port junction allows flow back through the pump and is very likely the source of your air leak. The red handled valve looks to be a primary release to me and the way you would vent the bag to atmospheric pressure when taking it all apart.

It you inserted a second valve between your filter and four port junction, you'd have a way to seal off your bag and keep everything else the same. It seems that everything else is working for you, so it doesn't make sense to change it all.

[particle]

Thanks shtoink - as I was studying the picture, I was beginning to think the same thing. I'm wondering if I should move the lever to be inline with the moisture filter, and close off the port pointing downward. I've used my bag so many times, I'm probably due for a new nipple valve so I can make use of the other half. The part I'm using right now does have a few holes in it (but it never held suction even before the holes....). My main goal for holding suction is so I can turn the pump off while I'm forming - the motor makes it hard to hear my Hulu tv shows while I'm working...

[Denster]

Particle. I see your problem. The screw in the end of the tube opposite the vacuum gauge needs to be backed out to about 3/4" and locked with the nut. Without going into a long detailed explanation of why it is there it is not needed for our purposes so back it out an lock it down.

I also presume that you have the red handle at 90deg to the air filter when you start the pump and only turn it in line with the filter to release the vacuum.

Small holes in the bag can be fixed nicely with a piece of duct tape.

[particle]

Thanks Denster - I'll give that a try. I was never sure what that little brass thing was for, so good to know it's not needed! I actually never actuate the red lever. I never noticed it doing any good, so I just leave it alone. I always just figured I got a faulty pump, but once I figured out it wasn't holding suction, I'd already thrown all the packaging away and couldn't send it back.

[electrathon]

I have pretty much the same system and it works well. I find I'm running low on the pump oil. Does anybody have a good source for the "High Vacuum Oil" for the pump? I don't find it at Harbor Freight (where I got the pump). Is there an automotive equivalent?

Any shop that sells air conditioning parts will have oil. It is a mineral oil like was used in the old days with R12.

[supercub]

Any shop that sells air conditioning parts will have oil. It is a mineral oil like was used in the old days with R12.

Thanks, found some at NAPA.

[Dwight]

I got mine from McMaster Carr, . . .

Remember that name, . . . write it on a stickey note, . . . don't lose it.

Other than groceries, . . . I don't think there is much they don't carry for the mechanical / working world.

Sometimes they can be a bit on the pricey side, . . . but they have supplied stuff for me since somewhere back in the early 90's.

AND, . . . if you order it before 4 in the evening, . . . you can look for it the next day. I used to marvel at that when their nearest location was Chicago, . . . I'm just north of Columbus, Ohio, . . . I had it at 10 the next morning when the big brown UPS van backed up to our door.

May God bless,

Dwight