About Vacuum Forming

[Denster]

I second what Dwight said about McMaster Carr. If they don't have it no one does.

[Jaymack]

What do youy use for the valve on the vacuum bag?

[triage1998]

I have the exact setup as Particle. Thanks to Eric for the wonderful thread about a year ago. Its a pricy setup but my holster look better than they ever have with his setup

[Dwight]

What do youy use for the valve on the vacuum bag?

I don't. My pump goes directly to the bag, . . . no valve, . . . no filter, . . . just a 3 foot long section of black rubber gasoline hose.

I keep my bag clean on the inside (as much as I can ), . . . always put the holster a ways away from the intake, . . . and I use a rod or something that channels the air from the holster area back to the pump intake.

Turn on the pump, . . . form, . . . turn off. Maybe slightly re-position the bag or the gun or the holster. Turn on the pump, . . . form some more (detail type stuff), . . . turn off. (Repeat as many times as necessary for that particular piece of work)

All has worked well so far.

About 5 seconds after I turn the pump off, . . . the vacuum will break, . . . and air will start migrating back into the bag.

May God bless,

Dwight

Edited July 27, 2013 by Dwight

[hestes]

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.

So you put it in the bag with your holster to create some space to allow for more air to be pulled out? Is that all that is for?

[supercub]

I've used a piece of plastic mesh from the bag air valve intake to the gun to provide a path for the air to evacuate. It works okay, just don't get the mesh between the wet leather and the bag unless you want to leave permanent grooves (mesh impressions) on the leather. I've also used an empty plastic pistol ammo box (with holes around the perimeter) as a platten - it worked, but I like the mesh better.

[hestes]

Have any of you ever tried the space bags & a vacuum cleaner?

[Dwight]

I would think that unless you had the grand daddy of all vacuum cleaners, . . . it probably doesn't pull enough a vacuum.

BUT, . . . nothing ventured, . . . nothing gained.

I do know that if I could hook up my bag to my old Mustang I used to have, . . . or my Olds 442, . . . those would have done the trick. Either one pulled a strong 25 inch vacuum.

May God bless,

Dwight

[hestes]

Ah. I don't have any experience with any of the vacuum pumps so I wasn't sure what the difference was.

[camano ridge]

I have not personally tried it myself however there is a maker on cascity.com (leathershop forum) and occasionally on this site boothill bob he uses the space bags and vacuum looking at the work he does it seems to work for him. http://leatherworker.net/forum/index.php?showtopic=48288&hl= this is a sample of his work and he used a space saver bag and vacuum and or course additional hand bonning.

Edited July 27, 2013 by camano ridge

[particle]

Yep, it just helps to keep a seal from forming right at the nipple. Uh, I think that's what it's called... Allows more air to be sucked out of the bag, more quickly.

[hestes]

I don't. My pump goes directly to the bag, . . . no valve, . . . no filter, . . . just a 3 foot long section of black rubber gasoline hose.

Dwight, what size of hose do you use? I couldn't tell from the picture.

I just tried forming one with a space bag and vacuum. It looks better than when I was forming them by hand (or is it the placebo effect? lol). We'll see how it turns out once it's dry.

Thanks to everyone for all the helpful info in this thread!

[Dwight]

My vacuum hose is 3/8 inch black rubber gasoline hose.

One thing you can do, . . . use your fingers and thumbs to assist the vacuum in pulling it into the shape you want.

Again, . . . I never tried the vacuum cleaner, . . . my experience came from owning a vacuum forming sign shop a couple of decades ago.

It took power to make the signs, . . . so when I started thinking about this, . . . I added my HVAC experience where we also used a vacuum pump, . . . and I bypassed the rug cleaner, . . . in favor of equipment I was pretty sure would work.

May God bless,

Dwight

[SooperJake]

I'm running the same pump but bought the good poly bag from Veneer Supplies, along with an extra bag clamp and hose kit. I have since cut the bag in half to make it more storage friendly. I can spritz the bag with water on the outside and a bone folder will slide along nicely while the gun/holster is vacuum formed. I've also been casing and plastic bagging the holster for an hour or so before molding which lets me use less water and hastens the drying afterward. I seem to get crisper boning this way.Great demo Dwight.

[olds cool]

My brother-in-law (cgriff54) and I were just discussing the vacuum storage bags. Good to know some other folks have had decent results with them. I think we'll give that a try since I can't afford the pump right now. I've got one of the big 30 gal Shop Vacs that outta get some good suction. Hope to get around to it this week. I'll try to remember to post some results.

[Denster]

Pretty much any source that will establish a vacuum will work. Remember it is not the suction that does the work it is the difference between the air pressure inside the bag and the pressure of the air outside the bag. When a vacuum is established the pressure inside the bag is 0 outside of the bag it is about 18 ftlbs/sqin give or take a little depending on your elevation. The flexibility of the bag is an important issue which is why I recommend poly over vinyl. Having a dedicated vacuum pump is important to folks like Particle, Dwight, Sooper Jake and myself who conduct a business as time really is money. It is not necessary for the hobbyist and good results can be obtained without it.

[hestes]

Here is a picture of the one I did using the space bag. It only held up for 1 holster. When I tried to do a second one, the zipper edge broke. Oh well, it was a cheap bag.

Anyway, I'm pretty happy with the results. I've bought a pump from HF (Thanks to a 20% off coupon) and ordered some of the other supplies from veneer supplies. I can't wait to get them!

[Denster]

Nice looking holster.

[hestes]

Nice looking holster.

Thank you! I'm still working some of the kinks out, but I was pretty happy with how that turned out.

[Dwight]

Yay, . . . hey, . . . hey, . . . good looking holster.

May God bless,

Dwight

[hestes]

Yay, . . . hey, . . . hey, . . . good looking holster.

May God bless,

Dwight

Thanks!

[specialcases]

Thank you all for this thread. i have read in in line with others on press forming. I have a question related to both methods but thought I would ask it here.

In your experiences which method is best for forming when there is already stamping/tooling/carving on the piece? Such as mag pouches or cell phoen cases as well as holsters. I think i read mention of it in one of the the many threasd but woudl like a one stop source of feedback.

Thank all again and in advance and Dwight thanks for blessing and may He bless you.

[Dwight]

Sorry to be the bearer of bad news, . . . but detail forming a stamped / tooled / carved piece, . . . for the most part, . . . just does not work.

The press or the vacuum bag will distort the tooling, . . . and there just isn't much that can be done about it.

You can tool, . . . form, . . . and as it is just about dried from forming, . . . take your tools and "touch up" your tooling, . . . but it will not be as good as it was before you formed it.

If I had a customer who demanded and was willing to pay the extra labor, . . . I'd make sure he knew he was paying for two toolings and it may not be to his total satisfaction.

And I would definitely use the vacuum bag method. A press will work over your tooling like a 2 year old in the chocolate frosting with his fingers.

May God bless,

Dwight

[specialcases]

Thanks Dwight,

Not all bad news and not completely unexpected. I guess for cases and magpuches etc. which are shaped and tooled I should proceed as I have which is to shape then tool with a metal bank or anvil underneath. up until know I shape by hand and as taught by Al Stohlman in his books on case making.

I think as for new ways of forming I will try a variety of methods depending on the piece and quantities...and without a huge capital outlay. I am a super small producer and can McGiver up most gagdets I need for small production. experiment = experience

Great pieces on your site by the way and great experience to be shared on the forum.

I will post some pictures later of my experiments and results.

Thanks again.

Blessings,

Murray