Could you make a pneumatic bladder from scratch?

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Slant
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Could you make a pneumatic bladder from scratch?

Post by Slant »

I've been shopping around for new fire hoses for our press. There aren't a whole lot of options and they seem over priced.

I think instead of repurposing firehoses it would make sense to use one custom size bladder that you sew and seal out of the proper material. You could make it the exact size you want. Like an inflatable sleeping pad shape.

The downside is more of the pressure would be in the middle, but the cat track should take care of this. And I think if you have a bladder the same size as your cassette I shouldn't make as much of a difference.

I was checking out torr: http://www.torrtech.com/Pages/Inflatables.htm
I like the one on the bottom.

But wouldn't it be great if you could just cut & sew up your own pneumatic bladder?

I guess the the real question is what material and what stitch or seal methods for the seams?

You guys have any ideas?
I'd be willing to document the process if I'm reasonably sure it would work.
twizzstyle
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Post by twizzstyle »

Meh, sounds like more work than it's worth when left over old fire hoses work great. If you're looking for a side project, sure, but I don't think you will gain any benefits.
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MontuckyMadman
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Post by MontuckyMadman »

Ha. Chrismp did this with some sleeves I sewed I think.
This can be done. Urethane backed material then sewn and coated with urethane again on the inside.
Pvc materials are also an option.
I looked at parachute sew methodes of large overlaping box style stiching. Totally doable with a decent Industrial style machine.
I woukd look at a high quality 1680denier nylone backed with urthane
The adeprine urethane is tixic and kinda tricky tk work with buts its some bomber shtuff.
its inexpensive.
Not sure what hardness to gk with shore 60a?
sammer wrote: I'm still a tang on top guy.
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Slant
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Post by Slant »

Thanks for the ideas MM!

I've done some more research and I think i'm gonna try and stitch together a bag made of vinyl coated polyester. It is basically fire hoses in sheet form sold by the yard. It has some impressive characteristics on paper. Plus it's only $14.25/yard and 62" wide!

https://www.ahh.biz/vinyl/vinyl_rubber_ ... _vinyl.php

Here is some better stats on it:
http://www.glfi.com/marinecatalog_tarp.htm

You can seal it with a couple types of glue, one being Vyna Bond. They told me the glue has a chemical reaction with the vinyl surface, bonding the layers stronger than if you stitched them!
I might build a tiny test bag first without stitching to see what kind of pressure it can take..
Plus, look at all the colors you can order! I may just get the white, then sublimate graphics on the bags..Next level shit!

I'm gonna do this. I'll keep you posted....
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MontuckyMadman
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Post by MontuckyMadman »

I highly sugest useing the 1680 nypon they have over that poly vinyl garbage. If you ar relaying o the stiching at all you will want a higher tenacity fiber.
This is what I do for a living.
sammer wrote: I'm still a tang on top guy.
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falls
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Post by falls »

these guys make inflatable press bladders
http://atlinc.com/inflatables.html scroll down a bit

I contacted someone once about one and got a quote of $2000

The other thing you could do was I saw a photo the other day where someone used round metal bars to clamp the ends of the hose. You could move the clamped spot back and forth to make different length hoses.
Don't wait up, I'm off to kill Summer....
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chrismp
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Post by chrismp »

I tried vinyl sheets both with tetrahydrofuran glue (also called cold welding) and heat welded and all samples ripped apart at the seams (overlaps were about 15cm wide) at pretty low pressures. Maybe if you do a much wider overlap it would work.

As MM already suggested coated nylon/cordura works best. We made samples out of the sleeves he had sewn for our old cloth press frame by coating them with polyurethane resin. I would have gone that route if I were able to find someone to sew a long enough hose out of that stuff, but for now we're trying someting else first. The 1680 nylon they have in that store you posted really looks interesting as it is already PU coated, so you'd just have to seal along the seams.
gav wa
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Post by gav wa »

Whatever you make you will want to very carefully test it to at least 1.5 the desired working pressure. The safest way is to use water to test it (even your tap will go to 40 psi no problem). Big volumes tested with a gas are always scary. I used to do pressure testing for a job and any test with compressible gas was done in either big tanks of water or behind blast walls.
A bag that big blowing apart at 40 psi will probably knock you over (remember 45psi is 3 atmospheres), anything metal blowing at you from it could easily kill.
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Post by Dtrain »

I got 10 feet of 12 inch (19" flat) firehouse for $229 Canadian dollars.
Anyway, if anybody needs standard 6 inch let me know. I am a fireman and have access to tons of it!

Derek
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Slant
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Post by Slant »

MontuckyMadman wrote:I highly sugest useing the 1680 nypon they have over that poly vinyl garbage. If you ar relaying o the stiching at all you will want a higher tenacity fiber.
This is what I do for a living.
Sounds good, I will order some of that then. Planning on stitching with high strength nylon thread and then sealing the seams with adeprine. I will use a Full Flat Felled Seam stitch. Supposedly then your stitch is as strong as the fabric.

Im thinking since the nylon is 60" wide I will roll it to the width I need and then have only one seam that goes the full length and of course one at each end. I'm thinking this is stronger and simpler than creating a box shape.

I will also need to figure out how to secure an air valve.. Probably the same as I do with the hose.

I'll be putting an order together by tomorrow.
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MontuckyMadman
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Post by MontuckyMadman »

I dont think you will be able to flat fell the seam u less you have an extra long arm cylinder bed machine even then it will be tough. Consider a protruding seam with overlapping box stich like they use in parachute co struction.
I was thi king you could try some flex seal. They sell it by the gallon.
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chrismp
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Post by chrismp »

The sewing and the lack of fabric width to make the size of hose I want were what always held me off from really giving this a go. But the sample I made worked well and that had the overlapping box stitch like MM describes.
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Post by skidesmond »

Dtrain wrote:I got 10 feet of 12 inch (19" flat) firehouse for $229 Canadian dollars.
Anyway, if anybody needs standard 6 inch let me know. I am a fireman and have access to tons of it!

Derek
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plasticpress
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Re:

Post by plasticpress »

Slant wrote: Wed Jun 15, 2016 3:59 pm
Sounds good, I will order some of that then. Planning on stitching with high strength nylon thread and then sealing the seams with adeprine. I will use a Full Flat Felled Seam stitch. Supposedly then your stitch is as strong as the fabric.

Im thinking since the nylon is 60" wide I will roll it to the width I need and then have only one seam that goes the full length and of course one at each end. I'm thinking this is stronger and simpler than creating a box shape.

I will also need to figure out how to secure an air valve.. Probably the same as I do with the hose.

I'll be putting an order together by tomorrow.
Hey Slant, any progress on this project? I'm looking to do something similar for a project that I've got going on. A local supplier (in Guatemala, where I live) says that the seams of simply heat welding pvc coated 1000-D fabric would be as strong as the fabric, but they obviously don't know what they're talking about. I'd want to sew and seal the seams - not sure if simply heat sealing after sewing would be enough, or using some sort of a flexible resin/glue on top of the seams would be necessary as well. Any tips or feedback from your efforts would be much appreciated!
chrismp wrote: Tue Jun 14, 2016 11:49 pm I tried vinyl sheets both with tetrahydrofuran glue (also called cold welding) and heat welded and all samples ripped apart at the seams (overlaps were about 15cm wide) at pretty low pressures. Maybe if you do a much wider overlap it would work.

As MM already suggested coated nylon/cordura works best. We made samples out of the sleeves he had sewn for our old cloth press frame by coating them with polyurethane resin. I would have gone that route if I were able to find someone to sew a long enough hose out of that stuff, but for now we're trying someting else first. The 1680 nylon they have in that store you posted really looks interesting as it is already PU coated, so you'd just have to seal along the seams.
hey chrismp, could I ask you more about your experiences with this? What pressures did the seams burst at? Also, you menionted in another post that the samples that you sewed with an overlapping box stitch worked well - what was the exact process? Assuming you had a big sleeve with a seam along the length, did you simply coat the outside of the seams with PU resin and clamp the ends with some sort of angle iron as I've seen done here?

Depending on dimensions, perhaps a tweak of this idea would be to not even sew or seal it at all - simply take a long sheet, fold it over, and clamp the long edge and two ends with angle iron and bolts. Maybe with some sealant inside somewhere as well. Rather than needing numerous narrow hoses, you could make one big, rectangular bladder that would presumably inflate flat, similar to this photo Image
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chrismp
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Re: Could you make a pneumatic bladder from scratch?

Post by chrismp »

The overlapping box stitches were done by MontuckMadman for me. I simply coated the whole inside of the fabric tube with flexible polyurethane resin and then clamped the open ends shut with iron bars.

I can't remember the exact pressure it started leaking, but I think it held up fine up to my usual pressing pressure of about 50psi.

Not sure if your idea of clamping shut the long side of a fabric with steel would work that well as the tube would try to bend into the shape of your mold and put the clamped seam under a lot of force.
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