Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 62 users online :: 5 registered, 0 hidden and 57 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Ultra-tiny seals

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
Sponsored 
  • Author
    Message

Ultra-tiny seals

Unread postAuthor: inonickname » Wed Sep 02, 2009 4:18 am

There are several applications for which I need rubber seals on an extremely small scale. For example, I would like to machine a miniature TAC (brocock tandem air cartridge) in around 2mm cal. The smallest O-rings I can get for this are much too large. In this application they work in a similar way to a quick dump valve crossbred with a toolie valve opened by a hammer.

What's the best way to go about making these seals? Drill a hole in rubber sheet, epoxy it on then turn it down on the lathe?

Any ideas?
  • 0

PimpAssasinG wrote:no im strong but you are a fat gay mother sucker that gets raped by black man for fun
User avatar
inonickname
Lieutenant General
Lieutenant General
 
Posts: 2606
Joined: Sun Dec 07, 2008 3:27 am
Reputation: 0

Re: Ultra-tiny seals

Unread postAuthor: Technician1002 » Wed Sep 02, 2009 4:31 am

inonickname wrote:There are several applications for which I need rubber seals on an extremely small scale. For example, I would like to machine a miniature TAC (brocock tandem air cartridge) in around 2mm cal. The smallest O-rings I can get for this are much too large. In this application they work in a similar way to a quick dump valve crossbred with a toolie valve opened by a hammer.

What's the best way to go about making these seals? Drill a hole in rubber sheet, epoxy it on then turn it down on the lathe?

Any ideas?


Alternatives in that scale include the rubber bands used in dental braces. :D Look for Orthodontic products.

http://www.orthomechanic.com/store/product.php?productid=84&cat=12&page=1
Image
  • 0

Last edited by Technician1002 on Wed Sep 02, 2009 4:38 am, edited 1 time in total.
User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: inonickname » Wed Sep 02, 2009 4:37 am

1/8"..sounds close, but might not hold up under high pressure. If these work out well I could make a jig and fill them with a fridgy..

I'm thinking punch a hole in my 6mm neoprene sheet, spread thin epoxy over the reduced section of the shaft, force rubber over then trim around. When dry turn round with lathe.

I'm also looking for a way to fill the bloody things that can be adapted to a common thread. (eg. schrader)
  • 0

PimpAssasinG wrote:no im strong but you are a fat gay mother sucker that gets raped by black man for fun
User avatar
inonickname
Lieutenant General
Lieutenant General
 
Posts: 2606
Joined: Sun Dec 07, 2008 3:27 am
Reputation: 0

Unread postAuthor: Technician1002 » Wed Sep 02, 2009 4:43 am

inonickname wrote:1/8"..sounds close, but might not hold up under high pressure. If these work out well I could make a jig and fill them with a fridgy..

I'm thinking punch a hole in my 6mm neoprene sheet, spread thin epoxy over the reduced section of the shaft, force rubber over then trim around. When dry turn round with lathe.

I'm also looking for a way to fill the bloody things that can be adapted to a common thread. (eg. schrader)


Ask your dentist for free samples. Saves money on both the purchase and shipping. :D I use those little buggers on the stems of the keys on my keyboard for stealth silent typing.
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: theBOOM » Wed Sep 02, 2009 7:08 am

If tiny orings you want go open up a disposable lighter, take out the "outlet valve" it has 2 very small orings i calculate 1.5 mm or 2mm , not sure. Just look around different valves, most tiny ones use 2 orings for sealing. Carerful when taking out the valve in the lighter, wear gloves or take it out fast.. :wink:
  • 0

User avatar
theBOOM
Major
Major
 
Posts: 374
Joined: Wed Jun 03, 2009 10:49 pm
Location: San Antonio, TX
Reputation: 0

Unread postAuthor: Hubb » Wed Sep 02, 2009 7:51 am

Have you considered making your own o-rings? Most hardware stores sell o-ring material that can be cut and trimmed to the desired length.

Another option (and probably cheaper) is to try rolling a strip of teflon tape until it is the right diameter. I don't know much about the smaller applications but this technique (which was actually not mentioned) was what I did in The Sprinkler Valve to seal the valve for the piston and diaphragm upgrade.
  • 0

Attachments
homemade piston2.JPG
homemade piston2.JPG (35.26 KiB) Viewed 451 times
User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: mobile chernobyl » Wed Sep 02, 2009 8:09 am

Hubb wrote:Another option (and probably cheaper) is to try rolling a strip of teflon tape until it is the right diameter.


That idea will work for a static seal, but I can't see it holding up under dynamic sealing (if he needs his sealing faces to move).
  • 0

User avatar
mobile chernobyl
Colonel
Colonel
 
Posts: 732
Joined: Sun Dec 03, 2006 11:53 am
Reputation: 9

Sponsored

Sponsor
 


Unread postAuthor: Technician1002 » Wed Sep 02, 2009 8:10 am

Hubb wrote:Have you considered making your own o-rings? Most hardware stores sell o-ring material that can be cut and trimmed to the desired length.

Another option (and probably cheaper) is to try rolling a strip of teflon tape until it is the right diameter. I don't know much about the smaller applications but this technique (which was actually not mentioned) was what I did in The Sprinkler Valve to seal the valve for the piston and diaphragm upgrade.


For my 2 inch QDV I did for a long time until I found a source of the right size rings. I couldn't find a hot vulcanizing kit. Rubber cement has no strength for pulling. It peels right apart even with several days of cure time. Instant glue (CAV) is better but wasn't up to the task of high pressure floating rings. Teflon blows out and only works where firmly clamped in threads. It's useless in moving joints.
  • 0

User avatar
Technician1002
Chief of Staff
Chief of Staff
 
Posts: 5190
Joined: Sat Apr 04, 2009 11:10 am
Reputation: 14

Unread postAuthor: Hubb » Wed Sep 02, 2009 8:13 am

I stand corrected. I kinda dismissed the idea of doing this with a moving part. In the above image, I didn't even secure the teflon. I just wrapped it and tucked it in the groove.

Thanks for the correction fellas.
  • 0

User avatar
Hubb
Major General
Major General
 
Posts: 2390
Joined: Mon May 28, 2007 8:39 am
Location: South Georgia
Reputation: 2

Unread postAuthor: jeepkahn » Wed Sep 02, 2009 9:57 am

o-rings are available all the way down to 1mm id and .25mm cross section... check auto parts stores...
  • 0

My Cannons can be found by clicking the following link.
http://www.spudfiles.com/forums/viewtop ... tml#256896

jeepkahn
Colonel
Colonel
 
Posts: 747
Joined: Fri Jan 09, 2009 1:11 pm
Location: Triad, NC, USA
Reputation: 0

Return to Pneumatic Cannon Discussion

Who is online

Registered users: Bing [Bot], Exabot [Bot], Google [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'