Best flashlight O-ring material..and more.

[donn_]

I've decided to put together a supply of o-rings for flashlights, and want to compile a list of appropriate materials and sizes.

Here are the materials available:

Buna-N
PTFE
Kalrez Perfluoroelastomer (whew!)
Viton
EPDM
Fluorosilicone
Silicone
FEP-Encapsulated
Aflas
Neoprene
Polyurethane
Hytrel

Please give me opinions, including reasons why. I figure different locations on different lights will call for different materials, ie: more heat resistance on head rings in hotwires, etc..

I'd also appreciate any size lists, or links to sizes for various lights, including Surefire, Maglite, Aleph, McGizmo, Mr. Bulk, ArcMania, etc..

Thanks in advance!

 

[donn_]

I'll keep the list here. I'm using the industry standard "Dash #" when applicable.

Aleph tube switch end: 015
Aleph tube head end: 015-017
Aleph Mule head inner: 017
Aleph Mule head outer: 018
McLux PR, PR-T, Aleph, Longbow PR heads: 023
Aleph 2, Aleph 19 and McLux PD head: 019
Aleph 3 head: 36mm(ID)x3mm(thickness)
Lummi Raw NS/Al/T1: 16mm(ID)x1mm(thickness)
Lummi Wee NS/Ti: 11mm(ID)x1mm(thickness)
Lummi Wee NS/Ti, switch: 6mm(ID)x1mm(thickness)

 

[Yoda4561]

I figure the best ones from a chemical standpoint are going to be the fluoro-whatever ones. Usually plastics that are fluorinated have near-perfect chemical resistance. I've heard that butyl(I think that's buna-n, or was that nitrile?) is best for mechanical sealing and durability among the common rubber o-rings.

 

[precisionworks]

I often refer to this chart from Marco: http://www.marcorubber.com/material_chart.htm

 

[Sgt. LED]

I'd love to have a set of O-rings in multiple colors for my Aleph Mule. Blue orange red yellow! Not sure where or if some of those colors are offered. The exterior window lens and the boot retaining ones are the only ones I would want to bother with.
I have the black EN one and colors would look really nice in contrast. The Mule is with Milky right now but on it's return I am going to try to put in GITD ones I got from Sigman.

 

[csshih]

ooh. can anyone post where to get these o-rings cheaply?

 

[saabluster]

ooh. can anyone post where to get these o-rings cheaply?

I get mine at smallparts.com.

 

[Black Rose]

ooh. can anyone post where to get these o-rings cheaply?

I get generic o-rings from dealextreme.

Thanks for that link saabluster.

 

[Mirage_Man]

I'll keep the list here. I'm using the industry standard "Dash #" when applicable.

Aleph tube switch end: 015
Aleph tube head end: 015-017
Aleph Mule head inner: 017
Aleph Mule head outer: 018
McLux PR, PR-T, Aleph, Longbow PR heads: 023
Aleph 2, Aleph 19 and McLux PD head: 019
Aleph 3 head: 36mm(ID)x3mm(thickness)

Donn, is this the A1 head? I was just getting ready to do a search to find out the size of that o-ring.

 

[Mark A.]

An excellent source for O-rings and for technical information regarding them is www.applerubber.com
Apple Rubber sells to the aerospace, military, and medical industries, to name just a few.

A good source for small quantities is McMaster-Carr, which is www.mcmaster.com
McMaster also has a great search engine & filters that would help someone determine the dash number of any proposed O-ring, if available.

Mark A.

 

[PEU]

I always used Nitrile/Buna-N orings for my builds, never a problem with oils or lubricants. I buy at a local ISO9000 manufacturer, these aren't expensive unless you go name brands such as Parker, etc.


Pablo

 

[LuxLuthor]

I often refer to this chart from Marco: http://www.marcorubber.com/material_chart.htm

Great resource!

I get mine at smallparts.com.

Also a very handy site.

An excellent source for O-rings and for technical information regarding them is www.applerubber.com
Apple Rubber sells to the aerospace, military, and medical industries, to name just a few.

A good source for small quantities is McMaster-Carr, which is www.mcmaster.com
McMaster also has a great search engine & filters that would help someone determine the dash number of any proposed O-ring, if available.

Mark A.

I forgot how much I needed various O-Rings for an assortment of lights and household things. The problem with those typical assortment kits is that they have mostly the same black material, and only larger O-Rings. McMaster's costs $5-6 for a minimum quantity of each size O-Ring plus shipping.

 

[Mark A.]

Donn,

Rob is good enough to post O-rings sizes (and kits of them for sale) on his Lummi site. Find such offerings here: http://web.mac.com/Lummii/Lummi2/Extras_Options_&_Parts.html

Mark A.

 

[donn_]

Thanks for all the replies.

McMaster-Carr will be my source for most, if not all of them. I receive 1-2 orders from them every week, and will just add to these orders until I have all I need. Place an order one day, and receive it the next. Great service and an astonishing inventory.

I'm particularly frustrated I can't find the dash# of the various Maglite rings. All I can find is their part#, but they are generally way overpriced. I guess I'll have to break down and measure them, and see how close I can get.

Thanks for the tip, Mark. I'll add Rob's sizes to the list.

 

[donn_]

Donn, is this the A1 head? I was just getting ready to do a search to find out the size of that o-ring.

I haven't found the Aleph 1 head ring yet, Brian. All the rest are from the Shoppe, but if they list the A1, it's well hidden.

Edit:

On a second look, the 023 ring listed for all the PR heads and Aleph, may well be for the Aleph 1. 023 is 1.051" x 1.191" (ID/OD). That's dangerously close to 27mm.

 

[csshih]

thanks for the site, saabluster.

 

[mosport]

Here's another good online resource when evaluating material suitability, I've had good luck custom sizing automotive seals from this local manufacturer-dealer in the past.

Elastomer Temperature Range chart

General Physical Properties

 

[Boltgun]

The Viton O-rings will be good for heat. One of the smaller ones is used in the AR-15 bolt to assist in extraction. This is subjected to noticable heat during long firing sequences. I would have no reservations about using that brand.

Boltgun

 

[precisionworks]

Another great resource, this one from Parker Hannifin Corporation • O-Ring Division:

http://www.sealingdevices.com/orings/oring_chemicalcompatibility.pdf

At 53 pages total, there's a ton of info.

 

[underwatermike]

Use nitrile (buna-n) or viton. Either will work. The important thing is to get the proper interference fit. A minimum interference fit of .010 and a maximum fit of 0.28 is the range to work in. The Parker seal catalog is the standard reference on this.

The 70 durometer O-rings should work just fine. 90 durometer will work also, but will be harder to assemble.

Unless you have a special application, any source of O-rings should work. I buy from McMaster unless I need traceability. Then I go to a local seal specialist.

I used to run an elastomer testing lab. O-rings are easy once you learn how to design a proper seal glang.

underwatermike