Do splicing o-ring's affect properties.

[drivefast]

I need to create a 41" o-ring that will seal a vacuum plenum on an intake manifold. So it will need to be gasoline resistant and able to withstand 250 deg Fahrenheit. Will splicing a viton o-ring affect the properties of the o-ring material.

 

[nickelkid]

In a static application splicing will be ok. I have seen spliced o-rings in high pressure H2 service (less then 350F) work fine, but it is/was not preferred.

Your may find o-ring.info helpfull.

 

[btrueblood]

We splice EPDM o-rings all the time, and just use cyanoacrylate (super glue)...but then, the acrylate is compatible with the fluid we are containing (water), so we don't have any issues (besides the possibility that the CA adhesive might crack as the EPDM deforms, but that is why we hydro and leak test).

-- what I'm trying to point out is that how well the splice holds might depend on how you splice, and what you use to splice with.

 

[jet1749]

Hi, Ive spliced orings in static applications using superglue as an adhesive. Also bind the finished spliced joint with ptfe thread tape to isolate the process medium from the joint.

regards
John

 

[crabbymecheng]

Your best bet for splicing an FKM material is to use an angled cut. Glue using a viton based adhesive, and heat the joint up to allow the adhesive to cure. This will provide a much better join than using glue - especially on a FKM material. I believe alot of the supply houses (mc master, etc) have splicing kits. Otherwise, your o-ring supplier may be able to splice the ring for you.

Again, as stated above, it would not be the prefered method, but should work for your applicaiton.

 

[mecoman]

A few thoughts,

Two best materials are NBR (nitrile) or FKM

Super glue is only rates for water. Nothing over 200F and then with hydrocarbons, don't count on it.

Splicing requires human craftsmanship, if having to repeat, likely to fail occasionally.

Could it be changed to a flat gasket with a tapered dovetail cut?

Loctite 510 bedding compound is good in many hydrocarbons.

Lastly, look for a ball and socket o-ring. They are pricey, but available. See Chesterton

Hope it helps or you already have the problem solved.

Cheers,
MECOMAN

 

[leftyone]

Temperature is the only failure mechanism for the joint. For Viton which contains about 68% Fluorine on average, one must use fluorinted epoxy to splice. However, 41" O-ring can be easily molded in one piece. I have found O-rings as large as 120" ID molded in one piece, without splice. Check out Gumlast and others, it is not that difficult.

 

[chief]

I have spliced many sizes and materials of o-rings,for water, hydraulic systems and hydro carbons using a Loctite glue.
It is my experience that the most important factor is to clean the intended joint using clear alcohol,by dipping the joint ends and shaking dry.
The use of a 45 degree cut gives a greater surface area and it helps if only a minimum of glue is applied.

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