Suitable Gasket Materials 1

[xydrex]

I'm looking for a suitable gasket material for intake chamber.
It is to seal an aluminum surface with a composite surface. Max temperatures will be around 130 deg celcius. The surface of the composite is not machined & is slightly textured so the gasket must deform & seal this region effectively. Naturally the first thing to consider is some type of rubber, but for the main objective of durability & re-usability, what type of rubber would be best or maybe something other than rubber?

 

[patprimmer]

Will the gasket be exposed to fuel or oil. If fuel, which fuels.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[xydrex]

No fuel just air. I've done some extra searching can anyone comment on urethane gaskets or any other ideas.
Thanks..

 

[MikeHalloran]

Polyurethane melts at around 100C.

If the composite were flat enough, paper would work, once.



Mike Halloran
Pembroke Pines, FL, USA

 

[IceStationZebra]

Sorry to see that your search engine has died :-( I did a quick search and looking at an O-ring vendor came away with many choises choices. Cut a groove in the Al bit and go. Viton should be easy to find.

Viton®(Fluorocarbon Type A) Temperature Range: -15ºF to 400ºF
Silicone Temperature Range: -65ºF to 450ºF
Chemraz® / Kalrez® / Simriz® (Perfluoroelastomer) Temperature Range: -10ºF to 615ºF
Fluorosilicone Temperature Range: -80ºF to 450ºF

ISZ

 

[patprimmer]

Plain old RTV silicone rubber will work

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[xydrex]

Thanks for that, my search that came up with urethane was off the web not from this site. What attracted it to me was that it comes back to shape after it was removed (but didnt mention the temp limit). As I said it was re-usability we wanted to look into as a main objective, I couldnt find discussions regarding specifically this for all the commonly listed materials.

 

[tbuelna]

xydrex,

If you can afford the non-recurring costs, take a look at Parker's Gask-o-seals:

http://www.parker.com/ead/cm2.asp?cmid=3245

They can be re-used indefinitely and don't require any expensive machining operations for small o-ring grooves.

As for the elastomer selection, you will need something resistant to fuel, oil, ozone, creep, compression set and have capabilites well within the adjacent manifold temps (266degF). Fluorosilicone or Viton will work nicely, but they are suprisingly expensive.

Give Parker a call.

 

[xydrex]

Thanks for that tbuelna, a great link. Its led me to so far the best option which appears to be HNBR hydrogenated nitrile rubber. This has high tensile strength, low permanent set, very good abrasion resistance and high elasticity, & suitable for withstanding the relatively high temperatures in the engine compartment which can reach 135-140°C in the region of interest. Just going to check on price now.

 

[xydrex]

Turns out it would have to be moulded as its uncommon in sheet form. Does anyone know of a supplier of this in sheet form, our desired thickness is 1mm.

 

[patprimmer]

How many do you need.

There are several options open to you.

Find a local rubber supply house and find out what they do have in stock in thin sheet, and what temperatures it will withstand. If it is fabric or reinforced even better.

Find the cost of having a mould made. The cost will be very dependant on production rates required.

If the numbers are low, use silicone rubber. To do this, wet the smooth mating surface of the metal part with washing up soap solution.

Lay a bead of silicone rubber a bit thicker than your required gasket final thickness onto the rough dry surface mating surface of the carbon fibre part.

Gently press the parts together, possibly using a jig to keep them at the required gasket thickness.

Leave until the silicone is cured, then tighten down against the gasket that was cast in place.

The gasket will stick to the carbon fibre part, but not the metal part on disassembly.


Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[thundair]

This blended rubber is good to 450*F and can be cut with a steel rule die. I basically use a hand held paper punch to nibble out my 'one of' stuff...

Cheers

http://www.mcmaster.com/

p/n 9556K81


I don't know anything but the people that do.

 

[wgknestrick]

Regular Buna O-rings are probably your best best for cost and for sealing. I just designed a set of ITBs with them throughout and they work with just hand tightning the bolts and are quite reusable. They can also fit most shapes (don't just have to be round grooves) as mine are Oval ports.

http://users.rcn.com/wgknestrick/ITBs 001.JPG

You can see the Orings (they are white) around the ports.

 

[reidh]

I'm surprised that you can obtain the required compression of the O-ring by hand tightening the bolts.

As far as O-ring material, Viton is fairly durable and readily available. Apple Rubber has a very good O-ring design guide that can help you with everything from material selection to groove design, etc. Even if you decide not to use an O-ring for your application, this is a good resource to have around.

http://www.applerubber.com

-Reidh

 

[Tmoose]

Will this be a bolted joint?
If so, I'd expect to have to consider whether or not to include features to limit compression and allow fastener torquing, flange thicknesses to provide uniform clamping, how much hardware will be supported by the gasketed joint,
and to resist the temptation to tap the composite material for threads.