o-ring material

[blockmanjohn]

I plan on using o-ring piston rings in the Stuart D10 that I am building. The bore is 3/4 inch. I am wondering what is the difference between silicon rubber and viton rings? Also, what type is usually stocked in auto parts stores? Can either one be used? Thanks, John.

 

[toolznthings]

Hi,

A good source for information on o-rings is McMaster Carr. Go to their web site and there will be easy to understand information.
I have not used them, but I believe Viton is the choice most builders use.

Brian

 

[Brian Rupnow]

Viton is heat resistant--That is why I use it for the piston rings in my i.c. engines.

 

[Cogsy]

Viton is high temperature material whereas standard o-rings are normally made from nitrile rubber. I'd imagine a steam engine wouldn't get hot enough to require viton O-rings.

 

[pickleford75]

Silicone would be a better choice less friction but I've had better luck making them out of Rulon

 

[chucketn]

Harbor Freight has both nitrile and Viton 0-rings in assortment packs.

Chuck

 

[Blogwitch]

John,

If you use WD40 for cleaning things up or for inhibiting your engines after a run, DO NOT use silicone 'O' rings. WD40 does all sorts of weird things things to them.

John

 

[blockmanjohn]

Thanks for all the help. Great information. John

 

[vederstein]

Remember that everyone has an opinion and you may be more confused than when you started....

Now onto more info:

My experience with silicone o-rings is that they can handle very high and low temperatures. Their downside is that they are not very abrasion resistant. Polyurethane seals tend to be more resistant than other materials. I don't know how they handle steam though.

Quite honestly, unless you're going to run this engine all the time, just go with viton or buna. I use buna in my engines with no problems on either compressed air or live steam. But then they only run for a few minutes at a time.

No material is ideal they are all a compromise of availability, performance and cost. Evaluate how you're going to be using your engine and choose accordingly.

...Ved.

 

[mayhugh1]

Here is a comparison chart I've used.

http://www.marcorubber.com/material_chart.htm

Terry