Best Isolastic friction washer material

Can anyone tell me what is the best material to make the friction washers out of and what their thickness is new? I have heard that earlier types were made of bronze impregnated fiber. Read somewhere about teflon being used I think. Any learned comments about your experiences with these is appreciated. I know that they can be bought . I prefer to make my own if I can.

Update: I have found that the new MK3 units from Norvil have nylon washers. They look about 3/32" thick

As far as I know there are two types of washer, bronze impregnated ptfe (teflon) and polyurethane.
If you buy new genuine spares you will probably get the bronze/ptfe type, I've never been sold the white ones.

seaguy said:

Can anyone tell me what is the best material to make the friction washers out of and what their thickness is new? I have heard that earlier types were made of bronze impregnated fiber. Read somewhere about teflon being used I think. Any learned comments about your experiences with these is appreciated. I know that they can be bought . I prefer to make my own if I can.

Update: I have found that the new MK3 units from Norvil have nylon washers. They look about 3/32" thick

Click to expand...

I made a set out of teflon filled Acetal. It comes in 12"x12" 1/8' thick sheets and is much harder than the stock. After about 20,000mi no sign of wear. Kinda pricey. #63386213
http://www1.mscdirect.com/CGI/GSDRVSM?P ... 0100809313

The bronze impregnated PTFE washers are the ones you want. They last a long time. The early polyurethane ones disintegrate and leave a pile of dust in the boot. The PTFE is the only one most dealers will sell.

Just a minor point - they're not intended to be friction washers. They're to keep the out of balance vibration motion allowed by the Isolastics in the vertical plane of the bike and prevent any side-to-side motion. The original design were polyurethane, and we didn't have any significant problems in the moist, cool UK climate during testing.

I can see that material being a problem in other climatic conditions.

From a materials engineering poin of view, the PTFE-impregnated phosphor-bronze should work very well. Whatever material you choose if making your own, it needs to be as low a friction coefficient as you can find and sufficiently wear resistant to take small-displacement circular motion at high frequency without excessive wear.

Thanks for the info Frank. McMaster-Carr sells ptfe washers in a lot of sizes only no phosphor bronze impregnation. That was what I was considering. I was also wondering how well micarta or even phenolic rod slices would work. If the movement is predominately in the Z axis the encapsulation washer may cause too much stress for the phenolic material. I have some teflon but it may be too soft for this application.

Rich,
I still have a half a sheet of this Acetal. It's perfect. Let me know if you want to try it. I don't have any other use for it.

Bob

Thanks Bob. I have some of the Andover ones now. I had asked "Racinnorton" if he had some and yesterday they were in the mailbox so I have to send him some money. Guess I'll be sticking with the bronze impregs/ptfe.