Thinking about using some UHMW blocks for my generator set and was wondering if biodiesel will attack the stuff.

I've found scant evidence even with google about what biodiesel exposure will do to UHMW. Personal experience and perhaps links to more information would be most helpful .

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UHMW

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Thinking about using some UHMW blocks for my generator set

What is UHMW? A plastic perhaps? Are you intending to use them as mounts for your genny or something else?
If your intention is for mounts and they are plastic my advice would be to use steel or hardwood and for the mounting points use proper rubber vibration isolators rated for the weight of your generator. I have seen old railway track made into a decent frame as well...
Jon

Sorry John, my mistake. I should have been more specific. UHMW is Ultra High Molecular Weight plastic. I'm not concerned about the weight of the generator mounted on these blocks but I can concerned about biodiesel attacking the plastic.

I want to use the UHMW as a vibration isolator. When I was working for Genie, we would use machined UHMW blocks for the scissor link pads that slide in guide channels of the frame. A 'link stack' could weigh as much as 3000 pounds, so the UHMW can take the pounding.

I see. Personally I would not use that stuff for your purpose. A bushing or linear bearing on a skyjack will take very little vibration or abuse and can not be compared to the stress put on a generator mount in my opinion. Of course I am not sure how big a genny we are talking about here?...
It sounds as if this stuff is solid if it can be machined, how will it isolate the vibration if that is the case?
The proper rubber or coil spring isolators for your purpose can be had relatively cheap at any industrial fastener supplier and that is the ONLY thing I have ever seen used for any type of vibration isolation in many different applications.
Cheers,
Jon

HERE is an example of some ultra cheapies...
Jon

UHMW is a bearing material used for applications which require two surfaces to move against each other in a dry environment. It has very low friction properties.

UHMW is not appropriate for vibration mounts or mounts of any type really. It is not a strong material and will easily elongate, tear, rip or squash under repeated hammering.

Use a high density polyurethane. A 90 durometer material with holes drilled through it would do wonders.

I believe we are talking UHMWPE. I love the stuff:

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...a very tough material, with the highest impact strength of any thermoplastic presently made. It is highly resistant to corrosive chemicals, with exception of oxidizing acids. It has extremely low moisture absorption, has a very low coefficient of friction, is self-lubricating, and is highly resistant to abrasion (15 times more resistant to abrasion than carbon steel). Its coefficient of friction is significantly lower than that of nylon and acetal, and is comparable to that of Teflon, but UHMWPE has better abrasion resistance than Teflon.

Its the material of choice in knee replacement implants & hip replacement implants: its the only material that even comes close to the slip and longevity of human joints.

And its dirt cheap: you can buy a 1 sq-ft piece an inch thick from McMaster for under $30. I just bought a sq-ft piece to fix the glides on my dryer drum for $6 when the factory parts would have been $28 plus S&H.

The ST generator head weighs in at about 340 pounds. I was planning on using the UHMW as mounting blocks through which the mounting bolts would attach to the frame which the engine is attached too. The 2 cylinder HA2 Lister runs fairly smoothly with the enormous flywheel/cooling fan on the back of the engine.

I can get the higher durometer material you mentioned Murph. I have plenty of plastics suppliers here in the Seattle/Tacoma area I can call.

I plan on mounting this whole infernal mechanism on a boat trailer or inside a horse trailer so that I can tow the generator set to wherever power is required. The engine weighs in at about 1000 pounds.

Smooth eh? Check this out!

In my opinion your barking up the wrong tree with the plastic blocks for many reasons. Try and find an example of plastic blocks being used for this type of application anywhere, (honeycombed or not) and I think you will come up with nothing.
Let us know what you end up deciding on.
Jon

I have a vid of my HA2 running up on youtube, it's just sitting on the ground. It's surprisingly well balanced.

Nice!
That does look pretty smooth!
The video I posted must be of a one lunger...
I would settle for nothing less then a quality mount if that were my beast. I would likely use something like THESE.
Cheers,
Jon