Casting Polyurethane For Replacement Elastomers?

phill77 · Jun 23, 2014

Anyone tried to cast their own elastomers? Seems like plenty of people have done it to make custom engine mounts and suspension bushes.

Other than the hardness, I'm not sure if all 2 pack polyurethane is the same and whether it is all suitable.
Was going to get some of this for a play unless anyone can suggest something better.

Ten quids worth of material would keep an awful lot of forks going if it works!

Thias · Jun 24, 2014

Now that is interesting!

But I have to say the hardness is very important. We had the discussion about where to get new elastomeres from in the German classic bike forum. And there are some companies around that sell elastomere "sticks" in the correct diameter. You only have to cut them to the right length and boar a hole in case your fork/frame needs it.

BUT.

The they are usually too hard. IIRC the softest are ~70 shore. I for instance would need something about 50 to 60 shore. I weight 85kg.

But if it only about getting the fork to work and look ok: Use something like this:
http://www.ebay.de/itm/like/11138248495 ... ue&viphx=1
These are synthetic wine corks and this is as cheap as it gets

phill77 · Jun 24, 2014

Well, the compound I am thinking of getting is 60A, which from a bit of googling sounds like a medium fork elastomer.
I like the idea of casting as drilling and cutting soft polyurethane is tricky.

Just hunting around for a good mould now.

Thias · Jun 24, 2014

phill77":2yo2nk4j said:
I like the idea of casting as drilling and cutting soft polyurethane is tricky.

Absolutely. Please report your outcomes

Scvintage · Aug 8, 2020

Re:

Did you ever cast any?

Scvintage · Aug 8, 2020

Re:

I got an email from a casting supplier, SmoothOn; in their product line a (shore80 a & shore 90 a) urethane rubber with the name pmc-780dry & pmc-790. They cast amber & light amber. It’s possible these are the same materials as the company supplying suspension fork replacement elastomers.

ishaw · Aug 9, 2020

Re:

Cutting elastomer isn't that tricky. If you buy it with the bore hole in you can slot some wood in it to keep the shape. Better still. If you have a vice tool for clamping rear shock shafts you can use this to help hold the shape even more while cutting.

marc two tone · Aug 9, 2020

Re:

I'm not sure how this thread relates now but, I know sod all of casting.

However you can save a load of effort, alchemy and probably money by buying this..

See below...

I bought some to revive a shock post with certain success and rockshox indy with some follow up to do, mine has no bore hole, on below has it ready casted.

Can be bought by selected diameter and as fore shore rate....the stuff below is very much medium. I reckon its red counterpart is to a more firm shore rate.

Bike Hoarder · Aug 9, 2020

Re:

PM John Deverill (I think!) - sells through eBay too. Does the all sorts of fork kits, good price too considering you don't need to put in effort getting the right grade, cutting it, boring it etc.

phill77 · Aug 9, 2020

Well following up from my original post, I found some plastic caps from work which were the perfect size for Manitou elastomers.
I mixed up some 60 shore 2 pack but got the ratio slightly wrong and they didn't harden/cure completely.
Then family got in the way so I bought some replacement elastomers from Pace which were the right stiffness. However they were too long but rather than cut them I increased the travel of my Manitous with some longer bolts.
Every other fork I have is air spring, so never bothered again and it sounds like the chap on this site who started selling Proflex elastomers has everything covered if required.

Casting Polyurethane For Replacement Elastomers?

phill77

Thias

phill77

Thias

Scvintage

Retro Guru

Scvintage

Retro Guru

ishaw

marc two tone

Attachments

Bike Hoarder

phill77

Similar threads

Latest posts