I finally got round to casting some bushes from polyurethane (shore 80A)..turned out pretty well...



Bushes

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Ik like to see how nutty we are
Nice job, everyone is using optimal their skills.....

so i bought mine (steel-ones from a peugeot 205)

Fantastic. Haven't heard of someone doing this themselves.

What's involved in doing this? Special equipment needed? Is machining needed after casting?

hmm very impressive, but why do this when you can get them off the shelf?

Is it to get just the right hardness?

Thanks guys...a few answers.

No special equipment needed, just a mould to pour the liquid into.
No machining required after casting, you just figure out the size you want up front.

I couldn't get the size I wanted off the shelf, and I HATE machining the stuff hence my motivation to do it this way.....once the mould is made it works out pretty economical.

Yes, you do have some choice of hardness but that wasn't a major factor.

My nephew does something similar, he makes false teeth He can get two part mix for the pu and it must be cheaper than buying them for £1.55 per half bush.

Pete, yep it is a huge amount cheaper than that..if you calculate the volume needed pretty accurately there is very little wasted...a one pound tin makes a LOT of bushes.

Christ! Don't let Trueblue see this....

it'll be his next thing after his finished vulcanising the DIY tyres!



James

Looks like you're gonna be my one-stop supply shop! Yesssssss!

I currently buy mine from a local off-road shop. I then have to machine them to fit my application. It just takes a long time and is very messy. So if you're going to stock up.... Let me know!

Sounds as if you're onto a fledgling business and providing the market is there go for it. Can't beat a low cost, high margin product no-one else has thought of!
Cheers, Pewe

Alan, a few Q's...

What exactly is the process involved to "mix your own"?
Any clue where in the UK the materials/powder or whatever could be obtained from?
What's the cure time?
Does it require heat application or just time?
Were you just careful to pour the liquid into the mould to minimise bubbles or did you have a way of expelling them?
Any other "tips" that you can offer as this seems like a pretty easy DIY thing (once the mould is made obviously).

Wouldn't mind having a bash myself as I've looked for pre-made rod to turn my own but can't seem to find the right stuff.

Edited to say... I've found this stuff on eBay. Would this be good stuff to use?

[Edited on 9/4/2008 by andyd]

If you type casting polyurethane into google you get the same kit at half the price.

http://www.tomps.com/shop/polyurethane-fast-cast-resin-p-129.html

http://www.notcutt.co.uk/polyresins.html

[Edited on 9/4/08 by jono_misfit]

Ah but the eBay ones *are* from Tomps and are subject to VAT on top of their website price?
Perhaps... maybe, I've not checked before posting though.

[Edited on 9/4/2008 by andyd]

alright alan b do you need any release agent,do you get much shrinkage,if so how much cos i'm gonna make the mould and die shortly
regards wayne

Hi Guys...a few answers/observations..

The mix is two liquids.....no heat required
Shrinkage is fairly minimal.....not enough to bother about.
I did use a release agent...just sprayed it on the mold.
Cure time is about 24 hours I think.
To avoid bubbles I pour very carefully in a thin stream...it seems to work.

Alan