Talk Composites - The Forum for Advanced Composites

Xencast Flexible Polyurethane Rubber

http://www.talkcomposites.com/Topic22523.aspx

By TURK - 1/6/2017 1:13:47 PM

Hi all,



I've got a few questions regarding the 'new' product 'XenCast Flexible Polyurethane Rubber' advertised on your website.

Basically I'm making a couple of moulds with the intention of casting 'Vac-Cast Epoxy Resin' into them,  what I need to end up with are two perfectly reproduced tooling plugs for vacuum forming my final parts into ABS plastic.



The following image will hopefully explain in greater detail my procedure.  I've recently used a product from 'Smooth-On' called 'OOMOO 30',  but had a disastrous result.  I must admit,  as good as it seems to be I just hate working with it.  Here's what my original mould box looks like with my plug secured in the base,  I then poured the silicon rubber into the mould box .........  it was an awful lot of work,  trying to mix what was a consistency of partly molten lava,  and the impossibility of pouring made the job needlessly difficult,  the result was a failed pour and a very badly formed mould  !  >>

 



Pouring the mix in a thin stream in a low corner was just impossible,  I almost had to resort to 'trowelling' it in ! >>

 



When I demoulded the following day,  it wasn't too bad,  but strictly speaking an appalling result.  Not something I would want to cast resin into that's for sure .........  I put it down to a good learning experience  >>





Because the silicon rubber wasn't 'fluid' enough,  full coverage of my plug wasn't achieved,  leaving large voids and air pockets  >>

 









So basically,  my question is,  would that 'XenCast flexible Polyurethane rubber'  be an alternative to OOMOO 30  ?

I've been looking at the 'XenCast PX30',  it seems to have the same characteristics as the OOMOO 30  ( both Shore A of 30 ),  how will it react to Vac-Cast Epoxy Resin being poured into it  ?







To further explain my situation my entire procedure is here >  Headlight mounting bracket moulds
 











TURK
By TURK - 5/15/2018 8:56:47 AM

 
Hanaldo - 5/15/2018 6:19:03 AM
I'd be hesitant to do 40mm in one hit, I think much over 25mm in one go may provoke a pretty high exotherm. You could do it in 2 layers, you would just want a 'coupling coat' of the gelcoat in between the layers, which is a bit of a waste really. I'll let EC clarify on that as I'm not too familiar with their putty specifically.

Yeah,  I was going to apply the layers gradually,  a cm or two just like the video shows,  wait for it to cure then apply another cm or two.
I don't know what a coupling coat is Hanaldo,  I'll ask the tech guys at EC what they say.

Thanks again


TURK