Before placing an order (asap, march 07) I would like air these thoughts.
It all concerns making a mold for the tank/seat part in the picture,
the final part will be made with epoxy and carbon.
In the past I have always made polyester based molds, and yes I have mostly
produced polyester parts in them, but a few times epoxy based parts with
good result and no problem with release. (letting the molds air for a while)

But the question is, would you strongly recommend to make epoxy molds for epoxy parts?
And if so, is the components in the "Epoxy Mould Making Kit" suitable for something in this size?
(We plan to buy the gelcoat and putty separately, not the kit)
Would it be a good idea to ad extra reinforcement, chopped strand mat,
to get extra strength?
Would adding that with EL2 on top of the putty work?
Would skipping the putty and only use gelcoat and EL2 work? (with chopped strand mat).




Also, when making the actual part that we plan to envelope bag,
is the EL2 slow, the slowest epoxy you have?
We feel that time will run out whilst laying up carbon and peel etc
on this "large" part.
I can work in a slightly lower temperature, that should slow things down right?

Hoping for a quick reply.
Thank you.

http://motoform.blogspot.se

Hi PRSW,

If you are familiar with working with polyester for mould construction I would recommend using the Unimould system, Although it is completely possible to use the epoxy tooling gel and putty system for a tool of that size it would work-out to be slightly more expensive. In answer to your other questions yes you can couple the EL2 resin with either the tooling gel coat or the putty, allowing you to construct a mould using any combination of reinforcement, the powder-bound chopped strand mat will work with epoxy but we have found that it is still fairly tricky to wet-out and work with so I would recommend using woven glass and core-mat; this should make a neater job.

Here's a link to a 'first edit' video of how the Unimould system works, although it takes slightly more skill to build a mould this way (compared to putty) if you have experience with polyester mould making it should be straight-forward enough for you. This tooling system shares all of the same characteristics of an epoxy tool; dimensional stability, compatibility, durability etc, which makes it ideal for larger tool construction.

The EL2 does not have a slower hardener than 'slow', if you with to extend your working time working in a colder environment until the layup is complete is the perfect solution, for instance your times will be doubled if you work at 15degC as apposed to the design temp of 20degC. Once your layup is complete you would want to elevate the temperature back to 20degC to ensure a full cure in sensible time.

So to summarise; It's really up to you, you would not be making a mistake using either method, both would produce great moulds, if it was my choice I would use Unimould for that application, for smaller, more complicated parts the putty system would be the better choice. It looks like a really great project and I look forward to seeing you progress with it.

Paul Statham
Easy Composites / Carbon Mods - Technical

Thanks Paul

We will talk about it during the day, we have a lot of polyester and chopped but only poly based gelcoat,
so we might go for the unimold gel and coupling, guess it would be safe to use it together with other poly resin?
I understand that the unimold resin might be better in keeping the shape, but I feel any resin can
be used if we lay up the layers in stages to keep the temp under control.
Would you disagree?

(I recently did a 12sqm / 12mm mold this way with no heat, distortion or problems)

It is a nice project yes, more bike projects going on, mostly in the claymodelling stage now, but this is a hard model.

Thx
/Petter

http://motoform.blogspot.se