Hi, I am in the process of making a mould that I want to use with prepregs to make a brake lever, so far I have taken a mould of the lever using the easy composites epoxy mould starter kit (green gel coat).
I want to make a pattern from this mould and then a final mould from that, that can be used with prepregs in an oven.
My question is what should I use to make the pattern?
My understanding is that it will need to cure at a low temperature but then be post cured to a much higher temperature in order to make a final mould from it using tooling prepreg?
Sorry if my terms are incorrect, this is all new to me.
Thanks, Luke.

For use with the tooling pre-preg, it will also need to be an epoxy system. The initial cure temperature of the tooling pre-preg is 65°, so it isnt super tough on pattern materials but you do need something that can handle at least 70 odd.

Unfortunately that puts it beyond the capabilities of the green EG60 tooling gelcoat, and you might need to get the EG160 tooling gelcoat unless you can source another product. The EG160 is substantial overkill, but at least you know it will work.For the reinforcement, you should be able to use the regular EL2 epoxy laminating resin, rather than anything high temp.

You just need to make sure you conduct an elevated temp cure on everything before putting it into service. The EG60 mould will be fine, so you can just lay up your new pattern with the EG160 and EL2 and allow it to cure at 25° for 24 hours before demoulding. Then you need to post cure this pattern to 70-75°, and it needs to be done quite slowly, only increasing the temperature by 0.1° per minute. If you don't have a controller with programmable ramp rates, just manually increase the temperature by 1° every 10 minutes, or 12° every two hours.

The TDS for EG160 says you can start your post cure at 50°. Personally I would start at 35°, to help maintain the surface finish of the mould. So you put your pattern into the oven at 35°, then ramp it up to 75° over 6 hours and 45 minutes. Then it needs to soak at this temperature for 3 hours, before being allowed to return to ambient temperature as slowly as possible (just turn the oven off and wait until it is fully back to room temperature before opening the door). 

That will give you a pattern with a service temperature of about 70°, meaning you can just follow the initial cure cycle directions described in the XT135 tooling pre-preg TDS. And easy as that, new pre-preg brake lever mould!

Thanks for your reply Hanaldo,
things are starting to make more sense now.
Once its back in stock I will order the EG160 and EL160 and get on with making the pattern.
Looking further ahead I wanted the final part/parts to have a ud surface finish, but reading the description for xc130 UD, it looks like I can't put this down as the surface ply...
Is there any way around this, apart from using an autoclave, such as a pressurised mould? Or is it best to use a different method such as infusion?

Thanks again,
Luke.

You can just use the XC130 UD and clear coat it afterwards. They are small parts, so there wouldn't be a lot of time in refinishing some pinholes. 

Infusion would work too, though I really don't like infusion for parts this small. It's so much more hassle than pre-preg.

Ok I will give that a try, what is the reason for the likelihood of pin holes when not using an autoclave? Is it the lack of pressure? Is there anything I can do to reduce the chances / amount of imperfections when oven curing?
Also is clear coating as tough as a normal resin finish?
Thanks, Luke.

The UD simply doesn't breathe as efficiently as the woven materials, so it''s harder to get the air out when it is on the mould surface. There's really nothing you can do about it when using out of autoclave.

Toughness depends on the clear coat, there's a million different clear coats so it's a bit of a how long is a piece of string type question. Some clear coats are significantly tougher than a raw resin finish, some will scratch with your finger nail. You'll have to speak to your suppliers about that one, but here's a hint: toughness tends to correlate closely to price.

It can work. For such a small piece, it will probably be fine. Really the component pre-pregs have a much lower resin content, so they experience 'issues' like print-through more than the tooling pre-pregs will, and they will wear much quicker than the tooling pre-pregs. Neither of which are a huge concern for you.

That said, if you are already using the EG160 and EL160 to make the pattern, just use that to make the mould. Once post cured, this is perfect for use with the XC110 system. Really you've gone about this the long-hand way, and you could have skipped the mould you've made from EG60 and just used the EG160 straight away. I had sort of assumed you were set on using the tooling pre-pregs and that is why you needed to make a higher temperature stable pattern.