Talk Composites - The Forum for Advanced Composites

Curing box query

http://www.talkcomposites.com/Topic1198.aspx

By mclocks - 4/3/2012 7:21:10 PM

Hi friends,

Please can someone advise me -

I have been making small carbon fibre boomerangs for a few years - quite successfully - using a mould which I wet lay into, and then clamp the two halves together. 3 days later, after curing at room temp, the part is released. All OK. My mould material is Poracast, which is great.

So, I have just made a curing box - a simple themoboard design which is heated internally by using a 40W light bulb. The box maintains a steady 50 degrees celcius. In here I intend to place my clamped mould.

My first question is - what is the recommended temperature for my curing box - a 100W bulb for example will take the box up to 85 degrees. A 60W bulb at 65 degrees. A 14W bulb to 30 degrees. Is 30 degrees best or 60 or what? How long should I keep my mould in here for...?

The reason I made the box was because I read that using heat to cure the part results in a stiffer part - which is very important for this type of boomerang - so the second question is - is this correct? Does it make the cured part stiffer than one set at room temperature?

Any advice here would be much appreciated, as I am a bit unsure (as you can probably tell!)

Thanks,

Adam
By Joe - 4/8/2012 5:12:42 PM

Hi Adam,

FOR THE FIRST QUESTION:

The first thing to know is what is your resin ideal maximal cure temperature (along with ideal cure cycle). You need to get the datasheet thru the manufacturer website or get it thru forums or whatever. I know getting over temperature would not help getting better results.

For example the EC IN2 epoxy needs 60°C to achieve full mechanical specs. See it here.

The EC High temp needs 160°C. See it here.

I know some resins that would need 300°C , and yeah, thats no joke, it exists.

So you see it really depends what you have, but i dont think any epoxy resin would suffer post cures to 50°-60°C.

FOR THE SECOND QUESTION:

Yup, post cure will help your laminate get better mechanical properties.

Hope it helps.