Hi
I need to build very large molds.
Could someone please recommend an affordable Tooling Epoxy or maybe VE that resistc curing at 120ºC? I have found some but they are very expensive. Behind it would be backed up with laminierkeramik that holds up to 150ºC.
Check Sika Biresin S-8. Heat resistant up to 130 degrees C, well polishable and very affordable prices.
excellent thanks. Looks good will ask for price
Hello Berridos,
I understand you are building an airplane. Sika has also LBA approved resins like Biresin CR122.
The prices are very reasonable, much better than competitive suppliers have. See e.g. the following website: http://www.haufler.eu/
For vinylester you could use Nord Composites gelcoat GC206 of 207 (brush or spray, Tg 135C) and resin RM842.
In epoxy there are a number of solutions, indeed Sika, but also Sicomin, Huntsman and Momentive have suitable systems. (even infusible)
Well it seems i will need to do a little market study to save some bucks.
Oh, yes. Chase some distributors of the resins named, check the datasheets of what you would like to have, and ask for quotes, and pref. samples.
While reading thorougly the data sheet of laminierkeramik they state that the material can be heated up to 150ºC. However in conjunction with an epoxy mold-gelcoat they do not recommend heating up more than 50ºC because the epoxy coat shrinks and the laminierkeramik doesnt shrink. As a consecuence the compound deforms and wobbles the mold. Anybody could think of a solution to this problem.? Are there gel coats that do not shrink when heated? Maybe postcuring the gelcoat on its own initially and when postcured apply a thin non shrinking layer that bonds to the laminierkeramik?
I never had any satisfying results with those kind of methods in high temp. mould building. Distortion in the moulds, cracks around bolt holes, etc.
I switched to a high Tg epoxy gelcoat, and built up thickness with the fibre alone. No core’s or other materials. For carbon products I used carbon fibre, for glass just glass fibre. Those moulds held up better than the one produced by advanced composites in prepreg. Guess that’s the strength from gelcoat 
The problem is my molds are too large and making them purely out of high tg epoxy would be way out of my budget. I lack bolt holes.
I understand you are building an airplane. Sika has also LBA approved resins like Biresin CR122.
The biresin cr131 seems to have a viscosity of 410. Isnt that a little bit high for infusion? potlife 140 minutes should be okay
Raising temperature by 10 deg C would reduce your viscosity by about 50%. It will however double the reactivity of your resin system.
A mold temperature of 35 deg C will also help you to get rid of water vapour under vacuum more easily.
Try stabond corporation in Gardena California…they make high temp. epoxy tooling …they have 2 kinds RT and Oven Cure
check stabond corporation low density epoxy
Shipping epoxy from the USA to Europe makes no sense, unless you can do container loads.
Also availability and pricing seem to be much better in Europe.