Hi,
I tried to create an heavy duty hinge with the carbon starter kit but I came across the same mistake every time apparently.
I "paint" a glass surface with the PVA release agent and let it dry for 20 minutes then I applied a layer of epoxy resin mixed with the epoxy hardener ( ratio 2/3 epoxy and 1/3 hardener) and let it dry for 2 hours.
I weight the number of CF sheet I will use and the following relationship to decide which amount of resin I should:
Epoxy Hardener weight = CF weight
Epoxy Resin weight = 2 * CF weight   

I lay each layer of carbon one after another "paint" the resin on it and remove the excess resin from time. Leave it alone for the night.

First: no way I can separate the CF from the glass surface. Should I leave the resin solidify for precisely 8 hours or "at least" 8 hours that may explain why the two are "glued" permanently together.
 
Second: once I had a strange reaction in the pot where I mixed the epoxy & the hardener. It started to get really hot with fumes and it solidified almost instantly. What did happen? how can avoid that?

I'm aware that for an hinge resin infusion is more likely the best course of action but my lack of success with this technique  and the entry cost prevent me to use it.

Thanks in advance.
Benji

With regards to the sticking, glass is actually a bit of a difficult tool surface because your traditional mould release agents like release wax and/or PVA can be a bit inconsistent. Due to the low very surface porosity of glass, wax and PVA don't tend to stick to the surface very well, so if you are using wax then it tends to be completely removed from the surface when you buff it off. And PVA will also tend to bead up and streak rather than forming a consistent layer, so in your case what has likely happened is there were lots of gaps in your coat of PVA that allowed the resin to contact and bond with the glass. 

Hi Benji,

I have looked through your order history and you have had a laminating kit from us which uses our EL2 laminating epoxy resin. This has a mixing ratio of 100:30 by weight. Ie you need 100 parts of resin to 30 parts of hardener.  It is critical that you get the mixing ratio as accurate as possible other wise you will have curing problems.  a part cured resin or undercured resin will grip the mould quite well making it hard to remove which might partly explain your demould problems.

However, Hanaldo is spot on with the release agents.  Glass can be tricky so unless you were 100% sure you had a good even layer of PVA then I suspect the part has stuck as a result of the PVA layer not being even.  Epoxy sticks to glass VERY VERY well which is unfortunate in this case. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

I found a suggestion elsewhere that I have used recently to keep resin from curing to quickly, using ice water under your resin container to keep glue cooled, sort of like an ice bath. Last week I molded my first vacuum bagging project and during one trip to hardware store I found a small painter's mug or miniature bucket that has disposable liners. It probably holds about a liter of fluid. 

Hi,
Thanks for the reply. I had given a though about the cold bath the issue is you have to use plastic cup and not the one provide by easy composite which are in "paper".
Meanwhile I'm quite surprise about the relation I though I was producing much more resin than I needed this make even more.
Quick question: by curiosity if glass is a bad support what you would recommend?
I haven't use my mold kit as I have found a quicker way to do things so I guess I will try this to create something close to my need.  
Thanks for the help

Why on earth would you want to cool the pot down in a pot of ice water?? All that's doing is increasing the viscosity, changing the chemical reaction, making it harder to work into the fabric and potentially introducing water into the laminate - it's just a recipe for disaster imo.