Talk Composites - The Forum for Advanced Composites

Carbon Fibre Gel Coat?

http://www.talkcomposites.com/Topic18538.aspx

By AdamHutchin - 6/23/2015 11:49:13 AM

Hi, I've been reading through the forum but can't find the specific answer I'm looking for so wondered if anyone could advise?

I have some previous experience (although quite a long time ago now!) of working with pre-preg carbon and wet lay up glass but have yet to try wet lay up carbon.

When I used pr- preg carbon, it was just laid straight into the mold and vac-bagged.

When I used glass, I first coated the mold with a gel coat, allowed it to go tacky, then laid in the CSM.

With wet lay up carbon, I'm unsure of the correct process here and there seem to be different answers around the internet.

I know it's a bit of a noob question but I thought I'd post here as this is where I'll be ordering the materials from and there are often differences between manufacturers products to consider too.

My aim is to produce a few cosmetically pleasing, lightweight, non-structural parts.

I will be vac-bagging the parts and have the resources to cure at elevated temperatures.

My question is, can I achieve my goal by applying a layer of epoxy to the mold and proceeding with the lay up or should I allow that coat to go tacky before proceeding?  I have seen different recommendations from different sources.  Alternatively do I need a separate gel coat?  I intend to use EL2 Epoxy Laminating Resin and "Easy-Lease" release agent, the mold contact surfaces are a mixture of mild steel and chrome.

Thanks in advance.
By Dravis - 6/29/2015 11:50:06 AM

I do not seem to have all that much of a problem with the "Gel Coat Cup Gun" from EC ... The real trich is to run it at a lower pressure than a "normal" compressor delivers..
I bought a reduction valve from my local supplier, an have set that to 4 bar (= 58 psi) That makes the "cup Gun" much easier to use.  But the dripping is something that you will have to live with.

Generally I only spray outside under an open roof.  I really do not want styrene based droplets all over my workshop .. This of course means only spraying in nice weather ... Since I'm not trying to make a living out of this, it's not really a problem.