I currently went from wet layup to prepreg. I built a small oven and bought regular prepreg. When I pulled my first piece from the mold I had quite a few pinholes. I have been trying to find a place in the US that sells OOA prepreg, but I am having no luck finding it. Looks like I need to have an LLC to purchase from larger companies and everywhere I find OOA prepreg it seems like its in the UK. Does anyone have a recommendation on where to purchase OOA prepreg or a certain type of clear that can cure the pinholes and make a nice smooth finish?
yup same problem.
can you increase the dwell time any longer? May potentially help with pinholes if the length of time for air bleed is increased and resin flow…
Contact Prepreg , he might have something that can help you.
hi guys,
u cant get a gd finish using regular prepreg in vac only application. simply wont work. u know that anyway. we are looking to expand in north america as im aware of theres not much companies supplying/producing OOA prepreg over there. OOA prepreg is a relatively new product and so many companies claim to have pinholefree results but only a very few of them figured out the chemical formula of the epoxy resin to give pinholefree results. hence the big price difference in OOA prepreg and regular prepreg, so beware of committing to buy any OOA preppreg which claims to give pinholefree result before try. I suggest get a sample and u try and u know urself it works or not.
regards
In the US its not too difficult to find, theres a few companies supplying good stuff, but it is pretty pricy. In China however, it is even more difficult, and shall I say even more costly as the duty cost is high on import. Would be nice to see a prepreg company actually produce and sell it here.
I found gurit sells it but I can’t seem to find a way to buy from them without an LLC number. I’m just looking to purchase to do some projects. I want to see if it cures my pinhole issues.
Here in the UK it is cheap (£15 = $25ish) and easy to register a Limited company; maybe it’s worth you doing this?
If you keep your reciepts and log your accounts then if you ever start to sell stuff you can offset the setup costs the company has incurred against tax on profit.
I also have the same problem but have just learned to deal with it and fill as needed.
With vacuum only I can get a pinhole free finish off sticky back PTFE and metal moulds but not from a composite mould.
How do you go about filling? dabbing with a small brush into each imperfection, or do you have a technique that works over an area?
Same release system?
Mostly I brush west system epoxy to fill and then sand and spray 2 pack clears.
I also brush two pack clears and spray build up over that.
I have the duratec sunshield on the way to try next.
PTFE does not need any release system although I still use a semi perm on the mould behind the PTFE since it may not cover every piece of mould depending on the shape, it is not very good with compound shapes.
Thanks for the reply, I was thinking more of the metal to composite mould comparison - so you’re using semi-perm for all types of mould?
fasta have you experimented with diff semiperms to see if they could be the culprit?
I have used, Zyvax, K&H and Frekote on all moulds metal and composite and generally get the same result. Metal moulds are always far better.
My boat hulls really push the limits with using just 1 x 200g carbon each side of a foam core with no film glues so the is not much resin to go around.