Well this was exciting. What amazing stuff fibreglass is. I read and re-read numerous fibreglassing guides from across the net; use a spatula, use a paintbrush, use a roller. I just came away quite confused.
So I’m going to recount my experiences for you, and probably it’ll just help to confuse you too. Probably main suggestion I have is to find your own way of doing it.
Anyhow, here’s my fibreglassing lessons gleaned from doing the inside of my hull and deck.
Firstly, I think it does make it easier to seal the wood with a thin coat of epoxy first. I ended up deciding that a bit of rag was as good as anything else at applying the epoxy. Wear two layers of gloves to be sure they don’t rip, then dab the rag in the epoxy and rub it on the wood. Worked fine for me and a lot cheaper than any other tool. Certainly means you can apply a very thin layer.
Secondly, for me, rollers suck. I’ve decided that a flat plastic spatula made from the lids of takeaway plastic food containers work great. They’re sufficiently flexible that they can get into funny internal corners easily and they don’t grab at the cloth. They especially good and removing excess epoxy and spreading it away from where it might otherwise pool.
Thirdly, and perhaps most importantly for me, on the internal sides of the deck and hull you should cut the cloth on the bias. This makes a huge difference. The pain with which I watched my first attempts to lay the fibreglass just pull away from the internal corners whenever I ever so slightly stretched the fabric was truly irritating.
Cutting the fabric on the bias (at an angle – 45 degrees seemed good to me) gives it much more stretch on those internal angles.
Here’s the result of my first attempt:
Compare that with this: