My advice about fibreglassing (with polyester type resin) is;
1. Take note of the temperature in your room. If it is a hot day the resin will set up a lot
faster - you can end up wasting a lot if you mix up too much in one go - it will set in the cup before you can use it!
If it is a very cold day it will set up very slowly. But below a certain temperature, the resin will not set. Ever! It will remain permenatly tacky and the whole project is ruinned.
2. The larger the quantity of resin mixed up in one go the faster it will set in the cup, as the concentrated thermal reactions heat the whole batch up faster. It is best to keep mixing up small manageable batches of resin as you use it.
Applying the Glass matt
1. Wear gloves
! The strands are glass
and feel uncomfortable and prickley against skin. Not to mention the resin which is very stickey and will not wash off your hands with anything normal!
2. Pre-cut your peices of matt to fit around the hull shapes, positioning them on dry before
you mix up any resin. Then carefully remove the pieces and arrange them in order on the table, ready to go. This will save you time and nervous enrgy when you start applying the resin.
3. It is important that the glass matt is fully impregnated with resin. If not then your hull can have areas of structural weakness and be perforated with tiny holes in, ie not fully watertight. So take each piece of matt and impregnate it from both sides with mixed resin using a stiff brush. Then lay it on the hull. When applying the resin always use a stipple action - never brush (brushing seperates the glass strands). Stab the brush to get the matt into corners, (the matt is a lot more pliable when soaked in resin).
Steadily cover the hull, overlapping any joins in the matt pieces.
One layer of matt may result in a weak hull, you may need two layers.
Good luck with the project.
btw What submarine type are you building exactly