Epoxy Resins contain Bisphenol A.
Before using traditional petrolium based epoxies you should consider the flood of new scientific evidence on adverse effects of BPA.
with most things in life you get what you pay for.
Good quality marine epoxies are expensive.
The less you pay the more likely it is that the resin has been diluted.
Whether it’s been diluted with cheap filler or non solvent thinner it will reduce its quality.
Stick to (sorry about the pun) a good quality, well known brand of ‘marine’ epoxy, it’ll pay in the end.
Epoxies are hard therefore brittle. There are additives which will make them less so but these will reduce their other good points. So it is best not to use them on anything which needs to flex, such as sheathing a carvel boat.
They will deteriorate under prolonged exposure to UV light (sunlight). Even clear epoxies will yellow. So they will need to be over coated.
As they cure a waxy coating (blush) will form on the surface. This needs to be completely removed before over-coating with anything. Nothing will stick to the wax.
When over-coating with another layer of epoxy this is best done after hardening but before it has fully cured.
Any contamination of the wood such as oil, wax or moisture will prevent the epoxy soaking in. This can result in the coating peeling off.
Before planning a big project involving epoxy resin make sure that you are not allergic to it.
It never used to bother me but I now find that while I’m ok doing small jobs, prolonged exposure leaves me with a skin rash and I have occasionally felt quite ill.
It is always best to stick to the recommended ratios. However curing times can be altered by altering the ratio. But beware some products are less forgiving than others.
Mixing must be thorough.
The working time (pot life)is the interval after mixing during which the epoxy can be applied. This will vary according to the product used.
Only mix the amount that you will have time to apply during the ‘pot life’.
Make sure you have all the components, tools, etc ready before mixing.
At the end of the ‘pot life’ the mixture will begin to get warm and can become dangerously hot. Be careful especially if using plastic mixing pots.
Although the epoxy will ‘harden’ quite quickly the actual ‘curing’ can take days before full strength is attained.
Most epoxies are best used when temperatures are between 15C (60F)and 25C (80F) and when humidity is low.An increase in the temperatures will reduce the working time but will thin it making it easier to spread.
Chopped glass strands, these are low cost adding bulk and stiffness but not much strength.
Woven and knitted cloths where the strands are aligned to give multi-directional strength
Unidirectional cloths where the strands are mostly aligned in one direction to give longitudinal strength.
These are available in varying sizes from tape to sheets.