10 myths about epoxy resins – hardening 1 part
You may have thought about using epoxy products for one of your projects or you are a uli rumor that epoxyd in some way ? In the first part of these articles about breaking myths our personal Guru Gnjec avih things , David Johnson, ” hardens ” a couple of myths about epoxy resin .
Myth 1: Epoxy doesn’t stick to polyester
I h heard many times. Me đ utim, op ć e is known to all shipbuilders < span dir = "ltr"> š team and yacht inspectors that the easiest š e make č species, long-lasting i izdr ž ljiv popravak sta maple fabric on polyester or vinyl ester hull use ć and epoxy . Č the fact is, when properly executed š imo repair with epoxy resin and finish š imo sa polyester gel coat – om that such a repair is superior and longer lasting od tako đ er pra vilno izvrš š enog popravka sa polyesterom. The only conditions that exist are that it must be outside the surface š of water and that epoxy must be well dried š en.
This is because once the epoxy dries, its dimensions remain the same and will not shrink (squeeze). A typical polyester repair can end up being uneven and thick, plus the edges can shrink and coat the surface – but if dried properly, epoxy won’t work at all. At the shipyard, you would use heat lamps to make sure it dried enough but if you do it yourself as a standalone project (DIY), then you will be left in the sun for seven days to dry enough. This allows us to be sure how the epoxy has stopped reacting when we apply a polyester gel coat over it. You also need to make sure you have sanded the epoxy thoroughly before applying the next coat.
Myth2: Epoxy is more expensive than polyester
Yes that is correct. Epoxy costs more than polyester per pound. However, the fact is that you will not use nearly as much epoxy resin as you would use polyester resin. You will also spend less glass cloth and other materials. In a shipbuilding scheme using epoxy composites, for example, you will need a lot less epoxy resin to build a strong ship hull than you would need to do a ship of the same size in / with polyester. This is because dried epoxy is much stronger than polyester resin. You can afford to use less glass cloth because the shear strength of epoxy resin will make the fabric you use much harder. For example, a 12mm thick hull with polyester resin could be slightly reduced to 4mm using epoxy would be incredibly strong and flexible. you could cut the laminate all the way up to 2mm and put a foam core inside –laminating over the back of the foam creates a sandwich – for a structure that is just as strong but even lighter. In essence, it is possible to construct an epoxy craft that will be strong and light while with polyester you would have to choose between light and strong. So while epoxy can cost 2 to 3 times more than polyester, you will generally end up spending a lot less on the structural materials on the epoxy craft. If you’re building a fast ship, then especially, I think the answer is obvious.
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