Re: Seacast developments.
First let me say that I have not used SeaCast but have production experience working with polyester, epoxy and casting res (catalized and water based). I have worked enough with the stuff to walk out to the shop and do a batch without worrying if it will work. BUT...I have NOT tried to identify exactly what is used in SeaCast...from earlier research they hinted that a thickener (alias casting compound) is used plus stengthing compound (glass fibers). They may use a high strength casting resin instead of a true epoxy or possibly polyester (vinyl ester?). Casting resin is usually a very slow kick and long cure time...up to days and the reason is to let air bubbles reach the surface and to prevent cracking from heat. Their product is designed to stick to polyester but not wood...that leads to either use of polyester OR lots of thickeners (which reduce bonding abilities of all resins). Poly is too brittle so it is either epoxy or casting. Asking them if their product will stick to epoxy will give that answer...poly won't & epoxy will.<br /><br />Generally, there is one main structural thickening agent for resin...glass fibers (1/4"- 1/2" is what I use). Most others (glass balls, alum balls, aerolite, cabosil, etc.)are fillers and they reduce strength. Fillers included in the mix will help keep the resin and fibers suspended together vs resin separating. SeaCast also hints that the have fillers already in the resin.<br /><br />Ratios really depend on what vis the resin is and how you want the mix to act (such as stay liquid enough to let air bubbles come to the surface in a thick application or be able to pour). Bubbles will not make it to the surface in a thick pour and can weaken the job. The thickest mix I use is 1:1 by volume for thin laminating resin (any type)and is not pourable...it is buttery and will hang upside down. <br /><br />When doing your own home brew take a quart of resin and do several 4-6 oz test batches to get the consistancy you want. Remember that thickening promotes heat so a slow kick resin is best for "5 gal pours".<br /><br />If you are bent on doing this the home brew way doing some calls to resin mfgs will uncover the right resin to use. You need to call the factories and speak to the chemist or the tech person. This is what I do to get details.<br /><br />I've cut my own glass fibers from strands of woven roven when in a pinch by using sissors. All I can say is it takes a long time to cut a 1/2 gal volume of them. I guess paper shredder would work if the blades can handle the glass.<br /><br />There are other ways to do a pour without mixing fibers. Suspending steel rods and pouring around them will work.
