Re: Beginner fiberglass question: how to fiberglass a cutting board
Rino,<br /><br />Keep this difference between polyester and epoxy in mind. When you use poly you control the set time by the amount of hardner you use. With epoxy you have to mix the hardner/resin at exact ratio and you control the set time by the type of hardner you use. It really is a major difference.<br /><br />As to the 3'x4' application to stop flexing. Once again you will be very disapointed. Glass, when thin, has very little strength. To make it strong you have two choices of how to proceed. The first is the make it thick, which works, and the second is to make it anything other than flat. Fiberglass gets extreme strength when you have curves in it. So if you want to stop the flexing what you really need to do is make the underlieing plywood strong first. To do that simply screw in braces on the bottom side. Take yourself a couple of length of something like 1"x1" wood and screw them to the bottom across the long end, a foot apart or so. That should tighten it up pretty nicely. Then you can glass the top to waterproof it and if you want to add cloth or matt you can do that too. If you do add cloth or matt let me suggest this to you. First lay down the cloth on the dry wood and then take either a paint brush or a roller to apply the mixed resin/hardner (already premixed of course). Also, use this method of application of the juice when making small repairs, just use those dirt cheap throw-away paint brushes you can pick up for less than a buck apiece at most home improvement stores. A bunch of those plastic cups is a good thing to pick up too.<br /><br />MarineTex, ah, Marinetex. I think its great stuff where it makes sense to use it and that a lot of guys use it in a lot of places where it has no business being used. What it is very very good for is filling wollowed out screw holes so you have new material for a good bite for replacement screws. It is also good to use as an adhesive in a place where you want permanance and waterproofness, anywhere you might more sensibly use 5200. What it is not so good for is almost anything else. There is no place where you would need it that you can not make up your own thickened mix a lot cheaper by simply using one of West System's fillers. West System makes a whole host of them for special applications, all of which work very well for their intended use. You can mix the amount you need of the sort that suits your needs and to a consistancy that fits what you need to do with it. Also, while West System doesn't mention it the fillers work just as well with polyester resin as they do with epoxy. At the very least pick up a can of 404 High Density filler.<br /><br />While I'm on the West System kick I sould mention that they have available a series of booklets that are inexpensive and give a lot of basic information on the use of their products. These things are really more like pamphlets, usually around 20 pages or so, with lots of pictures and drawings and very good explainations of where and how to use their products. The information applies to all epoxys. Also,
Rakahas a
Users Manual that is pretty brief but that they send with each sale that can be very helpful. The link will take you to a copy of it.<br /><br />By the way, there is a process called vacuume bagging that can take all of the aggrivation out of corners when laminating. It takes a bit to set up for it but if you plan to do a lot of glassing it can be a godsend to know about. Its not out of the reach of the typical do-it-yourself sort of guy.<br /><br />I should tell you this too. I don't do an awful lot of glassing other than repairs and an occasional small building project. About once a year I buy one of
Raka's 6-quart kits. The 'kit' includes a gallon of resin, a quart of fast hardner and a quart of slow (they can be mixed to control set time). I have a set of their mixing pumps and the stuff lasts forever. It is one of the most handy things I keep at the house. Anytime I need to the stuff is there to laminate, glue, make up pastes for fillers, do hole patches, and on and on. The last one I bought cost me $75, I think it may be a buck or two higher this year. It is well worth the money. The same amount of material by West Systems would run you well over $100 and wouldn't work any better (or any worse).<br /><br />By the way, as I recall if you go to Raka's price list he actually gives you a lot of information about the appropriate use of the stuff he is selling in the various kits. Of course he also sells everything individually. Also, I should mention this too because in a lot of ways its even more important. When I say Raka and then say "He" what I mean is that the company is really just one guy, named Larry, who takes your order and ships the stuff. If you give him a call he will make up a package to suit your needs and he will, or always has anyway, give you all the information and advice you need to have your project work out as well as possible. I'm not a glass person myself so I've found his advice invaluable over the years.<br /><br />I hope this helps you out.<br /><br />Thom
