Hi. Can anybody offer me some advice on how to make a mould for making my own fibreglass fins. What materials do I need to make the mould and how do do I make it ? Any advice wouldbe really appreciated
Brian. This is a lot of work to do if you only want to make one or two sets of fins.Firstly you will need a fin / fins to use as plugs.Is the mould you want to make a single fin or a thruster set? David.
Hi dave. I’d like to make a thruster set. I’ve got 3 fins here that I wantto base my mould on. I’ve started to shape a few boards so I want to be able to make fins rather than buy expensive FCS. As before any advice wouldbe welcome . Thanks
Well, you see, you can’t just stuff cloth into a mold, pour in resin and have an acceptable fin come out when the resin’s gone off. What you’ll get is mostly resin and very brittle, so that it’d break the first time you used it. What you need is something that’ll give you a really good resin to glass ratio, say something along the lines of 50/50. I haven’t tried it, but I’d think you might be able to do it by - 1) Getting what’s called a vaccum bagging setup - see the archives here for more details on that. They are kinda involved, though they do turn out a nice lamination. 2) making female molds from a good set of fins using your vaccum bagging setup. This means a separate mold for left fin, right fin, right side of center fin, left side of center fin. 3) Through a lot of trial and error, making a production setup/method for making the fins, sticking the center fin together, sanding/grinding and polishing these fins so that they’re going to fit the boxes or plugs. As you can see, this is a lot of work, plus a lot of materials. Quite a few hours involved, quite a lot of materials for one set of fins and it wouldn’t start to be economical until you’d made a lot of them, at which time the FCS patent attorneys come down on you like a plague of locusts. While I think it’d be worth it for some obsolete fin systems that you can’t get fins for any more ( and which fins you can charge in excess of $100 US for - I may have to think about that myself…) - well, when you can get the FCS sets easily, in a variety of shapes relatively cheap, I wouldn’t bother. Hope that’s of use doc…
…your also going to need the FCS plugs. If you just buy the plugs it ends up costing the same as buying a set of FCS from Fiberglass supply. They can be machined fairly easily, but it takes some time and if you use a decent material it still end up costing a buck or two.
While this might not be what you want to hear, why not just spend the 20 bucks and get a set of glass on fins. Unless you are going into massive board production making your own is expensive and really time consuming. Glass on fins are way more durable than FCS, and usually when FCS fail they demolish the plug and snap the fin. So you have just as much to repair as a cracked glass on fin. Also in my opinion Glass on fins are better quality, foiled better, better looking on a board,and of course way stronger, but that’s another thread. -Jay
Thanks for all the advice guys. One of my neighbours kids (17) is a bit of a genius when it comes to fibreglass and moulds. He built a whole body kit for his mums car. I think the car looks a bit flash but the boy’s got talent He’s ofered to try and build me a mould. If / When they’re finished I’ll post a web address with a pic. Thanks again Brian
Seems to me most trifin side fins are flat on one side. To mold these, I would suggest laying it flat side down on a flat block of something (like a countertop) with some release agent (Pam spray, wax, crisco, whatever), then set a couple layers of wetted scrap cloth over it. When it sets, peel it off, peel the fin out, and there you have a mold. To use the mold, coat with mold release agend, mix up a thick paste with Qcell and lam resin, pour it in the mold and let it set. Peel it out when it’s fully cured. The resulting fin will be very close to the original (basically exact), and quite light but very fragile. You’d have to glass it on with at least several layers of glass particulaly on the leading edge. Maybe a rope halo on that front edge particularly the tip if there are rocks you may drag the fins over. HOWEVER, this is all too much work, you have to really have a reason to want to duplicate a particular set of fins this way. Note also that it does not present a solution for the double convex center fin. There are rubbery molding materials available at craft supply stores, you could use them and the Qcell paste for a both-sides-foiled center fin. Again, more trouble than it’s worth.