A Photo & Discussion Forum for Wharram Design Enthusiasts
I have finally started glassing the starboard hull of the Tiki 31 I have been building for some time now. While filling the wire stitch holes and the keel, stem, stern gaps and sanding to prepare the hull for glassing I realized that it will be impossible to accomplice a perfectly fair surface unless I used some kind of fairing compound.I am using West System products and thinking of using Low Density Filler to fair the ups and downs of the plywood but I don't know at which stage of the glassing process should I do it. I am giving the hull a coat of epoxy, applying the glass cloth and then two more epoxy coats. Should I then wait for the last coat to cure, sand the surface and apply the filler? There are also some larger hollow areas that need to be filled. How thick the coat of the filler can be without the risk of cracking ? Should I mix it with colloidal silica if I want to make a thicker coat ( up to 5-6 mm)? My epoxy and paint supplier suggests I should use an Awlgrip epoxy fairing putty for this job but this material is very expensive and I already have large amounts of Low Density Filler.
I would be grateful for any ideas or advice on this matter.
I´m in the process of filling and sanding too. I'm using ceramic microspheres with epoxi-resin. A filler made this way costs less than a prepared epoxy filler and you can prepare it with the consistency you need. You can sand it easily. We don't use silica because it makes it too hard to sand. Before applying the glass, we only filled holes or gaps that would leave an air bubble under the glass. I wouldn't do 6 mm coats at once, because it would be very difficult too sand. Try to apply the second glass coat 1 - 2 hours after the other, so you don't have to sand that much. Glassing is quite fun. Sanding.... agh! Good luck.
Thank you all for your advice! Despite the fact that it made things much more clear in my mind, it also helped me remember one of the principals of these designs: simplicity. Often, in a building process that seems to have no end, I find my mind trapped in details that probably won't make my boat sail better but are certainly delaying my work and postponing the launching day over and over again.
I think I will use what I already have and know how to use it and that is Low Density Filler for the larger hollows (these aren't so large after all). Can anyone tell me if I have to give the fairing compound a final coat of epoxy after I have sanded it and made it fair or should I go on applying the primer directly to it?
There are also some spots where I had some runs of excess epoxy underneath the glass cloth (no air bubbles. Just runs of epoxy on the vertical surface of the upside down hull that cured underneath the cloth making it uneven). Is this a problem to the bond of the glass to the plywood? Should I sand these areas to bare plywood and apply the glass cloth again or should I leave it as it is and just fair it with some fairing compound?
Thanks for your answer. I think I will go for a sooner launch and live with the 1/100 of a knot less in boat speed ;)
By the way, you are doing a great job with the Amatasi!
I think the hardest decision is to know when to stop, you can keep perfecting and sanding and sanding until the moon turns blue and the stars fall from the sky, you will always find another imperfection. In hindsight i spent way too long on this fairing lark and knowing what i know now i could have had just as good finish if i stopped 6 weeks ago.
I am working on my Tiki 46 in the yard of a very luxury catamaran builder here in South Africa and their latest all carbon-fibre 60ft cat has just been launched. Even with a huge team of 40-50 guys working non stop for over 2 years, when i cast my critical eye over her hull i still find imperfections and that is a boat with a retail of 35,000,000 South African Rand. Will the new owner ever see these imperfection... I don't think so...
Anway good luck with your build, at the end of the day don't get caught up in the really small details because honestly, you'll be the only one to ever see them...