In the excitement of the initial TFlex build I had a number of blanks cut with the rails cut off. Ove the course of a couple of builds I found that epoxy parabolic stringers were overbuild. Sanding the epoxy stringers also took more skill than I have, so I ended up gouging the EPS a fair bit. Also if the stringer is a bit proud then the veneer bends around it under vac and does not end up looking good.
I used black double sided tape to attach the rails on the current board. The intention was to get a nice pinline on the bottom deck (where there is no veneer). Actually the pin line fades in and out because I spackled over the tape in places where I did not get the tape exactly even to the deck. The stringerless board with bamboo top deck feels great but it might be underbuilt (2oz, boo, 5 oz top and bottom) more from the materials (cheap cloth) and lack of proper epoxy post cure than the glass schedule.
Now I’m ready for another build. Any suggestions on what to use to glue the rails on? I’m tending towards wood glue and vac bag, but I’m sure there are better adhesives out there. I know some people swear by foaming adhesive for EPS. Is this the best stuff?
Thanks,
Red
Here’s an example of the blank with rails epoxied on:
I like to use foaming PU glue and build up with a 3/16 strip of basswood next to the eps and then 3x 1/4" strips of corecell. I use the offcuts from the blank as a clamp and only do 1 side at a time. takes a little extra time but I'm a backyarder and I like how thw boards turn out.
I use SUMO glue next to the EPS as it cures white and then Elmers or Gorilla glue between the corecell as it cures to a yellow that matches close. It is easy to sand and gives a better bond because it doesn't become brittle like epoxy will.
I don't think wood glue will dry in a vac-bag, as it is an air cure, If i understand your post correctly. Maybe clamping first, allowing to cure, then the vac-bag for the skin lamination, would though.
Thanks for the info. Nice to know about the wood glue. Would have been bummed to pull soggy rails out of the bag after 4 hours.
It seems that Gorilla glue and foaming adhesives such as SUMO are not available in Australia (please let me know where to get them if they are available).
There are 2 local alternatives that might fit the bill.
AV515,
manufactured by A.V. Syntec and Bostik expanda foam.
The AV515 is air cure, so possible only suitable for small joins. Both are yellow. Yellow pinline here we come!
what are you using for the rails? i have a few blanks coming from a friend and he does comsands so has the blanks already cut without the rails. i dont want to do compsand style rail builds.
just whack some more foam and bamboo veneers. but what type of foam and where is the best place to get it?
I use the vice stuff and it works well. Haven't found a white foaming poly glue yet.
If you use epoxy to glue your rails just use a nice thing coat and it will sand off pretty well without tearing the eps.you have to get the blank and the rails nice and neat and then you wont see the line and there wont be any need for such a thick coat of resin.
Hey Scot,
Use any foam you can get your hands on. Shape the offcuts from PU blanks and glue them up or corecell from ATL, Klegecell from FGI. anything you can think of.
Keep in mind that the foaming glues, though fast, are still air cure. So for best results, cure the rail adhesives prior to bagging EDIT add on - If your looking to one step; If you make sure the work is very dry, (like have the blank and rails in a heated room prior to using foaming glue),. It should cure by absorbtion, maybe leave the vac on a bit longer.
FYI, you can use pigments in PU foaming glues. I've used white and black with GG. It doesn't foam as much, which is sort of a plus for me. However, if you use black on EPS, be sure and spackle the facings of the glue-up before you glue it or the stuff will foam into the blank and it really shows. White will actually be an off white color but it looks a lot better than a brown glue line.
I’ll bag the bamboo on after glue and spackle dry.
Bamboo from Fethers. They have heaps of different veneers but only sell certain ones as leaves.
The rails are fully shaped EPS. Rails in the tail are 1/4"thick and pretty flimsy. An example of the kind of high precision machining that’s possible outside surf CNC.
The yellow mess in the pic is off colour talc (don’t use the no-name brand!)
FYI, you can use pigments in PU foaming glues. I've used white and black with GG. It doesn't foam as much, which is sort of a plus for me. However, if you use black on EPS, be sure and spackle the facings of the glue-up before you glue it or the stuff will foam into the blank and it really shows. White will actually be an off white color but it looks a lot better than a brown glue line.
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Thanks Surfthis I'll give it ago. The smaller amount of foaming will probably be an advantage to me.
there’s also non-toxic Roo-Glue for foam as well as water-based contact cement for foam that can be brushed or sprayed on. check some older threads here…
it works the same as 5 min epoxy
some of the solid wood parabolic guys are using it with success.
i think it they discovered that you’re goiing the glass the rails 2x3 times over anyway so why add to the shaping mess with an epoxy or PU glue line right where you need to turn a fine line like a rail band.
of the PUs I found that sumo is the easiest to cut after it drys and it doesn’t foam as much as the rest.
