Should resin be filled or unfilled for gluing stringers?
Poly or epoxy?
I have never done poly, but for epoxy I use regular Elmer’s glue for wood stringers. If I wanted a cool pigmented glue line, I’d seal the raw eps on either side of the glue joint with epoxy/micro and then glue it up with pigmented epoxy…
JSS
What were you going to use as a filler ?
Milled fiberglass is one of the best , OR MY FAV: Diaper filler(archive “exo-filler”)…but just lam resin will do…Here’s a tip from the MAN Jim “The Genius” Phillips : Pour out enough resin , into a bucket , enough to do the job,and let it sit for a day or so…This will thicken it up by letting the styrene evaporate,which will not allow the lam resin to saturate as much and bond better///////////////////////////////sticky=slow drying/curing time.H
Some kind of polyurethane foam sealant. Just spray and clamp together. It’s lightweight and nice and easy to plane down.
Epoxy.
If you’re doing a wood or pvc foam stringer, no color, straight epoxy works, add some microballoons if your lengthwise stringer cut has wiggles from a kinked hotwire to fill in the gaps…the lengthwise cut is hard to get right unless you have a jig setup for it, and 2 people…
For colored glue lines, seal the mating surfaces so you won’t get pigment seepage in either direction (I’m pretty sure you do not have to seal pvc foam, but I would if I were doing it, as I don’t know for certain), you want to keep the pigment between the stringer and the foam. Epoxy works for the sealing, just a very thin coat, with or without microballoons, your call. Squeegee off the excess sealing material before it completely cures, so you don’t introduce any bumps on the surfaces.
To make things easier, use a roller to spread the epoxy. squeegees suck for such long and thin areas, at least for me. Too much drips off the edge just to become ‘glue balls’ to be discovered later (usually during finish sanding), and much cussing ensues…
Use the foam block you cut the blank from as the support for gluing, with wax paper or plastic for a barrier. If this was a purchased eps blank you are adding stringers to, use a bunch of sawhorses set at the right heights to cradle the blank as well as you can for clamping…
If your lengthwise cuts are awesome and dead straight, you will not need many clamps. If they are like mine, you will need lots o’ clamps (I use about one per 14-18 inches or so, with each clamp having 4"x6" cauls to distribute the pressure on the foam), test clamp everything before gluing to find out how many clamps, where to put them, and the pressure you will need to make the parts fit together well. Do not try to figure this out once the epoxy is curing…
Gluing in stringers can be a bitch, but with proper preparation, enough clamps and good support, it is a breeze. Just like everything else, you will spend almost twice as much time setting up to do this than actually doing it…it’s the only way to get things right (for me, at least)…
JSS
…PU glue is better than resin
is what almost all the non Clark, Walker foamers have been using
hey dean
adhesive technologies 5 min epoxy is all you need
it is stronger then the strongest eps foam
use 300 wide blocks so you have planed faces to glue together
and so you cut two 3oo wide blanks
use sellys doublesided office tape to hold the 3mm mdf template onto the foam block for hotwiring (wharehouse stationary)
it is easier in every way then dicking around with screws
use a thin smear of glue so it doesnt drip
glue the stringer to one side with a few weights
wait 5 minutes and then glue the other blank half
hold in place with hands for 5 minutes
or use a few weights
no clamps no fuss
your shaping within 15 minutes from cutting
or not
Cheers.
no wuckas