For laying up fiberglass laminate?
Aeropoxy PR2032/PH3660 is best, if you're patient, but you
have to order it (Shadow and Aircraft Spruce carry it) and
it takes a long time to harden unless you heat-cure it...
"Marine" epoxies such as West, System 3, or TAP may be available
locally from over-the-counter sources, may be a little cheaper,
and the turnaround time on room-temperature-cured layups can be
a lot faster... the Aeropoxy stuff is about 24 hours to full
initial cure (i.e., not sticky or flexible), while TAP "marine
grade" with "fast" hardener takes about 6 hours or so.
For laying up glass cloth (especially fine glass like
1.8 or 3.5 oz. that I prefer) the Aeropoxy is still my
favorite because it has low viscosity and wets the cloth
so very easily and efficiently.
The simple answer for epoxy *or* CA type glues is that anything found at a
home improvement, grocery, mass market, or other such store is GARBAGE.
Hobby and specialty (boat building) stores tend to stock some better
Another easy give-away for low quality epoxy is a 50:50 mix ratio. This is
an indication that fillers have been added to one or both components.
Especially when doing glass layup, you need low viscosity (almost
water-like) resin with long curing times.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD"
>>> To reply, remove the TRABoD!
I regularly use _a few drops_ of denatured alcohol in my "cheap" finshing
epoxy when I need to put a layer of 1.5 ounce glass on the center or
dihedral joint of model sailplane wings for reinforcement. You can
significantly cut the viscosity so it it is easier to get it wet without
adding a lot of weight. The alcohol then evaporates and leaves the epoxy to
If you have really slow epoxy, a coupla seconds in the microwave will speed
cure and temporarily thin the epoxy as well, though I would probably not use
both heat and alcohol together together (the notable exception is while
drinking beer and working on a model)
As my experienced (old) friend says - glue weighs one ounce in the cup and
three ounces on the plane. The moral is to use as little as gets the job
done, and no more.
Feel free to substitute "rocket" for plane anywhere it is mentioned.
BTW, the sailplane guys have gotten into the habit of using +/- 45 degree
orientation of the strands when glassing wings. Kinda makes sense in that
all of the fibers are contributing instead of just the ones in the right
orientation. It also prevents fraying the edges when you cut and handle it.
The only downside is that all of the pieces you buy come cut on the 90's
instead of the 45's.