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flybynightkarmarepair wrote:
>
>
> None of the Big Borg stores in my part of Northern California, nor the
> local, well stocked and well run Ace stock resorcinol, and I was told
> by the proprietor of a specialty woodworking store that it isn't
> stocked or distributed in California.
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Go to the DAP web-site and click on the 'Find Retailer' tab.
One of the Home Depot stores in Escondido ( 11 mile from the house )
carried it for a time and will apparently special-order it. DAP lists
the Home Depot store in Lemon Grove ( abt. 30 miles away ) as a
retailer.
Resorcinol apparently from China(!) is leaking across the border. The
powder is in a sealed foil/plastic/paper pouch, the liquid in
non-resealable tin can. Used primarily at small boat yards around
Sandy Eggo. (Same brownish-purple stuff; absolutely impervious to the
72hr boil-test.)
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> How are you getting it down in Vista? Or have you decided that in spite
> of it's advantages, it's not worth the hassle of getting it, and that
> for most uses, moisture cure urethanes, epoxies, and plastic resin glue
> are Good Enough?
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I still prefer resorcinol for props. And as shown above, it is still
locally available. However, given our weather, Weldwood 'Plastic
Resin' does just fine for most everything else.
Despite the recent FAA warnings, if you'll check the provenance of the
failures that prompted the warning against urea-formaldehyde glue (ie,
Miles 'Messenger' and deHavilland 'Mosquito,' both in tropical
Australia) and compare that to the conditions under which Fly Baby's
(and others) enjoy here in the States, I think you'll see why I
continue to use it, at least until I hear of a documented case of
Weldwood 'Plastic Resin' failure. (Hint: If you want it to last,
do not leave your plywood-skinned bird parked out in the open, on the
equator, for four years.)
Which doesn't mean it is the only glue I use. I have posted several
comments and some test results regarding one-part urethane adhesives
and cyanoacrilates. I do not care much for the latter due to their
short working time (typically <30min ) but I have found urethanes to be
trustworthy when properly applied and sufficiently clamped. In that
regard, the FPL clamping and application instructions have proven to
give more reliable results than the instructions provided by most
urethane manufacturers. (ie, apply to both surfaces, limit open time
to <15min., clamp with up-to 150psi for 24hours and don't stress for
up to 72hrs) Indeed, I recently failed one of the hold-down bolts of
the vise I use to hold coupons for shearing tests whilst testing
urethane-glued coupons of Douglas Fir.
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As a point of interest, I am presently testing urethane for attaching
door-skins to hemlock stringers using pneumatically-driven brads and
staples. For a 'standard' I made up some test pieces using Sitka
spruce, resorcinol and nailing strips (ie, the 'traditional' method).
The tricky bit is determining the best type of fastener and the spacing
between them. Project is presently on hold due to cold weather (the
work is being done outside the shop).
I have taken advantage of the cold weather (it got close to freezing
Monday night) to test coupons of T-88. In theory, the chemical cure of
epoxy simply slows down, as opposed to urea-formaldehyde which must be
maintained above a certain temperature. Allowing the epoxied coupons
to remain clamped for up to seven days should result in an adequate
bond. The sledge hammer will tell me if that's correct :-) (2.25 sq.
in. of gluing surface should fail in shear at about 2365 psi for DF @
12% moisture content. )
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When building a Box Store Bomber I feel the adhesive is even more
important than the wood. The tricky bit here is that while using
locally available wood has a dramatic effect on reducing the cost of
the airframe, the RELATIVE cost of the adhesive goes UP if you spec
something like T-88 or FPL-16A. This is what's behind my interest in
'Plastic Resin' and urethanes.
-R.S.Hoover
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Re: Glue it to it
