PVA/Polyurethane glues vs. PL Premium construction adhesive
 

I had a glue-up that was going to take some significant time (not
to mention a few somewhat loose mortise and tenons) and some
left-over PL Premium in a caulking tube, so I decided to test it out
by gluing some maple blocks together (and one with a 1/8" gap)

The one with the gap had laughable strength, but the wood came
apart before the joint did with the no-gap test...not much point
in anything stronger than that.

Has anyone else dumped other glues for this stuff? it's dirt cheap,
waterproof, gap-filling, wood-colored, sandable, gives you something
like 30 minutes of reposition time, seems to hold some stain once
sanded, and seems to be rated for "structural" load... at least one
of my yellow glues specifically say that it's not (if you ever get
yellow PVA wet, it turns to jelly, so maybe that's the showstopper
for load-rating an adhesive... not very safe for holding up a house :-)

Has anyone else dumped other glues for this stuff?

I just started using that stuff when my local supplier of Liquid Nails
ran out. I like it! It is great for outdoor stuff like utility
furniture, or where you can glue where no one can see the squeeze out.

I have used it on interior trim as needed (like glueing a bent piece of
trim on a bulged wall, including the scarf joint) and it holds really
well.

Since it is also waterproof when dried, I have used it for tile repair
instead of buying mastic, and have glued metal corners on bead board
wainscot using the glue, taped in place for 24 hours. Works great!

Robert

Funny, I experimented with this just two weeks ago. I had some Gorilla,
some Nail Power (mfg. Henkel), and some PL Premium. They're all
polyurethane glues for wood, the first two marketed for cabinetry
stuff, the last as a construction adhesive. The first is about 2x the
price of the second, and the second is about 10x the price of the
third.

Couldn't help but wonder if there was a possibility that the PL could
used as effectively as the first two in similar applications, so I did
a test.

The first two have about twice the viscosity, which makes sense since
PL is a construction adhesive, not a cabinet glue. The runnier
viscosity is desirable for how I wanted to use it, however, so the
first thing I did was read to see what I could thin it with. Nothing on
the tube, but it did mention mineral spirits as a cleanup agent, so I
thinned it with that, and it seemed to work. You don't need much, and
you have to spend a minute to get it mixed.

I cut some scraps of pine then glued up and marked a couple of blocks
for each glue.

After they dried (and all had the similar foaming cure), I put each one
in a heavy vice and pounded at the seam.

They all held up admirably, all splits were in the wood not the glue
line.

Hardly scientific, but enough to satisfy my curiosity. If I have a
project that's not valuable, I wouldn't hesitate to use thinned PL
premium. I think I'd pick it over yellow glue most of the time.

2=A2
H

wrote in message news:DPfKe.214581$on1.88917@clgrps13...
I had a glue-up that was going to take some significant time (not
to mention a few somewhat loose mortise and tenons) and some
left-over PL Premium in a caulking tube, so I decided to test it out
by gluing some maple blocks together (and one with a 1/8" gap)

The one with the gap had laughable strength, but the wood came
apart before the joint did with the no-gap test...not much point
in anything stronger than that.

Has anyone else dumped other glues for this stuff? it's dirt cheap,
waterproof, gap-filling, wood-colored, sandable, gives you something
like 30 minutes of reposition time, seems to hold some stain once
sanded, and seems to be rated for "structural" load... at least one
of my yellow glues specifically say that it's not (if you ever get
yellow PVA wet, it turns to jelly, so maybe that's the showstopper
for load-rating an adhesive... not very safe for holding up a house :-)

Well they are intended for 2 different purposes. You could probably enter
screws and or nails in the mix as they too fasten pieces of wood together.
That said, the caulk construction adhesives tend to keep the wood pieces
spread apart due in part to the viscosity of the adhesive. Polyurethane on
the other hand can be squeezed/spread out quite thin and over the entire
surface with out the mess that a construction adhesive would present if you
wanted to cover the entire surface.

Leon wrote:

Well they are intended for 2 different purposes. You could probably enter
screws and or nails in the mix as they too fasten pieces of wood together.
That said, the caulk construction adhesives tend to keep the wood pieces
spread apart due in part to the viscosity of the adhesive.

That's true, PL Premium almost has a putty-like consistency. But I
like that! It's probably partly due to the extremely high solids
content, perhaps something like talc is used as a filler.

I can definitely see how separation could be a problem -- even under
clamping pressure -- but I don't usually make too many joints where I
could see this as being a problem (e.g. a lap joint)... mostly mortise
and tenon joints, where the viscosity actually seems to be benificial.

My usual process is to caulk-out a huge wad of the stuff (since it's
*dirt* cheap) and use popsicle sitcks to "butter" all the surfaces.
After I slather it on the tenon, I can wave the stile around for 20
minutes (while I try and remember where it's supposed to go) and the
glue stays put with zero drips.

With PL, I've never had to clean up all the dried glue drips off
clamps, tables, floors, etc.

hylourgos wrote:

--snip--

first thing I did was read to see what I could thin it with. Nothing on
the tube, but it did mention mineral spirits as a cleanup agent, so I
thinned it with that, and it seemed to work. You don't need much, and
you have to spend a minute to get it mixed.

I'd be afraid to thin it. I usually go by smell, and it didn't smell
like anything I've ever smelled before. I've been burned by the like
smell test too, though:

I hold sandpaper on blocks with *rubber* cement so I can replace it
easily, and my bottle was getting a little gummy and had some
*contact* cement thinner handy... if you take a whiff of the two, they
both smell like they'd make you high in a few seconds (qualitatively,
they seemed similar enough) but they definitely don't mix... it turned
the rubber cement into something new --- "chunky" rubber cement, for
which I have yet to find a practical use.

Also, there's that spray foam stuff (i.e. "great stuff")... It's
polyurethane too. It says to clean it up with acetone, as I recall.
So, it's either two diferent solvent bases, or those were just the
best alternatives their product testers could come up with that you
can actually buy at the borg, implying that it's probably not the
ideal thing to thin it with.