I was watching a good video on YouTube on woodworking, and the guy
just glued one piece of a board before clamping. I use Titebond III
and try to avoid end grain joints with tenons, rabits, or what ever.
But I generally apply glue to BOTH pieces before clamping. For
example, gluing up 3 six inch boards to make an 18 inch panel, 3/4
inch final thickness: Glue to all edges, then clamp.
So, What is the concensus for putting glue on one piece, or both?
Is there a risk of glue starvation on an otherwise snug joint?
Thanks for any comments. Rich.....
On Mon, 5 Jan 2009 12:19:08 -0800 (PST), firstname.lastname@example.org wrote:
I put glue on both mating surfaces, as recommended by the
manufacturer. But there are some glues that should only be applied to
one surface. Based on experience, I can get very close to limit the
amount of squeeze-out. In my earlier days glue dripped all over the
place. Like global warming, I don't believe "glue starvation" is an
issue and never heard glue manufacturers address it.
Both surfaces. Always. Ever brush glue onto a surface over a large
area then come back to where you started and see all the places you
missed or where it didn't get into the pores? I'd imagine the same
thing would be true of the unglued piece inside the joint that you can't
see once you've put them together.
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
In 30 years I cannot remember a time when I applied regular wood working
glue to both sides unless end grain in involved. You really don't want to
glue both pieces if one is a veneer. I have never had a joint fail because
I did not put glue on both sides. Really, the glue gets on both sides when
you put them together. If you have a good tight joint to start with there
will be no starvation.
That said, if you glue both sides you do have more open time on a
complicated glue up.
The conventional wisdom is to wet both sides with glue. I think the
reasoning is partial skinning, with yellow PVA especially, prevents full
wetting of the mating face. It's easy enough to check. Stick two faces
together and then pull them apart and see if both faces are fully wetted.
There were distinct dry patches when I did this even, with an excess of
glue. What does it mean? I guess most joints are over-designed in regards
glue surface to begin with.
Which is made up for by requiring more time to spread glue on the other
side. I do wish it were so, though. I'm tired of rushing the glue up to get
them into clamps soon enough.
Yeah but if the glue skims over, it does so on both pieces does skimmed over
glue stick well to skimmed over glue? ;!)
With lots of practice you eventually learn to get the glue out spread
quickly qirh out muxh fuss. I remember a time when glue up required lots
of set up time. Not so much any more. I probably should have qualified my
statement more. If glueing end grain I tyically apply glue to the end gran
and let the soaking in start up, glue the mating surface and then rewet the
end grain side and then clamp.
I wrote unclearly. By the time you're done painting up the one side, part of
it will have already skinned over. If you glue only one face, leaving the
other face dry, that joint will be skinned glue on bare wood, and probably
compromised. Skinned glue on skinned glue is the normal case, I think, and
Might be that my view is skewed from using glue that seems half dried from
the start. The low humidity isn't helping, either.
A coupla weeks ago, I did a simple box shape, 4 sides and a ply sheet, 16
biscuits in all, that had to come together as one glue up. The glue was some
old yellow Elmers I had left over from last century, and skins over almost
as it's leaving the bottle. I'm thinking of chucking the remaining half
gallon and just get simple white glue. Fuhget about Titebond dis or dat, and
watertight nuthin. I just want the glue to still be glue when I stick the
pieces together. It was a hectic footrace, and I had 12 of them to do. The
last few weren't any more fun than the first few.
As the old saying goes, glue is cheap compared to your time an other
materials. Get rid of your old glue. I keep several glues on hand and
mostly for color. TB II IMHO has a pretty long open time for a regular wood
glue but tends to be runny and a bit messy and you need very good fitting
joints to hide the yellow. The old Elmer's Tite Bond had a fast tack but
fried closer to white. TB III seems a bit thicker and dries to an actual
medium brown wood color. Recently I have used Gorilla WHITE PVA Woodworkers
glue because it is white and does not dry with a distracting color, this was
for a maple project. Also TB Trim Adhesive is white and dries to a non
yellow color however it dries a bit more quickly and is very thick, IIRC it
will not pour out of the bottle, you have to squeeze the bottle to dispense.
Then there is the slow set TB glue for longer open times. I buy poly
urethane as needed, it's expensive, has a short shelf life, and is really
messy if you are not careful.
I've never had a "skim over," but I plan a glue up carefully to get
the piece assembled quickly. Glue brushes, glue roller, unused credit
card, and finger is what I use to spread glue quickly. Clamps, jigs,
damp rag are nearby. Dryfitting everything speeds everything up and
if the item is complex, I'll glue up part of it.
It's funny (and fun) how we get so caught up with simple things.
Musicians do the same thing.
A drummer friend of mine once said,
"We have a tendency to make rocket science out of hitting things with
"Playing is not something I do at night, it's my function in life"
With most common woodworking glues - yellow, white - the glue dries from the
outside in. If you put a drop somewhere it will form a skin...push on it
and fresh, unskinned glue gushes forth.
Yours is probably "higher viscosity" because it is a thin layer and the
higher viscosity is because it has skinned. Higher viscosity/skinned is not
good because it won't wet out the wood as it should.
"skin" could be defined as viscosity gradiant. In my experience, I do not
notice any gradiant, just thicker glue.
Then again, maybe I just work quickly. If I don't think I can get an
assembly together within 10 minutes, I try to find a way to get it done with
The OP initially asked (paraphrased) Gluing, one side or two? More often
than not my glued surface stays open to the air for less than 2 minutes ...
viscosity/skin seldom comes into play. It would probably be fair to say
that gluing both sides buys wou a little more working time if you need it.
Trimmed for brevity...
>>> you still have to physically break through the "skin"
I conceed that I did not address the surface tension interpretation of
I believe that assembling a joint would provide sufficient force to overcome
surface tension a.k.a. hydrostatic pressure.
The other half of that thought is if there's anything under that skin to
squeeze out, it's more squeeze out than I like. Normally, I run a squiggle
down each edge, and smear 'em to flat films with my finger. Each face is
fully wetted, leaving very little that can squeeze out. I suppose if I put
the same amount of glue, the same amount as for both edges, onto just the
first edge, there should be enough to squeeze out. I dunno. I guess it could
work, but just seems so hit or miss. You run a double size bead, and then
smoosh it around blindly with the other piece. Too small of a bead means not
enough glue; too much means lots of cleanup. As it is, I inevitably have to
wipe some extra off my finger, or move some of the extra to a slight dry
area. It could work. Just put on a double size squiggly bead, smoosh the two
across each other for half the squiggle distance, and come back a full
squiggle distance. It could work. It just seems so... so... imprecise?
Come to think of it, that's not the real problem. Flat straight edges are
fast and easy, either way you do it. It's buttering up the biscuits and
feeding their holes, or painting up the M&T that takes up time. There's not
enough sliding room to do the smooshing around with biscuits, and none at
all with M&T. Do you just clamp and hope for the best?
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