A lot of people tell me if your joints aren't very tight
you can just use Gorilla Glue because Gorilla Glue expands to fill the gaps.
Well, I'm not so sure that's such a good idea.
So, let's try this out. I'm gonna glue these 2 pieces of wood.
And I'm just gonna wipe this with a moist piece of paper towel
to make sure I'm gonna have some moisture in the joint.
So, certainly enough that this will fill the gap all right.
And, I'm going to put
these plastic shims on the corners of the joint.
And that will make sure there's gonna be a slight gap when I clamp this together.
And now the other piece of wood on top.
So I've got enough glue in there to completely
fill the joint even if it doesn't expand.
But, I'm assuming that is for the better.
So, I gave this glued joint a whole week to set.
And, as you can see it's expanded by quite a lot.
The question is really how strong is this joint?
So, let's give it a scientific test.
(Grunting Sounds)
Actually, I was just kidding. Let's really try this.
(Snap) Not very strong at all.
So what makes this glue so weak?
I think the problem is that it expands.
And it expands into a foam. And foam is
just not a very good glue.
So, for instance, here is a dab of glue
that I put on this piece of wood.
I can just break this stuff. Look at that, it's just bubbles.
So, why do I want to flog a dead horse?
I already know Gorilla Glue sucks with gaps.
The problem is, before I did my breaking test by hand I prepared a bunch of samples.
So I might as well test those in my apparatus to get a reading.
Each joint is 4 by 4 centimeters
And I'm extending that out here because I didn't want to waste that much wood
to 20 centimeters. And I'm applying the force with a bottle jack
which is on a bathroom scale.
And I've got a camera to record the weight just in case I miss the maximum reading.
And I've already adjusted to zero on here
so that it's zero with the jack already on it.
All right. Here goes sample number 1.
This is a gapped Gorilla Glue joint.
So, pumping very carefully.
5 10
12
15
It doesn't go over 15.
Yeah, I can see it yielding.
Or hear it yielding.
Yeah.
So, about 15 pounds for the Gorilla Glue.
All right. This is sample number 2.
It's Gorilla Glue without a gap.
And I have to put my hand on there while I'm pumping it
because some of these joints are so fragile.
Just the part falling would wreck it.
I think this one might do better because there's no gap in it.
15 20
25 30
205
210, no not quite.
215, wow.
220
220 I can hear it crackling now.
It's about to go.
230 Not holding.
Yeah, I can't count that 235.
(Crashing sound) Holy shit.
Joint number 3
Yellow Elmer's Glue, with a gap.
210
210 (Crashing sound)
So close.
This sample number 4. Yellow Glue
with no gap in it.
190
195 Uh oh.
Is it gonna pop? I think so.
(Crashing sound) Yup.
Sample number 5.
Gorilla Glue with no gap. So, this one could do fairly decently.
200
205
205 And let's wait for that one to pop.
(Pop) Bang.
It's sample number 6.
Is yellow glue with no gap in it.
180
185
It's coming.
(Crashing sound) Whoa ho.
This pin up here is very important, just to make sure I apply the force
at the right place. Sample number 7. Yellow glue with a gap.
205
It's a coming.
(Crashing sound)
I have to be careful when I clamp these pieces on here.
And now pushing this part of the glue joint.
Because that might bias it one way or the other.
All right. This one's gonna be an easy one
because it's a gapped Gorilla Glue joint.
So, I have to crank it very carefully.
10
15
Here we go.
Well, 15 pounds again.
At least it's consistent.
Joint number 9. Gorilla Glue without a gap.
(Pop)
So, this last one is another Gorilla Glue joint that's gapped
and I know it will do pretty poorly, so I'll
rely on my own brawn and brute strength.
Hi-yaa.
I think that reads about 15.35 pounds.
Yeah. (Laughs)
Now, there's no question that the gapped Gorilla joints performed terribly.
But, when I tabulate the numbers I actually found that the
ungapped Gorilla Glue joints were a bit stronger than the ones with yellow glue.
So, Gorilla Glue can make for a fairly strong joint.
You just have to make sure your joints are really precise.