If it foamed, there was enough moisture. I would check that you had a
tight enough joint, or that the opposite wasn't true - that the joint
was too tight and became glue starved.
Brian
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Aidan Place wrote:
> Hi all,
>
> Just bought a bottle of the titebond "foaming" polyurethane glue and the
> first two projects (mortise and tenon joints) have just "broken" apart with
> a slight tap.
>
> I am aware that one surface should be damp. I am guessing that I wasn't damp
> enough. How damp is damp?
>
>
> Aidan.
>
>
Greetings and Salutations...
On Wed, 26 Nov 2003 21:52:48 -0000, "Aidan Place"
<[email protected]> wrote:
>Thanks for the replys,
>
>I am confused now. At first I also thought that perhaps glue starvation was
>it, but the joints are a firm hand push fit. Also i reglued the joints with
>PVA this afternoon and they are solid as a rock.
>
>Its very cold and damp here today, perhaps thats something to do with it.
>
>
>Aidan
>
>
Perhaps not. I have found from experience that Polyurethane
glues CAN be fairly brittle. That is good, in that they are
sandable and will not mess up your paper. That is bad, in that
they do not survive impact.
Another bit of information that I did not see whas
how the joint looked when you took it apart. Did the layer
of glue seem "foamy", or was there just a little foam, and
most of it was glassy and smooth? In the latter case, the
glue might have "skinned over" before the joint was
assembled.
Regards
Dave Mundt
> Perhaps not. I have found from experience that Polyurethane
> glues CAN be fairly brittle. That is good, in that they are
> sandable and will not mess up your paper. That is bad, in that
> they do not survive impact.
> Another bit of information that I did not see whas
> how the joint looked when you took it apart. Did the layer
> of glue seem "foamy", or was there just a little foam, and
> most of it was glassy and smooth? In the latter case, the
> glue might have "skinned over" before the joint was
> assembled.
> Regards
> Dave Mundt
Glassy and smooth if i remember rightly, but i did clamp up imediately after
applying the glue.
Aidan.
"Aidan Place" wrote...
> Just bought a bottle of the titebond "foaming" polyurethane glue and the
> first two projects (mortise and tenon joints) have just "broken" apart
with
> a slight tap.
The glue could be old and might have been sitting on the shelf for a long
time. My favorite local hardware store was a great place to get things
(before the BORG assimilated them) but I would never buy glue there because
I knew that it sat on the shelf way too long.
--
Cheers,
Howard
----------------------------------------------------------
Working wood in New Jersey - [email protected]
Visit me in the woodshop - www.inthewoodshop.org
Theoretically the moisture in the wood alone should be enough to allow the
wood to cure. Misting one side just kind of helps the cure along.
Assuming the glue was good and you know it if it wasn't, it'd be somewhere
between Jell-O and rock, the fault has to pretty much lie in joint
construction, glue application, or clamping. Don't like the stuff much
myself but, to give the devil his due, it does make for a strong joint.
--
Mike G.
[email protected]
Heirloom Woods
www.heirloom-woods.net
"Aidan Place" <[email protected]> wrote in message
news:[email protected]...
> Hi all,
>
> Just bought a bottle of the titebond "foaming" polyurethane glue and the
> first two projects (mortise and tenon joints) have just "broken" apart
with
> a slight tap.
>
> I am aware that one surface should be damp. I am guessing that I wasn't
damp
> enough. How damp is damp?
>
>
> Aidan.
>
>
Damp is just a slight enough moisture to help the poly cure. I doubt that
was the problem if a slight tap broke them apart. More likely the joint was
not as tight fitting as it should have been and perhaps you were thinking
that the poly is a gap filing glue? Its not and the web the foam makes as
it dries is very weak.
Clean it off and use some epoxy glue if you need to fill a gap, or add some
"shim" material to the cheeks then re-mill them to have a nice firm fit in
the mortise. Be sure the mortise walls are clean and flat and are parallel
to the tennon cheeks.
Bob S.
"Aidan Place" <[email protected]> wrote in message
news:[email protected]...
> Hi all,
>
> Just bought a bottle of the titebond "foaming" polyurethane glue and the
> first two projects (mortise and tenon joints) have just "broken" apart
with
> a slight tap.
>
> I am aware that one surface should be damp. I am guessing that I wasn't
damp
> enough. How damp is damp?
>
>
> Aidan.
>
>
The next post made a good point about maybe being to tight and the joint was
starved for glue. Also, is the poly glue out-of-date ?
Bob S.
"Aidan Place" <[email protected]> wrote in message
news:[email protected]...
> Thanks for the reply Bob.
>
> The mortise and tenons were a great fit even if i do say so myself. :-)
>
>
> Aidan
>
>
>
Any chance the poly got frozen?
"Aidan Place" <[email protected]> wrote in message
news:[email protected]...
> Hi all,
>
> Just bought a bottle of the titebond "foaming" polyurethane glue and the
> first two projects (mortise and tenon joints) have just "broken" apart
with
> a slight tap.
>
> I am aware that one surface should be damp. I am guessing that I wasn't
damp
> enough. How damp is damp?
>
>
> Aidan.
>
>