On a recent post, I was advised not to use Polyurethane glue on an
external structural frame. (150mm square posts to 227mm deep Glulam
beam)
Somebody mentioned using an epoxy glue ... any recommendations (avail
in UK)
On previous structural jobs I have used Cascamite ... is there
something better ?, a gap filling or expanding glue would be preferred
(but may not be possible)
Toller wrote:
> "Osprey" <[email protected]> wrote in message
> news:[email protected]...
> > On a recent post, I was advised not to use Polyurethane glue on an
> > external structural frame. (150mm square posts to 227mm deep Glulam
> > beam)
> >
> > Somebody mentioned using an epoxy glue ... any recommendations (avail
> > in UK)
> >
> What's wrong with polyurethane? It is rather cheaper and easier to use than
> epoxy.
> Not as strong as epoxy, but as the joke goes; either is stronger than the
> wood, so what does it matter?
I was going to do a new post on this subject after a weekend's using
polurethane and ask if there is a viable alternative as I find it
horrible stuff to work with - sticky and doesn't remove easily - and
all that blasted foaming out of the joints.
Rob
Osprey wrote:
> On a recent post, I was advised not to use Polyurethane glue on an
> external structural frame. (150mm square posts to 227mm deep Glulam
> beam)
>
> Somebody mentioned using an epoxy glue ... any recommendations (avail
> in UK)
>
> On previous structural jobs I have used Cascamite ... is there
> something better ?, a gap filling or expanding glue would be preferred
> (but may not be possible)
Two months ago I did a test. I glued poplar with epoxy and Guerilla
glue. I soaked them in a bucket of water for a month. Niether came
apart. I tried to hammer both apart and they are staying together.
Not a scientific test, but a test.
[email protected] wrote:
> Toller wrote:
>
> > What's wrong with polyurethane?
>
> Neither polyurethane nor epoxy will last well outdoors, owing to UV
> degradation.
>
> However it's easy to make epoxy UV-resistant by mixing it with a cheap
> opaque filler, such as chalk dust (whiting).
..or cover it with something.
> >
> >On previous structural jobs I have used Cascamite ... is there
> >something better ?, a gap filling or expanding glue would be preferred
> >(but may not be possible)
>
> Sikaflex 221:
>
> <http://www.google.co.uk/search?hl=en&q=sikaflex+221&btnG=Google+Search>
>
> or have a look at the rest of the range.
But Sikkflex 221 is a polyuretahne glue ... which others advise is
liabel to UV degradation, and while gap filling is crap when there is a
gap ? i.e. not a furniture grade joint.
[email protected] wrote:
> Toller wrote:
>
> > What's wrong with polyurethane?
>
> Neither polyurethane nor epoxy will last well outdoors, owing to UV
> degradation.
>
> However it's easy to make epoxy UV-resistant by mixing it with a cheap
> opaque filler, such as chalk dust (whiting).
what will last well out doors ? (excluding a home mix as described )
Toller wrote:
> "Osprey" <[email protected]> wrote in message
> news:[email protected]...
> > On a recent post, I was advised not to use Polyurethane glue on an
> > external structural frame. (150mm square posts to 227mm deep Glulam
> > beam)
> >
> > Somebody mentioned using an epoxy glue ... any recommendations (avail
> > in UK)
> >
> What's wrong with polyurethane? It is rather cheaper and easier to use than
> epoxy.
> Not as strong as epoxy, but as the joke goes; either is stronger than the
> wood, so what does it matter?
> > On previous structural jobs I have used Cascamite ... is there
> > something better ?, a gap filling or expanding glue would be preferred
> > (but may not be possible)
> >
Interesting follow up .... I contacted several major glue manufacturers
... the fact that has come out is that Epoxy is NOT suitable for
external wood joints, unless they are protected by painting or similar.
Epoxy is not UV stable.
So it looks like I have to use Resin or Polyurethane.
[email protected] wrote:
> [email protected] wrote:
>> Toller wrote:
>>
>>> What's wrong with polyurethane?
>> Neither polyurethane nor epoxy will last well outdoors, owing to UV
>> degradation.
>>
>> However it's easy to make epoxy UV-resistant by mixing it with a cheap
>> opaque filler, such as chalk dust (whiting).
>
> ..or cover it with something.
Like polyurethane. Umm... varnish, that is.
Mike
The message <[email protected]>
from [email protected] contains these words:
> > However it's easy to make epoxy UV-resistant by mixing it with a cheap
> > opaque filler, such as chalk dust (whiting).
> ...or cover it with something.
Like wood?
--
Skipweasel
Pay no attention to that man behind the curtain.
Toller wrote:
> What's wrong with polyurethane?
The stuff is about as useless as breasts on a boar hog.
Osprey wrote:
> Interesting follow up .... I contacted several major glue manufacturers
> ... the fact that has come out is that Epoxy is NOT suitable for
> external wood joints, unless they are protected by painting or similar.
> Epoxy is not UV stable.
Yes, epoxy is not tolerant of UV; however, if your joints have anything
but an edge exposed to UV, you probably have problems other than UV
damage to address.
Edge exposure to UV is not going to be a problem.
If you think it will be, then use the "purple stuff" (powder & liquid
mixed).
(Have a mental block at the moment and can't think of the proper name
for it)
Lew
On 17 Sep 2006 13:12:49 -0700, "Osprey" <[email protected]>
wrote:
>On a recent post, I was advised not to use Polyurethane glue on an
>external structural frame. (150mm square posts to 227mm deep Glulam
>beam)
>
>Somebody mentioned using an epoxy glue ... any recommendations (avail
>in UK)
>
>On previous structural jobs I have used Cascamite ... is there
>something better ?, a gap filling or expanding glue would be preferred
>(but may not be possible)
Sikaflex 221:
<http://www.google.co.uk/search?hl=en&q=sikaflex+221&btnG=Google+Search>
or have a look at the rest of the range.
Alternatively Marineflex is much the same, and quite a bit cheaper if
you buy it direct by the case:
<http://www.google.co.uk/search?hl=en&safe=off&q=marineflex&btnG=Search>
cheers,
Pete.
Osprey wrote:
> On a recent post, I was advised not to use Polyurethane glue on an
> external structural frame. (150mm square posts to 227mm deep Glulam
> beam)
>
> Somebody mentioned using an epoxy glue ... any recommendations (avail
> in UK)
>
> On previous structural jobs I have used Cascamite ... is there
> something better ?, a gap filling or expanding glue would be preferred
> (but may not be possible)
>
IIRC, polyurethane glue is subject to UV degradation but the same is
true of epoxy. I'd use the poly but a construction adhesive formulated
for exterior use should work too.
Jess.S
[email protected] wrote:
> [email protected] wrote:
>
>>Toller wrote:
>>
>>
>>>What's wrong with polyurethane?
>>
>>Neither polyurethane nor epoxy will last well outdoors, owing to UV
>>degradation.
>>
>>However it's easy to make epoxy UV-resistant by mixing it with a cheap
>>opaque filler, such as chalk dust (whiting).
>
>
> ..or cover it with something.
>
Same with polyurethane. Paint it or cover it with trim.
"Osprey" <[email protected]> wrote in message
news:[email protected]...
> On a recent post, I was advised not to use Polyurethane glue on an
> external structural frame. (150mm square posts to 227mm deep Glulam
> beam)
>
> Somebody mentioned using an epoxy glue ... any recommendations (avail
> in UK)
>
What's wrong with polyurethane? It is rather cheaper and easier to use than
epoxy.
Not as strong as epoxy, but as the joke goes; either is stronger than the
wood, so what does it matter?
> On previous structural jobs I have used Cascamite ... is there
> something better ?, a gap filling or expanding glue would be preferred
> (but may not be possible)
>
In article <[email protected]>,
<[email protected]> wrote:
>
>[email protected] wrote:
>> Toller wrote:
>>
>> > What's wrong with polyurethane?
>>
>> Neither polyurethane nor epoxy will last well outdoors, owing to UV
>> degradation.
>>
>> However it's easy to make epoxy UV-resistant by mixing it with a cheap
>> opaque filler, such as chalk dust (whiting).
>
>..or cover it with something.
>
For maximum strength, polyurethane glue also requires woodworking or
furniture quality surfaces and joints. It is not gap-filling like
epoxy is; it may foam up and fill a gap or void, but it will not have
any strength. Epoxy will maintain it's strength even with a relatively
poor fit. On a construction project, that is often what you get. OTOH,
there are poly construction adhesives that come in a tube; The are
similar to liquid nails in consistency. I've used some of these; PL1
brand claims to be 3 times as strong as "conventional" construction
adhesives (like liquid nails?) IIRC
--
Every complicated problem has a simple solution that doesn't work.
Larry Wasserman Baltimore, Maryland
lwasserm(@)charm(.)net