"Brian Nystrom" wrote in message
news:LT8xe.14504$Q27.5022@trndny02...
wrote:
Joints which were glued with Gorilla Glue and then screwed together (on
the boats) easily came apart by prying, the glue failed. I was
horrified when I saw how weak this stuff is.

If the joints were that weak, the screws must not have clamped them
tight enough and the glue expanded. The same is probably true of your
chair repairs. With tight joints, the wood will fail before the glue
does. You CANNOT use PU glue to fill gaps; it says that right on the
bottle. Epoxy is definitely more forgiving and does fill gaps well, but
you can't blame the PU glue if you use it improperly or in the wrong
application.

But the problem with boats is that you cannot make tight joints most of the
time. It's almost impossible to apply 4kg/cm2 on a joint which is several
meters long.

Meindert

"Norm II" ) writes:

What exactly is PL Premium...Something I can find at Home Depot?? Thanks.

It's a different formulation of polyurethane (PU) adhesive, a mastic in a
clauking tube often referred to as "liquid nails", used in house
construction. PL Premium is supposed to be their stongest althoug I'm not
sure it's any better than the slightly cheaper PL400. You can find them at
any building material store. I don't shop at Home Depot but they are sure
to stock it. Here in Ottawa I get it for a lower price at Canadian Tire.

David Beede has done some trials with different polyurethane mastics and
put the results on his website at www.simplicityboats.com. I think it's a
good replacement for urea formaldehyde (plastic resin) marine adhesive
(Weldwood was a popular brand). I used plastic resin on my first small
plywood boat (Dogskiff on my website) and PL Premuim on the other three.

PL Premuim is a lot easier to work with. You lay a 1/4" bead on one
surface. I spread that with a putty knife to get it right to the edge and
to get complete and even coverage in the joint. You can reposition the
parts up to 45 minutes. Then clamp (or use screws) and allow 24 hr to
cure. You can even pump it into voids in cheap plywood to fill them. If
the glue gets on your hands it dries flexible and stays for days. If you
don't want dirty-looking hands afterwards, wear gloves.

I don't think you can get a more suitable adhesive at a better price
for a small screw-and-glue boat like the OSS.

--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-FreeNet email must have "notspam" in subject or it's returned

On Fri, 01 Jul 2005 04:24:44 GMT, Lew Hodgett
wrote:

Subject

Over priced and under peckered.

Strictly garbage IMHO.

Lew

Yes, but what do you really feel? Don't hold back now.

I agree. Another miracle product bites the dust.

"Meindert Sprang" ) writes:

But the problem with boats is that you cannot make tight joints most of the
time. It's almost impossible to apply 4kg/cm2 on a joint which is several
meters long.

So true. If it weren't for the precision fit on the cheap boats I throw
together, PL Premium would have failed. Maybe my aim is a little better
than Mini-cup builders. Not by much I'd wager. PL Premium expands, fills
gaps, and holds just fine thanks. I've never had to mix it with any kind
of filler as I do with epoxy and did with "plastic resin".


--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-FreeNet email must have "notspam" in subject or it's returned

I admit, my building skills are poor. However, I'd still not reccomend
Gorilla Glue to anybody building boats. I used enough screws that it
should have held better. I also think that if you are going to spend
all that time building a boat, dont you want it to last?

Meindert Sprang wrote:
"Brian Nystrom" wrote in message
news:LT8xe.14504$Q27.5022@trndny02...

wrote:

Joints which were glued with Gorilla Glue and then screwed together (on
the boats) easily came apart by prying, the glue failed. I was
horrified when I saw how weak this stuff is.

If the joints were that weak, the screws must not have clamped them
tight enough and the glue expanded. The same is probably true of your
chair repairs. With tight joints, the wood will fail before the glue
does. You CANNOT use PU glue to fill gaps; it says that right on the
bottle. Epoxy is definitely more forgiving and does fill gaps well, but
you can't blame the PU glue if you use it improperly or in the wrong
application.


But the problem with boats is that you cannot make tight joints most of the
time. It's almost impossible to apply 4kg/cm2 on a joint which is several
meters long.

Fine, then use an adhesive more appropriate to the task.

DSK wrote:
wrote:

Do not use it. DO NOT USE IT. I used it for my two MiniCups and now
regret it. It has no strength in gap filling.


Well, sure. That's one of the really great things about epoxy & fillers.
Of course, it means old-time precision ship carpentry is a thing of the
past, but we don't need it.

I have used Gorilla Glue to repair chairs and within a month they
needed to be repaired again. I then used epoxy and they are solid
months later.


I wonder if Gorilla Glue has a very low number of fatigue cycles to
failure. Another amazing thing about epoxy!

In an appropriate application, either one is stonger than the
surrounding wood. The concept of fatigue cycles doesn't even apply,
since the weak link is the wood, not the adhesive.

Don't misunderstand and think that I have something against epoxy or
that I'm claiming that PU glue is a viable substitute for it in every
application. That's not true at all. I just don't like seeing a good
product get maligned because someone used it improperly and got a bad
result.