Cascamite and end- grain wood - help pls !

[viago]

cascamite doesn't like washing up water too much. i made a fruit bowl from off cuts at school using cascamite which has been in constant use for the last 40 years. for the last 7 it has stood next to the kitchen sink and the base came off last summer where it gets constantly wet. all the other joints are still perfect.

i had to repair the 8" x 1" x 1/4" edge of a mahogany writing box panel recently. following advice from the lounge i drilled seven small holes into each side of the joint and used hardwood dowels (barbecue sticks) and glue to produce a very strong repair. so +1 for dowels.
however, my boy has made an oak framed ipod dock using epoxy for the 4 butt joint uprights (end grain onto cross grain and about a square cm contact area) and it has proved pretty strong.

 

[srp]

A couple of comments:

Cascophen was the glue commended to me by a surveyor when I was repairing a wooden boat. I had suggested I would use Epoxy or Cascamite and he said both were too brittle for the mast I was glueing and the Cascamite had the problems in extremes of water conditions as already mentioned so I am just reinforcing what others have said about Cascamite.

I agree that Cascamite is brittle, but epoxy is one of the more elastic glues and easily capable of withstanding the bending in a wooden spar. I have had failures with Cascamite both because of brittleness and water, but never with epoxy. I have also found that PU is not all it's cracked up to be in wet conditions - I only use it for interior boaty stuff, nothing structural like a mast beam. I also rarely bother to degrease with acetone unless i have a particularly oily piece of teak. I do rough up the surface with some 80g first though, especially on timber that has been through the planer.

 

[VicS]

I never had much success with Cascamite. I much preferred Aerolite, which is what we used at school.

In any case i would have thought 18 hours was not long enough for a good bond on hard wood

 

[PCUK]

I use Cascamite and biscuit joints. No problem inside the boat or in the stables!

 

[Scotty_Tradewind]

I am quite happy glueing wood cut along the grain. However, I tried some oak test pieces yesterday, using end-grain to with-the-grain, and the result is pretty poor. I was exploring the gap-filling properties of Cascamite.

Glue is Cascamite (new tub), proper ratio, air temp 15C, time from glueing to testing 18 hours, etc.

It is clear that adequate adhesion of the end grain piece has NOT taken place, as I could break the bond very very easily by hand. Another piece of oak (along the grain) glued to the same piece of wood is rock solid. The test piece was not clamped, to allow - as I thought - the gap to remain unsqueezed.

What am I doing wrong please ?

View attachment 40780

PBO Jan 2014 p. 83-86 ..........

an article about making wooden spars, recommends glueing up with resorcinol resin 2 part glue which is UV-resistant.

Perhaps that might do for your job with additional joints, dowels, screws etc?

I'm just glueing up some parts for my boat using a polyurethane glue, 'Gorilla Glue'..... forgot to use gloves..... now have very black fingers!

S.