Cascamite and end- grain wood - help pls !

[sarabande]

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

 

[Poignard]

What you're doing wrong is glueing end grain.

Either make a proper joint, eg mortice and tenon, or at least strengthen the joint with wood dowels

http://www.raygirling.com/wwjoints.htm

 

[westernman]

Cascamite is not good for filling gaps. Epoxy (with micro-balloons or some other filler) is much better for that.

Usually to get a good joint with cascamite you have to clamp it solidly and have a good fit. The bond is then stronger than the wood itself.

 

[sailorman]

Cascamite is not good for filling gaps. Epoxy (with micro-balloons or some other filler) is much better for that.

Usually to get a good joint with cascamite you have to clamp it solidly and have a good fit. The bond is then stronger than the wood itself.

Note - End grain, it wont work it need a mechanical joint at above

 

[viago]

i've had reasonable success with super steel epoxy on end grain. in fact on most things. it's black though. araldite might be a better colour on wood

 

[Scotty_Tradewind]

Yes as above....... you need to strengthen those pieces of oak with dowels, joints, biscuits, screws etc.

Cascamite is very brittle too and will not like any flexing although is waterproof to a great extent.

Oak not very porous and not the easiest of timbers to accept any glue, especially end grain.
Polyurethane glue can be very strong as long as a tight clamping takes place but is not a good strong filler although spaces do get filled.

Epoxy would possibly be the strongest in imho but no better for that butt joint with end grain.

It would be easier to advise if we could see the whole design of job in hand.

S.

 

[sarabande]

"It would be easier to advise if we could see the whole design of job in hand."

I am new to Cascamite, so am just trying bits out with the huge amount of sawmill oak offcuts I have around.


What I want to build is a saddle rack, similar to this:-

View attachment 40791

before moving on to complicated boaty things.


I'd be really happy if I could end up achieving this sort of construction - preferably in green oak.


View attachment 40793

 

[Danbury]

If you're not a carpenter and don't need to be cutting proper joints... I'd use pocket screws... very quick, very easy and provides a good strong joint (add your choice of glue, moisture cure has good gap filling properties)

View attachment 40792

 

[sarabande]

thanks everyone for advice so far.

I just want to work competently with the wood I can get from t'mill for free, and I really like functional designs rather than yer actual Chippendale stuff. The equivalent to Landrovers in oak timber.


Pocket screws ? Need a template for drilling them ?

 

[stav]

"It would be easier to advise if we could see the whole design of job in hand."

I am new to Cascamite, so am just trying bits out with the huge amount of sawmill oak offcuts I have around.


What I want to build is a saddle rack, similar to this:-

View attachment 40791

before moving on to complicated boaty things.


I'd be really happy if I could end up achieving this sort of construction - preferably in green oak.


View attachment 40793

No glue required with green oak just the dowels or are they called tree nail in the green oak world?

Cascamite does require strong clamping, even a simple housing would improve things or a tounge. Also have an experiment resorcinol glue.

Lucky you having access to lots of free off cuts.

 

[Daydream believer]

Cascamite .................................... although is waterproof to a great extent.



S.

Actually you are not entirely correct, unless the formulation has changed in the last 15 years.
When I had my joinery business I could not use Cascomite for certain exterior situations as it is not rated for extreme external conditions.
Retirement has lead me to forget the BSS references that applied to this so I will not try to quote.
Of course many have used it for years in boat making ( dinghies & small cruisers) with no problems- that does not mean that the manufacturers class it as high as the old Aerolite etc ( is it still made?)

If you want to speed up the curing process of cascamite to about 15 mins there is a chemical made which is applied to one face of components to glue. Apply cascamite to the other & clamp together.
Once again I forget the name,, but Borden Chemicals sell it especially for the purpose so a query to them will supply the info
I chucked out a couple of litres only last year when cleaning the shed

 

[andygc]

Data sheet for Cascamite here: http://www.polyvine.com/index.php?o...id=15:adhesives&Itemid=2508&lang=en#datasheet

 

[blackbeard]

Of course many have used it for years in boat making ( dinghies & small cruisers) with no problems- .....

not strictly true .... has been known to give up after several years under damp conditions. Apparently a problem with GP14 dinghies, and presumably some others.

 

[Amulet]

..
Of course many have used it for years in boat making ( dinghies & small cruisers) with no problems- that does not mean that the manufacturers class it as high as the old Aerolite etc ( is it still made?)..

Last I read Cascamite didn't claim to be waterproof, but it does pretty well. Today there are much better alternatives. History has proven Aerolite to be incompletely waterproof on the 40 year time scale - see my mast. I do like Cascamite but wouldn't use it in boat building.

 

[Scotty_Tradewind]

I've quickly searched through woodworking websites via Google and see that quite a few people have had problems with Cascamite

giving way easily.

It's suggested that it does have a limited shelf life.

Green oak doesn't really like glues, but try cleaning off the oak surfaces with acetone to get oils and moisture from the faces of the

timber. Allow to dry then glue.

S.

 

[sarabande]

that data sheet is good. Particularly the Bonding Tips section, where it talks about 'glazing' preventing adhesion. I must take a hammer to the planer/thicknesser blade in that case.


I'll also try the acetone suggestion next time.

 

[david100952]

One quick note to consider if you are using oak and a water based glue ie Cascamite. The acids in oak can react with the water before the glue cures creating a black staining on the end grain. For proof of this just look at your palms if you have been pushing boards through a table saw for a few hours!

 

[Scotty_Tradewind]

One quick note to consider if you are using oak and a water based glue ie Cascamite. The acids in oak can react with the water before the glue cures creating a black staining on the end grain. For proof of this just look at your palms if you have been pushing boards through a table saw for a few hours!

Yes often best to get acids and oils from timber faces to be glued together before applying glue.

Teak can be poor at accepting some glues, so acetone can again help.

I laminated several 7mm pieces of oak together a few years ago with 5 minute polyurethane to form curved beams to strengthen

beneath the mast step on my Twister. We cleaned the surfaces with acetone before application and it proved very successful.

S.

 

[sailorman]

Yes often best to get acids and oils from timber faces to be glued together before applying glue.

Teak can be poor at accepting some glues, so acetone can again help.

I laminated several 7mm pieces of oak together a few years ago with 5 minute polyurethane to form curved beams to strengthen

beneath the mast step on my Twister. We cleaned the surfaces with acetone before application and it proved very successful.

S.

when aerodux 500 was in production one didnt need to degrease teak for a good bond

 

[john_morris_uk]

when aerodux 500 was in production one didnt need to degrease teak for a good bond

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.

Pocket screws are simple and easy to use and you can get a jig from Axminster: http://www.axminster.co.uk/ujk-technology-pocket-hole-jig

You need a special drill as well: http://www.axminster.co.uk/catalogsearch/result/?q=pocket+hole+drill

Buying both for a simple job would be a bit pricy!

Blind tenon joints with wedges to expand the tenons as they are driven home would be a 'proper job' as they say down our way. You've got a travelling router table so the tenons would be very easy to make. Get a morticing attachment for your pillar drill?

Dowels or biscuits would be considerably quicker and even easier to make/use.