Cascamite and Iroko

[SkinnyB]

Wow! Didn't expect this kind of response.

To answer a few questions I read as reading through your posts:

Clamping was sufficient. 4 heavy duty F clamps.
I glued a 400mm section of Iroko onto the main upright then machined afterwards. Both surfaces were machined on the thicknesser.
Glue was mixed to exact instructions as found on the bucket of Cascamite.
There was a good amount of squeeze out when clamped.

The wood was clamped at around 10c or a little less then brought inside the house. So this could be a factor.
Perhaps I should send some samples to Matthias Wandel for testing...

I will be sure to go with a doweled version next time to increase strength across this thinner section.

After discussion with my client and a previous company whom he had some bespoke Iroko windows off (who also said they had issues with Cascamite) we have decided to change glues.
Ill update once I know the brand. I think someone mentioned a red glue previously which is what I think it is.

Im getting a general feeling that Cascamite being a water based glue may not be the best glue. However I have used TB3 in the past with Teak/Iroko with success.

I think being an oily timber water based adhesives are not the way to go.
If I get time I will make up a few samples to of different glues and techniques.

Thanks for everyone input.

IMG_6780 by jamie skinner, on Flickr

 

[Phil Pascoe]

Tell me more about this "Red Glue"

https://en.wikipedia.org/wiki/Resorcinol_glue

 

[Trevanion]

https://en.wikipedia.org/wiki/Resorcinol_glue

£40-60 per KILO!?

Think I'll stick to the Polyurethane! :lol:

 

[SkinnyB]

I think this is the glue, probably end up getting the 6kg which works out at £33 a kilo. £££!

https://www.seaware.co.uk/aerodux-185-r ... -glue.html

 

[deema]

The instructions are wrong / misleading. Mixing by volume and by weight requires different ratios. Proper Cascamite comes in a white plastic tub with clear instructions on both the ratios for both wright and volume and how to mix it.

It seems to me that the glue used was some imitation of Cascamite.

There is also Polymite which is another good Cascamite glue.

 

[ndbrown]

I was having a nice relaxing Sunday night until I read this post. I mainly use Tightbond 3 but the last few furniture projects I have used Cascamite bought earlier in the year from Axminster as I had more complex assembly and was looking for more assembly time. So far so good and nothing has fallen apart yet.
However recently I built a new side gate from Iroko, first outside project and also the first time I have worked with Iroko and most of the web said that Cascamite was fine with Iroko so that was what I used. I have used traditional mortice and tenon joints throughout for all the large parts and also pegged the joints with Iroko pegs as well. I used some Dominoes for the small blocks between the vertical slats but wiped everything with Acetone before gluing it up, the Dominoes were also made out of Iroko as well. The workshop was warm and the glue mixed up fine. Gate has been hanging for a couple of months with no problems so far in the very wet Scottish weather but should I expect to see problems over time? Like most people, I hate having to do jobs twice. Some of the previous comments have worried me about how durable this is going to be!
Nigel

Photo of gate

Close up of pegged rails, hopefully the coach bolts in the hinge strap will help to hold the left hand side together

 

[Benchwayze]

I have used Polymite and the last time it was on Western red Cedar. Completely useless, and wouldn't adhere at all. The original Cascamite never failed me.

Now I use Evostick Resin W; ( even if it's a bit old!) or hide glue where it's called for.

John (hammer)

 

[MikeG.]

.......If I get time I will make up a few samples to of different glues and techniques.........

Whilst you're at it, make up some more Cascamite in the same way as you did for the failed piece, and glue together a couple of scraps of pine. Test these in a day or two, and that should give you a good idea as to whether or not your tub of glue has gone off.

 

[deema]

I’ve used Cascamite for years, and apart from one case of the glue having gone off it’s always been my preferred glue for all external joinery, doors windows etc. I wouldn’t worry too much about your lovely gate

 

[transatlantic]

For those of us that might not use it in months, I wonder if it should always be good practise to always knock up a test piece when using Cascamite? to see if it is off or not.

Better safe than sorry.

 

[Mike Jordan]

These days I only buy Cascamite in 3K tubs since I don't use a lot of it. I have never known any to go off in any way, even when bought in sacks and stored without any special precautions other than keeping it dry. As mentioned by others above I habitually break off cuts of edge jointed material and have always found the glue to be stronger than the timber.

 

[Hattori-Hanzo]

No doubt cascamite is still an excellent glue, we use it almost daily.
I was referring more to Iroko specifically here and other similarly oily woods.

I think a large part comes down to it's intended use.
Take your lovely gate that used tight fitting mortise and tenon joints with draw bores.
The glue won't be adding much additional strength to the joint and isn't under stress once the wood has acclimatised.
I'm sure cascamite in this situation will hold up fine.

When you're solely replying on the glue to hold the join together like in the OPs example you may run into problems with cascamite.
Again I'm refering to Iroko here, I'd have little concern using casco for a butt joint in another timber.

Iroko is a strange timber, we've had pieces with mineral deposits the size of grapes that ruin cutters instantly.
We've had bits that are dark brown almost black that are hard and dense as any thing, then others that are light and soft like Idigbo.
Seemingly the really dense bits not gluing as well but we've had no fails since using the 2 part red glue.

 

[Trevanion]

Iroko is a strange timber, we've had pieces with mineral deposits the size of grapes that ruin cutters instantly.

I haven't used any Iroko for a couple of years but I've still got a couple of pieces kicking around that had large calcium deposits, as you said, you may as well have been planing nails.

 

[rafezetter]

It's basically a weak joint with too much cross grain but it wouldn't be the glue failing if you'd done it properly in the first place, it'd be the wood.
Looks like you've wiped it on too thin, and/or left it to dry too long before joining, and/or not clamped tight enough. The glue has only taken at the points where you can see that the wood has broken out.
Do it again but brush the glue on thick on both faces, clamp it quickly and tightly so there's a bead squeezed out all around the join. Where there isn't a bead there is not enough glue.

When the OP wrote "I had plenty of squeeze out" I was thinking "glue starvation" TOO MUCH clamping force, a possibility?

Also - no loose tenon? Knowing Iroko can be a bit of a pig to glue, surely that's a must?

 

[Jacob]

I'm still mystified. There is obviously a coating of glue on both faces but they clearly didn't bond except where there are tiny bits of tear out. There's no way a bonded glue layer could shear like that, so there's more to this than meets the eye. Something went wrong, but not the glue.