Why use cascamite?

[Paddy Roxburgh]

Be careful with the idea that PU glue is good for gap filling. Sure the foam fills the gap but not with any strength. Check out https://woodgears.ca/joint_strength/gorilla_glue.html
Paddy

 

[custard]

It also foams up for incredible gap filling

PU glues have zero gap filling properties, you can prove this for yourself very easily, let some of the foam dry out and set on a piece of scrap, then see how much strength the dried foam has. The answer is absolutely none at all!

But this idea that PU glue is gap filling, is one of those myths that refuse to die. I guess people see the foam and just assume it'll foam up in a cavity and be incredibly strong, when it's actually like asking soap bubbles to be load bearing.

 

[Phil Pascoe]

Sure, But for external joinery if a gap is full of expanded polyurethane, it can't be full of water as well.

 

[Phill joiner]

It also foams up for incredible gap filling

PU glues have zero gap filling properties, you can prove this for yourself very easily, let some of the foam dry out and set on a piece of scrap, then see how much strength the dried foam has. The answer is absolutely none at all!

But this idea that PU glue is gap filling, is one of those myths that refuse to die. I guess people see the foam and just assume it'll foam up in a cavity and be incredibly strong, when it's actually like asking soap bubbles to be load bearing.

It depends on the size of the gap. A one or two mm gap you wont pull apart. Anything bigger than that would have to be wood filled . The beauty of the foaming is that filler has something to grip to also.
I've been using it on all my segmented bowls and it works a treat. I can have a bowl cured and ready to turn in four hours.....That's cutting all the blocks as well.

 

[custard]

It also foams up for incredible gap filling

PU glues have zero gap filling properties, you can prove this for yourself very easily, let some of the foam dry out and set on a piece of scrap, then see how much strength the dried foam has. The answer is absolutely none at all!

But this idea that PU glue is gap filling, is one of those myths that refuse to die. I guess people see the foam and just assume it'll foam up in a cavity and be incredibly strong, when it's actually like asking soap bubbles to be load bearing.

It depends on the size of the gap. A one or two mm gap you wont pull apart. Anything bigger than that would have to be wood filled . The beauty of the foaming is that filler has something to grip to also.
I've been using it on all my segmented bowls and it works a treat. I can have a bowl cured and ready to turn in four hours.....That's cutting all the blocks as well.

Phill, I'm not having a go at you, but I am having a go at this idea that PU glue is gap filling. It isn't. However it still might be a good choice for segmented bowl turning because it delivers at least some end grain glue strength, not as much as UF glues like Cascamite, which in turn are not as good with end grain as epoxy, but way, way more than PVA which has zero end grain strength when used normally, and low end grain strength if the end grain is first sized with dilute PVA.

Here's a useful glue property summary chart from Marc Fish,

http://www.marcfish.co.uk/docs/F&C167P3 ... cutsah.pdf

 

[dickm]

Xy - the hardener for Cascamite is phosphoric acid iirc. although I tried interchanging formic and phosphoric and they both worked (obviously stress tests etc. might say differently).

Not clear why additional hardener would be needed. Isn't the hardener already incorporated into Cascamite, and activated (or at least brought into solution where it can work) when water is added? IIRC, the old CascoPHEN used a separate hardener.
Seeking knowledge!

 

[Phil Pascoe]

Speed - it sets it in minutes.

 

[dickm]

Thanks, Phil. Must try it sometime. Just wish it was easier to get any UF adhesive up here!

 

[iNewbie]

Thanks, Phil. Must try it sometime. Just wish it was easier to get any UF adhesive up here!

There a retail locator page on their website:

http://www.polyvine.com/index.php?optio ... 15&lang=en

 

[mindthatwhatouch]

cascamite-semforite-supplier-t92701.html

 

[jim_hanna]

Thanks, Phil. Must try it sometime. Just wish it was easier to get any UF adhesive up here!

I've just ordered some on ebay (item number 361014322145) with free delivery to my local Argos store. Might be an option if you have an Argos branch convenient.

 

[Phil Pascoe]

I'm using Everbuild Resintite atm. Loads of builder's merchants sell Everbuild stuff - I've not found a bad product yet. Their epoxy is excellent.

 

[kinverkid]

One more use for Cascamite is as an MDF sealer. I was advised this a few years back but only just had a reason to use it this way. I agree that it is an excellent adhesive that I've used for many years. But, recently I made my own roller/thickness sander and made the 500mm roller from several 125mm x 18mm MDF disks glued together in sets of four (and a three). Once these were all sanded level on the spindle, I sealed them with Cascamite. I used just a tiny drop more water than normal to give me a slightly thinner mixture then coated the roller. Once dried I lightly sanded the roller then apply another but a final watery mix. With a light sand to remove any nibs I could then affix the hook side of a self-adhesive hook and loop strip before attaching the loop backed sandpaper. The sealed surface helps to stabilise the MDF and gives a good surface for the strip to adhere to.

 

[Yojevol]

Buy from www.restexpress.co.uk £12.95 + £3.95pp for 1.5Kg. Remember for storage over a lengthy period, water vapour can get through plastic so I put a tub of silica gel in with it.
I always use cascamite when making curved laminations as PVA will creep under stress.

 

[MusicMan]

Yes PVA is pressure sensitive as Custard says.

As xy mosaic says, Aerolite 306 is very similar, and was used to glue Mosquito bombers together, so I don't think there'll be any problem with brittleness of the joints. The main difference is that Aerolite is certified for aircraft construction for wooden parts, the only adhesive that is, I believe.

Keith