Cascamite - In case I might.....

[wobblycogs]

Rob, I've tried to find out the chemistry of how Cascamite sets but I've drawn a bit of a blank. I'm guessing the water is just used as a solvent but it could be taking part in the reaction. Either way it appears that water getting into the can is the problem. At a guess Urea-formaldehyde is going to be fairly hygroscopic so stopping water getting it will take some effort.

The best way to stop water getting in is to put the can in a plastic food box, sprinkling a desiccant around the outside and sealing the top. If you are really paranoid wrap cling film around the seal of the can and the plastic box too. If you want complete belt and braces pop the whole lot in the freezer. As a rule of thumb for every 10 degrees you drop the temperature the rate of reaction will halve.

Regular salt will act as a desiccant but it's not very good at it. Bake it in the oven at 120 deg C before use. A much better (and safe, it's actually a food additive E509) desiccant is Calcium Chloride again baked before use.

The only problem with this solution is getting it out each time you want to use it (which of course will introduce some water). If you only use it once in a blue moon I suppose it wouldn't be that much hassle.

 

[9fingers]

It looks like cascamite is sold in plastic tubs now so should seal fairly well. The potential problem is the air space above the powder harbouring water. Keeping a range of ever smaller tubs to decant the powder into might be an idea together with some of those desiccant 'tea-bags' suitably re-generated in a moderate oven.

Bob

 

[wobblycogs]

Smaller tubs would be good so re-opening isn't necessary but I'd still double box it for longer term storage. A plastic lid will seal pretty well but if the material is very hygroscopic it will be constantly trying to draw water in through the seal.

Small linen pouches with silica gel (or very dry clay if you can't find silica gel) would be easy and cheap to make. I wouldn't place Calcium Chloride pouches on top of anything though as it can absorb enough water to turn into a liquid itself.

A cheap version of this http://commons.wikimedia.org/wiki/File:Desiccator.jpg is what you want to aim for. The top and bottom halves have ground glass faces and are smeared with a little high vacuum grease. A vacuum line is attached to the top which sucks the two halves together making the seal air tight. Desiccant is placed in the bottom with a wire mash over it that rests on a lip. The vacuum helps dry a damp material by, essentially, sucking out the water which is then captured by the desiccant. As you can see small desicators (right) don't generally have vaccum valves.

Water is really very hard to keep out completely though. Some of the work I used to do was under a dry nitrogen atmosphere and even then it was possible to detect traces of water via side reactions.

 

[xy mosian]

How about keeping Cascamite in a plastic bag? That way you can store it with no extra air.

xy

 

[dickm]

My father often used Cascomite, and I also remember the horses on the log - similar to the Levi jeans logo, but ultimately, I suppose, based on the Magdeburg hemispheres story. My father always told me that it was made from casein resin, which was effectively skimmed milk. He used to say that Mosquito planes were made of plywood and skimmed milk.

Hadn't thought of the Magdeburg connection, John - nice one.

But I think your dad was confusing CASCO, which was the long ago discontinued casein glue, with Cascamite. From memory, Casco came in the same tin, but possibly different colour. It was definitely not water resistant and if allowed to get wet after use, stank of sour milk before the joint fell apart. I think it was a version of Cascamite that was used in the Mosquito, but may be wrong.
W.R.T. storing Cascamite/Extramite or whatever it's now called, I've had some success dividing the pack into smaller containers, small plastic jars or even film cassette holders (remember them??? ) It's kept happily in these for a year or so.

 

[JohnBrown]

Well, Wikipedia has this to say

The fuselage itself was separated by seven bulkheads made up of two plywood skins parted by spruce blocks, which formed the basis on each half for the outer shell. The bulkhead was a repeat of the spruce design for the fuselage halves; a balsa sheet sandwich between two plywood sheets/skins. Among the glues used was Casein resin plus many other screws and flanges (made of various woods) which held the structure together. After securing the two halves, the fuselage was covered with fabric and was then doped with cellulose dope which was either sprayed or brushed onto the surface. A coat of silver dope was then applied before exterior camouflage was applied. The underside was cut to allow for wing assembly.[32]

On the other hand, my father certainly wasn't infallible!

 

[yetloh]

I've found it stores pretty well in the tub over about a year or so in my, admittedly dry, workshop. The Resinmite tubs have a very tight fitting lid although I do wrap sticky tape round the seal for added protection. I think the idea of dividing it into plastic bags sounds a good one.

Jim

 

[NeilO]

Storing Cascamite tip....

Empty said contents from tub into a poly bag and expel as much free air as possible then tie with wire wrap ( can also be done with resealable poly bags to same extent ) then place back in orginal container so you know what it is in six months time , then simply use however much and repeat the process.

HTH

 

[Jake]

I think I read somewhere that the first mosquitoes were built with casein and then they moved over to UF. Even vaguer memory that it may have been prompted by tropical theatre service.

 

[JohnBrown]

tropical theatre service.

What - as in "it ain't half hot, mum"?

 

[GraemeD]

I think the glue they used for the Mosquito was Aerolite, which is similar to Cascamite, but a two part mix. Whereas Cascamite uses water to activate it, Aerolite has a liquid hardener which you apply to one face to be glued, and a powder glue which you mix with water and apply to the other face to be glued. When brought together, the glue hardens after a few hours....quicker than Cascamite, but still with a decent open time. The upside is that the mixed powder lasts a few days. The hassle is that it's a bit more effort to use than a one-part adhesive. Very strong though, and also very waterproof.

Many years ago I blagged some from the manufacturer who were local to me.....Ciba Geigy as I recall. They gave me a bit of a tour round the factory, and told me about the Mosquito heritage. One of those experiences that still leaves me with fond memories.

Seems to be still available at Axminster too!

Graeme

 

[frugal]

The bowyers I know use Cascamite when laminating longbows, as you really don't want one of those coming apart at the seams when at full draw

 

[9fingers]

The bowyers I know use Cascamite when laminating longbows, as you really don't want one of those coming apart at the seams when at full draw

I'd have thought that casamite would have been too brittle for a bow but then again I have no experience of bow making.


Bob

 

[woodbloke]

The bowyers I know use Cascamite when laminating longbows, as you really don't want one of those coming apart at the seams when at full draw

I'd have thought that casamite would have been too brittle for a bow but then again I have no experience of bow making.


Bob

Me too, I'd have thought you would have wanted something a little flexible for that application - Rob

 

[jimi43]

The bowyers I know......

I'm still reeling from the eloquence of FRUGAL with those four words....

 

[Benchwayze]

Cascamite never failed me.

The only drawback to it is that you usually mix more than you need and it's an expensive waste.

I used it (when I could get it) for everything. Just like the 'old-timers' - older even than me - used hide-glue! I believe Cascamite is sold under a new name these days.

But is it ever expensive! So I now use waterproof PVA, and none of my stuff has fallen apart... yet!



Regards
John

 

[yetloh]

This does't seem that expensive to me, http://www.agwoodcare.co.uk/gbu0-prodshow/resinmite.html certainly compared with Titebond or other well known PVA brands.

Jim

 

[woodsworth]

How expensive is expensive? It's £14 for a container of it. I can also get it in 25 KG bags. I haven't checked the price because i'd never be able to use it all before it's gone off. Wonder if it would be worth re-baging and passing on the savings to other woodworkers though. I'll find out how much the 25 KG bag is.

 

[Benchwayze]

This does't seem that expensive to me, http://www.agwoodcare.co.uk/gbu0-prodshow/resinmite.html certainly compared with Titebond or other well known PVA brands.

Jim

It is if you keep on mixing more than you need (Not always easy to gauge it!)

But I think I can stretch to 750 grams for those jobs where I need it. Cheers Jim

John

 

[woodbloke]

...I now use waterproof PVA, and none of my stuff has fallen apart... yet!



Regards
John

Same here John, I use TBIII for everything and I bought some Everbuild D4 PVA the other week which is supposed to be even better than a D3 adhesive.
I think the probably the biggest 'plus' factor for me would be the long open time of a urea-formaldehyde glue...something to bear in mind - Rob