Weldwood

[Sakari Aaltonen]

North American sources often mention Weldwood as a water-resistant glue. It seems to be a powder that is mixed with water to make up the glue. I say "seems to", because I have never seen it. The explanation might be that I live in Europe. Is it? I mean - is Weldwood a purely North American product?
A patent, maybe?

Thank you,
Sakari Aaltonen

[Dave Carnell]

Weldwood® is a brand name for powdered urea-formaldehyde resin that is mixed with water to make a water-resistant glue. It was used for boatbuilding before epoxy resins existed. It requires good fits and high clamping presssure.

Look for urea-formaldehyde glue.

[nedL]

I don't know if it is a purely N. American product or not, but you do have the basics of it corect. It comes as as a fine powder that is sort of sawdust colored, mix it with water to a 'thin custard' to 'gravey' consistency & apply & clamp. It is not listed as "waterproof", but its about as close as you can get without being labeled as such. (I think it doesn't quite pass a 24 hour boiling water test.) I've used it for years & have always been pleased with it. Can't think of a time that it has failed.

[John Meachen]

I have read numerous descriptions of weldwood and it seems to be a lot like Cascamite.They both seem to be powdered urea-formaldehydes which are not theoretically waterproof but which can be used to build reasonably durable boats if you look after them.

[kc8pql]

Originally posted by John Meachen:
I have read numerous descriptions of weldwood and it seems to be a lot like Cascamite.You're right. Weldwood and Cascamite are basicly the same.

[Ross M]

I used this adhesive to build the framework for my Folbot Super 20 years ago.

Long story short, pulled the fabric from the boat a few years back. 50-60% of the joints had failed; the remaining structural integrity was due to the mechanical fasteners.

I would not use it again; largely because it gave an excessively stiff and brittle joint.

I will say that the failures may have a lot to do with the very small area of the average joint (probably around 3/4 sq in). It may also have something to do with the longerons being cypress, which I did not treat with a solvent.

Regardless, the boat will be rebuilt with a more flexible adhesive - probably 5200.

Ross

[JimConlin]

The only boatbuilding application i'd think of using it for would be glueing up a spruce spar.
The plus there is the thin, neutral-colored glue-line.

[Sakari Aaltonen]

Originally posted by John Meachen:
I have read numerous descriptions of weldwood and it seems to be a lot like Cascamite.Thank you; this pointed me in the direction of Casco (big European maker of adhesives.) However, they don't seem to make Cascamite anymore. Not with that name, at least, and not in powder form. They have (liquid) urea formaldehyde adhesives, but I haven't found anyone yet who could say with certainty which of these, if any, is a modern equivalent (of Cascamite.)

[Wild Wassa]

Originally posted by John Meachen:
" ... but which can be used to build reasonably durable boats if you look after them."

That is critical as I witness often.

One of the boats I'm working on is a British Moth and I'm guessing her age is about 25-30 years, since construction. The urea-formaldehyde glue has failed badly, hense a total rebuild is required. This glue has failed uniformly across the boat. The glue has a pop-off factor.

From what I see, I would not choose this glue (or similar types) to even stick bookends together. The Urea-formaldehyde has become brittle, fallen off the boat or just turned to a gritty powder (mostly). The ply is an Australian Red Cedar (Toona Australis).

The boat's condition is not a good add for these types of glues. The Moth is my only experience with this type of glue.

Warren.

[ 10-26-2004, 05:09 AM: Message edited by: Wild Wassa ]

[John Meachen]

In England Cascamite is available fron Humbrol who used to be better known for their model paints and glues.
In the dark ages-before epoxy was commonly available-a huge number of British racing dinghies were held together with Cascamite.If after 25 years or more they start to fall apart,they have not had too bad a life span.For comparison,seek out a similarly old racing car and note its condition.Racing use and long term durability are sometimes conflicting aims.

[Wild Wassa]

Originally posted by John Meachen:
"If after 25 years or more they start to fall apart,they have not had too bad a life span."

Most of the dinghies that I work on, are between 20 and 40 years old. The Sea Scouts have not been kind to their boats over the years, maintenance wise.

The urea-formaldehyde glued dinghy is the only dinghy where the glue has really failed. The polyurethane glue (on my dinghy probably one of the first polies used in Oz, by Mr Harold J Lang) is in her late 30's and still remains sound. Similar to the old epoxies. Both of these glues have generally outlasted the wood or I should say, lasted despite a lack of sound maintenace.

What is the deep-blood-red coloured glue, that is on a 25-30 year old imported (from England) dinghy?

This is also a fine strong glue and was only used to glue the rails on to the dinghy, the rest of the dinghy was stuck together with epoxy as She is a stitch and glue.

Warren.

[ 10-26-2004, 07:54 PM: Message edited by: Wild Wassa ]

[Bob Smalser]

I've used barrels of Weldwood and other UF resin glue and think it's great stuff...

...for general interior joinery.

For hulls today, I think you'd have to be nuts to use it. Spars and topside joinery remain a common application, but today with epoxy and poly, I'd think real hard even about those. It's water resistant all right...but it's brittle compared to epoxy or even resorcinol. I've had it work fine outdoors when the piece in question was well-protected by paint...but I've also had it fail under deteriorated varnish.

I always figured it was the wood movement caused by lack of protection that did it...not its lack of water resistance or general deterioration....all our inside stuff glued with are still going strong after decades and decades.

[Alan D. Hyde]

The deep red or purple colored glue is Resorcinol, which is good stuff; when properly used it makes a strong rot-proof joint.

Alan

[John Meachen]

As Alan says,the red glue is resorcinol.The two principal brand names in England being Aerodux or Cascophen.Good glue,but difficult to get the boat clean enough for a top class varnish job.Hence the popularity of Aerolite 306,Cascamite or Weldwood.

[Roger Stouff]

12' bateau, built in 1962, by my father, with Weldwood Glue and galvanized nails. Solid as a rock today. He built all his boats with Weldwood, including a 35' cabin boat, flat-bottomed.

http://members.teche.net/rstouff/images/dadboat1.jpeg

As with all such things, it depends on how it's taken care of. No adhesive will last if the boat is neglected.