Epoxy versus Cascamite & compatibilities

[Peter2004]

I'm a beginner and I apologise in advance if this is a stupid question.

I've been looking at boatbuilding techniques based on diagonal wood veneers using the West System or similar epoxies to build a 34ft sailing hull.

My only boatbuilding experience was 30 or more years ago when I built two small wooden boats, both in plywood using Cascamite, a resin glue that comes in a powder that you mix with water. I liked this stuff, it was easy and tough.

So, now as I read about using epoxy as a wood adhesive I learn that it is expensive, messy and that the cure time may demand a lot of speed.

Would it be realistic to laminate the veneers using Cascamite glue and then with the planking complete to finsih the interior and exterior surfaces with epoxy? Are these systems compatible?

Going a stage further, I read that the Pardeys in their book "Cruising in Serrafyn" didn't have epoxies but applied three coats of creosote to their finished hull before painting. I assume they did this to protect against marine wood borers but there must have been some protection against rot also gained through this process. Could creosote be compatible with epoxy and with cascamite?

I am wide open to being told that I'm complicating matters and should stick to epoxies pure and simple. Any advice would be valued. Thanks.

[Alan Jones]

Cascamite has been used for many years in the UK to produce many different types of boat both sail and power using different construction methods including cold molded.
Adhesives of this nature require a mechanical fixing to back them up such as screws or nails and so on. They do not enhance the qualities of the wood they just bond. I have sailed on a cold molded 26 footer made 30 years ago and she is still a fine yacht but is suffering from the ills of any 30yr old wooden boat.
Epoxy will bond without the need for screws and nails and on some light weight designs it is recommended you remove as many as possible after the cure is complete. The main reason in using epoxy is that it makes the material stronger, more stable and provides a moisture barrier that prevents most of the problems associated with wooden boats. This does not mean that it is the answer to everything and will give a quick repair solution to aging wooden boats but when used with a boat that has been designed to be built with epoxy it is second to none. The question of creasote is not relevant, whilst it might prevent rot and have some antifouling properties it can not enhance the timber in any way, suffice to say that this method suits the boat and the owner so its fine but if I remember the Pardy`s boat was of traditional construction and was not designed for epoxy.

[Peter2004]

I am obliged to you Alan for your reply. You're exactly right about the need for screws with cascamite. Now as I remember my earlier projects I recall all those screws spaced closely together. First I drilled and put a steel screw in each hole to establsih the thread and then I replaced it with a brass screw. It took me forever as I didn't have a mechanical screwdriver in those days.

[Alan Jones]

Hi Peter,

I see from your original post that you are considering building a 32ft boat using cold molded veneers. Whilst I certainly wouldnt want to try and change your mind I have a few observations you might find interesting.

Yes epoxy is messy but cold molding using ply or veneer is a particularly messy method it is also very time consuming when used to build a big boat.
If the design calls for 3 layers you are in reality building three hulls using lots of epoxy to bond the layers together. With strip plank once you have set up bulkheads, frames and dummy frames on you go. Doing this uses very little epoxy at this stage as all you are gluing is the plank edges to each other and the plank to the main frames and bulkheads. The hull progresses at a much faster rate and it is between you and the designer how you finish it. The main two profiles for strip plank are bead and cove and tongue and groove, these have made the construction much quicker and easier, anyway dont think of the bad aspects just the pleasure of sailing the finished boat.