Can a plank scarphed with epoxy be steamed

[Alan Peck]

It seems like the best way to avoid having to purchase overly wide and expensive planking stock is to use dog leg scarphs.

However, I understand that epoxy softens at high temperatures. Therefore, I wonder if it is okay to steam bend a plank that has epoxy scarphs in it. Or is the the maximum temperature for an epoxy scarph joint higher than 212 degrees F?

[Ray Frechette Jr]

Does the entire plank need steaming to fit?

Often times only the hood ends have so much twist steaming is necessary. And you can get close to 80-85% of what you would get steaming by siumply steeping...

IE Soak the end in water overnight, then lay on builders plastic wrap with a towel and pour boiling ater opn the area needing treatment and let steep for 20 minutes.

Limbers up the area right nicely.

I don't think I would be all that comfortable steaming epoxy scarfs myself.

[mcdenny]

Epoxy has a 'glass transition ' temperature of around 140 - 150 F. It gets cloudy and soft.

Water no problem; heat big problem.

[ishmael]

What Ray asked/said. I wouldn't trust epoxy in a steamed joint.

[Andrew Craig-Bennett]

I would have said "no". There is certainly a boatbuilding folklore that some commonly used epoxies soften in the heat build up of strong sunlight on wooden boats.

On the other hand as Bob Smalser says some epoxies are, or can be, heat cured. But you won't be putting an uncured scarph joint in the steamer.

What a pity The Chemist is not around any more.

[Jim Ledger]

And if you haven't actually tried it, why are we arguing?

I've had a perfectly good epoxy scarph fail completely, with boiling water poured on it, while wrapped in a towel.

[Bob Smalser]

I'm not surprised. Boiling water is a lot harder on the wood than steaming, as it's much less efficient in getting heat to the wood's core.

But I'm not fighting city hall. Use resorcinol if you're worried about too much heat.

[denp]

I scarfed and made epoxy joint on the chines and sheer on my boat. Then I steamed, and installed them. The epoxy joint never failed, but I had to build spare sheers du to sheers a bit thick to make a good bend without breaking.
Every time something was breaking it was du to the wood itself, never had an epoxy joint failing after steaming

[Mrleft8]

I've had a perfectly good epoxy scarph fail completely, with boiling water poured on it, while wrapped in a towel.
What were you doing working while wrapped in a towel Jim? :D

[erster]

It seems like the best way to avoid having to purchase overly wide and expensive planking stock is to use dog leg scarphs.

However, I understand that epoxy softens at high temperatures. Therefore, I wonder if it is okay to steam bend a plank that has epoxy scarphs in it. Or is the the maximum temperature for an epoxy scarph joint higher than 212 degrees F?

Well first off the requirement to steam bend a plank can be resolved with old fashion building techniques of laminating smaller and or thinner sized woods even in the rough in stage of building, removing and shaping after the epoxy has cured. . In small hulls a width of four to six inches seems to be the widest deminsion that I know of if you are building lapstrake or even carvel planking. So short of doing a compound bend which also still requires some form of a jig and having a very short working time anyway, better methods are indeed avaliable. But keep in mind that few folks actually use epoxy in solid wood planking to join parts together except for say frames which seems to be fine in the narower widths. .

So lets get back to the actual boat that you are discussing here. This issue can be resolved without a lot of speculation.

[John Meachen]

I suppose it would be best to ask the manufacturer of the particular epoxy for their recommendation.Not all epoxies are the same.

[erster]

Epoxy or whatever glue that is used, it still comes back to where the scarf is in the plank. But the scarf and the glue will not bend or take any assistance from altering the makeup of the wood no matter how much steam or wet cloths are placed on the wood if its positioned in any real extreme portion of the area of its intended bend. If positioned wrong, the wood will just splinter even if the glue holds since a scarf joint is a hard spot. Thw wider the planking, the more likely to break.

So far all we have to go on is the simple question of steaming a scarfed plank. If the intended scarf is somewhere in the middle of the plank and its in a boat that the planking is a couple sheets of plywood or even two lengths of 16 foot solid timber, than its not an impossible task to steam each piece by itself and place in place and let the plank take shape and then cut the scarfs and glue after the fact.