Monday, June 11, 2012


Well there was a big gap between posts there due to Jacqui being taken to hospital but she's nearly better again so it's been back to building the boat again this weekend. Above is the result of the bending we did.
The mistakes we made on the first one were significant and taught us a lot about bending bigger bits of wood.

The steambox MUST get to a high temp. I didn't realise we had a leak in the cap on the steampipe when we bent the first one and we couldn't get the temp past 75C/170F. It was in their for about 5 hours and I didn't want to have nothing to show for all that steaming time so we thought we would try it. Well we snapped the gunnel pretty good and had to discard it. I thought we would be able to make up for quality of temp with quantity of temp exposure but that was very flawed thinkin. We will never try to bend another piece of wood without it hitting min 95C/200F.
We had 2 in the pipe to bend and we got the second one bent but it was a lot of hard work and we were very afraid of breaking it.

We got the second gunnel bent yesterday .. after I discovered the leak (it was easier to see in broad daylight yesterday) and got it patched up we were able to get the steampipe up to 95C/205F pretty easily and we left it in for a few hours. I also did more research and found that it seems better if you don't try and force the wood all at once. Aim to bend it over 30 secs or so and allow the fibres time to stretch along with ya.
This operation was a much more relaxed affair, we both knew exactly what we were doing and the elasticity in the wood was way higher. 
Wood comes out of the steamer, (I note any natural bend in the wood before it goes in and bend it that way) goes in between the blocks at one end. Plywood cap swings over and keeps it from poppin up. You can see we're using a metal pole as some extra support but blocks would have done the job. I bend it and Dave keeps from twisting and also screws the squares of ply down so it doesn't pop up. Take your time, allow 20 to 30 secs to get it done. 
All the measurements for this will follow later but we're roughly going from zero to 20 inches at 6 feet in. At the of the gunnel there (middle of the boat) we bent it an extra 3 inches to take care of some of the pop back when it is released. I measured the pop back on the first one and it was about 12 inches but easy enough to get back to where we want it to be.
Update: When we took the second one from the form yesterday it only popped back 9 inches compared to the first one at 12 inches which didn't get to the higher temperature.

What's unusual about the way we're buildin a currach is that we're putting a compound bend in this gunnel. To be perfectly honest, we're not too sure if this is going to work out. We don't know of anyone who has ever built a currach like this before. A compound bend means that we are bending in the plan and also in the elevation. All currachs are built by bending the front in plan only. They then join the front part of the boat to the back an an angle and put in extra support there and glue and peg it all together. We're trying to skip that and hopefully make and even better-looking boat along the way. 
Why would we adhere to a few hundred years of other people getting things right????!

More of it tonight and maybe even a video to show ya how it all works as the auld pictures don't quite convey how we get it to bend.

1 comment:

  1. Hope the missus is alright Oscar.
    The boat is looking pretty classy now. You going to row her back?