Message-Id: <3.0.5.32.19980930075340.007e0c30@mail.itis.com>
Date: Wed, 30 Sep 1998 07:53:40 -0500
To: baidarka@lists.intelenet.net
From: Dan Miller <5lakes@itis.com>
Subject: Re: baidarka steaming versus boiling
In-Reply-To: <3612028A.2D94@agora.stm.it>
At 11:06 AM 9/30/98 +0100, Stefano Moretti wrote:
>Anybody can clear what the bottom line differences are in
>steaming/boiling thin stock ??
The main difference is that steam is a dry heat, while boiling
isn't. Boiling can get the stock a little hotter, but I have
no problem getting my 6 cubic foot steambox to 208-210 degrees F.
Steaming tends to dry out the wood, so while there is a minimum
time for steaming (rule of thumb is 1 hour/inch of thickness) it
is also possible to oversteam, the consequences of which are similar
to understeaming.
>
>I have very limited experience with steaming and found that 1/4 " white
>oak tends to crack or splinter even after 30 minutes steaming.
You are probably steaming too long. The rule of thumb suggests
15' steaming time. Of course the rule varies depending on your
own conditions - ie stock source, heat source, etc. Two things
I would suggest to improve success with stemaing. First is to put a
thermometer in your steambox. If it isn't getting to over at least
190 degrees F, it is simply not hot enough; boost your heat source.
Second is to presoak the stock. I can get good success bending even
kiln-dried ash if I soak it for at least 5 nights before steaming (for
3/4" stock).
Speed is of the essence getting the stock from the steamer into
its bent shape, whether it be on a jig or freehand. The thinner
the stock the less time you have before it cools off. If you are
bending over a jig, consider compression straps (check the archives).
Also check the grain of your stock. White oak should be aone of
the easier bending woods. Another rule of thumb (I'm all thumbs
today!) is that the grain should not run out within a 10"
lenght of stock. I think I picked this up from Rollin Thurlow's
steambending video (which is well worth watching - and takes place
in a wood canoe shop).
>
>Is boiling a better simpler way ??
Depends. What works is what is best. Shaker box buidlers, who
usually work with thin cherry and maple, generally boil. For
longer lengths, it may be harder to set up a boiler than a steamer,
however with boiling, you can't over do it, time-wise (unless you
let it boil dry...).
Boiling can be the answer for tough to bend woods like mahogany. I
called Old Town for advice on bending mahogany for canoe rails. The
answer was, and I quote as accuratley as I remember) "soak it for
a week, nad then boil the h*ll out of it".
Cheers,
Dan
--- Daniel Miller - 5lakes@itis.com Five Lakes Wooden Boat Center http://www.paddlin.com/fivelakes/canoe.htm "So many boats, so little time..."