Making a permanent bend in balsa wood

[Sigge]

Hi,

I want to add some wood to my fiber glass Bandit shovel nose to make the boat lighter. The hatch weighs 100 g (3 oz) and I just bought me some balsa wood and plan to build a hatch from balsa and throw out the original hatch, athough it is pretty nice looking.

The hull is a bit bent, so the new balsa hatch has to have a to bent too. A permanent bend.

Do you know how to make a bend staying permanent in balsa wood?


Best regards,
Sigge

[George Pfeifer]

Here are a couple of things to try:
Make a form from a block of wood that equals the bend you need.
Soak the balsa in either 1. Hot water or steam, or, 2. a solution of water and ammonia, then clamp it over the form and let dry. Ammonia will break down the cells in the wood fiber, making iteasier to bend and retaining the shape. Be careful working around ammonia.

Another way is to clamp a soldering iron to the edge of your work bench, heat it up. Take the balsa that has been soaked in water, work it over the soldering iron applying pressure to bend it, work it slowly, but don't let it burn. Repeat soaking as needed. Too much pressure could break the wood so work it slow and careful. When dry it should retain the bend.
George

[Doug Forrester]

George is absolutely correct in his advice. Ammonia is very effective. The household ammonia for laundry use works very well and is relatively safe to use. Surprisingly enough, there is enough ammonia content in ordinary Windex glass cleaner to work quite well too! Simply spraying both sides of the balsa and gently bending it around the form, taping it in place and leaving it to dry, works well.

Incidently, when fashioning your form it pays to have the curve slightly more than you want the wood to end up. When you release the dried wood from the form, the curve always relaxes slightly.

[AndyKunz]

You can get a videotape on molding balsa from Robin's View Productions (http://www.robinsview.com). He is about 15 minutes from my house and the plane on the video is gorgeous. And LIGHT!

I don't know the name of the video offhand but I'm sure if you ask he can hook you up with the right one. It's a rather new release (I saw it just before the final edit).

FWIW, get as many of the construction videos as you can afford. You'll learn LOTs of neat stuff.

Andy

[Paul]

Hello Guys,

A simple way to accomplish what your doing is to build a small frame out of 1/16" balsa and glue it to the underside of the hatch. Each end and one center rib of the frame would have the curve that matches the deck and the sides would be straight. That's the method I use and as a bonus it adds a bit of strength to the hatch with next to no weight gain. Simple and fast.

Paul.

[Sigge]

Thanks for all the ideas!

Today I wetted some balsa and it
is now under press on the boat so it will bend according to the hull's form. This will be fun to watch!

I will aslo try to use a water sprayer and a hair dryer on another piece of already painted balsa to check out how this will work out.


/Sigge

[Doug Forrester]

Another idea I have used when making hatch covers that only have a slight curvature and are essentially a single layer of 1/32" ply or 1/16" - 3/32" balsa, requires that first you make a form or frame that duplicates the curvature (female mold). Then with your hatch material held in the curvature of the form, apply strips of 2-3 oz. glass cloth along the edges of the underside of the hatch with thin CA glue. Sand the edges smooth and you will find that the glass not only will reinforce the edges but will help to retain the curvature.

[Sigge]

Now the two hatches are finished. They look both good.

Here is a picture of the boat with the new hatch.

[Sigge]

Here's a pic of the yellow
hatch.