How do you bend balsa?

[paul]

Hi Guys

I would like to know how to bend the balsa wood to the shape of the picture
I have tried numerous times trying to soften the wood, but still cracks

The instructions only say:
Rudders (laminated Outlines)
2 Lams 1/32 x 1/16 soft balsa

Thank you
Paul

[joecrouse]

Steam or at least VERY hot water.

[Wildpig]

You have to soak it for a few hours or even overnight. Steaming it takes less time.
I thought I read somewhere that soaking it in ammonia helps it to bend.

By the way, that looks like an Ercoupe vertical fin.

[Goldy]

Agreed, make yourself an steam tube from an old paper towel or wrapping paper tube and put one end over an electric kettle, cover the other end loosely with duct tape. steam it for about 15 minutes and bend it immediately after removing it, with small pieces you literally have only seconds to work with it. Remember, these pieces are laminated from thinner bits. It may help to cut small nicks into the edge to help it bend without breaking.

If you just can't get it to bend, then cut it out in sections and glue it carefully together.

[Steve Blanchard]

There are several ways to do it. The method I have used for years:
1. You must make templates to form the balsa arund. They can be from balsa or I use foam meat trays. Rub a crayon or wax on the edge so the laminations don't stick to it when the glue dries.
2. Use at least 3 lams of 1/32" balsa (the thinner they are the less likely they will crack.
3. Spray the strips with windex or any other ammonia based glass cleaner. The ammonia softens the balsa considerably, and you don't have to wait.
4. Make a mixture of 50% wood glue and 50% water.
5. Take 3 strips of the proper width 1/32" balsa and coat the center strip with the glue mixture on both sides. Sandwich it between the other 2 strips.
6. Pin the beginning end against the form and start to pull the laminations around the form. Place pins in strategic places to help hold the strips against the form as you go.
7. pin the end in place when you get to end of the form and cut away the excess.

Below are two pics from my spitfire build:

[zoomie]

Steve, that is one slick trick, thanks! Must try using your straight Windex method on my next build.

Ammonia never did anything for me in the past, just followed the usual advice of "add a capful' or "add a splash" to the soak water. Trouble is, it was never enough to help. Most household blue glass cleaners have 5% to 10% ammonia and apparently that's what it takes to lower the water surface tension and allow the solution to rapidly soak into the balsa.

Tried 2 lams of 1/32" X 1/16" for NoCal wingtips and tailfeathers and it worked okay but unsure if it would do for larger and heavier models. Do you use the 3 lams for everything you build?


zoomie

[kittyfritters]

Check out this post for a slightly different take on the balsa bending.

http://balsamodels.com/phpBB/viewtopic.php?f=2&t=2331

Have fun!

[zoomie]

Howard, great "Cub-bashing" thread, picked up a couple of new construction tips - thanks

Let's see if I understand your laminating method:

1. All lams are 2-ply, 1/32" thickness of each individual strip.

2. The thin balsa strips are given a quick soak in room-temperature tap water, then the Original Gorilla Glue is applied to each wet strip. The Gorilla Glue rapidly penetrates into the strips, making each nice and floppy so they can be wrapped around the form without breaking.

3. The 2-ply lams are Scotch-taped to the form and allowed to dry. The tape is impervious to the Gorilla Glue so it can be easily removed later.

If I misunderstood anything, please clue me in...thanks again!


zoomie

[kittyfritters]

Zoomie,

Everything but the quick soak. The water is tap hot and you soak for a couple of hours. A piece of PVC pipe, with a cap glued on one end and a cap slipped over the other end when it is full with water and balsa strips makes a good soaker. Prop it upright so the water does not leak out of the slip capped end. I have also done this by putting the drain plug in the sink, partially filling it with hot water, putting in the balsa strips, and putting a heavy pot on top of them to hold them under. This, however, is rather crude.

The strips are already "floppy" before the glue. The glue is not on the inside of the strip that is against the form. The reason I use the Gorilla Glue (original) is that it is polyurethane foam glue that is "kicked off" by moisture. You do have to be reasonably quick (not panicky) on the assembly. The excess glue that is squeezed out becomes foam when it dries and is easily sanded off. You might want to wear nitrile or vinyl gloves when doing this since some people have skin reactions to the Gorilla Glue.

Howard

[paul]

Using a stripper, I cut strips from a sheet of balsa 1/32 (0.8mm) depth at 1/16"
With the wood being so flimsy I soaked it for about 10 seconds in tepid water
then wrapped it round a template pinning at every cm

Thanks for your tips and advice, thats why we are here

Not perfect, but practice makes perfect
Hope for a better result next time

[joecrouse]

Since everybody gave a Good answer including me

I think it needs some other answers from around the internet... (Ok I thought these were funny for like 10 seconds. )

Q :how do you bend balsa

A: Very carefully

Other answers include

"With my hands. "

If you happen to be Uri Gelar

"With your mind"

If you happen to be Keanu Reaves

Do not try to bend the balsa — that's impossible. Instead, only try to realize the truth: there is no balsa.