|
estebanana -> RE: poor man's side bending ideas (Sep. 30 2012 20:21:15)
|
If I may to add to what has been posted so far:
You might try using as little water as possible. As has been said, the wood is heated and reaches a point where it goes plastic and you can move it. Rosewood does this beautifully, cypress is more stubborn.
One problem with spring back can happen when the rib is too wet. The heat on the bending iron should draw the water out of the rib and leave it dry and hot. Then you hold the rib onto a tracing of the outline until it cools, dry.
The cell walls of the wood will become pliable when you wet the ribs and turn the water into steam inside the wood. But you have to work the water out of the rib because the mechanics of the wood fiber dictate that you let it cool in the position you want it to take. If the wood has moisture inside it it will not hold the bend because the cell walls and lignin in the wood will remain flexible while it cools. It needs to be dry as it cools. Very important.
The classic dilemma with rib bending is too much water equals poor bending and with not enough moisture scorching can happen. It's sometimes maddening to hit the right balance with certain woods, cypress can be tricky it is blonde and will show scorching.
One way to get water into the rib, avoid scorching and still bend fairly dry, is to use a strip of newspaper that you spritz water on. Also using a spritz bottle on your rib helps, or simply running a wet cloth on the outside of the rib an when wiping off the excess water. When you go to bend you can stick the damp newsprint to side of the rib you are bending and it gives you some margin of protection from scorching. A dry rib with a wet strip of paper can be just the right amount of moisture to drive steam into the wood, yet not make it difficult to dry out.
So the concept of how the wood works is: bend moist, draw out wetness with heat, wait for the point where the wood plastisizes and then hold the bend on a tracing until it cools. Then repeat. Cypress gives you a more subtle indication that it is plastic than rosewood, it's just more springy by nature. But if you think about the process as more dry than wet, without burning, you may have better results. What ever technical means you have to do to achieve this is up to your experimentation, but getting more clear on how and why wood will bend gives you an idea of how to work.
I soaked my first ribs in the kitchen sink, they were flame maple. I went to bend them and they broke like potato chips. You'll have better luck.
|
|
|
|
