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I have a set of cocobolo back and sides that has some cupping on the plates. I've read up on flattening woods and tried wetting one side of each board and letting them sit with blocks in between, but this didn't do anything. It seemed as if the wood was too oily to absorb any of the water. Anyone have any tips or tricks here?

How thick are they?
Are they slab sawn ?
Mc

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Mike Collins

I have had great success flattening back sets by simply ironing them with a clothes iron. I set the heat on "cotton", spritz some water on the wood and iron away on the convex side. Once I have it flat I sandwhich it between two flat pieces of 3/4" ply wood and hold it all together with spring clamps. After it has cooled off I take it out an let it sit un-restrained for a day to see if it is going to stay flat. If it doesn't, I iron it some more.

This process is just like what we do to a set of sides when we take straight wood and bend it to a guitar's shape by applying heat, moisture and clamping pressure. In the case of a back, it starts out curved and we make it flat.

Mark

Cupping is caused by one side being dryer or wetter than the other the concave side is dry. Wetting one side just reverses the problem.

This is what I do

1, Wet both sides
2, lay some stickers on your shelf or table
3, lay one side on the stickers
4, add more stickers
5, lay side 2 on those stickers
6, add more stickers
7, lay a piece of mdf on top of those stickers which is equal to the area of your sides

This creates perfect equilibrium and both side will be perfectly flat in 24 hours. I use MDF for stickers as I natural wood stickers tend to bend !

I'll post a picture tomorrow

Regards

John

I bend them flat with a heat blanket on my table saw top .... a littel spritz, wrap in foil, heat up just like bending a side, add weights, let cool .. works for me.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I use an electric griddle (the large pancake type) mine is big enough to do a 22" x 10" back. I think I got at Wally World.

Aluminum foil, spritzed wood, aluminum foil, thick plywood, heavy weight. Run up to 300-340f and wait for the moisture to bake out.

The wood comes out flat as a pancake (pun intended) every time.

Just a cheap twist on the table saw heating blanket idea. I looked at a heating blanket big enough but $$$.

My griddle was under $30 and has a temp control that turns out to be pretty accurate although I did use a thermo
couple to monitor the process.

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Keith MacKenzie
Location: Florida
"To err is human to really screw up you need tools"

I cut and pasted this from an old response of mine to a similar query.

Here is an extreme example.

A few years ago, I bought a set of curly BRW that had been left unstickered and was cupped and potato chipped. The wood was 1/4" thick, and resisted straightening. I did not want to heat it, because the ends were waxed, and the heat would draw wax into the wood permanently. I soaked it three days in water, hoping to sticker it under weight. After three days, it was still so stiff that I cold not flatten it, and I do not have enough large clamps. Then, I was going to set up a vacuum bag to get enough pressure. I poked aroung several days. When I went to get the wood out of the water, it was dead flat. Then I just stickered it with weights as usuall, and all is fine. It took not only some moisture, but a lot of moisture and a lot of time (7-10 days) and it just went back to the fresh-cut shape all on its own.