Took some pictures of the latest neck warm-up. Sometimes a neck is just a little bent and instead of making a difficult neck turnover with all that it entails, it may be enough to just warm and straighten it. The principle is that wood is a bit plastic in nature. Lignin and hemicellulose between the fibers become soft with sufficient heat and if you bend the wood, it will solidify in the new position.
I use aluminum shims (about 5 mm thick) which distribute the heat evenly from two travel irons with adjustable heat. The upper aluminum plate distributes the pressure on the iron. I do not use the hottest position, about 100-120 degrees can be used unless the grip board has studs or bindings in plastic. If there is plastic, you have to be more careful and maybe aim for a maximum of 70 degrees or even loosen the decorations. But the warmer you are, the more you can bend your neck.
The table top is restrained and the forceps hold the body and bend down the neck. The iron heats.
This neck had bent up at the attachment, but no more is that a heater can push down the neck so it becomes straight along the entire fretboard. A neck turnover is otherwise the method needed if the shape of the fingerboard is similar to a hockey stick… Tightened the two innermost clamps on top of the aluminum plate on the fingerboard really to force down. Other clamps are only there to hold the body and the iron.
One problem if you run hard with the heat is that the grip board can shrink and there will be a small joint on the neck itself. You can avoid much of the problem by oiling the grip board with a greasy oil, I usually use teak oil.
Here I had 120 degrees on the iron and aluminum plate on top of the old strips, 61 degrees on top of the grip board itself and about 45 degrees on the underside of the neck after heating for 20 minutes. It should feel hot but no worse than holding your hand under your neck. With the forceps, I bend about twice as much as I want to straighten the neck, the neck will fail back about as much as you can bend it back. Of course, it is a small lottery how it goes, but sometimes it becomes perfect 🙂 The ideal is not to have a compulsion under the neck itself as the varnish also becomes soft, I got a small print mark in the cellulose varnish of the top (unnecessary!) Forcing and countering. Such marks can be sanded and polished away.
This should be re-banded after the heating and then you can grind the grip board plane before. Mostly a good idea as you never get the board and neck perfectly straight.
You can heat several rounds, but each time it becomes harder to bend. Twice goes well, but after 3-4 rounds it can be difficult to bend more. The best thing is to meet a man the first time when the tree is the most flexible.