Just checking the usual websites and I ran across a drop top on Warmoth. Does anyone know how to do a drop top on an instrument? I once read something from Tom Anderson that he routed "channels" parallel to the bend in the top which allow for the bend, but he wouldn't go any further than that in his explanation. I'm just curious because I would like to do it in a tele I'm building for a friend...
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Drop top help...
- Thread starter Worshiper
- Start date
A "drop top" is nothing more than a cap of one type of wood over another.
What you're referring to is the bending of the top wood over the forearm contour. In this case, the top thickness should be no more than ~1/8" thick, and you basically carve the contour into the underlying wood first, then the top wood is steamed & bent into shape, clamped and allowed to dry, resulting in a pre-bent top prior to gluing. I've done it this way on three strat bodies with no problems (cocobolo over walnut).
If the drop top is thick enough, or the forearm contour shallow enough, you can simply carve the contour into the top without exposing the underlying wood. Then again, some folks like the look of the exposed under-wood.
What you're referring to is the bending of the top wood over the forearm contour. In this case, the top thickness should be no more than ~1/8" thick, and you basically carve the contour into the underlying wood first, then the top wood is steamed & bent into shape, clamped and allowed to dry, resulting in a pre-bent top prior to gluing. I've done it this way on three strat bodies with no problems (cocobolo over walnut).
If the drop top is thick enough, or the forearm contour shallow enough, you can simply carve the contour into the top without exposing the underlying wood. Then again, some folks like the look of the exposed under-wood.
Steam is not the issue. It is heat. Controlled heat. You can bend with steam but the introduction of water if you let it go on for too long can create problems of its own.
I use a silicone heat blanket with a temperature control for bending. In this instance I would want to make two cauls to bend the top in and then make a sandwich of caul, wood, heat blanket and second caul. Clamp it together and apply pressure when the wood softens.
The low tech way to do this would be with steam. If you have a pot big enough you are in good shape. If not, then you can get two of those big turkey roasting pans they sell around Thanksgiving and put one on top of the other. Make a small "table" to put the wood on inside the pan and the boil away. You don't need a ton of water for this. A small amount will boil faster.
Once you are up to steam put the wood into the boiler for maybe 5 minutes max. If you can't get it soft in that amount of time all you will be accomplishing is crystallization of the lignin and the board will start loosing it's ability to bend. Remembering that you are working around very hot materials, quickly remove the wood, place it in your cauls and clamp it up.
Remember that is it temperature that softens the wood not moisture. Leave the material in the caul for at least a day to minimize spring back. Let it dry thoroughly before gluing to your sub base. This would be a perfect scenario for a vacuum bag system.
The big companies will avoid most of the trouble listed above by simply shaping the body and then vacuum pressing a thin veneer on.
Greg N
I use a silicone heat blanket with a temperature control for bending. In this instance I would want to make two cauls to bend the top in and then make a sandwich of caul, wood, heat blanket and second caul. Clamp it together and apply pressure when the wood softens.
The low tech way to do this would be with steam. If you have a pot big enough you are in good shape. If not, then you can get two of those big turkey roasting pans they sell around Thanksgiving and put one on top of the other. Make a small "table" to put the wood on inside the pan and the boil away. You don't need a ton of water for this. A small amount will boil faster.
Once you are up to steam put the wood into the boiler for maybe 5 minutes max. If you can't get it soft in that amount of time all you will be accomplishing is crystallization of the lignin and the board will start loosing it's ability to bend. Remembering that you are working around very hot materials, quickly remove the wood, place it in your cauls and clamp it up.
Remember that is it temperature that softens the wood not moisture. Leave the material in the caul for at least a day to minimize spring back. Let it dry thoroughly before gluing to your sub base. This would be a perfect scenario for a vacuum bag system.
The big companies will avoid most of the trouble listed above by simply shaping the body and then vacuum pressing a thin veneer on.
Greg N
For my first I spritzed with water from a Windex bottle, covered with parchment paper, then used a steam iron. For the latter 2 I used Nelson's method with pre-shaped pine cauls.
Steam irons work very well for this sort of thing. Heat them up just until water dances on the surface and not much more.
Greg N
Greg N
I cut kerf cuts in my 1/4" top and bent it over by hand with lots of clamps. I wet the top with hot water as well. I was surprised how easy it bent.
If I understand the process correctly it seems like a more complicated way of sticking a body top laminate on an instrument as opposed to carving a laminated body blank.
Is this used in order to save wood?
Is this used in order to save wood?
A piece of material (Wood, MDF, plywood, metal etc.) to help apply pressure more evenly or precisely on your work piece.
What did you do about all the spaces left where the Kerfs were? Sonically, structurally and aestheically?
Greg N
Hey Mr. Erikbojerik
Greg N.?
Just wanted to say congrats on that "guitar of the month" over at Projectguitar.com
That thing is sick!
Greg N.?
Just wanted to say congrats on that "guitar of the month" over at Projectguitar.com
That thing is sick!
- Dec 20, 2004
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the other method for adding the drop top (and the one that Warmoth utilizes) is to vacuum bag the glue up and then load it into an autoclave. the combination of vacuum bagging and pressure in the autoclave provide an even pressure that eliminates most of the headaches and gluing mis-fires that can happen when gluing in the convention manner utilizing cauls and clamps. an added benefit to the autoclave is that it can also be used to heat the chamber so you can utilize various kinds of epoxies that require an elevated curing temperature (similar to what we do for curing composite parts in the aerospace industry)
here's an image of Warmoth's autoclave with a body about to have the droptop cured. note that the vacuum bagging in this image has not had the atmosphere sucked out yet - that will happen once the autoclave door is closed and locked
[Invalid or Expired Link Removed]
all the best,
R
here's an image of Warmoth's autoclave with a body about to have the droptop cured. note that the vacuum bagging in this image has not had the atmosphere sucked out yet - that will happen once the autoclave door is closed and locked
[Invalid or Expired Link Removed]
all the best,
R
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