Thanks for watching guys.
A little forward motion, got the ladder braced one together, strung up and playing. Sounds great, and plays good. Then a few steps backward, after a couple of hours playing I start looking it over closely, and the bridge is lifting on the back edge.
So, how about a few pics on bridge removal?
I mask off around the top to protect the surface from pallet knife marks.
Cut a mask from cardboard and cover with foil.
More layers of foil covered cardboard, to concentrate the heat from the old movie camera lamp on the bridge and shield the top.
Heating with the lamp, 2 to 3 minutes, then check with pallet knife. Took about 3 times, then the glue was soft enough to seperate, working the knife in carefully on all sides. The top stayed cool, so the shields worked.
And it came off clean.
Now why did my glue joint fail? I don't know, not clamped evenly? clamped to tightly, starving the joint? imperfect prep? who knows?
But we try it again, perfect sanding prep this time, clamps better aligned, not too much pressure, leave it clamped overnight, let it have a couple of days to cure before stressing. Keep my fingers crossed!!!
Also while looking closely at the lifting bridge, I noticed that the top is de-forming pretty bad. String tension is rotating the bridge, sinking the top in front of the bridge and raising it up behind the bridge. Now one problem is my neck angle needs a little adjusting. Too much height on the saddle needed to get enough action on the neck. There is a full 9/16" under the strings in front of the bridge, so that's increasing the torque on the top. But now look at the bracing photo.
I followed a pic of one of John How's ladder braced guitars, and added the bracing on each side of the sound hole. But seeing how the top is de-forming right off the bat, it's not going to work, sounds great but doesn't look like it will last long. Maybe John leaves his top thicker, I know he uses adirondack which is supposed to be very stiff, but this one definitely needs help. My first thought was that it needs a bridge docter to transfer the tension to the end block. And that might take care of it, but looking at how little bracing there is, I think I need to add a cross brace right in front of the bridge plate, and see how that levels out the top. I can then test it for a while and easily carve it down some with a small plane thru the sound hole if it's too stiff. What do you think?
Now on to some more forward progress!
These are some shots of the x braced Ditson, and so far so good. So far the bridge is holding good, and it plays well and sounds good. I need to play it a few days and let it settle in, get the ladder braced one's problems fixed and then I can start evaluating.
So, two steps forward and one step back, but it's moving in the right direction anyhow!
Joe