Ooops! I need to re-do the blocks...but how?

[nkwak]

Back in high school a friend always used to tell me "Smogorian" jokes. Those of you old enough probably know them differently as being "Polish" jokes. Since my friend knew that I am mostly of Polish descent he would spare me the humiliation while still sharing the humor. Still, every so often I'd resemble those jokes. This morning I discovered that not only did I make one of these mistakes, but I made TWO.

This past week I realized that I'd screwed up the kerfing and took a chisel to the sides. I was very careful and as the last little bit of kerfing popped off easily - probably a testament to my inadequate gluing skills as well - I breathed a sigh of relief as I was able to salvage the sides.

... then I took a not so close look at the block orientation:



To quote Homer Simpson - of whom I also resemble more and more each day: DOH!

Not my finest hour by far, but it begs the question: what's the best way to remove the blocks and re-orient them? Can they be saved or do I have to start all over? I'd REALLY like to salvage these sides.

FYI: I used Titebond I and this is east Indian rosewood and a little digging around online tells me that Titbeond I lets go at about 150 degrees with steam and heat. Is it advisable to use a clothes iron with some wax paper to perform this task?

PS: pay no attention to the lines for the lower brace faces. I was following the measurements and angles on my plans without taking into account that I'd widened the angle on the X brace; the original angle was too acute. I'd prefer it to be obtuse like its creator.

[phavriluk]

NO WAX PAPER! Wax off the paper may transfer to the nice, porous, wood. Finishing will then become quite an adventure. Just make sure that the neck block is really oriented wrong.

[tippie53]

I wouldn't worry too much about tail but get the neck block centered. You can use a cloths iron to pull the neck block and reglue it

[nkwak]

Okay, no wax paper. How about an old white cotton t-shirt rag sprayed with a little water?

As for the neck block, it's a pre-mortised Martin bolt on neck block and the mortise is off center. I made the tail block myself out of birch plywood - I learned the hard way that laminated tail blocks can really save a guitar from sudden drops on the end pin. It's clearly off-centered and the glue joint did not have 100% contact so off it comes too.

[MaineGeezer]

Is there any reason you can't bevel the corners, thusly? No particular reason except maybe to reduce the mass of the head block a little.

[nkwak]

Well, I did the deed last night. I used an ordinary clothes iron, some damp t-shirt rags, a painter's spatula and a small kitchen thermometer and it went well.



Not quite as easy as a hot knife through butter but no cracks either. I've successfully gone two steps back and couldn't be happier. New kerfing is on order and I have 3 days to clean up the glue joints.

I will also attempt to facet the neck block as well. Since I'm emulating the laminated neck that I did on my first it will be neck heavy enough.

Thanks for the advice everyone!

[tippie53]

I wouldn't take too much off the neck block. This is the load carrying block so don't remove more glue surface than you have to.

[nkwak]

Certainly. I believe he was referring to faceting the opposite corners facing inside the body. Stew Mac sells blocks prefaceted like this.

[Stray Feathers]

I had a similar issue on the head block of one of my first two builds - despite my watchful eye, it slipped out of alignment with clamping. I did not think to remove it using heat. First, I trimmed the block sides back to vertical (thus losing a little mass, but I was going to gamble on that.) Then I realized I had to level the top and bottom surfaces. On a first guitar I decided I better go back to square one and remove it. Not thinking about the heat procedure, I cut through the block with the bandsaw, removing in the process a saw kerf width from the front seam of the two sides. With the rim open, I could further cut away the now bisected block with the saw, and then finish with a chisel and sandpaper. It worked, but I lost the block. I'll know better next time. The guitars are on hold for a bit while I built a woodshed - way more forgiving.

[nkwak]

Having gone through the process of disassembling the guitar I feel more brave about trying my hand at repairs now. I have two guitars that need a little patching up - well, one needs patching and the other needs a full blown neck and bridge reset. That would mean putting the build on hold and the climate is right where it needs to be for building so I think I'll stick with this.

Anyway, after all is said and done I think I did things right this time. The blocks are back in and centered. Then I measured the sides and drew a line for the taper of the back. Then I took a block plane and got a nice gentle slope on the back side of the rims within 1/8" of an inch of where they should be then glued new reverse kerfing in. Now I have to finish my rosette and final thickness sand my plates. Pretty soon it will be time to work on the bracing in earnest!