#1 in progress: cedar/mahogany medium jumbo scratch build

[nkwak]

Today was a brisk December morning with frost on the rooftops and the furnace kicking on, reducing the RH to the mid-30% range. Perfect conditions actually to put the top on. After signing the underside of the soundboard and recording its tap tone one last time for posterity I did some final sanding of the tail and neck blocks to make sure that the angle right. Even if things aren't dead on at this point I can still still tweak things after the top is trimmed. :



At this point it was time start the day so I had to wait until after lunch to do the glue up.



Then I enlisted a little help with the go bars. He was adamant that he do one all by himself - even though I feared for his safety and the structural integrity of my ding-prone cedar top:



"It sounds like a drum, Daddy!"



That was right when I was supposed to be dropping him off at preschool; about 12:30PM. It's nearly 12 hours later and I'm itching to take the go bars out and pull the box out of the mold but I'll wait until tomorrow night.

[johnnparchem]

Looks great. Just keep from shooting one of the go-bars through the top when you take them off.

[nkwak]

Ooooffffff!!!

I went down to take the go bars off and noticed that one had failed. That's not the worst of it though. The top left bout didn't glue down well at all, and the sound board actually split due to bad placement of the go bars.









The break looks clean enough to glue up - provided it can take the stress. If not then Imay have to reinforce or laminate it underneath somehow.

[kencierp]

You should be able to glue that piece back in place and it will be an invisible repair.

Go bar decks can "kick your A** -- expect the unexpected.

Your son is a handsome little guy!

I'll relay this internet go bar deck horror story and you can find others that are similar. A little nudge could displace a bar and shoot it "right through the back or top" --- just a heads up.

[Jim_H]

go bar setups are fickle things.

Just be glad that the one failure didn't lead to the rest of them failing simultaneously. The ensuing chaos from a total go bar failure is quite devastating (and dangerous if anyone is nearby).

[tippie53]

Use tite bond for this not CA and you won't ever know it was broken.

[David L]

When I closed the box I used a one piece caul that covered the entire perimeter where the gobar rods were applied. Perhaps by using individual blocks promoted to the top splitting. Also I notice that you have quite a bit of overhang, if one of your blocks was not centered directly over the edge of the rim, this sort of thing can happen. I don't know if any of this applies in your case but it is just an observation.

David L

[nkwak]

Use tite bond for this not CA and you won't ever know it was broken.

Makes sense, John. There's another issue in play here though: there's a large section that didn't glue up on either side of this. I think it may have something to do with the side brace/shim for the UTB that I glued in this area. I had to sand/chisel the mortise so that the rim sat flush. I did two separate dry runs with the go bar deck under tension when the RH was a little lower and everything seated fine. Maybe things expanded? If so I have no idea how to get in there and sands things more.

[tippie53]

tite bond can be steamed and reglued if not cured. You can try getting more glue in there after steaming the area .
I think you should be fine. Here is a reason for Hot Hide or fish glue as you can reglue these without worry

[nkwak]

Yeah, I think I'll be fine. It ain't gonna be pretty though. Like a fellow newbie on another forum said, chalk it up as experience, take note of what went wrong, fix it and try and do better next time. Next time may be a kit though! :lol:

I also post this over at AGF and my friend and mentor sent me this reply. I've been working at my home because his day job varies with regards to schedule:

[QUOTE=Kitchen Guitars;2847213]Oh! Ooops Heck we can fix it. Next week is a lighter load (so far). DO NOT KEEP refitting the wounded wood. You'll knock out fibers[/QUOTE]

He's gonna be mad then:



Fate or God or whatever you all may believe in has this thing about kicking me in the pants though. This time another gobar let go and shot right into the soundhole. Another inch in any direction and things could have been MUCH worse.



No apologies though. I will work through this. I already have some ideas. I'll need to do one of those little Cole Clark inspired inlays though. I figure that it will be a small one since after everything is trimmed away only about 1/8" will be affected. That was probably part of the issue: too much overhang. In some places there's 3/4" overhang. As careful as I was any one of those cauls could have slipped for any reason. Next time I'm thinking of using clamps instead. It's easier - but costly.



My concern is actually with the fit of this mortise. This is what may be pushing everything upward. I may have to figure out a way to sand between those 2 surfaces to make it fit better. Odd that it did fit before but that's wood - it swells and contracts with changes in humidity and temperature.



There's also 4 consecutive points at waist that were not glued up either. Once I get that shored up I'll move on to putting some Frog tape on either side of that split brace and gluing it back down.