Harmony Stella H942 Repair Thread

[tateharmann]

Made some progress on that far back brace. After a failed attempt and subsequent cleanup using Titebond original I switched to Titebond liquid hide to enjoy a longer assembly time lol.

The brace went on straight, tight and feels very solid. There's no rattling with tapping and even though there wasn't as much squeeze out as I would have liked to see...I can't fit a .003" feeler gauge under the entire brace anywhere. The gauge will go in a tiny bit (maybe 1/16") in the spots that look like gaps (not sure if that will show up in the pics), though. Using a mirror to inspect the back side of the brace it looks to have slightly better squeeze out but still appears to have tiny gaps.

I think what may have happened is that when I cleaned up the braces I didn't keep them completely flat the whole way, as in they may have a slight crown in some spots. Either that or the back was a bit wavy in spots (which it indeed was as I noticed). Or may be some debris got trapped under the brace while gluing. I'm thinking I'll just use a syringe and squeeze some more glue along the joint line and lean the guitar so that gravity does the trick. Maybe thin it out a bit? Or I could just use my real HHG instead of Titebond? I'm open to ideas!

Lessons learned:
1. Use more jacks (should have used 3 instead of 2 perhaps)
2. Have clamps and cauls ready. I thought that I could skip clamping by putting a heavy object on the top to push the brace down. It didn't work as well as I thought so then had to scramble to find my clamps and cauls/plates. I probably should have done three clamps instead of 2?

Anyways...doing dry runs for the next brace while I figure out what to do with this rearmost one!

Brace in place with two jacks and finally some glue under it:


Clamping:


Glue dried and cleaned up:


Inspecting the back side of brace:


.003" feeler gauge attached to wire hanger:


Dry run on the next brace:

[tateharmann]

I opted to just run a quick bead of HHG on that brace. Front side is done...may also do the back side.

[tateharmann]

Managed to get a bead of HHG on the back of the brace as well...not as clean looking as the front but unless you've got a mirror and a light you won't see it lol.

[ArchtopLover]

Great work. Keep going!

One thing I have had difficulty in the past is applying the glue to a loose brace and also to the place where the brace is clamped (buttering both sides), without getting glue smudges and smears on the soundhole or somewhere else inside the guitar, unintentionally, while trying to place the brace in the proper position, to be clamped.

So, one day I came up with an idea that I would like share on this thread, since the idea can help others when replacing loose braces. To prevent the still wet glue from being disturbed, before clamp-up, do this:

Begin by cleaning off all old glue and sand lightly to expose some bare wood. Then, using a piece of low-tack masking tape, apply the tape to the back-side of the brace, or the side of the brace that is facing the tail-block. The tape should be half-on and half-off, since what you are creating is a "hinge". By folding the tape in half, you can then slip the brace, with the tape applied, inside the guitar, position the brace in the desired spot, unfold the tape and gently press the tape to hold the brace in place. Next, simply tip the brace over, toward the tail-block, thereby exposing both glueing surfaces. Because you made a temporary hinge, you can then apply glue to the underside of the brace and the back of the guitar with a small artist paint brush.

Here is the beauty of this idea; once the glue is applied, you simply tip the brace back up into the upright position, install your clamps, apply pressure, let the glue dry, remove the masking tape and bingo, no messy glue smudges to cleanup afterwards .

Let me know what you think of this technique (I should do a mock-up, take and post some photos).

[tateharmann]

Originally Posted by ArchtopLover

Great work. Keep going!



One thing I have had difficulty in the past is applying the glue to a loose brace and also to the place where the brace is clamped (buttering both sides), without getting glue smudges and smears on the soundhole or somewhere else inside the guitar, unintentionally, while trying to place the brace in the proper position, to be clamped.



So, one day I came up with an idea that I would like share on this thread, since the idea can help others when replacing loose braces. To prevent the still wet glue from being disturbed, before clamp-up, do this:



Begin by cleaning off all old glue and sand lightly to expose some bare wood. Then, using a piece of low-tack masking tape, apply the tape to the back-side of the brace, or the side of the brace that is facing the tail-block. The tape should be half-on and half-off, since what you are creating is a "hinge". By folding the tape in half, you can then slip the brace, with the tape applied, inside the guitar, position the brace in the desired spot, unfold the tape and gently press the tape to hold the brace in place. Next, simply tip the brace over, toward the tail-block, thereby exposing both glueing surfaces. Because you made a temporary hinge, you can then apply glue to the underside of the brace and the back of the guitar with a small artist paint brush.



Here is the beauty of this idea; once the glue is applied, you simply tip the brace back up into the upright position, install your clamps, apply pressure, let the glue dry, remove the masking tape and bingo, no messy glue smudges to cleanup afterwards .



Let me know what you think of this technique (I should do a mock-up, take and post some photos).

I like that idea! I don't have low tack masking tape...is it absolutely necessary for this? I've seen it used in other repairs so I suppose I should just get some. Some pics would be great but I also think I get what you are describing here without pics.

[tateharmann]

Second brace down. Learned a valuable lesson about my jack design while doing this: don't use pine and have some solid blocks to switch out with the dadoed/grooved one for situations like this. In this case the top of the jack wasn't anchored on a brace so there was nothing keeping the bolt from blowing through the pine. I lost two jack blocks during this glue up and had to improvise on the spot. I wouldn't normally anchor a bare jack bolt on the bridge plate like this but it worked in a pinch.

[tateharmann]

Third brace down...finally one went in without a fight!

[tateharmann]

Last one down. Of course, there is in brace in front of this one...originally it was the only one that stayed in place but now I see the glue on one end is breaking up and the brace is lifting/loose there. So, I will get to sort that also.

[tateharmann]

The entire back is now braced up again and feels very solid



On the foremost brace that was slightly lifting I ended up firing up the HHG pot and squeezing a bit under there. I always hear that the benefit of HHG is that it sticks to itself so that's why I went the easy route. It feels solid and doesn't move anymore so hopefully it holds. A little bit rolled into the corner where the side/kerfing meets the back but I figure that can only help lol.

[tateharmann]

On to the next phase. Remove the already lifting bridge...try to sort out the belly bulge and then reglue the bridge.

[tateharmann]

Initial cleanup of bridge and top done. First attempt to flatten the top a bit more. I'm not expecting much from the first attempt...I only heated the bridge area to around 98 degrees. In the videos I've seen of other folks doing this they heat it up to 120 or so. I think I will let it sit for 3-5 days and see where I'm at. The bulge creates a 3mm plus gap at the sides with a straightedge balanced on the top. The bridge also became severely warped from the same tension. It's dead flat at the front but pulled up into quite an arc at the back. Its also bent across the grain. I will need to try to steam and bend it flat as well but I will wait to see how flat I can get the top and then try to match the bridge to that.

I hear that extra moisture helps the top keep it's new shape so I've got a sponge in a zip lock inside with a life guard in the sound hole.

As always...I'm open to suggestions on flattening out the top [emoji106]

[Taylor Ham]

I think the top arch is acceptable given that some guitars come off the line with that level of arching. If the action is also acceptable that is. If you haven't thought of it already, I'd suggest trying to add two or three small fan braces under the bridge, spanning in between the ladders fore and aft of the bridge. That will mitigate the belly from returning or worsening should you be able to get it back to dead flat.

[tateharmann]

Originally Posted by Taylor Ham

I think the top arch is acceptable given that some guitars come off the line with that level of arching. If the action is also acceptable that is. If you haven't thought of it already, I'd suggest trying to add two or three small fan braces under the bridge, spanning in between the ladders fore and aft of the bridge. That will mitigate the belly from returning or worsening should you be able to get it back to dead flat.

Thanks for the reply! I'm fairly certain that this guitar did not have any dome built into the top at its time of construction. The action is a pretty awful 1/4" at the 12th fret. The neck angle is partially to blame but the belly bulge is a culprit as well. I like the extra bracing idea but this guitar has a strange bridge plate that extends the whole width of the guitar so I think this wouldn't be feasible unless I swap out the plate.

[tateharmann]

After waiting for some warm weather I'm back at trying to flatten this top some more. Heating it to 100 degrees didn't do much last time so here I'm trying about 120 degrees to see where we get. I used "solar power" to heat it to that point and clamp the plate back on.

If this doesn't work, I might try a little bit more heat...but after that I'm going to leave it as is. I will sand the bridge to match the top and glue back down. I'm resetting the neck anyways so I can just reset to wherever the bridge ends up [emoji106]

I've already pulled the neck and will post some images on that exciting process next lol.

[ArchtopLover]

Nice job pulling that bridge. Really clean. I would think that the small amount of top arch I see in your photo looks OK. Not sure if all the effort to flatten the top is necessary, but hey, what do I know, I prefer archtops anyway .