First Project - A rebuild

Take us through building your guitar step by step. Post pictures and tell us what you're doing.
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MaineGeezer
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Joined: Wed Aug 13, 2014 12:14 pm

Re: First Project - A rebuild

Post by MaineGeezer »

Clever clamping idea.

What kind of glue are you using? You may already know that you should use a glue that is reversible, i.e. can be disassembled. The traditional glue is hot hide glue. (n.b. the bottled stuff sold as "cold hide glue" is not the same at all.) HHG can be tricky to use until you've had some practice with it though.

Lately I've been using fish glue, which John (our host0 sells, as does StewMac. It has many of the desirable properties of HHG and is easier to use.

A lot of people use TiteBond (the original, non-enhanced version). While TiteBond can be taken apart, it is not truly reversible. It undergoes a chemical change when it hardens that cannot be un-done.

There is also the issue of glue sticking to old glue. HHG will stick to old HHG. I think fish glue will stick to old fish glue, but I'm not certain (can anyone confrirm/deny?). TiteBond will not stick to old TiteBond, or to other old glues

All that is a roundabout way of getting to the question: are the ends going to stay stuck?
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
Keith Reilly
Posts: 54
Joined: Wed Dec 06, 2017 10:58 pm

Re: First Project - A rebuild

Post by Keith Reilly »

I'm not sure what the original glue is that was used to glue the sides to the blocks. But I bought Titebond liquid hide glue. I suppose if I were going to build a guitar from scratch I'd have to use hot hide glue. But I think for the repair job here the instant stuff would be fine.
Keith Reilly
Posts: 54
Joined: Wed Dec 06, 2017 10:58 pm

Re: First Project - A rebuild

Post by Keith Reilly »

After I finished the glue up I was deciding wether to figure out the neck reset or if I should install the binding and perfling. It was about then I decided that I needed to check the kerfing that was in this guitar. What I found was a really really thin strip of wood that wasn't even kerfed. It was so thin that if I cut the channel for the perfling the guitar top would no longer be attached to the sides. So I needed to decide wether to abandon the perfling idea or take the top off.

Since this is a learning experience I might as well learn how to take the top off. With my heat gun I removed the plastic binding. Then a little heat on the guitar and lots of heat on my burger flipper, with the heat gun this time, I took my time and went around the guitar separating the glue. What I learned was to start where the bracing is and work out from there. I noticed as i head toward a brace the spruce top gets less flexible and cracks start happening. After about two hours or so I got all the way around the guitar and discovered that the braces were still glued in solid to the sides. Copious amounts of heat with the heat gun while I had my arm in the body pushing up on the brace worked. Next time I do that I'll put on a glove so i don't burn myself.

Strange kerfing. I ordered some new ones from Stew Mac. I need to figure out If i should put it on top of whats already there or if I should remove the kerfing I have. I guess the down side to taking it off is I might damage the sides of the guitar. What is the down side for leaving it on? Will the top be too stiff with the added kerfing from stew mac? Need some advice here on what to do.
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Keith Reilly
Posts: 54
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Re: First Project - A rebuild

Post by Keith Reilly »

Other problems I see in the guitar. The soundboard is braced funny. I'm not an expert on bracing but its not the normal kind I've seen. Also lots of plywood cleats. Instinct tells me those should come off and be replaced with spruce cleats. The tail block has a crack in the top, looks easy to fix. But below that is a crack in the side. Need some advice on how to fix that up. This top is .11 to .15 inches think depending on where i measure from. It is not even. Also the bottom of the soundboard separated a little after taking the top off.

The braces need to be glued down on the ends because it separated when using the spatula to take the top off. Does it make sense to take these braces off and put in x bracing? Or is this fine? Also should I try to "voice" the top by scalloping the braces.

I purchased a new bridge plate. Since the top was coming off and I was going to patch the holes in the spruce it made sense to me to put in a new bridge plate. Its indian rosewood from LMI.
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MaineGeezer
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Joined: Wed Aug 13, 2014 12:14 pm

Re: First Project - A rebuild

Post by MaineGeezer »

That style of top bracing is called ladder bracing. It is common on inexpensive guitars. It works, but X bracing doe does a better job and sounds better (they say). Since you're doing this project as learning experience, you may as well change it to X bracing.

I'm undertaking a similar rebuild of a 1964 Harmony Sovereign. It started as neck reset, but has sort of gotten out of hand. Anyway, I'm replacing the ladder bracing with X bracing.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
Diane Kauffmds
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Joined: Sun Mar 09, 2014 8:13 pm

Re: First Project - A rebuild

Post by Diane Kauffmds »

The center back of most guitars, has flat quarter sawn spruce called a zipper. It's 3/4" to 7/8" wide, and cut across the grain, so that the the grain runs perpendicular to the grain of the back wood. I've included a photo of a Panama rosewood build that I'm doing. Enlarge the photo and look at the zipper. You don't usually see this on tops, but it looks like the center top seam is coming apart. It needs moisture.

The end block can be glued and clamped, using CA glue (superglue). This is the ONLY time that something like a two part epoxy can be used for a repair. As Mainegeezer said, guitars are made to be taken apart. Obviously, no one wants a cracked neck or tail block. You can replace that tail block, but you'd have to unglue the sides and back. Unless it's in a mold, I think I'd just fix the crack.

I'm going to take another look at the crack in the side for you.

I have noticed that most of the cracks, as well as the center top seam, appear to be open. Before you attempt to fix any of this, hydrate the guitar. Put the box into a large plastic trash bag, along with a couple of plastic containers. Punch holes in the tops, and place damp wet sponges in the containers. Make them wet, but squeeze them out. They shouldn't be dripping. Close the bag. Check it daily and rewet the sponges as necessary. You should see those cracks narrow, and hopefully close completely. I think you'll be surprised at how much water the box draws from the sponges. The repairs will be much better with closed cracks/separations.
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Last edited by Diane Kauffmds on Sat Dec 09, 2017 7:48 pm, edited 4 times in total.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
Diane Kauffmds
Posts: 3246
Joined: Sun Mar 09, 2014 8:13 pm

Re: First Project - A rebuild

Post by Diane Kauffmds »

Okeedokey. I took another look at the tail block and cracked side. I would simply use superglue on the tail block and clamp that puppy good.

I'm trying to figure out that side crack. Are those laminate sides? Does the crack go through to the surface? The crack is across the grain, which is unusual. However, this is how you fix it. You need some thin wood, less than 1mm thick. You could put a strut there. I'd put one on the opposite side, at the same distance from the tail block. I think in this instance you should use wood, not cloth or ribbon, given the direction of the crack.

Use your cold hide glue, and evenly glue the struts, top to bottom, between the kerfing, in place on the inside. I use strong rare earth magnets, inside and out, to "clamp" this. You could use f clamps, if you use wood as a caul, placed over the repair, inside and out. I would first put some wax paper between them, otherwise you could end up with them glued to your repair.

If the crack goes through the guitar, you'll want to flood the outside crack with ca glue.

You need to hydrate that guitar before repairing the cracks.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
Diane Kauffmds
Posts: 3246
Joined: Sun Mar 09, 2014 8:13 pm

Re: First Project - A rebuild

Post by Diane Kauffmds »

Okay, I think I've figured out that weird crack. It's not straight through is it?. It looks like it's "peeled" for want of a better word, like wood that's been bent where there's figure. A strut is the fix. If it goes through the side, once the strut is glued and you take off the clamp, put CA glue along it. Once dry, lightly sand. I doubt you'll see it.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
Keith Reilly
Posts: 54
Joined: Wed Dec 06, 2017 10:58 pm

Re: First Project - A rebuild

Post by Keith Reilly »

The center back of most guitars, has flat quarter sawn spruce called a zipper. It's 3/4" to 7/8" wide, and cut across the grain, so that the the grain runs perpendicular to the grain of the back wood.
My guitar back does not have this. Do i need to put one in?

I do see the pieces you are talking about in the top that are acting like a zipper. Those are plywood and I was going to take them out and replace with spruce. But then I decided to take MaineGeezer's recommendation and replace this bracing with x bracing. Would I need the zipper in the top then?

As far as putting moisture in the guitar how will I know when to stop? I'll start that process tomorrow. The thing has never been humidified since i've had it 20+ years. By box do you mean the sides and back that are still together? Should I also do the same with the top?

As far as the crack goes I"m including a close up that is higher resolution. It does not go through the side. I didn't know it was cracked until I took the top off.

The center seam opened even more after I took the top off. I'll include a before and after picture of that as well. Good to know about the humidity thing. Was just going to go ahead and start making repairs.
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Diane Kauffmds
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Re: First Project - A rebuild

Post by Diane Kauffmds »

Keith Reilly wrote:
The center back of most guitars, has flat quarter sawn spruce called a zipper. It's 3/4" to 7/8" wide, and cut across the grain, so that the the grain runs perpendicular to the grain of the back wood.
My guitar back does not have this. Do i need to put one in?

I do see the pieces you are talking about in the top that are acting like a zipper. Those are plywood and I was going to take them out and replace with spruce. But then I decided to take MaineGeezer's recommendation and replace this bracing with x bracing. Would I need the zipper in the top then?

As far as putting moisture in the guitar how will I know when to stop? I'll start that process tomorrow. The thing has never been humidified since i've had it 20+ years. By box do you mean the sides and back that are still together? Should I also do the same with the top?

As far as the crack goes I"m including a close up that is higher resolution. It does not go through the side. I didn't know it was cracked until I took the top off.

The center seam opened even more after I took the top off. I'll include a before and after picture of that as well. Good to know about the humidity thing. Was just going to go ahead and start making repairs.
The top doesn't need a zipper. If you're back is a bookmatched set, it certainly wouldn't hurt to install one. If it's a single piece, I wouldn't worry about it

The box is the sound box. It's the assembled top, back, and sides. Humidify it until the cracks close, or they quit responding to the humidity. Include the top with the rest of the box. It can take a day or two, or two weeks. Check them daily. Unfortunately, those are probably old cracks, esp. the top separation. The best of all worlds would be a complete closure of the center seam. Then all you do is work some glue in there, and put a cleat. Don't use CA glue on spruce. It discolors it. Use hide glue, or original titebond.

If it doesn't completely close, then you'll have to make a thin splint of spruce to fit into the opening. Patience is a virtue. Try to make one that fits neatly into the opening. Don't force it, otherwise it'll create a wedge that will open the seam more. When you're satisfied with the splint, glue it in place.

This is an advanced repair. Since you're replacing the bracing, you could choose to replace the top entirely. But, I think this top is viable. Btw, try not to touch the cracks. Cracks that are fixed can almost disappear. It depends on the amount of dirt that's worked its way into the crack. Oil from your hands adds to the dirt.

Just add struts to the sides. This will take care of that side crack. I like to put them equally on each side. I'm going to be putting struts into my Panama rosewood build in a few minutes. I'll put a photo of it in this thread for you, when I'm done. You can see the placement. Struts prevent longitudinal cracks from spreading, should one appear. A piece of thin wood, running between the upper and lower kerfing, wide enough to cover that interior side crack, will fix that spot easily.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
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