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I'm looking for an opinion. This top split due to low humidity. I humidified it and this is as closed as I can get it. I worked in a little Titebond into it and it is stable. I have been wondering if I could make it look a little better with a spline. As it is stable it would be a cosmetic attempt. Would you leave it alone now, or put a spline in it?

For context, as I am in quarantine, I don't have much else to do

Thanks,
GS

If you've worked titebond into it then the only way you could get a spline in there is to remove all the titebond. Anything you glue in there won't stick with the previous glue.

If you feel like removing the titebond, then I'd say go for a spline. But when you glue in the spline I'd recommend old brown glue or hot hide glue. Also have you cleated it?

Sure, I used Titebond original, so getting it out will be pretty easy. It is closed tighter on the inside. I could cleat it. Hide grosses me out. I haven't tried Old Brown, what is the benefit over TB? Thanks.

GS

I would definitely cleat it given it's size. No need for anything oversized just enough to hold it closed.

On the Titebond vs. hide glue thing. Titebond outside of the original can create alot of problems for when a joint needs to be worked on. Hide glue has a *very* high adhesive strength which makes it very strong and reliable. Titebond has a good adhesive strength but it does swell up a bit to fill gaps. Hide glue allows the guitar to be worked on infinitely since it is easier to remove joints with hide glue (usually) than it is with things like PVA glue or epoxy. Hide glue also doesn't creep (move over time) and titebond does.

So for your crack repair, since it's in an area of the guitar where it gets alot of stress, you don't want a glue that will let the spline wiggle a little as the top shrinks and expands over time. Hide glue will get you a solid repair and if you have to undo it in the future it's not going to be difficult.

Old brown glue is formulated hide glue. It's exactly the same composition except it's had some urea added to give it a longer open time. Instead of the 30 second open time with hide you get maybe a half hour to an hour before it sets. It's basically just hide glue with a longer open time. I've used it for years now with a high level of success. Technically you don't even have to warm it up but it does help it flow better into a tight crack. Give it a shot, you might be surprised.

The big thing with hide glue is that it is *imperative* that you have a tight fitting glue surface, unlike titebond it does not fill gaps at all. So for your crack, make sure your spline is a tight fight with no gaps the length of the crack.

Most glues will only work if you have perfect flush contact and even then add clamping pressure. So while it might be stable now, dry that out again and it will open right back up. At this point if it were me I would rout a thin line right down the center of the crack and inlay a matching piece of spruce and cleat it from the inside. You might even want to lower the RH for doing that too. Get it stable at 45RH and then do the spline. Looks like you will need to remove the bridge too.

This all makes sense, thanks. Looking at it up close it seems to be reopening. and the RH is normal, so spline & cleat it is. It looks like the bridge is a little loose in the back so it will have to come off anyway. Thanks everyone.

GS