removing the top of a 1915 Washburn

[DMand]

So I've got a messed up 1915 Washburn flat back soundboard that I'm going to have to remove. It has cracks to glue and some warps I will steam out. I'm OK with fixing it once it's removed, but I just want to make sure that I take the top off properly (so apologies for a noob-like question, mandolins are not my primary instrument). Should I heat-gun and exacto knife the top at the lower end of binding attached to the side, or at the very inner edge of the soundboard? Thanks in advance. Dave

[jim simpson]

Can you provide more photos of your project? My experience with flat back mandolins is most of the time, the backs are already loose in places and I'll take the back off rather than the front to repair bracing. The tricky parts are usually separating the neck block area (and tail block to some extent) without damaging the plates. Old mandolins were usually built using hide glue. Often they will pop apart with a thin blade palet knife. A cup of hot water and an eye dropper will allow some control in starting a separation, a technique taught to me by an old violin repair man. Do not uses a heat gun!

[sunburst]

...Should I heat-gun and exacto knife the top at the lower end of binding attached to the side, or at the very inner edge of the soundboard?

The lower edge of the side binding is almost surely not lined up with the top-to-rim joint, but instead will lower (toward the back) than the top-to-rim joint.
You could use a technique that I've seen used on more than one Martin guitar. Saw through the rim along the edge of the binding with a thin razor saw blade, do the repairs and then glue the top back to the rim. You will still have to deal with the head and tail block glue joints.
If you feel really lucky you might be able to remove the binding and expose the top-to-rim joint. Then removing the top is pretty straightforward.

[DMand]

Can you provide more photos of your project? My experience with flat back mandolins is most of the time, the backs are already loose in places and I'll take the back off rather than the front to repair bracing. The tricky parts are usually separating the neck block area (and tail block to some extent) without damaging the plates. Old mandolins were usually built using hide glue. Often they will pop apart with a thin blade palet knife. A cup of hot water and an eye dropper will allow some control in starting a separation, a technique taught to me by an old violin repair man. Do not uses a heat gun!

I’m going to look at this again. The problem for me is the top has some warps I’m going to have to reshape and cracks I have to glue. I thought it would be easier to remove then top but maybe not. Let you know. Thanks!

[rcc56]

I also prefer to open fretted instruments from the back.
Violins are built to be opened from the top, and are easier to open than guitars and mandolins.
Violin tops are usually glued with a fairly weak solution of hide glue, and can generally be opened with a palette knife and perhaps an occasional drop of alcohol [do not use pure alcohol on instruments finished with spirit varnish].

I don't know if there is a "right" way to open a fretted instrument. It takes a whole lot of care, and an equal amount of luck.
Work extra slowly-- budget at least a whole afternoon to open the instrument.

The binding joint on most fretted instruments is not in line with the back or top joint. An exception is that at least some early A model Gibson mandolins are in line. I would expect a Washburn to be out of line.

Cut or scrape through the finish at the binding line to avoid pulling away wood slivers when you remove bindings.
Braces are often mortised into the linings. You have to find a way to loosen them without tearing up the brace.

A hot knife and drops of water can be useful. Maybe a little alcohol at the neck and tail blocks, but don't get any on the finish.

Wait until the rest of the instrument is open before you go to work at the blocks. I try to work from the inside out as much as possible at the blocks.
Sometimes you have to work from the wide part of the instrument to the narrow part, sometimes not.

If you hit a problem spot, cease and desist. Try a drop or two of isopropyl alcohol, wipe it off the finish immediately, let it soak in, then try the hot knife.
If it's still stubborn, repeat, or try the saw.

The last instrument I opened was a 1920 Martin guitar, and there were problems. The binding came off clean, but not all of the back wanted to come open. I wish I had used a razor saw at a couple of spots.

For those who doubt the long term integrity of hide glue, it can be tough as nails and solid as a rock after well over a hundred years.
I would not use a heat gun.

Good luck. If you can open it without cracking the plate or losing a shard of wood, nothing happens that doesn't require any major damage control, and you don't have to reduce the height of the sides more than half a millimeter when you reassemble the instrument, you've done a wonderful job.

[ProfChris]

One thought to add - whether you remove top or back, there's a good chance that the sides will move around, so getting them to line up again is a challenge. I've seen jigs to hold them in place, using machine screws to press blocks against the sides at critical places. Worth considering this beforehand, it's too late if everything distorts!

[rcc56]

You can make a temporary mold out of a piece of rigid insulation board.

[Ginridge]

I have worked on quite a few Washburn guitars and mandolins ober the years and I can concur that the lower edge of the side binding is definitely NOT in line with the top-to-rim joint. I recently purchased a very old (possibly 1894 or so) Washburn Auditorium sized guitar which had previously been "repaired" by cutting just below the binding. It had been cut right through the kerfing and the thin section of the side that remained after the binding slot was cut. It was glued back together with Tite Bond by simply re-gluing the split kerfing together; a very poor fit to say the least. I was able to remove the back by taking off and saving the binding, then gently heating and separating the original back/side hide glue seam. When I re-assemble the guitar, I will remove all the damaged kerfing and replace it with new.

I'd need more pics to have a full understanding of your particular situation, but I'd agree with those that suggest removing the back, not to the top. I assume this has back binding, though I can't tell for sure from the pic. If that's the case, I would carefully remove it and re-use if when I complete the repair. Gently heat, moisture, patience and a razor blade. If carefully done, this almost always works for me and it keeps the instrument that much more original. Once the binding is removed, repeat the moisture and gentle heat to separate the top/side glue joint. If there is a place where it appears to be loose, start there and work your way gently around the entire back taking particular care with the neck and heel blocks. I frequently get that far, then repeatedly add moisture and heat to loosen the old glue.

I like the idea of a temporary mold using rigid insolation... I'll have to try that.

A warped top suggests loose braces; an easy fix with the back removed. The access will also make it easier to glue up any splits or to splint large splits if needed.

[Richard500]

Don’t know if I’ve posted this before: Another odd thing from a tag sale. It’s a 45 Watt iron with an attachment for safety razor blades. Assume it is sold as a paint scraper of some sort. Mfg is MHT Model 400. Since it’s from Taiwan, can’t be too antique. Haven’t used it on a mandolin - yet.

[pops1]

Don’t know if I’ve posted this before: Another odd thing from a tag sale. It’s a 45 Watt iron with an attachment for safety razor blades. Assume it is sold as a paint scraper of some sort. Mfg is MHT Model 400. Since it’s from Taiwan, can’t be too antique. Haven’t used it on a mandolin - yet.

Now that is a handy tool, wonder where i can get one?

[jim simpson]

It is cool, I just watched this youtube video of a mod to make a soldering gun with an exacto blade - same idea and perhaps more versatile?

https://www.youtube.com/watch?v=IpZJrMWLSiM

Or just buy this:

https://www.amazon.com/WINONS-Temper.../dp/B098JNV5VS

[Tavy]

It is cool, I just watched this youtube video of a mod to make a soldering gun with an exacto blade - same idea and perhaps more versatile?

https://www.youtube.com/watch?v=IpZJrMWLSiM

Or just buy this:

https://www.amazon.com/WINONS-Temper.../dp/B098JNV5VS

Wow, I have what looks like that exact iron, but without the blade attachment!