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Project: 1935 Martin mandola
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=12444		 Page 1 of 1
Author:  Dennis E. [ Wed Jun 13, 2007 10:51 am ]
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Just for change of pace, here's a look at one of my upcoming projects: It's a Martin mandola picked up from an estate sale last weekend for $50. According to the serial number it dates to 1935. I know these aren't worth much, but that isn't always the point when I let one of these orphaned critters follow me home.



It has a spruce top and mahogany back and sides. The scale is 15? inches, a bit shorter than the contemporary mandolas I've seen. Judging from the scratches on the front and back, someone with a taste for fancy buttons owned it. My overall objective is to make this old beast sing again. I don't plan to do much of anything about the cosmetics except clean and polish it.

My first inspection reveals no problems with the braces, but there are some nasty side cracks on the treble side, upper bout. The cracks are tight, and there are four of them. They run most of the length of the upper bout. There's also a cross-grain crack between two of them. It's not quite all the way through, but you can see the fibers lifting along the edge of it on the inside. I imagine this is the point of impact for the event that caused the cracks in the first place.

I'm thinking of installing a thin mahogany side reinforcement brace below the cracks before I do anything else. After that I'm thinking of installing a pre-bent, very thin mahogany patch over the entire area behind the cracks. Is this too heavy handed? Or should I just glue the cracks and forget about it?

What would you do?

(I've posted a page with bigger pix here)
Author:  Dave White [ Wed Jun 13, 2007 5:52 pm ]
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Dennis,

That looks to be a very interesting project and I'd love to see how it works out. I'll let the repair experts weigh in with the best potential fix methods.
Author:  Sam Price [ Wed Jun 13, 2007 6:02 pm ]
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Wow!! A friend bought me a 108 year old Italian bowlback from Ebay; at first I was very keen to repair it; but at the moment, I'm obsessed with buildng new instruments

Be sure to post finished pics as well!!
Author:  Todd Rose [ Wed Jun 13, 2007 8:55 pm ]
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Dennis, what a great find!!! Man, I'm envious. That will be such a fun instrument to play.

As for repairing the side cracks, I'm a novice repair person myself, so I'm very interested to hear what some experienced repair people would suggest. My first thought, though, is that patching the side from the inside sounds like a good idea. Since it's not an instrument with particularly great historical value, or "vintage" dollar value, it would seem that you don't need to worry much about keeping it "original". Moreover, I wouldn't think that adding wood to the sides like that would have a noticeable effect on the sound. So, giving it the structural stability sounds smart to me.

Author:  robertD [ Wed Jun 13, 2007 9:51 pm ]
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Dennis, that is so cool!

I would love to be in your position right now!

To bring back to life, an old forgotten instrument, and make it sing again!

What a feeling that will be, when that first note is heard!

Sorry, I can’t be of any help, but, I sure can say that it’s going to be a fun project!

Robert
Author:  Todd Rose [ Thu Jun 14, 2007 9:22 pm ]
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Dennis, I hope you don't mind me giving this a bump. I'd really like to hear what our experienced repair people, such as the noble and mighty Evan Gluck (just to name one of several noble and mighty repair people who honor us with their presence on this forum), might have to say about this.
Author:  Evan Gluck [ Thu Jun 14, 2007 10:34 pm ]
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Wow Todd there have been so many adjectives to describe me
but I must say noble and mighty are new ones
Anyway I would use a bit of plexi glass and 2 magnets to make sure the cracks are level and a squeeze with some quik grip mini bar clamps. I probably would not reinforce it if it was solid. Since its a mandola I would not expect it to rest on the knee like a guitar so the odds are small it would be damaged again unless deliberate.
Hope this helps and have fun with it.
Best, Evan
Author:  Shane Neifer [ Sat Jun 16, 2007 3:19 am ]
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Bump! Evan's advice is always great!, hoping that David Collins will chime in as well.
Author:  crazymanmichael [ Sat Jun 16, 2007 3:31 pm ]
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first concentrate on getting the cracks glued closed and and flush.

given the size of the soundhole anything such as you propose would probably require removing the back to be able to secure that sort of reinforcement. studding with the tuner type crack repair devices is probably just as good and would not require the back to be removed and is probably thus preferable

Author:  Shawn [ Sat Jun 16, 2007 4:33 pm ]
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I collect historic instruments so I am always having to deal with instruments in various stages of neglect and/or disrepair so even though this instrument may not have a high book value, it is still generally best to follow sensitive restoration practices. You are correct to not refish or do anything more than just clean and polish it (gently).

The rule of thumb as far as preserving the original state of an instrument is to make sure that any of the repairs or additions of new wood be reversible. This usually means using hot hide glue or fish glue as these are water soluble.

If the repair can be made without the addition of any new wood and with repair the instrument will still be structurally intact, that is better. In this case it sounds like the cracks are partially through but still intact so closing the cracks is the best way to go.

One tip I picked up from Frank Ford's site is that when closing cracks you want to make sure to get out all of the dirt, polish and whatever else is in the crack. There is a section on it on Frank Ford's site and I think he also wrote GAL articles on the subject...what I remember offhand is that he uses distilled water in a squeeze bottle to flush the crack of crud and that when getting the cracks to close will also use moisture to close a crack if it opened by lack of humidity and dryness. The rest is as was mentioned using magnets to help to close the crack and draw the wood tight.

Hide glue also has the benefit of leaving as clear a glueline as possible.

In the end because you did not pay alot of it, being able to bring it back to a playable state is all good as it should be a blast to play.

Good Luck.
Author:  Todd Rose [ Sun Jun 17, 2007 1:59 am ]
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[QUOTE=crazymanmichael] studding with the tuner type crack repair devices
[/QUOTE]

Your Craziness , would you kindly explain what this means to us clueless ones?      

Thanks!
Author:  Colin S [ Sun Jun 17, 2007 2:25 am ]
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Shawn gives sage advice. I also undertake repairs on historic instruments. Golden rule #1 repairs should be reversible, so hidefish glue for the cracks as shawn says. Any replacement wood used should be of the same species and grain orientation as the original, but again must be able to be removed and be obviously repaced.(don't try and disguise a new bit of wood by making it dirty as used to be done). I wouldn't try and use any internal patches, and certainly no refinishing, clean only. I know it's not a valuable instrument but it has lasted more than 70 years and should be treated with due respect. Who knows what future generations will value.

Colin

Colin
Author:  Colin S [ Sun Jun 17, 2007 2:27 am ]
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If I had an edit button I'd put a / between hide and fish! But as I haven't got one use your imagination OK.

I won't sign this as I already sigened the last one twice!
Author:  Arnt Rian [ Mon Jun 18, 2007 1:18 am ]
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[QUOTE=Colin S] so hidefish glue for the cracks [/QUOTE]

Rats! For a minute there a thought Colin was going to tell us about a very interesting new glue...
Author:  WaddyThomson [ Mon Jun 18, 2007 1:21 am ]
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That would be the fish glue you can't ever find when you need it. 
Author:  crazymanmichael [ Mon Jun 18, 2007 1:48 am ]
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todd, the device i refer to is a just slot head single tuning machine mounted on one side of a small, u-shaped wooden block with the post spanning the u. it is used with a very fine gauge string, such as a .008" 12 string g octave, to pull the internal stud tight against the inside of the crack. it requires a tiny hole to be drilled through the crack using a numbered drill, the string is threaded into the sound box, fished out through the sound hole, the stud placed on the string and the ball tied on to hold the stud. thread the string onto the tuner post, pull it so there is just a little slack remaining, and wind the stud tight up on the crack with the tuner.

i first learned about them back in the 60's or 70's, probably from irving sloane's or don teeter's repair books. i'm not sure which.

i'll be going into town to the workshop today for the first time in a week as i've been somewhat immobile following some minor surgery. i'll try to take a photo of one and post it tonight.
Author:  Todd Rose [ Mon Jun 18, 2007 3:00 am ]
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Thanks, Michael. A photo would be great if you get the chance. I'll look in my Teeter and Sloane books also.
Author:  Evan Gluck [ Mon Jun 18, 2007 3:19 am ]
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Its in Teeter's 1 st book I think. I built a couple in very little time. For most of my uses magnets have replaced them but when you need that kind of external pull I am glad I have them.
Best, Evan
Author:  crazymanmichael [ Mon Jun 18, 2007 1:41 pm ]
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todd, i hope these come out ok; this is my first attempt(with the help of sweetie, swmbo) at putting photos on the forum. as will be apparent i am also not much of a photographer, at least not with a digital camera. my old nikon f was more my style.





hope they are helpful. you need the flat bottom as well as the round bottom to get at both the convex and concave curves.
Author:  Todd Rose [ Tue Jun 19, 2007 4:43 am ]
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Thanks, Michael. Got it. Pretty cool little devices.

Though I didn't start this thread, I want to add my thanks to Evan, Shawn, and Colin as well. I'm glad you corrected my inexperienced suggestion to add the patch, and I appreciate what I learn from you guys.
Author:  Dennis E. [ Tue Jun 19, 2007 5:35 am ]
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Gosh guys, thanks for the advice!

The cracks are actually very tight. The difficulty of getting glue into the cracks is one of the reasons I was thinking of adding an internal patch. But I think you're right — it's not needed. I'm still thinking of putting in a side reinforcement so the splits won't travel down the side while I manipulate the cracks to get the glue in them.

The tuner clamps are a completely new idea for me. Definitely one for the bag of tricks.

I hadn't thought of fish glue as I haven't used it before, but if I remember correctly, it's a lot like HHG, but gives a little more working time.

So, my current plan is glue the cracks with fish glue, skip the patch, clean, string and play!

I have some magnets ordered to use for clamping. I've been thinking of trying them and this project is a perfect excuse.

Evan ... Todd may have given you a new nickname: The Mighty Gluck! Now that's got a really nice ring to it.
Author:  Evan Gluck [ Tue Jun 19, 2007 6:43 am ]
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Sounds like a good plan Dennis, as for "The Mighty Gluck"
The next time I fall down I can say "Oh how the mighty have fallen"
Have fun!, Evan
Author:  Kahle [ Tue Jun 19, 2007 4:44 pm ]
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Cool project! I'd love to find deals like that. Guess I need to frequent the flea market/garage sale circuit more often. Good Luck!
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