Chinese Cello/Bass Fingerboards

DallasStrings · #1 04-28-2009, 02:03 PM

Anyone have a magic trick for not completely destroying a neck and fingerboard trying to separate them on chinese instruments? I'm screaming mad that I have cracked the neck and fingerboard in countless places in a futile attempt at separating them. This has happened to me half a dozen times now..

Doug D · #2 04-28-2009, 02:22 PM

silicone heating blanket? with maybe a hot knife...?

http://www.lmii.com/CartTwo/thirdpro...epair+Blankets

or just choose to sacrifice the board.

DallasStrings · #3 04-28-2009, 02:35 PM

I use a hot knife and the Weisshaar/Shipman method of removal. This works great on a better quality instrument but the wood is softer than the glue on some of these student workhorses..

I was disappointed to find that after wetting the surface, they are actually using hide glue and not something stronger.. I thought I might have been in an uphill battle with an epoxy/gorilla glue equivelent. This isn't the case but I do believe that the hide glue they're using is far more than 192 gram test..

Thanks Doug I'll give one of those blankets a try. They're certainly cheaper than a new fingerboard or worse a new neck..

Doug D · #4 04-28-2009, 03:09 PM

I'm guessing that those blankets should get hot enough to scorch the wood, not sure.

let me know...

kurt ratering · #5 04-29-2009, 05:58 AM

a little alcohol might help...in the joint, not the luthier

DallasStrings · #6 04-29-2009, 12:00 PM

Quote:

Originally Posted by kurt ratering

a little alcohol might help...in the joint, not the luthier

Bah, you got my hopes up..

DallasStrings · #7 05-12-2009, 07:23 AM

I have a needle bottle with alcohol that I use to help when the glue is being stubborn. It usually does the trick but not here..

I got the repair blankets. I tried the little one on a violin fingerboard and it worked quite well! The fingerboard sort of peeled off. It was disorienting not listening to the crackling of the glue giving way, but the two pieces separated nicely without any splitting.

The small blanket was 1 in. x 5 in. and used 25 watts. I plugged it in direct without any sort of regulator. It didn't heat up excessively but I do worry about the bigger one. It's 2 in. x 2 ft and 190 watts. I fear it might heat up a little too quickly and get too hot. I might need to get the regulator or just plug/unplug.

I think this is a great approach! Thanks for the idea Doug!

Ken McKay · #8 05-13-2009, 02:01 AM

You can use a router speed regulator.

smg_luthier · #9 05-13-2009, 01:15 PM

i have more experience with these pieces than i care to remember.
first, i need to ask, and you need to ask yourself, does the fingerboard really need to be removed? is it unworkable ?
are you removing it for a repair when you could possibly work around it, or drill through it and plug it after ?
if it must come off, i have a couple of methods that may work
forget about heating blankets & alcohol. that's like trying to pee on a forest fire.
i know this may seem redundant or pointless, but i always try the simplest thing first.

method 1) hold the palm of your left hand on the back of the neck, about midway, and place your right hand, palm down, making kind of a "spider" with your fingertips, on the belly of the beast, between the belly & the fingerboard, about midway between the heel of the neck & the end of the fingerboard.
now, simultaneously, push up with your right hand, using fingers, wrist, & forearm, while pushing the neck into the heel with your left hand, using an equally oposing force, so as not to pry the neck out of the mortise, or to break the neck.
in most cases, this will break the glue joint, and then you can work in knives and/or solvents as necesarry.

metod 2) sometimes, actually most times, good to use this in conjunction with method 1.
get a good chisel, at least 1" wide, sharpened @ about a 35' angle, with no micro bevel. very carefully, find the joint, BEHIND the nut, where the nut is glued to the neck. position the chisel, bevel side down (towards the neck) and rap it relly good with a nice heavy mallet. the nut should break loose after 1 or 2, maybe 3 good strikes. if you break the nut, no big deal. its a nut.
if you mar the neck slightly, it will only be behind the nut, in the pegbox. use your touch up pens.
once the nut is removed, carefully position the chisel, again, bevel side down, at the seam where the fingerboard meets the neck, where the nut would join the neck & fingerboard, and rap the chisel with your mallet. if nothing gives after 2 or 3 blows, you need to quit before causing any damage.

most likely, the fingerboards are glue on with C.A. stuff, and the only solvent that will work is acetone. unfortunately, acetone will destroy any finish except for pollyester. yes, the same stuff that is melted and drawn into a fine thread, and then woven with cotton thread to make that shirt you're wearing.

again, i think you're better off finding a way to do what you have to do without removing the fingerboard.

hope this helps. if you have any more ??s, email me:
sg914gt@comcast.net
smg.

arnoldschnitzer · #10 05-13-2009, 05:44 PM

Quote:

Originally Posted by smg_luthier

i have more experience with these pieces than i care to remember.
method 1) hold the palm of your left hand on the back of the neck, about midway, and place your right hand, palm down, making kind of a "spider" with your fingertips, on the belly of the beast, between the belly & the fingerboard, about midway between the heel of the neck & the end of the fingerboard.
now, simultaneously, push up with your right hand, using fingers, wrist, & forearm, while pushing the neck into the heel with your left hand, using an equally oposing force, so as not to pry the neck out of the mortise, or to break the neck.
in most cases, this will break the glue joint, and then you can work in knives and/or solvents as necesarry.

.

Where does one learn such butchery? Who is this person? If someone tried this technique in my shop I would whack them over the head with a mallet before they broke something!

smg_luthier · #11 05-13-2009, 06:10 PM

Quote:

Originally Posted by arnoldschnitzer

Where does one learn such butchery? Who is this person? If someone tried this technique in my shop I would whack them over the head with a mallet before they broke something!

i am the "butcher" who is trying to help someone NOT destroy any more necks than he already has.
what is your solution to the problem?
remember, we're talking POS chinese factory instruments, not FINE instruments.
well, i want to hear your solution.
smg.

arnoldschnitzer · #12 05-13-2009, 06:37 PM

Quote:

Originally Posted by smg_luthier

what is your solution to the problem?

Heat, sharp tools, solvent and patience.

smg_luthier · #13 05-13-2009, 07:01 PM

not very specific.
teach me, master.
i feel like we're about to hijack a thread, which was not my intent.
i was looking to help someone who was having difficulty in an area with wich i have had far too much experience.
smg.

Eric Rene Roy · #14 05-13-2009, 07:08 PM

wow...all I'm going to say is wow.

smg_luthier · #15 05-13-2009, 07:59 PM

sorry,
i misspelled "which"
smg.

Tomasito · #16 05-13-2009, 08:29 PM

And "smug"? :-p

Don Higdon · #17 05-13-2009, 08:34 PM

Quote:

Originally Posted by smg_luthier

not very specific.
teach me, master.

How about filling out your profile?

smg_luthier · #18 05-13-2009, 08:50 PM

hey don,
i just found this board a couple of hours ago, and i still haven't figured out all of that stuff yet.
cut me some slack.
this thread is about someone having trouble getting a fingerboard off.
what's your technique?
smg.

Don Higdon · #19 05-13-2009, 09:00 PM

Quote:

Originally Posted by smg_luthier

hey don,
i just found this board a couple of hours ago, and i still haven't figured out all of that stuff yet.
cut me some slack.
this thread is about someone having trouble getting a fingerboard off.
what's your technique?
smg.

My technique is to use one of the most knowledgeable and highly regarded luthiers in the United States.

Jake deVilliers · #20 05-13-2009, 09:09 PM

Quote:

Originally Posted by smg_luthier

hey don,
i just found this board a couple of hours ago, and i still haven't figured out all of that stuff yet.
cut me some slack.

Hey SMUG, you seem to have had plenty of time to alienate many of us, from highly respected double bass builders and repairmen to venerable double bass players. You have had time to admonish our friends and neighbours for even thinking of re-finishing an instrument and laid out for us an exceedingly brutal way of removing fingerboards.

You don't need to fill in your Profile for us to see who you are; its for you to try to establish some credibility.