Jump to content
Maestronet Forums

Hide Gue, WWII, and the Disappearing Cheval


PASEWICZ
 Share

Recommended Posts

David Burgess Wrote

I've seen hot glue alone hold up for a good long time if the joint was excellent and the glue was right. The only problem is that the neck needs to be kept varnished so perspiration doesn't attack the joint.

However, Jerry Pasewicz was giving a bow repair presentation to my group last week. He'd run into a guy who used to build the wooden WWII PT boats. When he asked what type of glue was used, the guy said,

"Regular hot glue".

By this, he meant the same stuff that we all use. smile.gif

I'll let Jerry come on and talk more about this if he wants to.

Sometimes you can get people to give information to a small group, but it doesn't necessarily mean that they want to share it with the whole world.

O.K. here it is. I am preparing an article about this very topic, but seeing how it is just our little group I will share.

First a little background. A cheval, for those of you that do not know, is a piece of ebony added to a frog, usually at the underslide, to replace missing material. This is traditionally done by removing the underslide, pins, and eyelet--planing away the surface receiving the new wood--gluing the replacement piece--and the refitting the underslide and shaping the frog sides. I was never very happy with this technique because the joint was always visible, and always a straight line. About 12 years ago I started to do rounded chevals. Borrowing a page from the instrument restorers playbook, a rounded cheval has a feather edge to better hide the joint. To do this the frog is milled with a ball end mill, an ebony dowel is machined to the same radius, and after lining up the medullary rays the new wood is glued and shaped like before. This technique was better, but because of the water insoluble glues that were available the joint was eventually noticeable as the joint buffed with time.

Cut to 2002

I had a nice gentleman bring in his bass to reglue the fingerboard. After a few days he came to pick it up and asked me what kind of glue we used. I replied hot hide glue. He responded "Really? we used that to put PT boats together during the war." With a confused look, I turned to him and asked how that was possible being as it is water soluble. He said "Not after you fumigate it with formaldehyde" At this point the heavens opened up and I could here the singing of angels. Now by using the hot glue that leaves no glue line, we can do restorations that are not susceptible to sweat and are invisible.

Needless to say we no longer turn out the lights and lock the door when we see a bass player coming up the stairs. (No e-mails please I am a recovering bassist myself) Pictures attached.

post-25008-1216158252_thumb.jpg

post-25008-1216158347_thumb.jpg

post-25008-1216158408_thumb.jpg

post-25008-1216158478_thumb.jpg

post-25008-1216155580_thumb.jpg

Link to comment
Share on other sites

  • Replies 58
  • Created
  • Last Reply

Top Posters In This Topic

That's really great! But would you please be a bit more specific? You glue the piece with hide glue, let it dry and then fumigate the glued piece?

I have since talked to my glue guy. He told me that you can fumigate afterward, paint it on before, paint it on afterward or even paint one part with formaldehyde and the other with glue. We have done all of the above and have never had one water soluble.

Link to comment
Share on other sites

I have since talked to my glue guy. He told me that you can fumigate afterward, paint it on before, paint it on afterward or even paint one part with formaldehyde and the other with glue. We have done all of the above and have never had one water soluble.

I think a good question is: will the formaldehyde have the same effect on other protein based things we use-- like a ground or sealer?

Link to comment
Share on other sites

Thanks! Do you thing it's a good idea for central joints on backs and bellies (on our new instruments, of course)?

I have never used it on instruments. As a restorer, I am just not sure what it will do to the varnish. Someday I would like to experiment. How about the upper right bout seam that gets all the sweat punishment?

Link to comment
Share on other sites

From http://www.zetatalk.com/shelter/tshlx010.htm

"To make hide glue water resistant just add tannic acid, formalin, or formaldehyde. These can be added either to the surface to be glued, to the glue surface, or can be mixed with the glue. Tannic acid can be extracted from tree bark, especially oak. Old literature reports that hide glue can be waterproofed by adding 40% linseed oil, but tung oil works slightly better, however the results are only mildly water resistant. (Formaldehyde occur naturally in woodsmoke so if the glued surface is held above a smoking woodfire the treatment is applied at the same time as it is dried by the heat.)"

Maybe that's why Vuillaume was cooking his fiddles! :)

Link to comment
Share on other sites

Yes, but restorers are quite conservative and the "untreated" hide glue is easily removed from the wood, that's why they love hide glue -and hate other types of glue.

There is quite a good article by Charles Beare called "History of Violin Restoration", it was published on the minutes of the 1995 Dartington Conference (I think it's out of print but I can e.mail it to you, if you want) he talks about new things (such as Araldite to glue bow tips) that eventually turned out bad... But we have to move on, I think.

Link to comment
Share on other sites

what are you thoughts about "liquid hide glue" such a s frankln....

the glue is kept in a liquid state via formalydhyde...and when dry will react to heat more so than water...

would this "nono" not be sufficient?

i have noted this reaction by using liquid hyde glue, allowing it to dry, then appying a second "wet" formaldhyde laden application...the seem when dry seems much less prone to re liquification when rubbed with a wet cloth...

Link to comment
Share on other sites

what are you thoughts about "liquid hide glue" such a s frankln....

the glue is kept in a liquid state via formalydhyde...and when dry will react to heat more so than water...

would this "nono" not be sufficient?

i have noted this reaction by using liquid hyde glue, allowing it to dry, then appying a second "wet" formaldhyde laden application...the seem when dry seems much less prone to re liquification when rubbed with a wet cloth...

I do not have any experience with franklin or other products like that. It is my gut feeling that it would be less controllable than hot glue, but I have a long history with hot glue.

Link to comment
Share on other sites

It would appear that formaldehyde is not nice stuff, so caution might be prudent.

Wiki Formaldehyde

"At concentrations above 0.1 ppm in air formaldehyde can irritate the eyes and mucous membranes, resulting in watery eyes. Formaldehyde inhaled at this concentration may cause headaches, a burning sensation in the throat, and difficulty breathing, as well as triggering or aggravating asthma symptoms."

Formaldehyde is classified as a probable human carcinogen by the U.S. Environmental Protection Agency. .... The United States Environmental Protection Agency USEPA allows no more than 0.016 ppm formaldehyde in the air in new buildings constructed for that agency."

The ppm stands for 'parts per million', so 0.1 ppm stands for 1 part per 10 million, and 0.016 ppm is the equivalent of 16 parts per billion.

Just don't want anyone thinking this stuff is nice, but then neither is war, so I guess you need to weigh the cost/benefits.

Link to comment
Share on other sites

what are you thoughts about "liquid hide glue" such a s frankln....

the glue is kept in a liquid state via formalydhyde...and when dry will react to heat more so than water...

Stay away from that stuff. It will come apart, and turn into a stringy mess when the humidity gets high enough. Almost as far from waterproof as you can get. I'm saying this from experience with instruments in Seattle (very rainy) and the Philippines.

I haven't tried Jerry's method yet, but have enough of a track record with him to put high trust his conclusions.

Link to comment
Share on other sites

It would appear that formaldehyde is not nice stuff, so caution might be prudent.

Just don't want anyone thinking this stuff is nice, but then neither is war, so I guess you need to weigh the cost/benefits.

Some guys in our business are starting to use fume hoods even for traditional cleaning solvents, like xylene.

Denatured alcohol is another possible hazard. Humankind seems to have developed a rather good relationship with ethanol, but the government insists on adding other things (methanol and more?) to make it poisonous.

Link to comment
Share on other sites

(Formaldehyde occur naturally in woodsmoke so if the glued surface is held above a smoking woodfire the treatment is applied at the same time as it is dried by the heat.)"

The nose is exquisitely sensitive to odours and I have never smelt formaldehyde in smoke. If it is there, it will be in minute amounts.

Of course, if you spend much time sniffing formaldehyde your nasal membranes will be as sensitive as a buffalo's butt.

Link to comment
Share on other sites

The nose is exquisitely sensitive to odours and I have never smelt formaldehyde in smoke. If it is there, it will be in minute amounts.

According to a number of sources, it seems it's there:

Potential adverse health effects of wood smoke

The abstract doesn't mention a concentration, however. Maybe it's within the paper. That's just one of a bunch of links that came up on a search. Seems it's in tobacco smoke as well.

Great repairs Jerry. As nice to view now as during your presentation at Oberlin.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.



×
×
  • Create New...