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Leif Luscombe Site Admin
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Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:45 am Post subject: Preparation of Hide Glue |
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I have been asked several times how properly prepare hide glue. Hide glue is the standard glue that is used by violin makers, and is prized for its organic nature and ability to be dissolved to remove a plate or other part of a violin and perform necessary repairs.
These very qualities are responsible for many of the small violin repairs - humidity and dryness can weaken the glue joints, making re-gluing of loose joints necessary. However, on the same note, the strength of a good hide glue joint is almost unmatched - it can easily be stronger than the wood itself. Spreading a thin film of hide glue on a plate of glass will damage the glass - often times breaking it (I have had clear glass baby food jars and ceramic pots broken while it is shrinking during drying).
Hide glue is available in a powder, granular or flake form. It needs to be mixed with water to dissolve.
Below is my glue set-up. This is working equipment - so is well used.
![](http://www.violins.ca/images/setup.jpg)
Last edited by Leif Luscombe on Sat Jul 12, 2008 9:37 pm; edited 3 times in total |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:46 am Post subject: |
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To heat the water for the glue I use a rather ordinary laboratory hot-plate with a dial heat adjustment on the front. An alcohol lamp, old clothes iron (upside-down), or other heat source could also work.
![](http://www.violins.ca/images/hotplate.jpg)
Last edited by Leif Luscombe on Sat Jul 12, 2008 9:37 pm; edited 1 time in total |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:46 am Post subject: |
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Hide glue is made in a double-boiler to prevent the glue from over heating or becoming scorched on the bottom. Half of a soup can or other metal container could be suitable. I use a copper glue pot from an alcohol-lamp heated glue pot assembly that I purchased some time ago.
This is the outer jacket that holds the (hot) water. The glue container is placed inside this.
![](http://www.violins.ca/images/jacket.jpg)
Last edited by Leif Luscombe on Sat Jul 12, 2008 9:38 pm; edited 1 time in total |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:47 am Post subject: |
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This is the copper pot that I use to actually hold the glue. Again, it is from the pot that I purchased. It is placed inside the water jacket (image 3) so that it is suspended in the (hot) water.
I have also used baby food jars, held with a simple wire frame to keep it from tipping. A tin can smaller than the water jacket would also be suitable.
![](http://www.violins.ca/images/pot.jpg)
Last edited by Leif Luscombe on Sat Jul 12, 2008 9:38 pm; edited 1 time in total |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:48 am Post subject: |
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The glue pot holds about 4 ounces. I usually start with about 2 ounces of cold water, and put one common teaspoon of dry glue into this. The glue should be fully dissolved while the water is cold.
![](http://www.violins.ca/images/spoon.jpg)
Last edited by Leif Luscombe on Sat Jul 12, 2008 9:39 pm; edited 1 time in total |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:48 am Post subject: |
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The glue should be heated to about 70 C, or 165 F. I must admit that I don't use a thermometer. The water in the jacket should be quite hot, but not near boiling point.
When the glue is ready, there should be a slight skin forming on the glue - but beyond this the glue will become too thick rather quickly. At this point I usually put a couple of teaspoons of water into the glue. Between the fingers it should feel oily, but not thick. If it feels watery, it is likely too thin.
If you refer to Image 1 (above), you will see a selection of tools that I use for applying the glue. A 1" brush (dollar store variety should be adequate) is great for applying glue to fingerboards, nuts, saddles, and other flat surfaces requiring glue.
I use a knife (the black handled artist's knife with the aluminum blade is one of my favorites) to apply the glue into an open edge seam (there is no way of getting a brush into these tight crevaces). Be careful to leave the metal knife blade in the hot glue for at least a few seconds before using it, or it can quickly cool and gel the glue on the knife. Once hide glue has gelled, it must not be clamed, as it will create a "cold joint" that will fail to obtain maximum strength.
For gluing cracks on the top or back of an instrument, rub the glue into the crack (this can be done with a brush or clean fingers) until it starts to come through the other side. Have appropriate clamps ready, so that it can be clamped while the glue is still warm and thin.
Make sure that all glue is wiped off of varnish, and washed from unprotected wood. Glue or glue-water can damage varnish that it is allowed to dry on. Unvarnished wood that absorbs glue or glue water will not accept stain or stained ground varnish as well as the surrounding wood, so will leave light spots under the varnish! |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:48 am Post subject: |
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Hide glue is available from http://www.violins.ca/supplies/hide_glue.html
I recommend the medium strength (315 gram strength) glue. All strengths of hide glue are capable of making a joint stronger than the wood. The major differences in the glue is the working time. The strong glue (380 gram) tacks faster, and the weaker glue (195 gram) gives more working time. In my opinion, the 315 gram gives the best of both worlds, and IS rated stronger than the weak one.
An excellent plastic glue pot, with 2 sections (one for glue, one for hot water) can be found here:
http://www.violins.ca/tools/tools_herdim.html
Dry hide glue can last indefinitely. Once the glue has been dissolved in water, however, it does not last long. In the summer (here in SW Ontario, Canada) when it is hot and humid, the glue will typically only last one day. The second day it starts to show very small pits in the surface (mold). By the third day it can be green and furry. In the cooler, winter weather it will usually last several days easily, but I usually make new glue each time to be safe (it is a small investment).
I have heard that refrigerating the glue can extend its useful life. This is probably true, though I have never found it necessary.
Ready-to-use hide glue can be obtained. It contains a preservative (formaldehyde?) that keeps it usful for up to several months. I have, however, heard of one maker who used it exclusively on his first several instruments with disastrous results - so I would not recommend its use, even if there are those who have good experience with it. Don't say I didn't warn you!
Here is an artice about hide glue that I have had around for a while, that may touch on some points that I have overlooked:
Last edited by Leif Luscombe on Sun Jul 13, 2008 8:25 am; edited 2 times in total |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:49 am Post subject: |
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PREPARING DRY GLUE FOR USE
Where really good mechanical stirring is available, powdered glue may be dissolved directly in water maintained by a steam jacket at 70-76’C. This method is commonly adopted in large scale operations but where equipment is not available to dissolve glue in this way the under mentioned procedure should be followed:-
1. Ground or powdered glue should be first soaked in clean water (not above 21’C) for 1 to 2 hours or more. The glue should be added gradually and stirred to avoid formation of lumps.
2. After soaking, heat the glue in a jacketed kettle or double boiler but do not allow the temperature to rise
Above 75’C. DO NOT BOIL or subject the glue solution to excessive heating which will cause deterioration of adhesive strength and reduce the glue to a lower grade.
3. If practicable, only make up sufficient glue for the day’s work. If more is required during the day make sure that the additional glue has been properly soaked before adding to the glue solution.
4. All glue pots and brushes should be cleaned at the end of the day’s work by scalding and use of a good disinfectant as a safeguard against bacterial infection. An infected glue need not have and objectionable
Odour, but whether odour is present or not bacteria will bring about a chemical change, and destroy the
Essential properties of the glue. |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:49 am Post subject: |
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CONCENTRATION OF THE GLUE SOLUTION
The proportion of glue to water in preparing a glue solution depends in the main upon the class of work for
Which it is required. For general jointing purposes the following percentages of glue to water will serve as
A guide:-
Russian glue 25 to 30 % of glue by weight
Match glue 30 to 33 1/3% of glue by weight
Cabinet glue 30 to 35% of glue by weight
Joiners glue 35 to 40% of glue by weight
Box glue 40 to 50% of glue by weight |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:50 am Post subject: |
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SOME "DONT’S" TO REMEMBER
Don’t buy glue on price. Buy the grade most suitable for your work.
Don’t use unclean water for soaking glue: bacteria may be present. Use clean water not above 21’C.
Don’t heat the glue solution above 75’C. To boil glue is a sure way to reduce its adhesive strength.
Don’t add dry or unsoaked glue to that already in solution.
Don’t use glue left over from the day before. There is always a risk of decomposition, particularly in
Warm climates.
Don’t use unwashed glue pots or brushes. All utensils should be cleaned by scalding and use of a disinfectant at the end of the day’s work.
Don’t guess the temperature of glue - use a thermometer. |
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Leif Luscombe Site Admin
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Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Sun Mar 25, 2007 7:50 am Post subject: |
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DESTRUCTIVE ACTION OF BACTERIA
If a fresh supply of glue is not made daily and glue posts are not thoroughly cleaned, preferably at the end of each day’s work, deterioration of adhesive strength and viscosity of the glue will often be observed. This
May also be accompanied by darkening of colour and development of an unpleasant odour.
It is now common knowledge that such effects as glue solutions. The bacteria secrete small amounts of complex substances known as enzymes, the chief function of which is to facilitate the chemical decomposition of the medium, and it is to the action of these enzymes that most of the destructive effects of
Bacterial action can be traced.
Bacteria are minute living organisms that cannot be seen with the naked eye (50 million could be placed on
A three penny piece) yet multiply so rapidly and the by-products of their life processes are so potent, there
Is no limit to the damage that may result when a glue solution becomes infected and remains favourable for
Their growth.
When conditions become unfavourable, for example, when de-composition of the media is complete, or
When glue in an uncleaned glue-pot has dried, or partially dried out, bacteria are able to form highly
Resistant "spores". In this form the organism can remain indefinitely in suspended animation ready to
Revert to a state of active growth again and infect a new supply of glue added to the uncleaned pot.
Fortunately the growth of bacteria can be prevented by the use of a dependable preservative and by
Thoroughly cleaning all glue pots and brushes with scalding water to which a reliable disinfectant has been added. The need for cleanliness in these respects cannot be over-emphasized. |
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Fiddlegem Junior Member
Joined: 25 Mar 2007 Posts: 5 Location: Bessemer Alabama
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Posted: Sun Mar 25, 2007 10:49 pm Post subject: Hide Glue |
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Good advice on the hide glue. Of all the many problems I have had in repairing and making Fiddles, hide glueing has been the most easy.
I prepare it the same way you do except for the glue pot. I bought a potpourri pot at a yard sale for 2$. The temperature heats up good to 165 deg. and no higher. I keep check of it with a thermometer stuck in the pot. What a great website! Glad to be aboard! _________________ JIM HADAWAY
Bessemer Alabama
Junior member
To carve the perfect acoustic Fiddle.????????????. |
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mapleleaf_gal Member
Joined: 24 Mar 2007 Posts: 73 Location: tucson, az
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Posted: Mon Mar 26, 2007 2:32 am Post subject: |
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that's an interresting looking glue pot.
the one i have has one bucket that heats water in it, i then set down a baby food jar into the water that contains the glue.
do you ever find your glue buring or scorching with the kind of glue pot you have? |
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Leif Luscombe Site Admin
![](http://www.violins.on.ca/images/lv45.gif)
Joined: 19 Mar 2007 Posts: 126 Location: Mount Elgin, Ontario, Canada
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Posted: Mon Mar 26, 2007 8:05 am Post subject: |
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mapleleaf_gal,
The water jacket prevents the glue from scorching.
Fiddlegem,
Glad you like the forum. Enjoy! |
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Michael Darnton Moderator
Joined: 23 Mar 2007 Posts: 1281 Location: Chicago
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Posted: Mon Mar 26, 2007 9:07 am Post subject: |
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Two thoughts on glue:
I rarely have spoiled glue, and I keep it out on my bench for weeks at a time. There are two things I do consistently, though. One is that my outer and inner pots both have lids, and I always put them on while the pot is still hot, on the theory that by doing that I can prevent anything growing that can't live at that temperature. Anything that comes in later will have to come through a double wall. The other thing I do is before I close things up, I put a bit of alcohol on the glue, to steralize anything I can. I've kept glue for longer than a month this way. When the glue is heated, I always check it by taking a drop between my fingers and pushing them together and apart until it dries, to judge the stickiness. If it's not up to par, I toss it. Bacterial degradation can be noted in two ways: it starts with tiny watery pits in the surface of the cold gel; after it's gone a ways, all of the hard glue will be less hard and have a skin of water on it. Either symptom means you should toss the stuff.
Second, I have learned that contrary to my intuition, I really do get better joints if I warm the joining surfaces of the wood up with a hair dryer or alcohol lamp before gluing. I was skeptical of this for years, but finally realized that it has a definite positive effect on centerseams. The Cremonese makers scratched diagonal scratches on their top and back seams, possibly in the mistaken opinion that this gives a mechanical bond, but more likely what it really does is limit glue squeeze-out by throwing up tiny ridges, but whatever, I do this also, and it doesn't hurt, at least. |
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