Protein Glues: What's The Difference?

Simple Chart: Temperature Vrs. Viscosity

I have spent my entire career as a woodworker using protein glues exclusively.  I have lectured and written lots of times trying to explain their advantages.  Features like reversibility, easy clean up, relatively low cost, quick or long open time as needed, bonding to itself, transparency to stains and finishes and, above all, no danger of working with toxic chemicals make it my first choice.  Protein glues are, by their very nature, organic.

Still, I get calls every day from woodworkers new to these adhesives asking simple questions.  Since the answers are generally the same I thought I would post a quick page for general information.

All protein glues have a common feature.  They react only to heat and moisture.  If you understand that concept then you can easily make them do what you want.  If you have a problem it is because you do not have both heat and moisture at the glue surface in the proper proportion.  If the viscosity is not right then check the heat and moisture ratio and adjust.  If the glue sets up too quickly or too slowly then consider the environment and make changes.

Consider that all antique furniture was made with protein glues, and craftsmen were often working in cold unheated workshops in winter.  So how did they manage to assemble furniture if the glue set up quickly.  Obviously, they were experienced and prepared for each operation by having all the clamps ready for the job.  Also, since the water component of the glue is the part which carries the heat, they realized that cold dry wood surfaces would quickly draw the water out of the glue and make it tack.  Therefore, they often used a hot wet rag to wipe the joint surface just prior to applying the glue.  The water molecules in the pores of the wood would prevent the glue from setting quickly, without actually diluting the glue strength.  I use this method for all large assembly projects where I need a longer open time.

Simply put: You add water to the glue and then heat it.  It sets by first cooling (which provides a tack) then by drying out (loosing moisture).  Protein glues are friendly molecules with lots of Hydrogen bonding sites so they easily hydrate and can be modified by a large number of other chemicals which can bond at these open Hydrogen sites.  Protein glues bond to protein glues, so an old joint with glue residue can be cleaned with a water wash and new glue will bond to the glue residue with both molecular and mechanical adhesion.  Synthetic glues do not do this.

Hide glue and Glue Pot

Hot Hide Glue (HHG)

There is one company left in America making hide glue: Milligan and Higgins.  Their website is www.Milligan1868.com.  You can find a lot of technical information there, and you can call them and speak with Jay Utzig, who is their chief chemist, with your questions.  He is always happy to talk about glue.  They sell wholesale only.

Hide glue is sold by "gram strength" which is determined at the factory by measuring the glue with a Bloom Gelometer.  Gram strength has nothing to do with the adhesive strength of the glue, so a higher or lower gram strength does not mean a stronger or weaker bond.  Gram strength is determined by how much force (in grams) it takes to depress a plunger a certain distance into the glue.  It ranges from a low of 50 grams to around 500.  Low gram strength glues take longer to set and are flexible and high gram glues set quickly and are brittle.

Woodworkers generally use gram strengths in three groups: 192, 222, and 251.  I have always used 192 and find it works well in general for all my uses.

Traditional Sheets of Protein Glue

It is available in sheets (traditional), pearl or granulated form.  I like the granulated as it has a larger surface area and is quicker to hydrate.  In a dry state, it has an unlimited shelf life.

HHG must be cooked and used hot.  You need a double boiler.  It doesn't matter if the double boiler is copper, stainless steel, porcelain or iron.  Just find one on Ebay and get to work.  Get a cheap hot plate, a common stainless steel meat thermometer and a glue brush.  Add cold water to the glue, wait about 15 minutes for it to gel and then heat it up to 140 degrees.  Do not heat above 160 degrees.  Keep a thin viscosity during use by adding water the same temperature as the glue.

I use HHG for all quick setting work, like rubbed joints, hammer veneering and assembling marquetry on an assembly board.  I used to use it on all furniture making and repair but now I use Liquid Hide glue for that work.

Liquid Hide Glue

Liquid Hide Glue (OBG)

When I was involved with an international marquetry conservation group in Paris in the mid 1990's I participated in research which modified HHG using Thiourea to extend the open time.  Since Thiourea is a carcinogen I did not want to work with it.  However, Urea is not toxic and the only difference between the two is a single Sulphur molecule.  I began to experiment with Urea to modify the glue and eventually was able to formulate a liquid protein glue which I named Old Brown Glue.

Franklin Industries was the first in America to manufacture a liquid hide glue some 80 years ago, and they sell it today under the name Titebond.  However they use ammonium rhodanate and dicyanodiamide as modifiers.  I was not happy with their product and when I used urea I found that the glue was much better in many ways.

Titebond glue does not need to be heated, and I think that is one of the problems.  OBG needs to be heated, by simply placing the bottle in a tub of hot water for a few minutes.  Hot liquid glue penetrates deeply into the cracks and pores of the wood and forms an amazing bond.  OBG actually works better than HHG for this reason.

OBG has a guaranteed shelf life of 18 months, and longer if refrigerated.  It can be frozen, heated and cooled as many cycles as you want without changing the quality of the glue.  It is common for me to reheat the glue dozens of times in a single working day.

You can find out more about HHG and OBG at my website www.OldBrownGlue.com.

Fish Glue

Fish Glue

For many years I purchased Colle De Poisson in Paris and brought it home for use.  I had a very unfortunate experience one time when the glue bottle and purple dye powder mixed together inside the luggage where my nice leather jacket was kept.  Everything would have been fine except the airline somehow drove a truck over my bag.  The worst part was when my wife found me at 2 am washing out my jacket in her bathtub.  That's another story...

Some time after that, as I was standing in the Paris supply house (H.M.B.) the owner asked me why I was buying fish glue.  He said it was silly, since the glue was made in North America by Norland Industries!  I stopped buying it there after that.  You can find it at Lee Valley or buy it from me.

Fish glue is normally liquid at room temperature.  We all used it in Kindergarten to glue paper together.  It was in a small glass jar with a rubber nipple top.  Some of the kids ate it.

Fish glue is used whenever wood is glued to something that is not wood, like leather, mother of pearl, ivory, brass, copper, bone, horn, tortoise shell, etc.  The reason is that fish glue has a very low sheer resistance and will allow surface materials to adjust to the wood movement during environmental changes without loosing adhesion.

Hide glues have a very high sheer resistance and will cause the wood to crack or the non wood materials to break free.

Thus, Fish glue is used for traditional Boulle materials.  The worst repairs I see on Boulle surfaces involve either nails or epoxy to hold down the surface.  That just makes it worse and my job more difficult.

Fish glue takes a long time to dry and can be easily cleaned up with cold water.  I would not use fish glue to make furniture or glue anything structural.

Rabbit Skin Glue

Rabbit Skin Glue

There are many other glues made from animal proteins.  The last one I will quickly mention is Rabbit Skin Glue.  This is diluted much more with water than HHG and used by gilders to apply gold leaf and gesso.

There is a lot more about glues to discuss.  Perhaps another time.  I will end this post and get back to work.  I hope this answers a few basic questions and serves to encourage others to explore the world of organic protein glues in their work.

You can find videos about working with these glues on our YouTube channel: 3815Utah.

There are also articles I've written which are posted on OldBrownGlue.com.  Note the article I wrote for SAPFM Journal Volume 2, "Why Not Period Glue?"  There is an excellent video on cooking and using HHG which was done years ago by Keith Cruickshank and posted on his WoodTrek's site.

Here is the video: Hot Hide Glue Video

A Dream Realized After 20 Years

What is He Thinking Now?

I have always been able to function day to day, taking life as it comes.  It just seems easier to me not to worry about schedules and appointments too much.  Of course, I am reasonably responsible in meeting demands on my business and other social activities.  I just don't write it down on a calendar or post it on my phone with alerts.  I figure that life will prompt me to do something when the time is right.  That means I need to be sensitive to the subtle indicators around me from hour to hour.

Instead of dwelling on what I need to do this week or next, I focus my energies and dreams on the event horizon, years in the future.  For example, in 1984 I started the North Park Main Street Business Improvement District, and directed the non profit management board for the next 30 years in a prolonged effort to revitalize the historic area with new economic development.  I retired from that board in 2014 after it was obvious that North Park was a positive success.  Last week the local paper had a photo of me on the front page, under the headline: North Park Renaissance".

In the same way that I could work towards a long term goal of improving my neighborhood, I had similar goals when I started the American School of French Marquetry.  Initially I just wanted to continue the environment of creativity which I enjoyed at ecole Boulle, so I built some chevalets and set up a workshop for students to learn the French method.

Since the French method I was taught is rather specific to the Paris workshops and uses the "chevalet de marqueterie" to cut the patterns very precisely, I knew that the biggest obstacle to my students was going to be how to get this tool.  While the student was working in the school they could use the various chevalets and get a chance to find out what size tool they needed.  They also got the experience of building and sawing packets so that they could begin to appreciate the possibilities of what the tool could do.

However, it was clear that there was no general awareness of the tool in America.  It's existence was unknown.  Even in Europe, outside of the general Paris region, it was the same.  Somehow, over 3 centuries, the Parisian marquetry worker had kept it secret.

Therefore, my initial goal was just to introduce the tool to students, so that they would find out if they needed one.  Then I began to create blueprints and order hardware so that students could build their own.  Still, the problem of building a chevalet was that you needed to have timber framing skills to build it, so that you could then use it to cut microscopic elements of veneer into exotic shapes.

In spite of these problems, I have sold dozens and dozens of kits over the past 20 years.  I suspect that not all of those kits ended up as built tools.  However, even if half of them got built, that means there is now something like 50 or so in workshops around the country, where previously there was none.

During the past 20 years, as I was selling hardware kits, I had a dream that one day a woodworker would appear and be more interested in building the tool then using it.  I needed a person who had access to good timber and all the machinery required to do the work in a efficient and professional manner, and at a good price.

Those of you who take the time to read these posts will remember that I posted on Tuesday, July 28, 2015 the prototype kit supplied by Mark Hicks, of Plate 11 Workbench Company.  I had met Mark at the Woodworking in America Show and he agreed to work on making chevalet kits.  However, his business making workbenches had a large backlog of orders and he was not able to get to the chevalet project until he cleared his shop of those benches.

At the last WIA show in Kansas City I met another woodworker, David Clark, who is retired.  We discussed the possibility of him making kits and he was excited to accept the challenge.  Since he had a very well equipped workshop and plenty of time, he started immediately.

10 x 20 x 48"

Last week the first kit arrived and it was perfect!  The chevalet of my dreams!  Beautifully crafted, exact in all dimensions, and ready to put together.  Less than two hours after I opened the box I was sawing marquetry on the fully functional chevalet.  All the surfaces were nicely sanded, edges rounded, and everything pre drilled to fit my hardware kit, which I had supplied to him previously.

I have bought and sold and built these tools over the years.  When they are available, which is not often, they sell for an average of $2500.  If I build them by hand, and charged for my time, they would cost three times that price.  If I sell the kits for $500 with blueprints, the buyer needs to then buy the wood and spend the time to make them, which can take weeks, depending on the skill and tools available.

Dave has worked out the specific costs: $400 materials and $1400 labor (at $30/hour).  Amazing!

This Is How You Pack A Box!

He is located in Missouri and was able to ship my kit to San Diego for $110.  Since he is in the middle of the country, I suspect that the shipping to either coast will be about the same.  The kit arrived in a box 10 x 20 x 48" and was packed beautifully.  I was impressed with how he was able to get everything in such a small box.

Wow!  Just Wow!  

As I laid out the parts on the workbench it was clear to me that finally I have found the perfect person to supply the Made in America Chevalet.  He is starting to build up an inventory of parts so that the lead time to supply a kit is expected to be only two weeks.  He says he can build left or right handed tools, in any size for the same price of $1800 out the door (plus shipping).  He told me he needs a $400 deposit for the materials only to place an order.

Two Hours After Opening Box

His contact information is David Clark, 2429 NW Ashurst Drive, Lee's Summit, Missouri 64081 and his phone number direct is 913 486 0344.  He has created a personal email for ordering these kits, which is "david.chevalet@gmail.com".  You can contact him with any questions or to place your order.

I will reduce the price of my hardware kit to $400, since there is no need for the blueprints.  My hardware fits his wood parts perfectly.  I sell the hardware and he sells the wood.  Now a student can simply order the chevalet, wait two weeks and put it together, ready to work.

It Even Includes The Knob!

The French chevalet is no longer a secret or a dream.  This is a reality!  Dreams can come true!

Homage To Trees

Photo Credit: Beth Moon, San Francisco, "Ancient Trees: Portrait of Time" 

I have always been lucky to be able to earn a good living working with wood.  I am surrounded by amazing species of exotic hardwoods, in all shapes, sizes and colors.  I spend hours looking through the wood pile searching for exactly the perfect piece for whatever project I have in mind.  I keep in mind how precious this material is and always recycle the scrap for future needs.  After nearly 50 years I have a surprising collection of material, and I am respectful of my treasure.

I have also spent years playing music, both on the violin and viola, in orchestras and quartets.  There is a sacred feeling which is created by wooden instruments.  They actually have a voice and personality, which is a direct function of the wood.  It is the voice of the trees.

I feel the same way when I get any chance to walk in a forest.  The sound of the wind in the leaves and the tree trunks and branches moving is amazing.  To me it is dramatic and intense.  I usually just stop in my tracks, close my eyes and focus my senses on the rhythm and "breathing" of the trees.

Perhaps, since I grew up in a desert environment, I am more sensitive to the trees than someone who grew up surrounded by dense timber.  Perhaps not.  For me, however, it is one of the most personal and intimate experiences I can have.  You are never alone in a forest.

There is a poem by Michael S. Glasier which expresses how I feel:

The Presence of Trees

I have always felt the living presence
Of trees
The forest that calls to me as deeply
As I breathe
As though the woods were marrow of my bone
As though
I myself were a tree, a breathing, reaching
Arc of the larger canopy
Beside a brook bubbling to foam
Like the one
Deep in these woods,
That calls
That whispers home.

Growing up in the 60's I read a lot of Hermann Hesse literature and appreciated his insight.  On this particular subject he wrote in his story, called "On Trees":

"When we are stricken and cannot bear our lives any longer, then a tree has something to say to us: Be still!  Be still!  Look at me!  Life is not easy, life is not difficult."

Recently I took a cruise out into the Atlantic ocean for several weeks.  For the first time in my life I found myself surrounded by nothing but sea and sky.  (Did you know that the horizon of the ocean is only about 12 miles away?  It seems like you can see forever, but not even close.)  I found a book in the library which gave me a lot of peace and solitude.  It was written in 2008 by Nalini M. Nadkarni, and the title is "Between Earth and Sky--Our Intimate Connections To Trees."

The author has spent her life as a scientist and philosopher living in the canopy of trees deep in the Amazon rain forest.  She has studied the ecosystem extensively and her observations of life among the trees is enlightening.  We all perceive our environment individually and her perception of the trees, as she wrote in her text, had a deep influence on me, as I floated in the ocean, far from any tree or land.

I had time to watch some movies on the television in the cabin and selected two which seemed to be sympathetic to the theme of her book.  The first was staring Eddie Murphy, and is called "A Thousand Words."  Eddy plays a fast talking salesman looking for some peace and is visited by a tree which looses a leaf each time he says a word.  When the last leaf falls he will die.  I read a similar story many years ago by O. Henry, one of my favorite authors.  (You may have realized that O. Henry deeply influences my style of writing, as many of my blog posts follow his story format.)  His story was called "The Last Leaf" and can be found online.  It is a story of a sick woman who looks our her window in the hospital and sees a vine, which looses its leaves every day.  She knows she will die when the last leaf falls, but a man secretly paints a leaf on the wall to fool her and she survives.  I will let you read the story yourself to find out what happens to the man.

Another movie I watched was related but very strange.  "The Odd Life of Timothy Green" was made in 2012 and tells the story of a couple trying to have a child.  They put their wishes in a box and bury it in the back yard.  Overnight a young boy grows up where the box was.  The strange part is that his legs are covered with leaves.  As he fulfills each of their wishes, the leaves fall off.

It is sad to reflect on the global destruction of the last remaining forests.  It is such a sad fact that the news does not even talk about it.  We are killing the very species which give us oxygen while at the same time we are producing machines which generate carbon dioxide.  It is not much of a stretch to imagine that when the last leaf falls we will die.

This is what I reflect on when I search for a piece of wood.  How important it is that I respect the life of the tree which was sacrificed so that I could create an instrument, or table, or cabinet or chair.  By properly using wood in a way that understands its strength and beauty, I pay homage to its life.

In Nadkarni's book I also found a simple statement by Rumi that inspires me everyday:

Every Tree

Every tree, every growing thing as it
Grows says this truth: you harvest what
You sow.  With life as short as a half-
Taken breath, don't plant anything but
Love.

POSTSCRIPT:  After I finished this post, I felt satisfied that I had created something insightful and personal.  However, the next day, as I walked to work, something happened which made me want to add a final thought to this message.

I have walked to work on the same quiet residential streets for 46 years.  Since I walk to work about sunrise and I walk East, I am treated with the rising sun through the various trees which live in the neighborhood.  I have watched these trees grow up over the years and have formed a personal relationship with many of them.  (Not palm "trees" however, they are just tall bushes...)

Last year a neighbor cut down the largest and most beautiful jacaranda tree I have ever seen.  The trunk was nearly 3 feet in diameter!  The reason they cut it down was that the purple flowers were "messy".  They replaced it with a palm tree, which promptly died.  Now they have no shade and the yard is a desert wasteland.

Yesterday, as I walked to work I was shocked to see that the only pine trees in the area had disappeared.  These trees, which do not usually grow well in this climate had reached a height of at least 60 feet.  Every day for nearly 50 years I would stop on my walk, under their branches, and play hide and seek with the squirrels while kicking the pine cones through the needles that lay on the ground.

Now, overnight, these beautiful trees were gone.  All that was left was a hole in the sky.

In my mind and memories, I still see them living where they belong, and pay homage to the ghosts of trees long gone as I quietly reflect on how they contributed to my existence.