[GSBN] 2 books gift: Vitruvius and Natural Glue

[Derek Stearns Roff]

Luckily, we don't face the challenges and concerns of building aircraft.  Glues are very diverse in their properties, and I suggest looking at the needs of the specific application, and the risks and advantages of the various options.  Urea-formaldehyde glue is one of the most widely used in the world.  I'm guessing that most of us on this list would prefer not to be associated in any way with the carcinogen formaldehyde.  There are many, many waterproof glues available, which might serve your purposes.

One thing to keep in mind, is that the standard tests for waterproof glues in the USA involve resistance to boiling.  I don't know if other countries use similar protocols, but I think it is unfortunate.  There are several very good, very waterproof glues, that can't stand boiling.  I'm forgetting the name right now, but one of them has been used for decades for boat building.  Boat builders answer the critics by saying, "When I start boiling my boats, I will stop using this glue."

Two of the criteria that are important to me are non-toxicity and working characteristics.  Working with cork, as Jorge mentions, might be a problem for glues with low viscosity.  If the glue is absorbed into the cork to a significant extent and makes it rigid as it sets, this would decrease the resiliency, which is usually a desired trait of cork.

An exquisite glue for woodworking is hide glue.  This glue has been used for hundreds of years, and is very non-toxic, in its basic recipe.  Some manufacturers introduce toxic ingredients.  This glue is neglected, because it is an old-time, natural material.  New synthetic chemical have to be better, right?  It also won't withstand boiling.  It is not considered waterproof, but a good grade of hide glue can take a lot of water and moderate heat without any damage.  The glue can be softened with steam, or very prolonged soaking in water.  I would have no fears mopping a floor made with hide glue.  I would be worried, if my floor were flooded for a week.  But this would destroy a wood floor, even if it had no glue.  Hide glue reaches its significant water resistance in a couple of weeks, rather than overnight.

I would try some experiments with hide glue.  Similar products, fish glue and rabbit glue might also serve.  Casein glue might be excellent for your purposes.  Some starch glues are very water resistant.

Marketing people have exaggerated the importance of glue strength.  Most glues have excellent strength when used with compatible materials.  Some people want a single glue that can be used on anything, but these glues are generally toxic, at least until they cure fully.  Better to choose a glue that is safer, easier to work with, and suits the chosen materials to be glued.  For example, hide glue used with wood is stronger than Gorilla Glue, a poly-urethane glue with various annoying problems and limitations, which has been marketed for years as "the strongest glue in the world".

Let us know about your tests and results.

Derek


On Feb 14, 2013, at 2:48 PM, Van Krieken wrote:

Actually, there is a report about urea-resin glue replacing casein glues in aircraft construction. I understand that In UK, those days,  they did not use the casein glues because milk was much more important for people comsuption.
I attach the report.

In 1967, the US Department of Agriculture published a new document, Casein Glues
Their Manufacture, Preparation, And Applicatrion:

"The  principal  ingredients  of  a  casein  glue  are  casein,  water,  hydrated  lime,
and  sodium  hydroxide.  A  glue  can  be  prepared  with  casein,  water,  and  hydrated
lime.  A  properly  proportioned  mixture  of  these  three  substances  will  give  a
glue  of  high  water  resistance,  but  its  working  life  will  be  very  short.  A  glue
can  also  be  prepared  of  casein,  water,  and  sodium  hydroxide.  When  properly
prepared  such  a  glue  will  have  excellent  dry  strength  and  a  long  working  life,
but  it  will  not  be  water-resistant  in  the  sense  ordinarily  applied  to  casein
glues.  By  adjusting  the  proportions  of  sodium  hydroxide  and  lime,  glues  of
high  water  resistance  and  convenient  working  life  may  be  obtained"

See the attach.

I want to use a glue for cork tiles, but also as a binder for the cork aglomerate. I apreciate all sugestions and help.

Thanks

All the best

Jorge

On Thu, Feb 14, 2013 at 8:30 PM, Lars Keller <larskeller at gmail.com<mailto:larskeller at gmail.com>> wrote:
Very interesting and thank you very much.
Also the Gutenborg.org<http://Gutenborg.org> was new to me.

The casein glue...
In our kitchen we have used a simplified version [1 lime : 5 casein; water, mixed and left for 20 minutes] to glue down cork tiles to a wooden-plate subfloor.
It has worked well for now 7 years. The clue hardened slow, so we weighted down the tiles with bricks.

I made a few samples, gluing 2x4's together. I couldnt wrench them apart. But after soaking in water they fell apart. I assume the waterglass makes a big difference.
Best regards,
Lars

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<CASEIN GLUES manufacture preparation and aplication.pdf><glues comparison.pdf>_______________________________________________
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Derek Roff
derek at unm.edu<mailto:derek at unm.edu>


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