Making Sturgeon bladder glue.

Pounding in a mortar with a pestle making a dough.
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Nice dough in a double boiler, no water is added yet. Temperature in outer kettle is 50 C for a starter.
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After only 5 minutes the dough starts to melt into glue, I am now raising the temperature to 55 C. in the glue.
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Photobucket is driving me nuts tonite, trying again.
After 30 minutes we have nice glue, it was a little thick so I added 0,5 dl rain water, still keeping temperature at ca. 55C.
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Now straining through a clean cloth, about one teaspoon of residue.

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Looks OK now, I let it evaporate a little while sizing test pieces of wood.

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Test pieces of Beech, Hickory and Spruce. I chose Beech and Hickory because I have found these two woods difficult to glue with animal glues.

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Clamped up, the pieces with the black lettering is drying without clamps.
I will let it dry 3 days before fastening in a vice and breaking them apart with a hammer. Will let you know results.

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Finished Isinglass , 30 grams of dry bladders yilded about 1 dl finished glue.

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Weighing exactly 10 grams of finished glue in order to check consentration ( I am not sure if that is the correct word)
The whole cooking took about one hour.
I' ll write some more tomorrow, I am sure there are many experienced glue cookers on this site, but I hope this can be of use to some. Markus.

I want to give credit to Jano Nagy and Zoran Pavlovic for supplying valuable information about bladder cooking. Combined with what I knew from before I think we had a good result. Markus.

Markus,
Thank you very much for wonderful step by step description of process. I've learnt more from your posts.
Best regards

Thats perfect as you did! :wink:

Nice isinglass.

After 3 days it was time to see if the glue would hold.
Test pieces was clamped in a vice and hit HARD with a hammer until they broke apart. From left to right: two pieces of Beech, dried without clamping, 100% clean break in the wood. Two pieces of Beech, clamped when drying, 100% clean break in the wood. Two pieces of Spruce, clamped when drying, 100 % clean break in the wood. Then two pieces of Hickory, as many previous tests with Hickory and animal glues had shown this wood is difficult to glue with these kinds of glues. Glue line was strong, but not 100% clean break in the wood! I would say 90%.
Test pieces was treated with a toothing iron and sized 3-4 times before glue up.
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Markus -- Thanks for a great description. Can you tell us where you got sturgeon bladders?

I bought the bladders from a man who uses the handle Pazuzu. He sometimes posts on this forum and I am sure you can find his contact info in the members list. Merry Christmas. Markus.

Thanks, Markus!

I came across this recent article:

https://www.academia.edu/4220133/Animal ... nservation

Very interesting article. Thanks, Stephen!

Taking this to the top, had a hard time finding it myself.