# How to use wood sap as a glue?



## evalon (Sep 7, 2009)

Hello woodworkers,

I'm looking for a way to use wood sap as a glue, however, don't know how to cure the sap in a natural way (i.e. without anything else than the "chemistry" freely available in the nature). 

Any of you have experience with this and have hints on how to do this? I have access e.g. to spruce sap ...

Thanks for any ideas ... :smile:

Jesper Mønsted (Denmark)


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## GeorgeC (Jul 30, 2008)

This is a most intrigueing question. The idea brings up several questions.

Why would you want to do this? Where did you get the idea? Where would you get the sap. Have you heard of it being done? etc.
]
Welcome to the forum.

George


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## evalon (Sep 7, 2009)

Hello George,



> Welcome to the forum.
> 
> George


Thanks!

Hmmm.. to answer as much as I can: 

The sap I can get from a nearby forest. I got the idea from feeling the sap being sticky and also hearing that tree sap/resin is used in many industrial glues. 

I would like to use it for fine woodwork, however need to cure the sap/resin and may also need to make it a bit more flexible (using natural materials) when dry so that it does not become brittle. 

I guess I would also need to thin the sap a bit (with a natural thinner) to enable it to sieve into the wood ...

Any ideas appreciated...

Best regards,

Jesper


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## Wood4Fun (Aug 29, 2008)

You have to go back beyond 2000 years before you find evidence of materials other than animal fats (Hide glue) used for adhesives.... so, I have to re-iterate George's question - "why"???

Are you trying to work in an authentic woodworking mode? Perhaps you should consider Hide glue if you are looking for a woodworking adhesive that was used for a very long time
http://en.wikipedia.org/wiki/Hide_glue


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## shivi (Sep 8, 2009)

HELLO.

Thank you for sharing.

Instructions
*Things You'll Need:*



 Sap
 Knife
 Wood
 Fire safe cooking pot with lid
 Long metal stirring utensil
 


*Make Charcoal*

 Step 1
Cut the wood into small pieces, no bigger than 4-by-4 inches. Cut enough pieces to fill a cooking pot.
 Step 2
Fill a fire pit safe cooking pot with the small pieces of wood. Pack the wood in the pot as tightly as possible.
 Step 3
Build a fire in a fire pit.
 Step 4
Place the cooking pot filled with wood on top of the fire. Put a lid on top of the pot.
 Step 5
Leave the cooking pot on top of the fire until the fire burns out.
 Step 6
Wait 12 to 24 hours for the cooking pot to cool off before opening it to remove the wood pieces.
 Step 7
Remove the lid from the cooking pot and pour out the blackened (charcoal) wood pieces.
*Making the Glue*

 Step 1
Collect dried sap from pine trees. When pine trees are injured, sap slowly drips out and dries on the trees' surface. Look for the thick light brown sap on the outside of the trunks of the trees. Carefully scrape the dried sap off the tree using a knife.
 Step 2
Grind up the charcoal into a fine powder using a rock.
 Step 3
Melt the sap in a fire safe cooking pot over a fire. Wait to put the sap into the pot until the flames are low to prevent the flames from touching the sap and possibly igniting it. The sap takes five to ten minutes to melt.
 Step 4
Pour ground charcoal into the melted sap. Use an equal ratio of ground charcoal and sap.
 Step 5
Stir the ground charcoal and sap with a long metal stirring utensil until it is thoroughly combined and remove it from the fire. The glue will harden to a putty like consistency when it cools off. Heat it over a fire before use if you want it to be thinner.


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## evalon (Sep 7, 2009)

*Thanks *

Hello Shivi,

Thank you also for your extensive description of how to make a sap glue! This appears to be the approach that I am looking for - thanks (thanks also to wood4fun for suggesting the hide glue!).

Pine trees are readily available here and I have observed exactly how the sap comes out and can be taken off of the tree. 

However, a couple of questions popped up when reading your description of how to do this. I hope you can help with these:

- I guess that since charcoal is mixed with the sap, the color of the glue will close to black. As I will use this for a purpose that also involves aesthetics I would prefer the glue to be transparent/slightly white. Can you say a bit about the chemical reaction going on (if any?), and maybe suggest a colorless alternative to charcoal (what is the function of the charcoal)?

- Do you know how strong the glue is? You write that it will have a putty like consistency... Since I didn't know the word "putty" I looked it up in my dictionary and it says that it is: "a soft oily substance that hardens after a few hours. It is used esp for fixing glass in window frames". A substance that I know of in traditional terms. Is this also the consistency that this sap glue will have? Can I somehow alter it in both directions (softer/harder)?

Maybe I should say that I will be making fine woodwork with the glue. Woodwork that is to be used indoors where it will be in close contact with the skin, hair and clothes. It should not leave stains and should accept moderate levels of moisture, yet high levels of humidity (like found e.g. in some forest areas in Asia).

- And an optional question since you appear to know about this: Do you know of any natural way to make a glue that is as strong (still _slightly_ flexible) as a superb epoxy? I am considering make a bike from flax fiber and am looking for a bio-glue ...

Anyway - thanks already for your reply :yes:

Greetings,

Jesper


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## shopsmithtom (Nov 3, 2009)

I read with interest about making sap/charcoal glue, but the question that comes to me is: if this glue was suitable for fine woodworking projects, why is it not in general use. I may not be the most knowledgeable guy on the planet, but I've been woodworking for a ton of years & have read a lot on glues, and I've not seen anything come up about sap based glues. I also would echo the previous comment about hide glue as a more natural and certainly time proven product. Some recent tests show it to be right up there in strength with most & actually better than some very current products. It's fine for interior use & about the only glue that's easily reversible. It might be better not to try to re-invent the wheel when it comes to wood glue.


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## cabinetman (Jul 5, 2007)

shopsmithtom said:


> I read with interest about making sap/charcoal glue, but the question that comes to me is: if this glue was suitable for fine woodworking projects, why is it not in general use. I may not be the most knowledgeable guy on the planet, but I've been woodworking for a ton of years & have read a lot on glues, and I've not seen anything come up about sap based glues. I also would echo the previous comment about hide glue as a more natural and certainly time proven product. Some recent tests show it to be right up there in strength with most & actually better than some very current products. It's fine for interior use & about the only glue that's easily reversible. It might be better not to try to re-invent the wheel when it comes to wood glue.



You're exactly right. If there was a natural method using sap it would be part of our "glue" selections as recycling has been a big issue. The recipe posted in this thread is from* this internet* *site*. It was a thoughtful gesture for *shivi* to post it. 'Pitch glues', or glues from sap would need some 'chemistry' to have any degree of predictability.


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## Streamwinner (Nov 25, 2008)

Have you considered making glue out of milk? That's essentially what elmer's glue is (hence the cow), and it works fantastically on wood and wood pulp products (e.g., paper). I remember seeing Mr. Wizard make a very strong glue out of milk on a kid's TV science program. And when I forget to wash out my cereal bowl and there's still a piece of cereal, it's like CEMENT!

BTW, this is a very interesting thread.


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## mics_54 (Oct 28, 2008)

why not just use regular old wood glue?? it works real good.


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## evalon (Sep 7, 2009)

*Thanks for your suggestions ...*

Hello woodworkers,

And thank you for your various suggestions and questions related to my question about using sap for glue. 

My reason for asking the question about using sap is that I live next to a superb carpenter who some time ago told me that sap apparently is a part of many wood glues. Wishing to only use nature's materials for my purpose I became interested in sap which I find to be very "adhesive". I now have experimented with sap and now know some about how to cure the sap so that it can be used. Thanks for your suggestions!

I will also look into using milk for glue and also wonder if pectin (plant starch) may be used for the purpose? 

So, I'll let this thread rest for now - however, feel free to continue should you feel inspired to do so 

Greetings, 

Jesper


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## rph816 (Dec 10, 2009)

*Shellac?*

Just a thought, generally used as just a finish, shellac is extremely sticky and really pretty hard. All natural, use denatured alcohol, processed, but natural, as a solvent. Judging by the tenor of your comments "flax fiber bike" and "all natural" I presume you may want to stay away from animal products such as hide glue (which in my opinion is one of the finest adhesives). Shellac is a natural resin made from Lac, which is an animal byproduct, but it doesn't harm the animal (it's essentially digested, I hate to use the word excrement, but that's pretty much it). Again, this is just spitballing. It sounds to me like you're after an "off-lable" use anyways.

Ryan


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