Repaired with pine sap?

[iliveinahole]

Anxious to hear input on this one. Not sure if this is a pestle, but it sits at about 9 inches long and has a definite flat side to it. One end appears to maybe have been shaped down to a smaller point?
The substance in the crack is the question I've been dying to have an answer to. This is part of a collection that my great grandfather started and there are a couple other pestles that are broken and have the other half to them. Just figured he must've glued it, but left we wondering why he wouldn't have tried gluing those together as well. I looked to see if they had some form of glue and that's when I saw the use of pine sap mixed with other ingredients.
Last thing and I'll shut up. Is there a way the substance could be tested?

 

Amazon Forum Fav 👍

Family Maps of Hinds County, Mississippi, Deluxe Edition - Grab it through Amazon!

[Tdog]

I think you're correct in your assessment that he or someone else in modern times glued the pieces back together. I've seen modern glue set up like that--Tite Bond is the one I'm familiar with. I think the pine rosin mix would have been smeared over more of the visible surface and not only in the break.

 

[iliveinahole]

I think you're correct in your assessment that he or someone else in modern times glued the pieces back together. I've seen modern glue set up like that--Tite Bond is the one I'm familiar with. I think the pine rosin mix would have been smeared over more of the visible surface and not in the break

Couldn't find any other examples online to compare this to so appreciate the help 👍

 

[dognose]

What test did you perform to determine the use of pine sap?

I have seen old relic collections with the use of a water soluble glue used to repair relics. Submersion in a warm water bath for a period softens the material. I did not think it was an Elmer's glue adhesive, but it may have been. After 20 minutes or about that the adhesive got very soft and could be removed with slight pulling.

I don't know if a pine resin adhesive would react that way. Never tried it.

It may be it is a pine resin, which when applied was very hot and runny, which could explain why its not only in the crack but around the crack also.

 

[Older The Better]

Just speculating, but the function of the tool doesn’t seem like a good candidate for a glue repair. pounding and twisting motions would be hard on the joint, I would think the time would be better spent making a new one. To my knowledge I’ve never heard of ancient glue repair of stone tools, I’d guess a modern job.

 

[releventchair]

I wouldn't want to mess with it.
But pine tar should melt without crazy heat. And catch fire with much heat.
Should have some charcoal powder and a fiber-ish filler in it when magnified.
Slight pliability when pressure is applied , vs hard like modern commercial resins used for household adhesives.

 

[Quartzite Keith]

The idea that it is a modern repair makes the most sense.

Long version: Pine pitch glue wouldn't work well for a situation like this. PPG is not a "true glue", it's more along the lines of a "mastic" or "filler". It's like when you put cement in the hole around a post to help keep it in place. If you had two blocks of wood and stuck them together with PPG they would be weakly bonded together and could be separated using relatively little force and little damage to the blocks of wood.

If such a repair were to be attempted using ancient methods the medium of choice would be hide glue. This a true glue, and when properly made, very strong stuff. If you glued two blocks of wood together with hide glue, the bond would be as strong or stronger than the wood itself.

PPG has the advantage of being waterproof while hide glue is water soluble.

 

[Indian Steve]

pine pitch makes good glue but needs a hardener. Powdered shells or egg shells works good. If you could scrape off a tiny piece of the "glue" in your piece and then hit it with a flame, you will smell the pine if it is pine pitch. It is more than likely "modern" glue though.

 

[Reulte]

Don't know about stone, but the oldest repair I've heard of was something on the order of 20,000 years. It was pine resin on mammoth ivory; fixing the holding spur on an atlatl/spearthrower. The atlatl was a work of art (carving of a mammoth with the spur being the upraised tail) and I can understand why someone 20,000 years ago decided to try to repair it.

The book "Holding It All Together" ISBN 1904982476 covers various repairs from the past, including someone testing out how the Romans repaired glass and how well those repairs lasted.

I think I'm with people who say this is a more modern repair - maybe because of it's smoothness, maybe because it looks like there's a power in the resin.

 

[iliveinahole]

First of all, you guys are AWESOME! Hope you all are seeing this because I greatly appreciate the input. I brought up using pine as glue was after looking up if they had anything they used as glue back then and ran across this site https://www.newscientist.com/article/mg14219212-500-science-golden-glue-in-ancient-weapons/ I did see that it was only used with arrowheads and clovis points, but wondered if that was my tool that I had for a long time and worked well and it broke if I would've tried fixing it as well. You guys made the point that it wouldn't have been strong enough and I suppose I'd possibly believe they used pine or other glue, if the pieces were found with glue residue found on it broken as though they attempted to savage it but didnt hold.
This was one of the many items that my grandpa and his father had collected while sheep ranching in eastern Oregon. My grandpa would pick up arrowheads and stones that stood out to him. He would bring them back to the house and put them in a box. I initially couldn't picture him, in particular, spending time trying to glue it back together but I agree after all your feedback that he must have. I might try putting heat to it to see how it reacts.
Thank you all again!

 

[Reulte]

Would love to know if the repair gives a lovely natural odor (pine or amber) or simply industrial (modern). I've heard just heating a needle and poking is easiest if you don't have a UV light.

Just as an addendum... google Kintsugi. Broken teacups repaired with lacquer and gold dust. Utterly beautiful.