anyone actively make pitch glue

C

Cliff Stamp

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I have been working with it recently as I will be making stone/copper/bronze axes/knives (or plan on it anyway), so need it for attachment. I have tried a few recipes and it is easy to get high bond strength :

http://i7.photobucket.com/albums/y269/CliffStamp/swamp rat/ratweiler/ratweiler_pitch_strength.jpg

That is a 25 lbs lead weight and the glue holds the wood together easily, I even snatched it fast and just cracked the cable. However it will still fracture readily under impacts and based on just whacking that stick around I don't think it would hold up under axe/arrow impacts.

Has anyone one done this and have any details on the exact recipe, common are 5:1:1 for pitch/ash/tallow. Does how long you heat it make a difference, can you overheat it, does the type of ash or pitch make a difference? Could you improve it by adding fish glue which is generally more runny so it could give maybe a san-mai type deal?

-Cliff
 
Very interested to hear the responses. Also, Cliff, can you go into more detail about how you are doing this. I thought there had to be some scat in the mix?
 
Gather the pitch from the bark, you can crumble it off with your hands or scrape it off with a knife. If it is a fine edged knife you might want to carve a scraper as it can be difficult to get off the blade, for large choppers I just leave it on and let it wear off.

Put the pitch in a tin (or on a rock) and put it next to a heat source until it melts, now pick out and debris. Add powered ash to the mix (and lots of other things like grasses / scat can be used as well) stir it well. Now dip small sticks into the glue and roll them to get a coating. As they dry they can be redipped to get a thicker coating.

You just heat up the pitch sticks to use, you can also let the glue cool and roll it out with your hands into sticks and then carry them or pieces. There are a bunch of pictures in the ratweiler review which is in progress.

-Cliff
 
You can infact heat it too much. This causes the turpintine to come out of it,or so I'm told and a double boiler is recommended. (I just heated it in a can). As far as the recipe goes it seems to be a bit of witchcraft.
The amout of tallow being the ingredient that matters most. Too much and it stays pretty sticky in the heat of a summer day, too little and it gets brittle. I used wood charcoal crushed for the binder and I kinda liked it, but want to use willow char sometime as it is finer than the boxelder that I started with.
As far as arrowheads being fixed, they were'nt meant to stay on. When a shot was made and went into man or beast the arrowhead would stay in and raise hell. A new point could be put on the arrow when retrieved. With axe heads I can't say but it seems to me that alot of repairs were needed. I do know that most "kits" had a pitch stick in them and sinew,awl, and hide glue for repairs.
This summer I intend to work on the pitch glue thing some more til I can get a repeatable recipe
 
ditto what mewolf said about the arrow heads. weren't most axe (or other tool) heads bound with cordage for this very reason??
 
Yes they were in conjuction with glue. Rawhide was a popular choice as it shrinks when it dries.
 
The stone blades were attached with cord as well as glue, my question was in the inconsistency of the two methods of attachment as pitch glue is really brittle based on what I have seen, so I was wondering if there is a way to make it much tougher for certain applications.

I don't doubt that some arrow heads were made to come off, but some definately were not, see how Davenport attaches them in Wilderness Survival for example. In reflection I think the pitch glue may have been used more to hold the tools stable in construction more so than in use.

The axes and other similar tools, adze, etc., may also have been used with *much* lower impacts than modern such tools both due to fragility of flint and the attachment.

-Cliff
 
Cliff,

Grind up some eggshells into powder and experiment with different ratios mixed in with the pitch (during heating in its liquid state). Try starting with 1:4 (eggshells/pitch). Eggsshells will give the glue some "flex" and reduce the brittle nature of the pure pitch. You can adjust as needed, and experimenting will give you the optimal ratio for your needs.

Best,

~Brian.
 
Here are some previous threads that talk about cutler's resin, a form of resin glue.

See our own MaxTheKnife's recipe, construction methods, and comments in the following threads:
http://www.bladeforums.com/forums/showthread.php?t=272230
http://www.bladeforums.com/forums/showthread.php?t=189539
http://www.knifenetwork.com/forum/showthread.php?t=7254&page=1

Other info on it:
http://www.bladeforums.com/forums/showthread.php?t=215503
http://forums.dfoggknives.com/index.php?showtopic=1403

From the Neo-Tribal world comes word that pinyon pine resin/rosin works better than some pines as the basis for a resin glue.

From Mark Marsay:
"I usually use cutlers resin when attaching handles to blades - seems to work better than epoxy with the marking knives and various odd shaped scraper knives and chip carving knives I sometimes make. Cutlers resin is 8 oz pine pitch, 1/4 cup Carnauba wax and 4 oz beeswax, melted
together in a double boiler and used hot. Make sure you preheat the items to be joined as well."

Link for commercially available pine resin (brewer's pitch). $8 per pound.
http://jas-townsend.com/product_info.php?products_id=373
 
Thanks for the links, there seems to be a lot of possible mixtures all starting with a basic sap base. I have lots of pitch, lots of wood, I'll try experimenting with various mixtures and examine the strengths and impact resistance.

-Cliff
 
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