Birch Tar... without a tin?

[y0dsa]

Sorry if this is a dumb question, but have any of you good folk made birch tar without a tin?

The question came up while in conversation with Karl Lee, of Primitive Technology, while in a flint knapping workshop hosted by Bassetlaw museum. It was felt that Birch tar wasn't an 'authentic' stone age substance as no-one seemed to know how to make it without a tin.

Thoughts appreciated. Thanks.

PS thoroughly enjoyable workshop, by the way!

 

[Stew]

Ihavent done it but I do have some old sketches of it being done with out a tin. I'll dig them out later.

 

[Janne]

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[Toddy]

Sorry, cross posted with Janne and his method sounds a lot tidier than mine !

You can do it just by 'roasting' a roll of the bark. You just need to mind to keep the original flow of the bark all going one direction otherwise you end up with a seeping mess.

Roll it up snuggly and put it right close to the fire, as close as you can get without it going up in flames. If you angle the roll so that the sticky stuff can dribble down one end and have something to catch it (clay just moulded into a wee hollow in the ground works) just let it work over the evening and through the night while it cools down.

I'm sure there are other ways, humanity is nothing if not inventive, but that works.

I do know someone who did much the same as doing it with two tins, but with just the roll of bark buried end on down under the fire and with again a pressed out bit of damp clay as a catch pot underneath it. He said it was messy, but it worked to make glue.

M

 

[Janne]

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[y0dsa]

Thanks, that's really helpful. Now looking forward to seeing some pics/ sketches!

 

[Janne]

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[Robson Valley]

The birch-building native societies of eastern north america made birch tar to seal birchbark canoes.
Spruce gum works as well and is far less effort to collect. That's used here in the central interior.

Since we have paper birch, the bark is so much more workable that the UK/European birches.
Making a cup from it is a cute piece of "origami" (ch 13 (Barkcraft), pl 138, in Wildwood Wisdom/Ellsworth Jaeger).

 

[Janne]

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[Robson Valley]

" One positive aspect with Bitch oil. . . .. " Does it stop them from squeaking?

Spruce gum does dry out over the years.
Locally sure not over 5+ years since I had some pruning done in the front yard.
The 3 spruce are 50' or more tall and 12" = 16" dbh and the lower branch stumps are still oozing.
Easiest to collect when it is very cold (-20C) as it is not sticky.

Just last month, the Leidli Ten'he in Prince George launched a new birch bark canoe, sealed with spruce gum.

 

[Janne]

zzzzzzzzzzzzzzz

 

[Toddy]

Spruce isn't native to the UK. Before the last ice age it's believed that it was present, but it didn't come back before the land bridge flooded.
16th century before it was introduced this time around, and early 1830's before the Sitka spruce was brought in.

We don't really have any 'history' of using it here for much apart from timber and paper making.

M

 

[Robson Valley]

Like our birch and western red cedar, spruce is another "multipurpose plant".
The volatile part of spruce gum doesn't seem to evaporate very quickly so it's flexible for ages.

The 4 sides of a Haida bent-wood box are a single slab of either western red cedar or yellow cedar with 3 kerf-cut and bent corners.
The 4th corner is sewn shut with nice flexible spruce roots.

The box is so carefully made that the fit of the bottom panel and the box is waterproof enough to cook in.
From all of my reference texts, it seems that all the corners are dry fits, carved so well as to be water tight.
I have watched it being done, I can cut a good corner in a 6" slab in about 20 minutes or less but I don't have the patience for steam bending the corners.
Maybe have another go at it this coming winter, the wood is in the shop.

 

[Janne]

=Toddy;1822859]Spruce isn't native to the UK. Before the last ice age it's believed that it was present, but it didn't come back before the land bridge flooded.
16th century before it was introduced this time around, and early 1830's before the Sitka spruce was brought in.

We don't really have any 'history' of using it here for much apart from timber and paper making.

M[/QUOTE]

 

[Dave Budd]

Ive seen birch tar made without tins a few ways.

The large scale method was to do a charcoal burn with the floor carved into a channel to direct the tar into a pot outside of the kiln. Ive seen this done usjng a modern ring kiln and a small earth clamp.

On a smaller scale ive seen both ceramic and aceramic methods used by experimental archaeologists. The ceramic method used two pots and a small camp fire, just the same as with a biscuit and bean tin. The aceramic method was using a ball of clay (with a fibre bibder, hair and moss i think) with a hole in it to drain into another clay bowl in the ground. The ball (containing bark) was placed over the dish and a fire was lit as before.

 

[y0dsa]

Very interesting, thanks all. I'm still curious about what evidence there is for making birch tar (non-squeeking variety) in prehistory. Would the wet clay method leave pottery traces? Dave Budd, do you remember if there were any such traces which would survive the process?

 

[SaraR]

I can't offer any evidence of pre-metal birch tar making, but I find it odd that anyone would think that something like that would not have been discovered before the invention of metal tins. I'm just thinking of how many other instances there are of "sticky stuff that comes out of XXX if you boild it/burn it/stick it in a fire" and especially since we know that birch bark and sap has been used for all sorts of things for a long long time and by people who used fires a lot more /frequently/ than later generations.

 

[Toddy]

Partially 'cooked' wet clay isn't pottery. Semi ceramicised clay is called rotten pot. It crumbles away with no substance.
In our temperate climate everything organic rots, except in very specific situations…and those are rare finds.

I think SaraR has the right of it too

M

 

[Dave Budd]

Unless the clay has been at least biscuit fired, it just dissolves back into the soil normally (if there is any soil movement/rain at all). When unfired clay (or very low fired as Toddy described) is found in the archaeological record it is normally when left in thick slabs/patches such as lining a water containing hollow (pond, etc) or as a random little splodge of reddish soft clay. Those splodges are very very common to find along with small amounts of charcoal around clay rich sites. They could be from daub used in buildings, clay sling shot, loomweights, temporary containers, tar making vessels, etc; but we will likely never know! Heck, my woods has so many of these splodges from anywhere near a bonfire or forging site!

Very interesting, thanks all. I'm still curious about what evidence there is for making birch tar (non-squeeking variety) in prehistory. Would the wet clay method leave pottery traces? Dave Budd, do you remember if there were any such traces which would survive the process?