DIY Smurf Poo?

haptalaon

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Nov 16, 2023
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I;m procrastinating on buying some smurf poo (blue substance you put on a leather strop for knife sharpening) and that's got me thinking: what did people in history use for this substance? Can you DIY it from natural materials in a survival situation? Can I put something viable together in my kitchen?
 

Broch

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Jan 18, 2009
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Honestly, most wood craftsmen (craftspeople) I know use something like Autosol or similar chrome polish. Toothpaste used to be used but few toothpastes contain much, if any, abrasive now.
 

Kepis

Full Member
Jul 17, 2005
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I have at a pinch used chalk or very fine clay as an abrasive on some of my strops when i've been out and about and needed something to abrade the edge slightly on a tool, 9 times out of ten though i just used the back of my leather belt or even the underside of my forearm, neither with any form of abrasive and they worked just fine.

If you want a proper natural bushcraft/survival strop, why not get some Birch polypore ie Razor Strop Fungus and just use that.
 
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Pattree

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Jul 19, 2023
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I would suppose that most people of say, more than 200 years ago used a fine stone and then leather strop if they really needed to.

In a working world even fifty years ago I never worried about a shaving edge on my tools. My sickle got a couple of swipes with a tapered stone through the day. My hoe got a file. My axe got more attention but it was still only a puck stone and spit. It went to the blacksmith for reshaping maybe annually. My grafting and budding knives managed a working edge with an oil stone in the morning and the palm of my hand through the day. Maybe a touch up at lunch time.

What did Edwardian surgeons use? I’ve only ever seen fine stones in those elaborate kits in museums.

How long has jewellers rouge been available? In my shaving days I had a Rolls razor that honed on a dry stone and whetted in a dressed strop. That was a rouge based paste. Finely crushed quartz in water should work if applied to the underside of your belt.
 

stonepark

Forager
Jun 28, 2013
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Carse of Gowrie
I use a 10000 grit diamond paste.

Smurf poo is a mix of aluminium oxides, ceramics, wax and oil and breaks down as you use it (from medium-fine grit to fine grit) but due to mixed sizes of grit, cannot be given a rating.
 

Dave Budd

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Jan 8, 2006
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historically everything that we use today has been used, stropping isn't a new thing. Modern abrasive polishing compounds such as smurf poo and autosol are just more commonly available and easy to use. A lot of the time people will get away with a sharpened but not stropped edge and just touch up frequently; there are some trades that actually require a stropped edge (such as wood carvers, leather workers, barbers, surgeons, etc)

'Canning' is a term used in metal polishing going back hundreds of years and is basically the coating of a polishing wheel (leather, felt, wood, etc) with grease (tallow usually) and an abrasive powder. The powder could be crushed stone such as quartz, garnet, glass, pumice, etc. That's proper industrial polishing of course, but the same grease and crushed abrasive was used on strops by any industry that needed fine edges (carving, surgery, leatherworking, taxidermy, tailoring, bookbinding, etc). Even at the rough end of the spectrum a sickle or scythe would be sharpened with a 'strickle', which is an appropriately shaped wooden stick coated with tallow and fine sand or other abrasive.

In the modern day, I really wouldn't bother with canning, just use a modern polishing compound that is graded and easy to use. They are usually marked in cut rate (1 to 10) and polish level (1 to 10); the higher the cut rate, generally the lower the polish level. Smurf poo is actually about 5 and 5 on the scale, the white compound that many of us good makers use is a 2 and 10+ (ie slow cut rate, but extremely high polish) ;)
 

C_Claycomb

Moderator staff
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Oct 6, 2003
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Felt like archaeology finding this one:

I haven't changed my views much since I posted in that thread. Still don't much like the wax bars due to glazing.
I have successfully used automotive cutting compound, used for rubbing back car paint, as a stropping compound. Babbit metal is meant to work too, although I don't fancy it myself. The paste products like Autosol and Tormek seem to work better for home use, they don't clog the strop so much, or get burnished, like the wax bars, but they are all but impossible to use in the field unless you carry the whole original tube. I have yet to find a way to carry a little Autosol/Tormek paste in my camping kit where it will not dry out, and won't bind up the thread of the container it is in. Wax bar scores high for field convenience, even if it does clog and get burnished on the leather surface.
As for DIYing based on what people did of yore....people of yore didn't have stainless or high alloy steel, and everything tended to be softer. This meant the steel would abrade more easily opening up more options for abrasive particles.
 
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Damascus

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Dec 3, 2005
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I was shown a trick nearly fifty years ago and use to this day, a rolled up news paper or card board box, again rolled up. Cheap and disposable too, easiest way to blunt an edge, cut card board so logic, it will give you a very sharp stropped edge! Simples.
 
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Ystranc

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May 24, 2019
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Carborundum powder, oil and beeswax. My Mrs bought some carborundum powder for making some historically accurate Georgian reproduction pin cushions. I cadged a little to play with, it works quite well.
 

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