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This is a look at my journey into making my own repousse/chasers pitch. It started by me wanting to decorate the aluminum sail of the wind chime I made. Looking around on Iforgeiron and a couple quick searches I see that pine pitch is a main ingredient. I have pines aplenty so I go gathering and choose a old vague recipe from Theophilus' On Divers Arts to start the journey.

"Grind a piece of brick or tile very small and melt some pitch in an earthenware dish and add a little wax. When these are both melted, mix in the powdered tile and stir it vigorously and pour it out into water. When it begins to grow cold, dip both your hands into the water and knead it for a long time until you can stretch the composition and draw it out like a skin. Immediately melt this composition and fill the cruet to the top."

 

During the time I was straining the pine pitch and crushing the brick I decided to do some more research. There was a little info here on IFI, but not much. Only one recipe.,(I don't know how to link other posts, so I'll just quote it.)

"Posted January 1, 2006 by meco3hp

8 oz of brick dust

1 oz of resin

1 tbl of linseedoil

Heated and mixed together."
 

I found a few more recipes when I did an online search for repousse or chasers pitch recipe. Sorry, I only got a few of the names of who posted them on other forums, and I forgot to get the site names. I wasn't planning on all this when I gathered them.

"Pine Rosin Pitch mixture: Matsu-yani

1 Kg finely ground fire clay or Plaster of Paris

750 grams of Pine Rosin

50 ml of vegetable oil

1 teaspoon of charcoal powder."

 

"from Oppi Untracht:

'Metal Techniques for Craftsmen', (p95):

6 parts pitch

4 parts plaster of paris

1 part vegetable oil"

 

"• 16 parts pitch

• 20 parts plaster of Paris

• 4 parts resin

• 1 part tallow

The pitch is heated until molten. Plaster of Paris is added a small amount at a time. Resin and tallow are then mixed in"

 

Then I found a thesis written by a RIT student named Russell Baron. His thesis is open source, so I'm including it here.Pitch problems and processes.pdf

It shows his experiments of trying to create a chasers pitch with similar properties to whats commercially available. He tries out different emollients (oils and waxes) as well as different proportions of pine pitch-filler-emollient. Very informative. He also has 11 recipes from jewlers literature with sources, which he uses as a starting point for his recipes. 

I ended up using a slight variation on his recipe, D-2. It looked like it had the best properties based on my available ingredients. 

 

The recipe I used is:

10 parts pitch= 2 cups pine resin

~7 parts filler=  a light 1.5 cups of brick dust (should be 1.4 cups, but I figured the ballpark was good for this one)

~1.5 part emollient = 1/3 cup BLO

Melt the resin. Mix in BLO. Slowly mix in brick dust.

I ended up with about 3.5 cups of finished product

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I lost my kitchen privileges when I strained the pitch, so I had to use an old microwave that barely works to heat the pitch instead of a double boiler. If you must do it this in a microwave, do it 30 seconds on/1 minute off. You do NOT want this to boil over into your microwave. I was careful and it only took 15 minutes to get it to mixing temperature, which is way too hot for bare skin so be sure to use PPE, leather gloves and safety glasses.

After it was all mixed I put it in my pitch bowl, a small stainless bowl that fits in a small rubber tire. I will test it out when I have a bit of time, hopefully in the next few days.

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I would think that RAW linseed oil would be required as boiled is designed to harden faster and you want it for non-hardening properties.

Did any of the recipes specify boiled? 

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None specified, though they use wax in its place in some recipes and that is hardened at room temp. It might have helped having the hardening in my recipe. With further reading and based on his (Russell Baron) description of what he was using I realized that while he says pine resin he meant pine Rosin, which is solid at room temperature. Resin turns to Rosin as it ages, but you can speed it up by boiling out the natural turpentine. I used resin that was still tacky at room temp and my pitch ended up way too soft.

I tried a quick sample of aluminum. It had good support under the piece, but it flowed over the top and I only got a few hits in before my piece was nearly buried in the pitch. By the time I melted the residue back into the bowl, the pitch in the bowl had settled back to flat.

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I'm not sure how well it will evaporate now that its been mixed with an oil, but I may be able to salvage this batch and boil out some of the turpentine to try and harden it. Though I may have to start over and boil the pine pitch longer to get Rosin to start with.

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9 hours ago, Shabumi said:

I realized that while he says pine resin he meant pine Rosin, which is solid at room temperature

I've occasionally thought I should see if anyone around me has any lumps of old violin bow rosin that they don't want anymore. Working for a higher-education institution with a world-renowned conservatory of music and being married to a violist should help.

10 hours ago, Shabumi said:

they use wax in its place in some recipes and that is hardened at room temp.

BIG difference between wax and BLO: wax simply solidifies at room temperature and can be remelted, whereas BLO hardens by chemical reaction (cross-linking polymers and all that).

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If it is too pliable and "sticky" add more powdered tile/brick/plaster dust.  The oil was not added to harden it; but to make it pliable; so adding a hardening agent (the "driers" in BLO), would not help what it was intended to do.

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9 hours ago, JHCC said:

old violin bow rosin

Yes, that's the stuff. When I looked into it, rosin has a long and varied history as a tool. From one of the earliest tools used by man, as a glue, to making torches, being used to increase traction at sporting events, to being a lapping base for polishing telescope mirrors. It should also be available at any apothecary at your local ren fair. If they dont have it, then I'd be wary of frequenting such a disreputable establishment.

9 hours ago, JHCC said:

whereas BLO hardens by chemical reaction (cross-linking polymers and all that).

Ah, there is the difference i wasn't seeing. Thank you for clarifying that for me.

8 hours ago, ThomasPowers said:

If it is too pliable and "sticky" add more powdered tile/brick/plaster dust.

Too pliable is a good term to describe it, but it's more flowy than sticky, it wipes away easily from the piece and your hands. It's more like the brick dust settled and left the goo on top. The piece felt supported underneath and didn't sink much. I will definitely try adding more dust to it, thank you for the suggestion. Im just a little worried that its still going to be rocks in a puddle of goo instead of a homogeneous glob. If more dust doesn't work, ill set up some sort of double boiler for it. While I'm at it I may gather some more resin to boil down to rosin for a second try.

The way I am understanding it now, and please correct me if I'm wrong, is that the brick dust adds body and heat retention, the rosin adds hardness and stickyness and the oil/wax tempers the other ingredients by making it more pliable and less sticky

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Working with medieval hints of recipes; try, try again is quite common.  Often why we try small batches till we get what we want and then increase the amounts to get what we need.

And a call out to Fannie Farmer of the Boston Cooking-School for her instance on *MEASURED* ingredients!  (I was watching a historical show where they were discussing such things as how a "wineglass" of XYZ changed over time as a 1700's wine glass was quite different from a 1990's one! However a pound of butter is still a pound of butter...)

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Ok, last night before bed I added another half cup of brick dust, because thats what I had left from before. It made it better, but there was still a goo slick on top after it sat overnight, and was soft enough to stir at room temp.20201014_185103.thumb.jpg.c3692894b25e978902b3e9e047588f9e.jpg

I took it this evening and boiled it in the microwave. 30 second on 1 minute off until it stopped bubbling at 250f on my IR thermometer, about 45 minutes. Even with the extra brick dust it reduced down to 3 cups. I'll see if it helped after it cools overnight.

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S:  I think that what you doing is trying to drive off the volatiles in the resin to turn it into rosin.  There may by polymerization going on but the light, volatile fraction is usually what makes things soft or liquid.  If you try a 2d batch try to collect the old, crusty, hard resin and see if it makes a difference.

"By hammer and hand all arts do stand." 

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On 10/13/2020 at 6:45 PM, Shabumi said:

being used to increase traction at sporting events,

Not to mention being used by ballet dancers to give the soles of their slippers just a touch more grip and keep them from sliding around the stage.

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Paracletes, didn't he say "The interpretation of dreams is great art."?

The pitch was much tighter this morning. Still soft, but homogenous and kept its shape at room temp, so thats progress. Im going to set this batch aside for now.

Instead I gathered some more pitch, and found a easier and reusable way to strain the sap. A large can with holes punched in the bottom, set upon a heat lamp shade, which funnels into a mason jar. Slowly torch the outside of the can and let it drip. I went for the more solid sap, but got some soft stuff as well. Turns out that I got it hot enough to draw off alot of the volatiles with this method as it came out around 300f and wasn't bubbling. I cooled a bit and it was hard at room temp. 

I did this all outside with an extinguisher and a lid to smother in case of flare-ups, of which there were 2.

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Edited by Shabumi
Added safety precautions
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So, I've been playing around with the rosin I made. I took 1/4 of it and made the same recipe I used before, only with rosin instead of resin, and it made a huge difference. Still too soft, but much better. I took half of the mixture and added more rosin and in the other half I added more brick dust. The one with more brick dust stayed the same, I just had more of it, while the one with more rosin got harder. 

With this information I went back to my first attempt and added the test samples and the rest of the rosin I had made, about a cup and a half more. It turned out really well. Between 60f and 70f It sticks well but all I have to do is give a quick jerk away from the bowl and the piece comes right off without much, if any, residue. Above 70f it takes a lick from a torch to release. Above 80f and it has the consistency of a warm Abba-zabba, so I'll need to keep it cool. I could add more rosin to make it harder, but I'm out for now so it'll do.

Here's the piece I played around with to test the pitch out. This was at around 65f.

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46 minutes ago, ThomasPowers said:

I sure hope you are keeping good notes on your experiments

I have so far, though the round about way of getting where I am isn't the most accurate. I've been chasing my tail with this pitch longer than I expected. From my smaller experiments the ratio I liked ended up at 10 pt rosin, 5 pt brick dust and 1 pt BLO. 

12 minutes ago, Frosty said:

sounds like what the catcher had to do when it was my turn to pitch

Haha, sounds like me. I couldn't hit the broad side of a barn if I stood 2 feet away.

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Chasing your tail with pitch:o? Do you dip your tail or swab it on and how hot? 

Oh I could put the ball right over the plate, just not fast enough to miss. When I tried to throw it fast it usually wasn't predictable which side of the plate it was just out of arm's reach of.

Frosty The Lucky.

Edited by Frosty
changed my mind, it's fine as is.
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Whelp, I've fallen into the rabbit hole of rosin. While there I found a pdf of "NAVAL STORES
HISTORY, PRODUCTION, DISTRIBUTION
AND CONSUMPTION". Its a good read about the ins and outs of the turpentine(raw pine sap), rosin, tar and pitch industry in the early Carolinas. One thing that stood out as I was reading was that a principal use of rosin was for hardening steel as well as for cores for foundry work, though no more info was given on either subject. Does anyone have any other information on either of these processes in regards to rosin?

 

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Wow; that's a new one for me; gotta hit the books later to see if anything pops up.  Theophilus mentions hardening graver tips by plunging into candle wax IIRC, "Divers Arts", 1120CE.

I know of the usual air, oil, water and brine, (also hideously dangerous hardening in Mercury), sperm whale oil, and a ton of odd suggestions from the Renaissance---radish juice or "worm water" anyone? ("Sources for the History of the Science of Steel, 1532 - 1786)

One of the great things about modern alloys is that hardening them tends to be a LOT easier than early shallow hardening steels!

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I did a bit more searching and found a few things from one source. "The Techno-Chemical Receipt book, William T. Brandt, 1887". It has a bunch of recipes on things like paint colors, sealing waxes, wagon greases, wool dies, and metal finishes, among other things

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Thanks; rather reminds me of the knifemaker's hardening goop....(see: "Goop Quench")

I'll still look into "Fortunes in Formulas" and see if they have a similar one.  I love the old "Take your life in your hands" books where there aren't any safety instructions; but they advise you to mix cyanide with sugar and sprinkle on red hot steel; or quench in mercury... What I call the "Disposable Apprentice" techniques.)   I'll see if the ASM handbook from the 1940's has anything too.

(Asafoetida!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!) 

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