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Jim Kelso

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There are bits of information on pitch here and there on TCP. I thought that it would be useful to have a more concentrated focus of information on this very important material for those engraving chasing, forming in metal.

 

Ford has offered to present the traditional Japanese formula given to him by Izumi-sensei. This is a very valuable and generous contribution as this sort of information contributes to the very underpinnings of the continuing practice.

 

Metalworking is a very diverse and complicated affair and one may find the variety and complexity overwhelming at times. It may be useful when trying out certain techniques to make concessions to the availability of commercial preparations. This can be useful in finding out one's particular needs and in finding energy and momentum that can be gained in actually putting a tool to the metal. This assumes of course that the commercial preparation is not total #*@!.

 

Pitch varies in composition and also is quite sensitive to heat, which means it is a highly variable material which requires experience to understand.

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Aloha Jim,

 

Thanks for saving me from shanghaiing yet another post in my search for knowledge. (Apologies to Patrick.) ;)

Doing what should have been done in the first place, I received a quick response from NWPitchworks. After also casting doubt on my sense of color, this is what they said:

"If it came in milk cartons it was almost certainly

ours. The color description I'm not sure of - I would

call it a greenish tannish color. Does that sound

right? Medium grade is what we sell the most of and

if it has been set out for general use without any

other marking I would assume it is the Medium. This

would be especially true if you find it working well

in an air conditioned room. Our Medium pitch is

designed to have a wide range of workability. If it

is used in a very warm or hot environment it will

definitely remain softer. Once solution might be to

cool the pitch first either in an ice water bath or in

a refrigerator. Some people want the pitch softer.

For them we recommend working it below a heat lamp or

in a very warm environment.

 

As for whether the pitch is old or not I cannot be

certain. I have sold pitch to a couple of different

customers in Hawaii during the last year. I'm not

sure if they were connected to your school or not.

 

The pitch does not lose life generally over time

unless it gets infected with dust or other particles

and begins to lose tackyness or adhesive. All of our

pitch grades are compatible so more Medium, or Soft,

or Hard grade pitch could be purchased to reinvigorate

and/or change the consistency of the pitch you already

have." NWPW

 

So I plan to send for a harder grade to mix for optimum performance in a warm climate. All it takes is a little more effort. Thanks again for the prod and the info. :huh: I'll leave the red stuff alone for now; it scares me. :rolleyes: Just kidding. (I won't even go on about the black stuff.)

 

mahalo

Karl

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Guest ford hallam   
Guest ford hallam

Hi Guys,

 

Here's the recipe I use, it's the same composition my teacher and his colleagues in Japan use.

 

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.

 

Gently melt the rosin in a metal container, do not allow to burn. When completely fluid, with the consistency of runny honey, start adding the filler material ( powdered clay etc ). As you add the powder gently stir it in.

Once it has been completely mixed add the oil and the charcoal powder. At this point resist the urge to stick your hands in the pitch! :huh: , this may cause some discomfort. :rolleyes:

 

If you are using a pitch bowl it's usual to fill it to within an inch of the top with lead, to give it extra weight and stability when working on it. Presuming the pitch bowl is prepared ( and cool ) fill the remaining space with the still very runny pitch. Once this has cooled enough to allow it to firm up you can begin to slowly add small amounts of now less runny pitch. You can use a cold hammer to help keep the pitch where you want it.

In this way you can build up a mound of pitch. An alternative to the pitch bowl is to spread the pitch on a thick wooden board. I have one that is roughly 1 foot square and 2 inches thick. The centre was hollowed out a bit and I packed some lead under the pitch. This arrangement is particularly useful for working largish plate etc.

 

Here's one outfit in the US who supply the stuff, link to pine rosin supplier. I imagine there are other suppliers around.

 

I made up my mixtures over 16 years ago and am still using essentially the same stuff. I lived in the UK for 18 years prior to returning to Cape Town just over a year ago and I cant say I've noticed any difference in the working properties due to the change in climate. ;)

 

regards and stuff, Ford :P

 

addendum; it's now become evident that on a couple of occasions when others have used this recipe it's not really hardened up at all. We've assumed that this may be due to variations in the water content of the raw rosin and as such have learned that by adding a little extra rosin may yield a suitable composition. I suppose we should remember that it is after all a natural product and probably subject to differing processing procedures. Seems it's a bit like cooking! thanks to Jesus Hernandez ( blade-smith ) and Hyllyn Rincones ( vagabond ) ;-), for bringing this aspect to light and resolving it. Cheers.

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Hi all,

 

As a new member, I am continually pleasantly amazed by the discussion topics posted here. I do a fair amount of repousse work with pitch bowls, and really appreciate the recipie.

 

A while ago, I had a need for a bowl that was larger than the one I normally use. I went to my local scrap dealer and found an old architectural fire bell. Basically, a large steel bowl about 12 inches in diameter. Filled with scrap lead or shot, and then pitch, as previously described, it makes an excellent over-sized bowl. It can be used on top of a standard leather pad, or on sand bags for higher angles.

 

Best regards,

 

Phil

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Hyllyn   
addendum; it's now become evident that on a couple of occasions when others have used this recipe it's not really hardened up at all. We've assumed that this may be due to variations in the water content of the raw rosin and as such have learned that by adding a little extra rosin may yield a suitable composition. I suppose we should remember that it is after all a natural product and probably subject to differing processing procedures. Seems it's a bit like cooking! thanks to Jesus Hernandez ( blade-smith ) and Hyllyn Rincones ( vagabond ) ;-), for bringing this aspect to light and resolving it. Cheers.

 

I hope you meant it like the first two:

1. wandering from place to place without any settled home; nomadic: a vagabond tribe.

2. leading an unsettled or carefree life.

3. disreputable; worthless; shiftless.

 

:D

 

Mind you I wouldn't exactly say carefree ;)

 

Ahh I am about to make matsu-yani again (actually probably in a month from now) so that I can restart using my tools after this long (not voluntary) break, haven't been able to find a bowl here and getting one sent from the U.K or the U.S is rather expensive so I will go for the wooden square and there's a variety of wooden bowls, rectangles, etc which I'm willing to try to skip the limitations of the square, will let you know how it works out. (I also have some stuff to send to you Ford to review my "progress")

 

And apologies for the change of subject, Ford taunted me (probably an attitude he learnt in Britain after coming across silly english kniiigits and french taunters) :rolleyes:

 

Ahh Ford would it work if I collect my own pine rosin as there's actually a fair bit of the stuff near where a friend lives in Caracas? or are there any specific things to watch out for that you might know about?

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DanM   

Hyllyn,

 

Where are you located? a pitch bowl can be made from almost anything.didn't volvo's have 6-8 inch sheet metal hubcaps at one time. you can fill 2/3rds of them with lead and then add your pitch above the lead base. the Tibetian metalsmith i know just uses a block of pitch with no base,you aren't constrained to any specific shape.

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Hyllyn   
Hyllyn,

 

Where are you located? a pitch bowl can be made from almost anything.didn't volvo's have 6-8 inch sheet metal hubcaps at one time. you can fill 2/3rds of them with lead and then add your pitch above the lead base. the Tibetian metalsmith i know just uses a block of pitch with no base,you aren't constrained to any specific shape.

 

For the moment and for the next half a decade I'm in the Banana Republic of Venezuela.

 

It's not really a big problem the bowl I'm sure I can find something to suit my needs, it is just that the bog standard bowl that is sold for people working with chasing and repousse I cannot get here unless it is for a tonne of money or sent over for an equally expensive amount, it is the same old story about buying at "specialized stores".

 

Either way thanks for the info, although finding a Volvo here is quite unlikely, it would be easier to find an intergalactic ship than a volvo.

 

How's the website coming up Ford?

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Guest ford hallam   
Guest ford hallam

Hi Hyllyn

 

I meant vagabond mainly in the first sense with 20% of the second sense. I'd never suggest any of the 3rd! ;)

 

I wouldn't recommend using pine gum that you've collected yourself as it's not been processed. Rosin is actually the by-product of a process that extracts turpentine from the raw pine gum. In my experience it's always been a fairly consistent product, however it seems from what we've heard lately that there are other types that are perhaps not so thoroughly processed and are not as hard.

 

cheers, Ford

 

I'm looking forward to seeing what you've been up to, and the web-site is "imminent" :rolleyes:

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Hi Hyllyn

 

I meant vagabond mainly in the first sense with 20% of the second sense. I'd never suggest any of the 3rd! ;)

 

I wouldn't recommend using pine gum that you've collected yourself as it's not been processed. Rosin is actually the by-product of a process that extracts turpentine from the raw pine gum. In my experience it's always been a fairly consistent product, however it seems from what we've heard lately that there are other types that are perhaps not so thoroughly processed and are not as hard.

 

cheers, Ford

 

I'm looking forward to seeing what you've been up to, and the web-site is "imminent" :rolleyes:

 

Hi Ford,

I have been collecting Sap directly from pine trees. I put it in a pan and heat it untill liquid. I simmer it for ten minutes and pour through a coffee filter onto my anvil. The heat boils out the Terpentine and the coffee filter is for Bugs and debris. The steel anvil makes it cool into sheets with out sticking. Then I break them up and store for making Japanese style pitch. The resulting amber is just like the processed stuff but slightly darker. I have also found the pitch from Douglas Fir tree to yield almost identical product save for an even darker color. One of the benifets of living in a huge temperate forest :D Lots of trees to collect drips from.

Patrick

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Guest ford hallam   
Guest ford hallam

Hi Patrick,

 

that sounds fantastic :) , so there we have it, an effective way of preparing raw pine resin. I must admit I really like the idea of collecting my own too. Perhaps I should take my sons resin tapping? :rolleyes: I bet it smells amazing too, don't sniff the turpentine though ;)

 

thanks for that Patrick, cheers.

 

Ford :D

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I tried a similar approach once to refine the resin. Ended up with a wicked headache from the turpentine fumes. It worked well though, but I wouldn't do it again without plenty of ventilation, preferably a fume hood.

 

Phil

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I tried a similar approach once to refine the resin. Ended up with a wicked headache from the turpentine fumes. It worked well though, but I wouldn't do it again without plenty of ventilation, preferably a fume hood.

 

Phil

 

Yes the fumes can be bad, but once they are boiled off the resin smells good. I have tapped a tree on the property, but I collect most of it from natural flows or places where the limbs have been pruned. Much of it is older and partially or fully cured. So the fumes are a minimal thing. The super fresh stuff I am tapping from a pine tree is really nasty fume wise and I think next time I will just do that stuff outside on the camp stove.

I collected a pocket full of fully cured resin today on a walk.

Patrick

 

Edited to add,

My own expirience in simmering of raw sap tapped from the tree directly takes 30 minutes to an hour to process about a Quart. I was reminded of this the other day when processing some pine sap. The ten minute figure I gave earlier was for Older more cured drips I collected from natural flows. The solvents naturally evaporate, but very slowly.

Patrick

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How necessary is lead?

 

Hi, I have a ring of steel 6" in diameter and 1" high, if I weld that onto a thick plate of steel, would that work as a pitch bowl (clamping the plate part to a solid working surface), or would the pitch be too shallow? (how shallow is too shallow for say, menuki forming?)

 

(i.e. does the lead get displaced as you work metal, or does it only function as a weight?

 

I've never seen pitch before, looking forward to mixing this up and sticking my hands in it.

JUST KIDDING, DO NOT STICK YOUR HANDS IN IT.

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Hi Brian,

 

The configuation you are talking will do just fine. The 1" depth will be more than enough to make menuki. You will note that some of us use heavy hemispherical bowls so we can tilt the work to allow easy access to the sides and help in rotating the piece. Others attach a shallow tray to engraving balls. This also allows you to modify the orientation of the piece you are working on so it can be attacked from many different angles.

 

The lead Phil talks about is for weight and should be used only in the deeper bowls. You do not want to get lead onto your piece. It can easily contaminate your work. Most of the bowls I use are make of thick cast iron. They are not exepensive and I would suggest looking into buying one. The can be purchased in different diameters and depths. Hemispherical bowls allow for greater tilting. I support my bowls in rubber lawn mower tires. They are cheap and easy to find.

 

I usually use plaster of paris to fill the pitchbowl 3/4 full. I wait a few days to allow the plaster to harden and dry out. I then fill with pitch. I overfill my bowls. When storing be sure to keep the bowl level or you might find it flowing out. Tucson is hot and sometimes I need to put the bowl with the mounted metal I am working on into the freezer to allow it to stiffen up before working on it.

 

I use Northwest Pitchworks' pitch. Medium and soft. I also use Japanese pitch bought in blocks from Komokin. This pitch is rock hard and is best used fairly hot.

 

WARNING! pitch can stick to your fingers and burn badly. I do NOT recommend sticking your hands in it. I use the face of a planishing hammer to move and model the pitch in the bowl. If the hammer warms the pitch will stick to it so you will need to cool the hammer periodically in water.

 

Hope I haven't confused you.

 

Fred

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How necessary is lead?

 

Hi, I have a ring of steel 6" in diameter and 1" high, if I weld that onto a thick plate of steel, would that work as a pitch bowl (clamping the plate part to a solid working surface), or would the pitch be too shallow? (how shallow is too shallow for say, menuki forming?)

 

(i.e. does the lead get displaced as you work metal, or does it only function as a weight?

 

I've never seen pitch before, looking forward to mixing this up and sticking my hands in it.

 

The lead is just for weight. With a bowl it helps it stay put at what ever angle you have it tilted. You can also just put a blob of pitch on a wooden block. I have a wood block with a few pound lead on top then covered in Pitch. Also a small bowl with just pitch and then a big bowl with lot of lead and an inch of pitch on top. As long as it is heavy and solid and stays still while you are chiseling it is good. I like the bowls for carving and Uchidashi, but the blocks work great for Polishing where you don't need to tilt it. You can also work around your block rather than turning it if you have the room.

Regards,

patrick

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Thanks for helping clarify, I will go ahead and use this steel ring to make a flat-bottomed bowl, and also try the pitch-on-board method.

 

I was just kidding about putting my hands in the hot pitch. I've had enough mishaps with hot glue to learn my lesson about hot gooey substances, but I've edited my post in case anyone reads it and get the wrong idea!

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Brian,

 

Uchidashi/repousse is a wonderful way of manipulating and sculpting metal. I have to say that I am adicted to the process. I wish you many hours of pleasure with this technique and be certain to keep us updated with your progress and projects.

 

Best of luck,

Fred

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