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Homemade pitch for polishing

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#1 slobeek

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Posted 27 March 2010 - 04:23 AM

Hi all,

I was searching for info how to make your own polishing pitch and stumbled on this : http://en.wikibooks....g#Lap_Materials

If I understand correctly you can use only rosin from conifer trees for your pitch

or

you can use only beeswax to make your pitch for polishing ( since I am beekeeper I have lots of pure natural wax )

Is rosin only or wax only pitch doable ?

#2 dane lambson

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Posted 27 March 2010 - 10:51 AM

Hi
My understanding is that pitch, bees wax, rosin and linseed oil are all components of tempered pitch such as that sold by many companies. Since the post from a few weeks ago concerning recycling pitch, I have been experimenting. I brought an old electric range that was in storage and set it up outside. I have in the past collected pinon resin from the pinon pine tree that is very abundant here. I have used it (also in the past) by dissolving it in acetone and letting it drain through a strainer cloth and boiling the acetone off, but that was very dangerous and time consuming. (done also outside away from every thing.) Last week I took a bunch of old pitch and even acculap and made a forces strainer from a #10 can and made pitch from it. It is still untried but looks good so far. It came out pretty close to the right hardness and could be easily adjusted. It is not as clear as the tempered pitch that I have bought. I ordered some rosin and refined bees wax from Willman Bell. (are we allowed to mention our sources here?). I will try different combinations and see how they work. This picture is the #10 can showing an air chuck attached to the top , sealed with rubber O rings. A two layer bed sheet filter and sieve will be attached to the bottom with the shown ring clamp. This is after the can is filled with the material to be filtered. The sieve should have ears for sitting on another container and the whole thing is sat on a steel bowl and heated in the oven for about an hour at 250F. Very gentle air pressure is then applied and the pitch runs out the bottom into the bowl.
Dane

#3 dane lambson

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Posted 27 March 2010 - 10:52 AM

Here are the pictures.

#4 dane lambson

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Posted 27 March 2010 - 10:53 AM

OK One more time

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#5 dane lambson

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Posted 27 March 2010 - 11:07 AM

Here are the results. The three small trays on the right are a mixture of recycled pitch and tree resin. They are about 8 oz each. The middle tray is a mixture of recycled pitch and acculap, which I heated together for a couple of hours and stirred and then left on the heat for a couple of hours more to see if they would seperate. They didn,t. Only some of the cloudiness settled to the bottom but the liquid component stayed consistant. Hardness of all items seems comparable, though I need to make a tester to compare them accurately. The bowl is what I could collect in the wild from trees close to the house in about an hour. It has not been filtered, only strained and has a lot of debris in it still. I will run it through the filter later.
Dane

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#6 dane lambson

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Posted 27 March 2010 - 11:10 AM

To answer Your Question after all my rambling, I think that wax only will be way to soft fo use alone. It is the combinatin of different material that give you the best results. want to trade honey for pitch? :jump:
Dane

#7 slobeek

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Posted 27 March 2010 - 12:43 PM

Dane, it makes sense to combine all the ingredients. I am wondering though if wax would work alone but don't want to experiment on my first mirror :)

So my plan is to go get some rosin from a tree and mix that with wax and see where it gets me hehe. I guess I will have to experiment but some "official" formula from you guys would be great.

I would trade right away hehe but we are thousands of miles apart ;)

#8 K. A. Scharf

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Posted 27 March 2010 - 01:43 PM

In the 'old' days (see the original SA ATM books) some people used bee hive honeycomb foundations (hexagon pieces of beeswax) as a polishing lap. The foundation material would be applied the warmed glass tool used to grind the mirror and then pressed with the mirror. It was a lot easier to use the beeswax lap than a pitch lap, so this was the perfect solution for a first mirror.

The 6" F8 mirror was also recommended to first time mirror makers for a good reason, the difference between a sphere and a parabola at this size and f ratio is very small. The normal, random grinding and polishing strokes will almost always produce a good sphere and by polishing with just a bit of extra overhang for just the right amount of time the 6" F8 sphere will be very close to a good parabolic figure (or so the teachers said). Many first time ATM's built their first mirror without any testing on faith using the described method. Sure the resulting mirrors were far from perfect, but they would work well enough to encourage the novice to try again and make a better mirror.

#9 slobeek

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Posted 27 March 2010 - 01:54 PM

K. A. Scharf , so only beeswax would kind of work ?
I am well into fine grinding 6" f6 now :) Originally the glass was grinded to f10 years ago and only needed polishing but I decided to go shorter :)

I have to come up with something in 2 days now haha :) Unfortunately even if wax works I don't have any foundation since I leave wax making to the bees ;)

#10 slobeek

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Posted 27 March 2010 - 04:28 PM

Ok was reading around about hcf polishing. If wax foundation works then my "wax only lap" should also work or is there a problem with polished surface when polishing with wax only ? I can make squares, etc, no problems there since I am kind of experienced with managing wax :)

Am I overthinking everything and should I just order some acculap or gugolz and wait like a month for it to arrive :D

#11 dane lambson

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Posted 27 March 2010 - 05:03 PM

My order from a company whose initials are WB took about a week. They even gave me a call to make sure the shipping address was right. Less variables using knowns unless you really like to experiment and don't mind getting into trouble once in a while. I do. Both.
Dane

#12 slobeek

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Posted 27 March 2010 - 05:10 PM

Getting into trouble ? Here I am heh.

I am overseas and I do order from US on regular basis and it takes from 10 days to a month for a package to arrive.

The thing is that I think I got some sort of a "mirror bug" and will just go ahead with wax. Maybe mix a little resin there and will see what will happen :)

If anyone would like to add something please do. I am 2 days from polishing :D

#13 dave brock

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Posted 27 March 2010 - 06:49 PM

My 2c worth.
Order the pitch now so by the time you give up on the wax you'll have it there.

Dave

#14 dane lambson

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Posted 27 March 2010 - 10:27 PM

My limited experience tells me that bees wax is very soft and will invariably give you a turned down edge pdq.
Dane

#15 slobeek

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Posted 30 March 2010 - 06:41 PM

I collected some spruce resin in the near forest which is also called burgundy pitch ???
I filtered it through cotton cloth and have it 50g. It is very "playable" and flows and flows and flows :) In this state it certainly is not suitable for polishing so I ask you guys what should I add to harden it a little ? Will cooking it a little help ?


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