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#1 ThomTapp

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Posted 15 January 2013 - 11:09 AM

Where do you get your pitch? Haven't bought any since the 80's and it seems to be very expensive now...

#2 gpelf

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Posted 15 January 2013 - 11:14 AM

Hi Thomtapp,

The most common places I know of are: Got Grit and Williman Bell....

#3 gpelf

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Posted 15 January 2013 - 11:15 AM

Oh yea, There is also Acculap which is a synthetic pitch.

#4 Pinbout

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Posted 15 January 2013 - 12:02 PM

firsthanddiscovery

stay away from acculap...

the black stuff is so much nicer to work with. :grin:

#5 ed_turco

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Posted 15 January 2013 - 02:18 PM

I have had a very very bad experience with W_B with pitch for my telescope group. I'd try the other outfits.

#6 Norm Meyer

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Posted 15 January 2013 - 02:54 PM

ThomTapp,
I've used both Gugolz and Burgundy pitch. Years ago everyone
was recommending Gugolz so I switched. Then at Stellafane
Bob Royce gave a talk on telescope making and he said he used
Burgundy and saw no problem with it. The last batch of Burgundy tempered pitch I received from WB seems to be a bit
softer than previous batches. This has worked to my advantage. My basement in the winter without the wood stove
going the temp is about66 deg F. This softer pitch has been
working great with the cooler temps. I presently am figuring
a 6" F12 mirror and I have almost finished it with burgundy
pitch. To say one type of pitch is always better than another is not true. Everything must be taken into account
temperature, humidity temper of the pitch,etc. You have to "feel" how the pitch is reacting and adjust accordingly. The lap I am presently using would be too soft in the summertime. I used to wait until warm weather to figure. Some of my best mirrors were
figured in the summer and now I know why, the pitch was a
little harder and didn't flow as well. Everyone has different techniques they don't all work the same for everyone. There is some "art" along with the science. We can
teach you the science but the art comes through experience.

my $0.02 worth

Norm

#7 mark cowan

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Posted 16 January 2013 - 06:56 AM

Some of my best mirrors were
figured in the summer and now I know why, the pitch was a
little harder and didn't flow as well.


That doesn't sound quite right...:question:

Best,
Mark

#8 kfrederick

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Posted 16 January 2013 - 07:20 AM

I polished out a mirror with very soft pitch[ dent your nail in one second] it was on the matching tool maybe only 1/8 thick It did not need triming and poished nice . I like very hard pitch with window screen pressed in . If you do not have the pitch on a matching tool make sure it is thick . I have a pitch mat it is only 12inches square but it works great perfect one inch squares no mess .Hard pitch tempered with motor oil will stay the same hardness for a long time .

#9 Norm Meyer

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Posted 16 January 2013 - 09:19 AM

Mark,
You're right I meant to say the pitch didn't flow as well
in the winter when the basement was cooler.

Norm

#10 jblockyou

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Posted 16 January 2013 - 03:36 PM

I use Acculap exclusively and I get it from Salem Distributing. Works great. Hardly no smell.

#11 sopticals

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Posted 16 January 2013 - 07:35 PM

Some of my best mirrors were
figured in the summer and now I know why, the pitch was a
little harder and didn't flow as well.


That doesn't sound quite right...:question:

Best,
Mark


+1 :confused:

#12 sopticals

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Posted 16 January 2013 - 07:48 PM

.Hard pitch tempered with motor oil will stay the same hardness for a long time .


The motor oil thing didnt work :bawling: for me. I added a quantity of motor oil to my pitch when molten, and it seemed to mix ok, BUT when the mix cooled the motor oil separated out from my Gugolz pitch leaving the pitch as hard as ever. I use "Stockholm Tar", (a soft runny pich used as an animal remedy,easily obtained trom a veterinarian shop.) as the softening additive.(Perfect :jump:, and softeness of the lap is maintained long term, unlike a pitch softened with pure turps or the like.)

Stephen.(44deg.S.) :cool:

#13 ed_turco

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Posted 16 January 2013 - 09:51 PM

No smell? The smell is what I live for, and when my polishing is going right, I get faint a pitchy aroma from my lap.

Then I know I have things going well, and the sweetness of the pull in stroking is something to be desired.


Ed

#14 Norm Meyer

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Posted 17 January 2013 - 01:01 PM

Sopticals,

Mark was right I misspoke but I corrected in a subsequent post.

Norm

#15 kfrederick

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Posted 17 January 2013 - 01:06 PM

Turco are you sure you are talking about making mirrors or kids . Ha Ha I know what you are saying . Your passion for polishing is cool

#16 Pinbout

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Posted 17 January 2013 - 01:55 PM

Hardly no smell.



acculap has a smell, use a soldering iron to open up the channels. my wife complains about.

gugolz smells so much nicer.

I like the smell of gugloz in the morning...it smells like success.

I like the way gugolz melts way better than acculap. acculap turn to water way too fast.

and when you recycle acculap and all the styrene turns into little white balls you have to filter out.

#17 jblockyou

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Posted 17 January 2013 - 03:31 PM

I do not melt the channels so I don't get a smell, and because of the way I make the lap, I can use each lap on about five mirrors and remove the pitch and throw it away. When I used to recycle the pitch, I never did get styrene in little white balls, but once I did get resonated chloride which formed in a hexagonal tubular shape with a small hook on the end.

#18 ccaissie

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Posted 17 January 2013 - 10:44 PM

Norm:

Did I ever give you any of Brower's pitch? I've used his recipe for a decade now and really like it...Burgundy, Rosin and Talc. Soft, but stiff, and holds its shape when machine polishing.






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