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Alternatives for Gugolz

beginner DIY reflector mirror making
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#1 Gnut

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Posted 17 September 2020 - 09:42 AM

Hi, 

I'm preparing to make my first mirror and I've started gathering the supplies I need. The only problem is with the polishing pitch. Since Gugolz optical pitch is mentioned everywhere, it seems to be the go-to material. Unfortunately, there is no way of obtaining Gugolz locally where I live, and there is no way to ship it here. I was wondering if there were any alternatives or a recipie to make a MacGyveresque optical pitchlaugh.gif.

 

I've also read online (from wikibooks: https://en.m.wikiboo...lescope_Making#) that pine resin can be used to make optical pitch. (I understad that if pine resin was a suitable material there would more references to it online, maybe can someone explain why it wont work and what properties should I look for in a suitable material).

 

Thank you and clear skies,

 


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#2 gr5org

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Posted 17 September 2020 - 10:38 AM

What country are you in?


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#3 dogbiscuit

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Posted 17 September 2020 - 11:35 AM

Astrokhan makes his pitch. 

Scroll about 2/3 down this page.

https://astrokhan.wo...me-2/materials/

 

And Youtube.

https://www.youtube....1OFlM94&t=1707s

 

It works good.  He made a fine mirror using it.


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#4 mark cowan

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Posted 17 September 2020 - 09:22 PM

You can use strained tar as well (like the stuff used to fill potholes).  John Dobson used to talk about waiting for the crews to patch the road near him and then going out and stealing some for polishing.


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#5 Lognic04

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Posted 18 September 2020 - 08:03 AM

If you can - try and get your hands on some Acculap. I love it, and for nearly every application it works the same. (less mess too!)



#6 Alley B

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Posted 18 September 2020 - 08:53 AM

My recipe for pitch is:

175g bitumen

375g rosin

25g beeswax

5ml linseed oil

50g walnut shell flour (400 mesh)

 I sometimes add a small amount of shellac - about 3.5 g

 

I vary the proportions of bitumen to rosin according to the temperature I am working at.

This recipe appears to work for temperatures where Gugolz 64 would be used, but as I've never uses Gugolz I cannot confirm this.



#7 ccaissie

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Posted 18 September 2020 - 11:04 AM

Burgundy Pitch

Rosin

Talc

 

Pitch is used in the hog butchering business as a way to pull the hair and bristles off the skin.....Melted and poured on, then pulled.  I can't seem to find a commercial source for the old cardboard cans of pitch...sort of like little Gugolz cans.  Never needed to use it, but I have seen it.

 

rosin can be tempered with linseed oil or other liquid oil to soften it. 

https://www.ebay.com...kevt=1&mkcid=28

https://www.walmart....lerId=101024980

 

If you've got conifer trees around, there's lots of web info on collecting and refining pine/spruce sap.  

 

If you could make a little bit of it, you could coat a lap made of inferior materials.  

 

HCF is HoneyCombFoundation, sold in sheets to Beekeepers.  It is talked about in the old ATM series of books, polishes fast, but not great for the final finish.  That's where I'd pour a thin layer of homemade spruce pitch or rosin mix to get the final finish.

 

https://www.amazon.c...swax Foundation


Edited by ccaissie, 18 September 2020 - 11:30 AM.


#8 ed_turco

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Posted 18 September 2020 - 11:16 AM

You can use strained tar as well (like the stuff used to fill potholes).  John Dobson used to talk about waiting for the crews to patch the road near him and then going out and stealing some for polishing.

I tried that trick, but no one ever told me that the stuff was full of grit.  That was the natural result olf it being used to fill potholes.  (:
 


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#9 Arjan

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Posted 18 September 2020 - 11:45 AM

You need to filter it through a fine mesh, I think Texereau published how to do that.

#10 LarsMalmgren

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Posted 18 September 2020 - 01:08 PM

I use a Swedish pitch called "Kronebeg" that is normally used for caulking wooden boats.

It's quite hard but i soften it with a little linseed oil.

 

 

https://en.wikipedia.org/wiki/Caulk

http://www.tbu.dk/sh...-kronebeg-5-kg/




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