Interesting mechanism inside the little brown Merz

The Merz has an interesting design, and not one I have seen before. Most microscopes of this age and style have a solid round  bar through which a triangular bar passes. The triangular bar has a screw at one end and a spring at the other and it’s a very effective, simple fine focus mechanism.

The Merz has a rather different set up – it also has a triangular block with a screw at one end and a spring at the other, but instead of passing through a round bar, the triangular block passes through another triangular piece. The outer triangle is constructed from pieces of flat brass which have been joined together by brazing – this might explain why Merz painted these parts rather than lacquering them I think. Using brazed pieces of brass would have saved a lot of wastage and money and it would easily have been strong enough.

A “typical” round Baker fine focus block on the left, the Merz brazed, triangular fine focus mechanism on the right.

Travel could only have occurred in a small area. The solid triangular bar has a cut out area and a small bar is inserted through the corner of the brazed piece which acts as a stop. The pictures make it much easier to understand.

 

Child in a sweet shop…

I have so many lovely microscopes that need work and I am like a child in a sweet shop, I don’t know which to do first! I’m overwhelmed with wonderful choices and I need to make a decision. I would like to get something underway this week. I have a beautiful double pillar microscope which needs a screw making and a bit of a clean but I don’t really think it needs re-lacquering. Do let me know if you agree/disagree with this opinion.  I enjoy re-lacquering more than anything else so I shall probably leave the double pillar for another day when I’m in more of a making screws mood.

I have the Merz which is simple to do and in need of lacquering, I have “the Beast” which is huge and will take many months to do. a selection of small Hartnacks and the like and a rather nice jug handled microscope which has been painted completely black and really needs some love. When I say it has been painted black, I mean completely painted black – even the objectives. Poor little thing.

I think I’ll start with the Merz and then move on to the jug handled microscope. Decision made. If I don’t post pictures of a dismantled microscope tomorrow feel free to come and beat me with a big stick.

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A microscope under the microscope

There are lots of pictures to look at today, I have been putting the little Merz under the microscope to check whether it was painted brown or whether it was chemically coloured and then lacquered.  I compared the brown foot of the Merz with chemically blackened areas on the Merz and with the paint and lacquer of a very old Reichert that I had to hand. I also looked at a microscope I lacquered myself to see how my lacquering compares to the masters! I used a trinocular Olympus SZ stereomicroscope and a Canon EOS 1100D

First, two pictures of the brown areas on the Merz. Click thumbnails to enlarge.

The picture of the left shows what a small scraping of the “paint” looks like. This scraping was made near the area of corrosion which will have to be replaced anyway. The picture on the right show some intact “paint”

 

It certainly looks like paint although it is an extremely thin layer. For comparison here are another two pictures. On the left, a chemically blackened area on the Merz, on the right the paint on the foot of a Reichert.

BELOW: The rather interesting pattern made in the “paint” by the corrosion is shown on the left,  in the centre is the lacquer on a lovely old reichert and on the right is some of my own lacquering. I’m pleased to say that the surface looks correct. the underlying metal on the piece I did is in worse shape but that is to be expected. It was heavily corroded when I got it. I wouldn’t have needed to lacquer it if it had been in the same condition as the Reichert.

 

I’m thinking that the microscope was painted, I can see brush marks in one area which also makes me think it was painted rather than chemically coloured/lacquered but it is quite hard to be sure. It could be that the chemical colouring has somehow soaked into the lacquer and coloured it. I may have to consult Henley’s 20th century recipes to check a few old methods of chemically colouring brass before I start doing anything drastic.

I wish I had a mass spectrometer.  I asked my husband, he said he’d put it on the shopping list and that as long as they have them in Tesco he’ll get me one.

Making paint

Pb or not Pb? that is the question. Pb is the chemical symbol for lead, today I shall be talking about lead. Hilarious aren’t I? ( please don’t answer that).

I have a new baby to work on.  You can see below that it has a patch of corrosion on the foot which has to be treated before if spreads. I shall treat it with a gentle rust remover, sand the area and prime before painting. Here’s the tricky bit – I like to use ingredients and techniques that are as authentic as possible. I am pretty sure that the original maker would have used a lead oxide primer. I can’t buy lead oxide primer and although I can buy lead oxide powder, it is very expensive and it’s not a clever thing to be working with. Also, the chances of me ingesting some are quite high, because I tend to lick things if I don’t have a damp cloth to hand.  I shall be using a commercially available non-ferrous metals primer instead, it won’t show underneath the paint anyway. Interestingly, I can see brush marks in the original paintwork so they weren’t being all that fussy.

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I shall be starting on it as soon as some brown paint pigments arrive from my chums at Ingilby. I need to mix my own paint for this one. For a bog standard black and chrome 1950s – 1970’s microscope I tend to use black enamel paint. either Japlac or a reasonably high temperature coach enamel, sometimes with lacquer on top, sometimes not. This baby is special, it is also much older than 1950 and painted brown not black.  Below is my paint mixing kit: pigments, linseed oil, a large ground glass sheet and a muller. Hopefully the brown pigments will arrive tomorrow.

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Brass stamp

My stamp arrived yesterday, it fits into my fly press and allows me to stamp my mark onto any brass items I make. I’m very pleased with it. It was made by two lovely chaps at Chalco Stamp and Die engraving in Wellingborough and looks so professional.

I can’t wait to use it on something. I plan to make a bullseye condenser in the next few weeks. A traditional feel for a contemporary item. Splendid.

Chalco can be found at their website here; chalco dies

finished jug handled microscope

This lovely little Baker jug handled microscope came to me in need of repair. The coarse focus pinion was horribly bent and the mechanical stage was sticking. The paint on the handle and the chemically blackened stage were very worn and a small area of paint on the on the foot was badly chipped.

The pictures below show the microscope before and after repair. Paint work renewed, stage blackened, pinion straightened and stage “un-stuck.” Nothing was re-lacquered

I have been awarded a grant!

I am overjoyed and very honoured to have been granted an award by the Gane Trust, a charitable trust which gives grants and awards to people involved in crafts, design, social welfare and the arts.  I have received a grant which will enable me to buy more hand files for producing small hand crafted brass items and spare parts.

Crofton Gane was a Quaker and a furniture maker who took great interest in craftsmen, he went to great lengths to encourage craftspeople, both young and old to develop their skills.

From the Gane Trust website:

In 1968 a fellow Quaker wrote “Crofton Gane’s main concern was that men should enjoy their work and find fulfilment in it. All his activities, spread over his long life, arose from his faith in man’s inherent dignity as a maker. He believed that man would come through because God is in him. He believed, therefore, in tomorrow. Beauty of form and excellence of craftsmanship were his delight.”

He was fascinated by fresh ideas and quick to give the word of encouragement, continually writing to people who were undertaking some creative service. To everything that was making a “contribution” (to use his favourite word) he was willing to give his great energy, his thought and his money.

I certainly feel encouraged, I hope Crofton Gane would have been pleased with my work if he could see it. I’m off to write a thank you letter now.

http://www.ganetrust.org.uk/

 

Interesting chemistry of walnut hull inks and dye

Juglone, a brown dye, is found in several consumer products, including hair dye formulations and walnut oil stain. Juglone is an active ingredient in dietary supplements prepared from walnut hulls. Walnut hull extracts and poultices have been used for many years in folk remedies.

citation

Melting Point: 155 C (Merck, 1997)

Solubility: Slightly soluble in hot water; soluble in alcohol, acetone, chloroform, benzene, and acetic acid (Merck, 1997)

CHEMICAL IDENTIFICATION CAS Registry Number: 481-39-0 Chemical Abstracts Service Name: 1,4-Napthoquinone, 5-hydroxy-(8CI) Synonyms and Trade Names: Akhnot; C.I. 75500; C.I. Natural Brown 7; 5-hydroxy- 1,4-naphthalenedione;5-hydroxynaphthoquinone; juglone; regianin; walnut extract Structural Class: Bicyclic; napthoquinone

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It works!

So here we have it , black walnut dye in alcohol. It came out quite pale so I had to evaporate off the alcohol and resuspended in a smaller volume. I started with 100mls and ended up with about 5mls but it’s the colour I wanted. Tomorrow I shall add a few drops to some lacquer and job done!

Walnut adventures continued

The walnut hulls in alcohol have been on the magnetic stirrer for about 6 hours with intermittent heat. I’m not terribly impressed with the depth of colour. It looks okay unfiltered on paper but I am not convinced it will be dark enough once it is filtered. We shall see. I’ll give it until the end of the day before I filter.

Sadly , my magnetic stirrer heating element is not thermostatically controlled so I can’t leave it on the heat unattended. I have to keep an eye on it. Makes for a rather boring day. I may concentrate it down after filtering. ideally it will be dark enough that I can just add a few drops to my usual lacquers to tone them down when necessary. I hope it’s worth it. I had high hopes.