Tag: scientific instruments

New website, new logo!

Logo

Brass and Glass has a new snazzy website with a new snazzy logo. I’m very pleased with it, I think it looks a bit smarter and it feels more personalized and special now.

My husband is the bearer of a coat of arms (technically his father is the current bearer, but let’s not split hairs). The Thoyts coat of arms consists of gold stars (mullets) on an azure background. In heraldry, the stars originally represented a knight’s spurs although it isn’t always the case. The symbol for the planet Venus is also present and it is unclear what meaning this has, if indeed it has any meaning at all. The meanings of heraldic symbols can be bad puns, their meanings can be lost in time or sometimes they are only there because they look good. The crest is a heath-cock (grouse) rising with the Venus symbol on its chest.

Through marriage the Thoyts family combined their coat of arms with that of the Burfoot family, and I have loosely based my logo on this. My family does not have a coat of arms because I come from a long line of non-conformist peasants, so for my contribution to the new coat of arms I substituted the Burfoot stars for microscopes while keeping the black background. I’m sure the Burfoots would be horrified.

Click on the thumbnails below to see the progression of the Coat of Arms

Ernie the Reichert

This is Ernie, he’s a Reichert and he used to work in milk testing. Unfortunately, I forgot to take a picture of him before lacquering. He had some deep scratches. I wasn’t able to get all of them out on the tube because of the enormous amount of engraving on the tube but I managed to get the really bad ones out of the foot. 

I did take one picture of Ernie before he was lacquered, just the foot. I took the picture because I was impressed by the difference in colour between the faded and unfaded areas. Where the upright was attached to the foot, no light could penetrate resulting in a dramatic colour difference. 

I’m very pleased with him, he’s come out well. 

New condenser for Oberhaeuser

This Oberhauser drum microscope needed a new mirror and a new condenser. The condenser arm and holder have been made using a coping saw and hand files and special screws were made which allow the condenser arm to be repositioned whilst remaining firm. The condenser mount was made on the lathe. It just needs painting olive green now to match the rest of the microscope. It can be removed and fits neatly into the box with the rest of the microscope as the original would have done.

This microscope does not need any relacquering as the original lacquer  is still 99% intact. I have taken some pictures using the microscope – one is of a xylophyte stem and the other is of radiolarians.

Pllischer progress

The Pillischer is coming along, as you can see I haven’t done the tube holder or bar yet because I have problems with them. The tube holder  has been attacked with a wrench at some point and is distorted so that the tube is extremely stiff. I am not entirely sure how to sort it out. You can get the tube in and out but it takes the strength of Atlas.

There’s a spring missing from the fine focus mechanism too so that will have to  be replaced. At least the paint is off. That took a lot of sandpaper and hard work.

Henry Crouch Binocular

This Henry Crouch had been converted from monocular to binocular at some point in its history but the additional tube had never been lacquered. The lacquer on the original tube was mostly intact apart from a few knocks and bumps so it was only necessary to lacquer the one, unlacquered tube. The original lacquered tube was a beautiful colour, a rich yellow with a hint of chocolate brown.  I was somewhat surprised when I saw this microscope because I have never seen such an eye catching colour before. The photos don’t do it justice, in some lights it appears chocolate brown and in other lights it appears yellow. I did wonder if I would be able to match the colour when I first saw it but the use of aniline dye made it much simpler than I first feared.  Henry Crouch microscopes often used  aniline dyes. The rest of the microscope was lacquered with yellow, a lovely two-tone specimen.

The microscope was missing an aperture wheel and tensioning screws for the rack. The mirror gimbal was broken in two (held together with string) and the mirror holder was thin and cracked. I made new screws, stage clips, an aperture wheel and a mirror gimbal and holder. The stage had lost all its colour so that was blackened and the foot which had peeling paint on it was stripped and chemically blackened as it would have been originally. The rack now moves as it should and it looks very smart indeed. The  before and after pictures are below

Spencer Jug Handle microscope completed

The Spencer is complete. If you recall, this poor Spencer had been spray painted black from top to bottom including the condenser, objectives and brass areas. It was quite a job to remove the spray paint and restore this but I’m really very pleased with it. The new paint is not perfect but it is much improved. The spray paint had been removed from the condenser iris and that is now moving smoothly and all in all it looks and functions very well. The knobs and brass areas had the spray paint removed and were relacquered with a rather lovely deep gold colour. My family are quite taken with it and they are usually somewhat immune to the charms of microscopes.

I just need to make a mirror for it, that’s on the to do list.

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.

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

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

Image result for Juglone

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.

Very impressed

I’m still waiting for my walnut hulls to arrive (damn you bank holiday) but I thought I’d try mixing some alcohol dyed with coffee in with some lacquer while I wait. I am NOT going to use coffee in microscope lacquer but it does give me an indication of the kind of colour I might achieve when the walnut arrives. Coffee in the lacquer gives exactly the colour I want. Hurry up Post-lady! Bring me my walnut!

Walnut, yes!

Cloth is either made from plant material (cottons, flax) or animal materials (wool, silk, leather). When dying these materials you need mordants – additives that help the colour grab on to the material and set it in place. It’s a complex art and experts are known as Master Dyers for good reason. The colour you get depends on pH and the type of mordant used. Common mordants are alum, iron sulphate, copper sulphate, tin chloride and tannic acid.  A dye may be brown with one mordant but green when used with a different mordant, and the type of fabric used also effects the colour. There’s a lot of information out there about using natural dyes on both wood and textiles but getting the colours right on metal lacquer is rather different.

Natural dyes are usually used in water and can react very differently in an alcohol and shellac mixture. Some simply won’t work (onion skins for instance) and others colour the solvent incompletely, or float to the surface of the lacquer and wash off (wood dyes are particularly bad for this, even those that are sold as alcohol soluble). Bismarck brown, a common Victorian stain, produces a brown/red colour when used as a wood stain but is scarlet when used in lacquer. It doesn’t adhere well either…

Brass contains copper and zinc but when you restore an old microscope you never know quite how much of each you are dealing with. Even though you are not really dying the metal, your lacquer sits on top of the metal, the zinc and copper content of the brass can still alter the colour of the lacquer. It can be tricky to know what will happen.  You might apply a lacquer that appears to be a rich gold on a test piece of brass, but when applied to the antique microscope it comes out a dull yellow. It’s a pain. I have one lacquer which when it first goes on has a slight green tinge to it (possibly a reaction with copper) but after a week or so the green tinge dissipates and it turns yellow again. I haven’t quite figured this out but I think the green copper complex is unstable. It degrades in daylight. It only happens on old brass, not new brass – just to add another layer of mystery.

Why bother, you ask? Why not buy a can of spray on nitrocellulose lacquer?

Why? because I like things to be done properly and I don’t want every microscope I restore to look exactly the same as the previous one. Different makers used different colours. Different lacquer batches from the same maker were different colours. Lacquer colours changed with fashion. Some early Watson microscopes used a deep orange gold lacquer, later ones were very pale. There was a lot of variation and considerable beauty. I like to restore things using the same ingredients as were used originally. If you don’t do that then you are not restoring anything, you are doing a bodge job. You wouldn’t use acrylic paint on the Mona Lisa would you? (God forbid she ever gets damaged). You might use a brush with a plastic handle, or maybe artificial bristles (if you can make the same brush strokes) but you wouldn’t use modern paints. Besides, it’s fun. Research is fun and experimentation is fun.

‘No synthetic dye has the lustre, that under-glow of rich colour, that delicious aromatic smell, that soft light and shadow that gives so much pleasure to the eye. These colours are alive.’ Violetta Thurston

As I have already said, not all dyes are created equal. Some are particularly wonderful. Dyes such as turmeric are known as substantive dyes, they don’t need mordants to adhere to fabric and they are not too temperamental in lacquer. In fact they are very, very reliable. Turmeric is the basis for almost every lacquer I make and it never fails to be yellow. Obviously, being a natural product there is some variation in the intensity of the yellow but it is always, without fail, yellow.

Today I had a small breakthrough, I have a tiny piece of a microscope which I repaired for a customer. The piece is repaired but the repair damaged the lacquer so I have to colour match and re-lacquer. This lacquer is a smoky gold colour. Warm gold with a tiny hint of brown. I have tried all sorts of ways to get browns and whilst I have had some success, I have not yet found a reliable source of brown which I can mix with other dyes. There are modern dyes, but I want to stick with products which were commonly used in the Victorian era.

I was browsing textile dying websites for inspiration when I stumbled across black walnut hulls. Walnut! Of course! They used to make ink for pens from walnut hulls. It was a VERY common ingredient in the Victorian era. I would be amazed if they didn’t use it. I have some water based walnut hull ink in the cupboard and it is a lovely nutty brown. A little research and I discovered that walnut is also a substantive dye that is brown in both alcohol and water. I’m waiting for walnut hulls to arrive from eBay. I am very keen to test it out. I don’t know why I didn’t think of it before!

 

walnut

Here we go…

Here is the Baker microscope with the bent pinion all taken apart. Since taking the photo I have cleaned it, sanded some areas and primed them ready for painting. Tomorrow I shall blacken the stage and do some more sanding and painting. I shall repeat this process about 10 times. It will be worth it in the end.

disassembled Baker

Stage and paintwork

A customer has asked me to partially restore his microscope, a jug handled Baker. He has specified certain areas that he wants repaired as he wishes to conserve as much of the original paint as possible. He wants me to re-do several areas of the handle, an area on the foot, and the stage. The stage is a little stiff in one direction so the movement needs looking at too.

As you can see, I will also have to make a new pinion as the original pinion attached to the coarse focus is badly bent. Here’s the before photograph – let’s see what we can do! I’ll start by giving it a good clean as it is very dirty.

 

Perfectionism

Today I have re-lacquered the same piece three times. The first time I did it it came out too orange. I stripped off the lacquer, diluted it and tried again. The colour was better but after staring at it for some time I decided it was still not quite right for the era.

I stripped one piece and I made a further dilution of my lacquer then did a rough and ready re-lacquering of a test area. The colour is better now but I shall have to do the piece properly next week. I am getting impatient and making mistakes now. It’s better to wait.

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Re-lacquering a piece numerous times seems to be par for the course. I seek perfection in colour, in shininess and in all round wow factor. No point lacquering a piece absolutely beautifully but in the wrong shade of yellow. I have to feel proud when I have finished. I never feel relaxed if I know there is an error, or the colour isn’t quite right. I don’t suppose this is a bad thing.