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

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!

 

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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.

 

Perfection! 

A small two tone Baker microscope appeared on eBay some years ago and I was quite taken with its beauty so when I happened across a very badly damaged Baker in need of re-lacquering I decided to recreate the two tone look.

This little chap has been something of an experimental piece as I have tested various brown and orange lacquers out on it. I am finally happy with it. I just have two small pieces drying and I can reassemble it properly. The slideshow below shows the microscope before and after restoration.

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My workshop

Today I have been tidying my workshop, it might look a bit of a mess still but I have removed a whole car-boot load of old boxes, used nitrile gloves and bits of emery paper today. The room is looking much tidier even if the worktops themselves still need some work. I shall finish tidying tomorrow – I need to use the milling machine so there is no escape!

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I am still not entirely happy with the little Baker microscope in the foreground of the picture, the brown lacquer comes out far too dark after it has been heated. I am making a new, much paler batch at this moment.  I want a muted earthy tone – not dark chocolate. I should have pictures to post at the weekend.

Polishing

I have been so busy polishing this week that I forgot to blog! I do all my polishing by hand and it can be quite therapeutic. The mind can wander a little while the hands are busy. Whilst polishing I tend to daydream about glistening golden microscopes and my next projects. Today I sanded and polished with various grades of pumice. I have one more extra  fine polish to do before I start lacquering this piece, and tomorrow evening I have another piece to finish which just needs heating and reassembling.

The excitement mounts. I hope I can get it all done, I have to do some gardening to do as well. The penstemon need urgent  attention.