Tag: brass

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.

The worst microscope I have ever seen

This one is going to take a long time for a small microscope. A Pillischer International, the serial number is 2905 for those that have records of such things. It’s my own microscope and I can only imagine I decided self torture was cool on the day I bought it. It has been spray painted a copper pink colour. The spray painter did quite a good job in that they took the microscope to pieces (mostly) but the paint has etched the surface really badly and stained it too. The metal is so badly damaged that I have spent a day just on the foot.

I have had to be quite aggressive, I have stripped the paint off with paint stripper and then I have filed the metal and used 600 grit sandpaper. I would usually not use such harsh abrasives. That was just enough to remove the last traces of paint. Once I had removed the paint I used pumice and rouge as normal. There are still some flaws in the metal but I have to console myself with the fact that the flaws are part of its history.

I have only done the foot so far. My hands are aching from polishing so it’s time for a break.

Another day, another microscope

This is a Watson Edinburgh that has been mistreated. I have taken it apart now and starting removing the traces of old lacquer with ultrafine wire wool and ethanol. Once that is complete I will have to decorrode and polish. I have recruited my husband to help me with thepolishing.

The Watson Edinburgh doesn’t need any new parts, the rack and pinion are fine and no screws are missing. It’s all down to the lacquer. I’m not going to to much to the foot or other chemically blackened areas, just a clean for them.

Let’s see what we can do for this little one…

The completed Ross

The Ross has turned out well, it had heavy pitting and took a lot of work. As you can see it does not look brand new, it still has signs of its age. The Ross was polished entirely by hand before lacquering. It needed several new screws at the rear and on the bar of the microscope as the original metal used contained a lot of lead which shears easily.

This is a complex microscope, every single screw was hand made to fit each screw hole. The left hand screw of a pair is not interchangeable with the right hand screw so it was important to write down and photograph where each and every screw came from as the microscope was taken apart. I’m a big fan of standardisation but that came later.

Not all of the screws were put in straight either! The legs which should be interchangeable, being identical shapes, were not interchangeable as whoever made the microscope screwed one of the screws in at an angle of about 20 degrees. Nobody could ever argue this was  anything but completely handmade. A handmade microscope deserves hand polishing and hand lacquering. I have a new respect for (and a few new grudges against) Mr Ross.

The only parts I have not relacquered is the Wenham Prism. The heat involved in hot lacquering could easily damage the prism so it’s best left as it is. The mirror being very chunky acts as a great heat sink so I was able to relacquer that.

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.

More progress on the Ross

I’m working my way up, almost everything is lacquered now but there are quite a few broken or missing screws that need replacing. These screws are not made to any standard I can find. Not completely surprising given the age of the microscope. Machinists often set their lathes up at x threads per inch and made everything at that pitch regardless of the size of the screw or what it was doing. Makes it a real pig to make new ones. Standardization is a blessing.

The stage is now lacquered – an odd thing to do but it was definitely lacquered originally. Just a few bits and bobs left. Not that this means it will be swift!

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The Ross is coming together

Slowly but surely the Ross is coming together, literally.  I have reassembled the base.  It’s much shiner now.  You can see that it is not going to look “as new” the pitting is too deep, and I don’t want to destroy all signs of its history by sanding it heavily.  In this case to do so would be to remove enormous amounts of metal and it is really not possible.  To get the name plate to a perfect finish would result in the removal of the engraving which obviously would be foolish.  The pitting is still present in places but the corrosion has been treated so it should be good for another 100 years.  There’s still lots to do though and this microscope is definitely one of the worst I’ve done, it’s in a worse state than my experimental Dunscombe which was black all over when I got it.  Each piece is taking hours of work.  It is enormously satisfying though when it starts to take shape.  Onward and upward – the tubes are already done so really I’m heading middle-ward, to the REALLY tricky bits.

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Plossl restoration

This beautiful little Plossl had been mistreated, either stored in an attic or garage, or otherwise abused. Very little lacquer remained and that which did was decaying casuing corrosion and pitting to the metal. I have stripped off the old lacquer, removed the corrosion and polished without removing all the scratches and pitting that show the age and history of the microscope. They are simply safely locked away under new lacquer which should protect it from any further degradation. I have not lacquered the mirror or the objective as the risk of damage to them by polishing and hot lacquering was quite great. I’m rather pleased with it.

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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.

 

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

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.

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!

 

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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.