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.

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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Verick 1 – Brasso 0

Oh the poor little Verick! In a photograph there didn’t seem much wrong with this Verick apart from the total lack of lacquer but it had serious issues. The  Tube holder was stuck fast, the tube was stuck fast in the tube holder and it took several hours to get it all unstuck. The cause? Brasso. Don’t use brasso on your microscopes, it removes the lacquer and clogs up the moving parts it’s like glue. Below is a picture of the aperture ring which was also stuck fast and what it looked like inside when I finally got it apart.

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There is hope though, if you can get the microscope apart the brasso can be removed quite easily. Here is the little Verick before and after lacquering, all parts are now moving smoothly and it is ready to return home.

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Verick frozen solid with brasso

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After cleaning and lacquering

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After lacquering

Merz restoration

I have been restoring this lovely little Merz microscope, it’s a very special, rare microscope so I want to be careful not to over-restore it.

Below is a picture of it as it started out, as you can see it is fairly grubby. The stage has lost a great deal of its chemical blacking and there is verdigris on the foot where there is paint missing. There is no lacquer on the tube and the metal has become extremely dark. Of course, many people like the look of patinated brass, but to me, a completely blackened piece of brass is beyond a patina and certainly isn’t what the original maker would have wanted.

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Merz

The first step in the restoration process is to clean the microscope inside and out. Corroded screws and small parts were placed in an extremely mild metal de-corroder. Larger parts were cleaned carefully by hand using decorroder or pre-lim as appropriate. Below you can see the tube in various stages of cleaning. Note that once the tube is cleaned you can actually see the guide lines the engraver used to keep his lettering a consistent size!

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I have got to this point without using any harsh abrasives – no sandpaper, no polishing, nothing that removes any metal. Just de-corroder and pre-lim. Whilst there is still a very small amount of staining and a few small pits I did not remove them and went straight to a very, very, light straight-graining followed by lacquering.

The finished tube. You can still see the engraver’s guide lines and note that the un-lacquered parts of the microscope tube have been cleaned  but have not been polished or otherwise altered.

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Now for the paint, the paint is a mixture of dark umber and ochre pigments ground on a ground glass sheet with a muller. Linseed oil is added until a paste is formed, it takes a long time to get rid of all the lumps. The linseed and pigment paste is then thinned with tung oil and turpentine. Tung oil dries better than linseed alone and gives a higher gloss.

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I have not re-blackened the stage as I do not want to take away all signs of age and character. There are a couple of deep scratches on the stage though which look to be fairly recent and I shall probably blend them in a bit by blackening just the troughs of these scratches which are currently showing bright brass. I can do this by thickening the blackening chemical with PEG and painting it into the scratch marks with a  very fine artist’s brush in much the same way engraver’s fill their work.  That way it won’t affect the rest of the stage.

In the next post I shall show the reassembled microscope, right now the paint is drying.

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!

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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