More Experiments with Hide Glue

Hot hide glue, as the name suggests, needs to be heated before you can use it, to melt it from a gel state to a liquid. Overheating it will damage it, so it's typically heated in a double boiler (bain marie). Carpenters of old would use big heavy cast iron or copper double boilers on a stove, and learned from long practice how to maintain it at the right temperature[1] and dilution[2] by judging its consistency. When I started using hide glue, I used a glass jar balanced on some coins or washers in a pan of water on a portable electric hob, using a thermometer to keep an eye on the temperature. This was rather a pain, particularly since the hob doesn't have a thermostat and would happily bring the pan up to a rolling boil if you got distracted and forgot to switch it off. I found myself putting off doing jobs that needed hide glue because of the hassle of keeping the glue at the right temperature for as long as the job took.

The modern (for 1950s definitions of 'modern') solution to the problem is a thermostatically controlled electric glue pot. Unfortunately hot hide glue is a bit of a niche thing mainly of interest to antique restorers and musical instrument makers, so there aren't many of them on the market and they are horribly expensive. Second hand ones seem to be very rare and keep their resale value well.

So I went looking for a cheaper alternative. I've heard of people using electric baby bottle warmers, however I don't know if the temperature controls on them go as high as 60C (Do they? The adverts I looked at all said meaningless things like, "the ideal temperature for your baby."), and while I was Googling around looking at different options, I stumbled across a forum post where somebody mentioned using a mini electric deep fat fryer. A bit more research and I ordered one of these for only fifteen of your British pounds, postage included. And it's ideal for the job. Collapse )

I keep the glue in a small Nutella jar (the type that's like a drinking glass with a plastic lid). I made a Perspex disc that fits snugly inside the cylindrical fryer pan, resting on top of the stainless steel basket. It has a hole in the middle that the glue jar fits tightly in, and a smaller hole for the glass mercury thermometer. This keeps the jar from moving around and minimises evaporation from the water bath. Closing the lid when it's not actively in use will reduce evaporation and heat loss even further. The water (filled to just below the Perspex disc) heats up in a couple of minutes (the glue takes a bit longer to warm through), and the thermostat maintains it at the set temperature to within about +/- 2C. The numbers on the front panel are way out, so you do need to use a proper thermometer to find the right setting in the first place (in my case, 60C seems to be slightly over 90 on the dial).

Best of all, it can also make very nice deep fried chips. Try that with a baby bottle warmer! The only disadvantage really is that it takes up quite a lot of space on the workbench, though not as much as the electric hob and pan did.

Edited to add: My earlier mention of electric glue pots being 'modern' in the 1950s was a wild guess. I just got curious about when they were actually invented and did a bit of poking around. Take a look at this patent filed in 1894!

[1] Various sources on the net recommend glue temperatures of around 60-70C, usually the lower end of the range. I get the impression that it isn't terribly critical. Too low and the open time suffers. Too high and it deteriorates, though time is also a factor. Briefly letting it get up to 90C probably won't weaken it very much but running your pot at 75C all day long might.
[2] Water continually evaporates from the hot glue, so you have to occasionally top it up to keep it from getting too thick.

Tuning a Melodica

I spent most of today fixing and tuning my old and rather clapped-out Hohner melodica. It's a cheap and cheerful instrument, mouth-blown rather than bellows, with a two octave range, a fully chromatic keyboard and one free-reed per note (so it sounds rather like a concertina). Collapse )
Bigger hammer

Success with the electric chainsaw sharpener!

A sharp chainsaw cuts like a dream, zipping quickly through the wood and producing a nice stream of big clean wood chips with no effort on the part of the operator. A blunt one slowly burns and polishes its way through the wood, making dust rather than chips. When they are really bad they cut a curved slot and get stuck after a couple of inches. Chains stay sharp for quite a while cutting green wood, but dry wood will wear the edges quicker and accidentally touching the ground with a running saw can trash the blade in an instant. Collapse )

Another Kind of Bellows

After being repeatedly frustrated by my camera's inability to take good photos of the tiny things I've been working on lately, I decided to look into putting together a low-end macro photography setup. A 'true' macro lens was well over my budget, so I did some reading about extension tubes and bellows and reversing rings, etc. To cut a long story short, I ended up buying an old set of macro bellows with a 60mm enlarger lens on the front. Annoyingly I found that I also needed to put a short extension tube between the bellows and the body because it wouldn't physically fit without one. Collapse )
Bigger hammer

Grounding Tool

I forged a carving chisel today: a small grounding chisel. These chisels made by Ashley Iles were my inspiration, but for the work I'm doing I thought it would be better to have a flat edge with a slight skew. They are used for flattening the bottom of a shallow cavity for relief carving or inlay work. I need a couple of really narrow ones for inlaying the twiddly sheet metal decorations on my new concertina ends. You use a scalpel to make a stop cut around the edge of the cavity, then use the grounding chisel to carve out the waste between the stop cuts. My plan had been to make a 3mm wide one first, then try to do a 1.5mm one.[1] Turns out it is extremely difficult to forge tiny tools.

My first attempt took all morning. The edge turned out about 6mm wide and a less than ideal shape. I must have got something wrong with the heat treatment too[2], because it refused to take a decent edge. After pondering the problem over lunch, I decided to cut off the tip and re-forge it as narrow as I could. About an hour and a half later I had produced a new tip that was about 4mm wide and a better shape. I think I solved the heat treatment problem too. Still not as narrow as hoped, but it is a useful width, so I decided to make a handle for it as it was rather than cutting the tip off again and trying to make it even narrower. Collapse )
Bigger hammer

Thoughts on the New Ends

I've been thinking about all the techniques that will be involved in making the new ends for my concertina. Several of them I have never done before, or not to the level of detail and finish I'm aiming for here. I've decided that it would be a good idea to make a partial end first to practice on, as I would hate to make an elementary mistake and ruin one of the real ends at a late stage in the process. Here's a photo of the kind of end I'm planning to make. I haven't yet decided whether to do the fretwork in the middle circle around the key holes - my concertina probably didn't have it originally (like this one).

Mainly to get my own thoughts in order and make sure I don't forget anything, here's a list of the steps that I think will be needed to make the new ends: Collapse )