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About uguntde

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    Birmingham UK
  • Interests
    Science, NMR, string instruments

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  1. uguntde

    UV Cabinet

    I recently tried UVC 35W for tanning (2 90cm tubes) - works extremely well. Just need to switch it off before opening the box, as UVC damages about everything on the human body.
  2. uguntde

    Can anyone help translate/read this?

    Makes some sense as the last letter of that name could be an ü. Hath..ü, could also be Häth zu Karlburg. The name Johann is as German as it gets, but also known as a Hungarian name. In their list starting with H nothing Hungarian suits your label.
  3. uguntde

    Can anyone help translate/read this?

    But there is no squiggle over u in Karlburg and the letter in the na,e looks clearly like an a. Hath or Häth. Admittedly, this would be a strinage sounding name though. The script is also not a cear altdeutsche Schrift, but a mix of the same and Druckschrift.
  4. uguntde

    Can anyone help translate/read this?

    Maybe he means that he replaced the front, looking at the front as a Deckel?
  5. uguntde

    Violin ID (again)

    Where would the red varnish drops on the inside come from? It doesn't look as if the varnish had been sprayed on.
  6. There is now a Facebook group to sell violins ... trying to look more serious than ebay. What I have seen there was massively overpriced or rubbish.
  7. uguntde

    Removing shellac overvarnishing. Help!

    Rub the new spirit stain stuff off with ethanol or isopropanol, hoping that the varnish underneath is not spirit soluble. Even an old spirit varnish will not come off easily. But you can make a terrible smear with this method, you may also be lucky. Otherwise there is probably no such thing as fine grit sand paper.
  8. uguntde

    Tool rust advice

    Vinegar will cause a disatser for some metals, please be vareful. Phoshoric acid works. I would get car rust remover.
  9. I thought Austria just offered the Tyrolians citizenship, so what's the difference?
  10. uguntde

    Thoughts on this interesting violin? n

    The fittings are old English fittings, probably made of holly. I see these pegs a lot on in England. Scratched in purfling is typical for some simpler 19th century English instruments. The scratch marks may have been done by a kid who was bored by practicing .
  11. uguntde

    Purpose of tuning the fingerboard

    I have a really good sounding viola. It is made very light, with a light fingerboard with reduced thickness (many Degani violins have this). If I don't touch the neck the open A has a strong wolf. As soon as I touch the neck this is gone (this is why it took a while until I noticed that interesting feature). I then experimented with small weights - I used roofing lead with doublesided tape - to tune this fingerboard. And with an extra 2g of weight the wolf disappears. The overall sound character is not much influenced though. I can try to get a spectrogram with and without the lead to identify how it shifts A0.
  12. uguntde

    Oil Varnish

    Chemists would use an electrical heating mantel. But this does not distribute heat evenly, nor does a sand bath. You also need a magnetic stirrer to keep temperature exposure more even. All of this seems an overkill, I can't see classical makers using anythong but a wood fire, maybe an oven, but without any temperature control.
  13. uguntde

    Oil Varnish

    The melting point of abietic acid is around 175˚C. A 'foaming point" is not a chemical property. Melting = boiling. This will be lowered by imputities (ebullisocopic propertes). If you slowly change colour you get all kinds of oxidisation products, unlikely carbon. If you really burn it you end up with residues of what is there besdies abeitic acid and some tar like long chained products, besides CO2 (in the presence of oxygen). Some slowly oxidised rosin can have very desirable colours for varnish. If I ready Hargrave's bass article correctly he colours his varnish just this way or by adding a little nitric acid. However 200 ˚C is certainly enough for all of this.
  14. uguntde

    Oil Varnish

    I think the darkening of the colour is a kind of burning the rosin. I can't see an oxidisatino process that would change the colour in the same way. The burn fraction is probably small and may have a desirable effect on colour. But some of it is probably not abietic acid any more.
  15. uguntde

    Choice of linseed oil

    I compared Kremer refined linseed oil with a food grade cold pressed oil from ebay ( they both dry. The latter I washed with water for several weeks. I will soon qualitatively compare drying times.