Michael.N.

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About Michael.N.

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  1. French Polish materials

    I was taught French polishing some 40 years ago. I think I've pretty much tried all manner of combinations throughout the years, different cloth types, oils, shellac type and various alcohols. I've been using isopropyl for a good few years now, not really noticed any difference between that and industrial ethanol. They flash off at different rates but the difference isn't worth worrying about. Cloth; cotton or linen both work. Waxy shellac is slightly softer but usually has more colour. Depends if you want more of a clear finish. I use mineral oil but I've also used linseed, olive and walnut. They all work.
  2. Everclear alcohol

    I've been using the high % isopropyl alcohol for several years, buying it in 5 litres. It's water clear, supposedly flashes off slightly slower than ethanol. In use I can't notice the difference whether brushing or french polishing. Don't know what the health problems are, wear a glove when French polishing, use a well ventillated area.
  3. Shellac

    I haven't found glair to be any better than shellac, at least not in an optical sense. Try them both side by side on an off cut.
  4. Polyurethane

    You could try Tru oil, which I think is a type of linseed/alkyd varnish. It's a thin wipe on finish but it can be brushed on (very easy to brush). It dries relatively fast, probably because of the added driers. On a test piece I brushed on 8 or 9 coats in one long day (one single UV light in the cabinet) and rubbed it all out to flat gloss the very next day! I mean guitar flat gloss too. The woodwork was taken to a very high grit which obviously helped to achieve a finish in such a short time. Of course there's no need to rush. I was just finding out if it could be done. No colour though (or very little). It's also readily available.
  5. Colophony shelf life

    I don't know what grade the Kremer stuff is. I don't think it is stated. I have bought some WW grade from another supplier but I've none of the kremer stuff left, so I can't directly compare. It probably doesn't matter, a varnish of some sorts will result. Next batch will be the Roger H. rosin straight into oil, the one he calls 'boring'. I don't need colour ( for a guitar) but I do need reasonably hard, so 60% 40% resin oil ratio might do it. The last one I did was cooked at 200 C or under. It has some colour and rather nice it is too, if you like yellow/amber.
  6. Colophony shelf life

    Over cooking/temperature too high can certainly produce a greenish colour. I've done it, yucky green brown. I still have the varnish. The only good thing is that it dries very fast. That's not much use when you can't use the stuff though.
  7. Colophony shelf life

    Yes. It's the stuff in a jar. Try putting that number in Kremers search box.
  8. Colophony shelf life

    60305 is the stuff that I used. Kremer even state that it is suitable for violins. In the past I've used powdered rosin (not Kremer) and that was obviously light in colour too.
  9. Glair and Oil Varnish

    I've tried the egg white on many spruce off cuts. Being lazy I left the remainder of the glare sitting in the cup for a few weeks. Apart from it crazing (not a concern when used as it normally is) it feels like a pretty hard resinous like substance, perhaps not that different from a shellac flake. I also tried to put multiple coats of egg white on. It's water soluble so the 'finish' probably never became that thick. Perhaps not surprisingly the optics weren't great, a bit murky looking. I suppose if you use it just as a sealer it will be OK. I think I prefer shellac though.
  10. Varnish, quick and dirty.

    100 hours is a quite a lengthy cooking time. I'll have to use a sand bath to save on the bills!
  11. Varnish, quick and dirty.

    Well I suppose I could always put it back in the pan, cook longer or take the heat towards 200 C. It's all good experience. I don't know if it's too late to add the lime but I can try that too.
  12. Varnish, quick and dirty.

    No, more like 1". I'll try it on wood today and find out how it dries over the next few weeks. This is all experimental, it's highly unlikely to be used on actual instruments - unless it proves itself over time. What is the purpose of the lime? Presumably it adjusts the ph but I've also read that it helps prevent imprinting, is that the case?
  13. Varnish, quick and dirty.

    I had some unused colophony left over from a batch of varnish that I made many years ago. The varnish turned out well but I promised myself that I would never make it again. Fumes, neighbours - no need to explain further. Then I came across the Courtnall/Johnson low temperature recipe. In went the colophony, heated to the point that it melted, which was around 110 C. I didn't have any linseed so I substituted some supermarket walnut oil that I had. I cooked together at 125 C for just over an hour. 45/55 oil to resin, no mastic. It had great clarity whilst hot but after I decanted it into a jar the varnish turned rather cloudy and murky looking. It had very little colour but at least it was clear enough when put on wood. A bit of a slow drier as it takes around 14 hours to become touch dry (UV cabinet). It was also sensitive to heat, taking a thumb print even after a few months of drying. Today I decided to put this varnish back in the pan. Another hour at 125 C but this time I spiked it to 160 C, perhaps just for 5 minutes or so before allowing it to settle back at 125 C. Now it's back in the jar and the murky looking varnish is now very clear. I suspect it will still be a little slow to dry. little colour and still heat sensitive. I'll find out soon enough. I'm now tempted to make another batch but using linseed, up the ratio to 60/40 and perhaps add a little lime. The fumes were nothing like the high temperature treatment of rosin, thankfully. In actual fact I did it all indoors but it was a very small batch.
  14. Oil varnish shelf life

    I have a batch of pine resin varnish that's nearly 20 years old. It's thickened up a bit but with a touch of turps it still makes for a nice varnish.
  15. French Polish ( Article )

    Over polished. That might be the clue. It isn't necessarily the shellac that is the cause, although it's possible that certain types of shellac exhibit this problem. I don't recall seeing it on any guitar though and countless thousands have been finished with shellac. They tend to use the more refined/bleached grades (dewaxed) but button lac isn't unknown. I've used anything from seedlac right through to blonde and platina. Platina is the one that I have little experience with and it's certainly too early for me to come to any conclusions about it. Guitar makers do use this grade and I've never heard of brown green reports. It's a pretty clear grade, so it would have to change an awful lot.