A repository of caveats, version II


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I don't see that workshop safety issues have been mentioned.  I feel it is important enough to have it's own topic heading.  I haven't found it by searching, but I'd be surprised if it hasn't been dealt with over the years.  If it has, please direct me to it, and if not, I'll start a thread.

Good one.

Safety first, and second.

Pete

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I bought a cheap induction hotplate, thinking it would be the safest option for cooking varnish. It works very well; it doesn't heat up itself, so any spill lands on a cool surface. I cook my resin and varnish  in my old BBQ. I leave the hood closed over enough to keep any rain out, so I can leave the rosin stew away outside the workshop. The vapors blow away, but they can hang about under the hood a bit. I made my varnish and all was well.

 

HOWEVER..

 

The hotplate is cooled by a fan, which draws in air from behind and sends it out the bottom. When I went to clean up I found the fan dripping with condensed syruppy rosin. I'd say that given enough time the fan would gunk up completely - probably as much a fire hazard than the varnish itself.

 

So,

 

The hotplate is great, but make sure it has a fresh air source for the fan!

 

Conor

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When you drop a knife, don't slam your knees together.

I had a bridge knife fly out of my hands one day, do a double somersault in front of my eyes, and swan dive into my thigh.  I was so proud of myself for not moving my leg out of the way and letting the knife hit the floor, thereby saving having  to regrind it.

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Once a knife has left your hand or fallen from the bench......"the die is cast".  You just have to grit your teeth and accept the results. Trying to get out of the way is a crap shoot.

 

I am very impressed with Jacob's admonition not to try to clap your knees together.   So few words .... such a vivid picture!  It's almost poetic.

 

Mac

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This is a pet peeve of mine.

Don't drop a bridge after you have fit the feet!

Much like the jelly side always landing on the ground, a dropped bridge will almost always land on a perfectly fit corner of a foot.

 

The resulting divot will almost always require further foot fitting. DAMMIT!

 

And I always seem to drop them right before I finish the cursed thing. Perhaps because at that point I handle the thing like a baby bird?

 

Anyway, caveat= don't do it.

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Some years ago the magazine Changing Times published some of the theories of an obscure scientist named Gumperson. This gentleman had come up with a theory about life that he formulated into a basic law: That the contradictory of a welcome probability will assert itself whenever such an eventuality is likely to be most frustrating.

That sounds pretty complicated, but the sense of it can be easily seen in the following "laws" that Dr. Gumperson formulated from his basic premise...

That you can throw a burned match out of the window of your car and start a forest fire, but you can use boxes of matches and the entire edition of the Sunday paper without being able to start a fire under the dry logs in your fireplace.

That after a raise in salary you will have less money at the end of the month than you had before.

That person who buys the most raffle tickets has the least chance of winning.

That good parking places are always on the other side of the street.

That a child can be exposed to the mumps for weeks without catching them but can catch them without exposure the day before the family goes on vacation.

Gumperson, it is said, met an untimely death shortly after WWII. He was walking along a highway, dutifully obeying the rule of walking to the left facing traffic, when hit from behind by an Englishman who was hugging the left side of the road.

—Although I found this on line, it appeared years ago in a column by Sidney Harris in S.F. Harris added that Gumperson was wearing an orange slicker and carrying a red lantern, too.

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David sometimes I envy your weather....

 

I have witnessed the problems that surface when Joe's rule is not followed....lots of extra work.... IMHO Joe's comment goes hand in hand with Will L's post.

 

Hard thing, is finding a good day in the rain forest..... :)

It follows that one should varnish indoors when it is raining......

still paddling,

Joe

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  • 3 weeks later...

At a Cleveland VSA there were a few examples of the Michelman varnish and they easily chipped.

 

This goes to prove how much work is really needed to develop varnishes. Here on MN we read about some weekend miracle that lead to claims of a new great varnish, but as Burgess notes, time tells a different story. That's why I gave up on developing varnish. Yes, it was fun, and I still love reading about experiments. However, it is work and competes with learning how to make a good violin.

 

Here's another little caveat about Michelman Varnish - the color is very sensitive to pH. This, I believe, is a property of alizarin lakes. I have an old test strip of the Zn-rosinate that seems to change color with humidity. I attribute that to absorbed atmospheric moisture that changes the pH. I recall as a kid having a device that changed color with the humidity - maybe the same chemistry is involved here. So, the trick is to lock up the metal-alizarin lake and "freeze" its ionic structure in your varnish. No matter whether my theory is correct, this is too much R&D for me.

 

Speaking of time, recall the stories about some modern makers' violins turning black because of slow reactions from long-lived nitric acid in the varnish. I just do not want to wait a couple of years to prove out a varnish. I guess I am just impatient.

 

Mike

 

 

I have only just started reading this and it all kind of precedes what I was about to say about varnishing the double bass but... Mike you are right about lakes generally, but especially Rosinates. They can react like litmus papers to both acids and alkalis. Which was what was happening to Dons experiment. I have made many hundreds of “lakes” in different ways and spent, as I am sure many of you have, thousands of hours and thousands of Pounds and DM’s and Euros and even a few USD’s. Neil also made many Lakes with me as did Koen, but for me they now almost (not quite entirely – never say never) carry a caveat themselves. But perhaps someone has already said this. Maybe I should have read on first, oh well! 

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But I will.  I thought it was worth adding to my reference data, and good thing I did, so I can paste it back here:

 

(from Captainhook)

I've made 15 or 20 fiddles with sodium silicate with generally better results than without. I use a drug store 46% solution diluted usually 3 to 1. However, the thicker stuff does not penetrate as much. After the silicate (all excess wiped off) I apply liberally a 10% calcium chloride solution, which reacts with the WG to form insoluble calcium silicate and sodium chloride. I'm sure the reaction is not complete, but the precipitated calcium silicate is within the wood rather than on the surface. Then, as VD (oops, Violadamore), I finish with a liberal vinegar wash, which converts most remaining soluble silicate to insoluble silicic acid in the form of approximately 0.2 micron diameter particles, again mainly within the wood. BUT I AM NOT RECOMMENDING THIS TO ANYONE. I AM A CHEMIST AND THEREFORE CAN GET AWAY WITH THINGS THAT OTHERS CANNOT.

 

 

I believe that has come to refer to Darnton Mastic Varnish.  Either that, or Department of Motor Vehicles.

 

 

Reading on; here is another caveat. With respect, you clearly know what you are doing, but in my opinion this is too complex. Complexity is also a caveat for me. I had to look up this word by the way. You are so well educated David. It’s such a shame that you don’t look it. Just kidding!  

Go ahead and use complex methods, but I doubt (even though they knew lots) that the classical makers made such a big meal out of varnishing. Some recipes may have been complex, but I doubt that their methods of application were. We must not confuse that which looks good and sounds good today with that which they were doing. There are two more things about this that I will talk about more on my bass thingy; time and deterioration. Time has certainly changed the appearance of varnish films, and we should not lightly condemn deterioration. We are not making boats that need all weather protection. Indeed, it seems to me that Cremonese varnishes were not particularly robust. Grounds perhaps, but varnish not. 

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A while back, I cut my hand on a razor-sharp tool, and started bleeding profusely. Grabbed some paper towels, but they didn't absorb fast enough and blood was going all over the floor, so I decided to grab a bucket from the next room. Got out of my chair, slipped on the blood, and went down like a Jamaican on ice for the first time, hitting my head hard on the floor. Made me woozy, but didn't lose consciousness, or it might have ended right there.

 

Did I learn anything? Probably not, but at least I've considered the following:

If you work alone, hire a cute nurse to be in constant attendance.

Address the risk the same way Guarneri did, by learning to avoid the use of sharp tools.

Wear one of those electronic things around your neck, intended so that old people can summon emergency assistance if something goes wrong. In my case, it would need to be modified so that it's automatically triggered by a tilt indicator, in case I'm unconscious and bleeding out on the floor. :lol:

 

On not varnishing, if you need to ask if it's a good day:

I'm always apprehensive about varnishing, and always wonder whether it's a good day. That's why none of my instruments would have varnish if I followed that rule. :)

I won't varnish unless I'm having a fairly lucid day, and there aren't thunderstorms in the forecast (it's too hard to varnish by flashlight if there's a power outage). My varnishing method is a fairly simple process, but it's time sensitive, technique sensitive, and there's still a lot that can go in a less than ideal way.

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You are so well educated David. It’s such a shame that you don’t look it.

But now that I'm sporting a beard (at least temporarily), people are saying that you, I and Joe Grubaugh  look so much alike, that even our mothers wouldn't be able to tell us apart. :D

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On working alone. I was eating lunch one day and swallowed an especially dry piece of meat that then got stuck in my throat. Would not come up, would not go down. I threw myself over the back of a couch, essentially the Heimlich maneuver, and dislodged the blockage. If you are alone either don't eat lunch or learn how to deal with a chocking situation.

 

Sharp tools vary rarely have caused me injury. Typically I cut myself on opening knives more often than on a bridge knife.

 

Oded

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 Indeed, it seems to me that Cremonese varnishes were not particularly robust. Grounds perhaps, but varnish not. 

 

I've seen Amati family varnishes that seem to have endured the centuries remarkably well. In fact if i had to come up with a rule of thumb I would say that the more highly colored the (Cremonese)  varnish the more fragile it tends to be.

 

But I could be wrong about that :-)

 

Oded

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I've seen Amati family varnishes that seem to have endured the centuries remarkably well. In fact if i had to come up with a rule of thumb I would say that the more highly colored the (Cremonese)  varnish the more fragile it tends to be.

 

But I could be wrong about that :-)

 

Oded

 

 

You may well be right. Perhaps later additives (color or whatever) weakened the varnish or perhaps they used different ingredients. I remember that Charles Beare once suggested that varnishes were most susceptible to wear in the first few years, and that after that they gradually became harder. He suggested that because del Gesù was making for jobbing musicians they received more wear more quickly.

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