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Yet another DIY slide ringing table
Posted: Wed Oct 28, 2020 12:11 pm
by Hobbyst46
Here is another DIY ring table, constructed mostly of scrap. Old dead PC hard disk drives provided the "engine chassis". All the gadgets inside the drive, except the spindle, were removed (especially the magnet). Altogether three platters were stacked to form a ~5mm thick wheel. The shaft was long enough to directly carry two platters, and the third platter was superglued on top, taking care to preserve coaxiallity. A printed drawing of concentric circles was glued on top of that, with paper glue. The base and arm-rest are made of wood and were coated with foam paper, to make it more presentable (just acceptable to me).
The slide is held in place by means of two Neodymium magnetic disks. Since hard disk platters are non magnetic, I superglued onto the top platter two juxtaposed rectangles of magnetic metal sheet (shims remnants), ~0.2mm thick.
To use the ringing table, I "pull" the wheel with one finger, then apply the sealant. Rotation lasts 11-13 seconds. This is far below aspirations, since the mass of the wheel, after all, is low. On the other hand, it works for me, at least with my sealant - nail polish. One advantage is the easiness of concentric alignment of the coverslip on the slide.
Clearly, the size and strength of the magnets are important. The disks are grade ~50, diameter 12mm, thickness ~2.5mm. Smaller disks will not do.
All appropriate precautions with Nd magnets apply !!! do not let them collide with each other. They are fragile.
Re: Yet another DIY slide ringing table
Posted: Thu Oct 29, 2020 6:37 pm
by hans
Nice to put an old hard drive to use. The problem I have is I slowly accumulate them thinking they will be useful for something, but then inevitably give up and throw them out just before a good idea comes along.
Re: Yet another DIY slide ringing table
Posted: Thu Oct 29, 2020 6:39 pm
by EYE C U
drive a nail through them first
Re: Yet another DIY slide ringing table
Posted: Thu Oct 29, 2020 6:40 pm
by Hobbyst46
Yes, I collected platters from several drives. They are all the same size. One needs torx screw drivers to dismantle.
Re: Yet another DIY slide ringing table
Posted: Fri Oct 30, 2020 12:23 am
by KurtM
Cool! What are you using for "ringing cement", and how is it working for you?
Re: Yet another DIY slide ringing table
Posted: Fri Oct 30, 2020 8:03 am
by Hobbyst46
KurtM wrote: ↑Fri Oct 30, 2020 12:23 am
Cool! What are you using for "ringing cement", and how is it working for you?
Thanks, Kurt !
so far I only used what was available - ordinary nail polish (NP).
It takes a couple of days to solidify completely and stop smelling of the acetate solvent and/or of Pleurax itself (Pleurax smells of phenol).
Gel NP might perhaps last longer, but is so viscous that I consider it unfit for ringing.
A good sealant should, among other properties, be resistant to immersion oil AND the solvents that remove oil. AFAIK, NP resists IPA as well as ethanol and heptane/petrol ether.
Are there easily available better cements ? what would museum curators suggest ?
Re: Yet another DIY slide ringing table
Posted: Fri Oct 30, 2020 9:32 am
by MicroBob
Hi Doron,
nice ringing table design from widely abvailabe parts! The next step might be an automatic ringing table with USB connection.
I built my table from heavy steel rollers from either a forklift or an elevator, a design useless for others as these parts are not available to copy the design.
So far I use rust protection paint from ALDI for making rings. It is creamy, has good adhesion and is resitant to cleaning solvents. I got two other ringing paints from a group member, ethanol based. One is black, applies nicely, but contains a bit little small amount of black pigments. The other is stained ultramarin blue but unmixes heavily unlike any other paint I know. The colour is nice but the base a the pigments are just not connected well enough to each other.
The classic ringing paint is shellac, dissolved in ethanol (96% household quality is good enough). It usually is stained (if at all!) with soot. The best soot is said to come from acetylene flame, but other soot will probably do as well. It might be an idea to put the soot through a fine sieve to remove bigger bits. The soot should be applied gradually to avoid the buildup of lumps.
In woodworking shellac is said to have a very limited shelf life. This also applies in lesser extent to the flakes. Just last week I tried to dissolve flakes that were over 10 years old - no success, the flakes swelled but didn't go beyond gummi bear consistency. Fresh flakes dissolve very well and shellac is nice to use.
Bob
Re: Yet another DIY slide ringing table
Posted: Fri Oct 30, 2020 9:57 am
by Hobbyst46
MicroBob wrote: ↑Fri Oct 30, 2020 9:32 am
Hi Doron,
nice ringing table design from widely abvailabe parts! The next step might be an automatic ringing table with USB connection.
I built my table from heavy steel rollers from either a forklift or an elevator, a design useless for others as these parts are not available to copy the design.
So far I use rust protection paint from ALDI for making rings. It is creamy, has good adhesion and is resitant to cleaning solvents. I got two other ringing paints from a group member, ethanol based. One is black, applies nicely, but contains a bit little small amount of black pigments. The other is stained ultramarin blue but unmixes heavily unlike any other paint I know. The colour is nice but the base a the pigments are just not connected well enough to each other.
The classic ringing paint is shellac, dissolved in ethanol (96% household quality is good enough). It usually is stained (if at all!) with soot. The best soot is said to come from acetylene flame, but other soot will probably do as well. It might be an idea to put the soot through a fine sieve to remove bigger bits. The soot should be applied gradually to avoid the buildup of lumps.
In woodworking shellac is said to have a very limited shelf life. This also applies in lesser extent to the flakes. Just last week I tried to dissolve flakes that were over 10 years old - no success, the flakes swelled but didn't go beyond gummi bear consistency. Fresh flakes dissolve very well and shellac is nice to use.
Bob
Thanks Bob !
some articles suggested motors from trashed VCR's, but my VCR died and had been trashed years before I started hobby microscopy.
I do have rust protection paint, it is a stuff that changes color when exposed to sunlight. Sold in 0.5-1liter cans. Will give it a try maybe.
I also have shellac, beautiful orange-brown flakes that do dissolve in ethanol. I was just thinking that shellac is less appropriate because:
(a) it has poor water resistance; so, if accidentally touched with the fingers...
(b) it dissolves in ethanol, so the slide cannot be cleaned with ethanol anymore.
(c) moreover, upon ringing, the ethanol of the shellac solution will penetrate into the Pleurax and lower the RI (??)
But these are not necessarily real issues. E.G. nail polish contains a solvent that probably also dissolves Pleurax, yet I use it so far...
And shellac IMO is more pleasant than metal paint. I must try it !
As for the soot, ordinary soot from a candle flame is essentially microscopic particles so IMO no need to sieve it.
Do you have Pleurax slides ringed with shellac, that stood the test of time (not decades
) ?
Re: Yet another DIY slide ringing table
Posted: Fri Oct 30, 2020 2:07 pm
by MicroBob
Shellac was much about all they had 100 years ago and it has been used even when alternatives became available. I don't have slides to prove the durability of shellac rings but I don't have doubts according it's longevity. For slide cleaning I use brake cleaner or lighter fluid that won't harm a shellac ring. Shellac is quickly damaged by ethanol but I don't think that limited contact to water harms it. A wet flower pot would damage shellac after some time though - have to remove flower pots from my microscopy tables!
How the ringing paint will interact with mountants is a big question. It might even lead to a more durable, less brittle mixture in the contact zone. Another aspect will be the diffusion resistance: This is the most important property for the sealing effect to take place. I think today other paints can be used as well as long as their mix of properties is useful. Important is good adhesion - the paint has to attatch easily to the glass and spread out well. I recently bought a water based paint and was astonished to find that it your drips of of the wood without making intensive contact to the surface.
I'm sitting right across from out living room woodstove and was thinking about using soot from the stove pipe. In candle soot there probably is nothing of a size that would disturb.
Re: Yet another DIY slide ringing table
Posted: Sat Oct 31, 2020 1:29 am
by KurtM
Here in the USA, I have tried quite a few ringing cements looking for that perfect one that will play well with Pleurax mounts (diatoms), and glycerin jelly mounts (pollen), and ended up calling Testor's black enamel the best of the bunch. It's a hobby paint most commonly known for dolling up plastic models, see:
https://tinyurl.com/y39p26p2
Rod tried it, and agreed:
viewtopic.php?p=28006#p28006
But that's here in the USA, can't begin to say if you have it or anything like it available over there (although I would assume hobby paints are a worldwide thing?).
PS: Doron, I still have those tiny shells safely stored in my lab, but just haven't had much lab time in the past couple years. Even now there's 200 miles between me and my micro-stuff. But I wanted to let you to know it's still perfectly possible to log in one day, and be surprised to see images of them.
Re: Yet another DIY slide ringing table
Posted: Sat Oct 31, 2020 2:45 am
by BramHuntingNematodes
I use shellac to finish my viola bow because it is traditional. I don't use it for much else. It's a good looking finish and a superlative seal, but relatively fragile in comparison to modern synthetics. Touching or cleaning it frequently will cause damage. It gets increasingly brittle as time goes on. Alcohol will strip it very quickly. It doesn't like heat. It's sometimes used under more durable finishes in cabinetry because it makes it simple to take the finish off, so readily does it strip in alcohol. You could put a layer of something on top of it if you use it to toughen it up.
Re: Yet another DIY slide ringing table
Posted: Sat Oct 31, 2020 9:35 am
by Hobbyst46
Thanks, Bob, Kurt and BramHuntingNematodes.