Rosin flux needle bottle users
 

In the now closed thread Liquid Rosin Flux I said to avoid catastrophic spills at all cost because your entire workbench, all the tools and testgear, and your clothes will be ruined. In particular avoid fumbling while handling the bottle as the resulting movement may be unexpected.

In the video The Bizarre Behavior of Rotating Bodies a mathematician explains the Dzhanibekov Effect in simple terms, using a needle bottle as an example

Re: Rosin flux needle bottle users
 

The Youtube algorithm fed me that video a couple of weeks ago. Very interesting.

What's the deal with liquids in unstable flat-sided bottles?

Attachment 237455

Are they designed to topple over and spill?

In the TV rental trade in the '70s we used gallons of Joynes Waxless Polish, which came in a glass flat medicine style bottle. I think most of it was accidentally used to polish the bench tops when the bottle got knocked over.

Re: Rosin flux needle bottle users
 

Most generally, a flat sided-bottle is wide and more visible on the shelf in the supermarket! It's not an efficient use of plastic, and it may well tip over and spill, but the key factor is that it gets sold.

For stuff like flux, that may not be a requirement, but the bottle makers are set up to make bottles of that form.

B

Re: Rosin flux needle bottle users
 

I keep the old bottle and decant a small amount from the new bottle, just enough so it does not run out when laid on it side. It will not prevent every spill scenario, but ok for when I knock it on it's side. I do it to tins Brasso as well.

John.

Re: Rosin flux needle bottle users
 

Great video!

Planet Earth is a bit more complex than a hard bottle filled with lossy fluid. The surface is somewhat fluid/flexible and floats on the core fluid. The rotation causes forces which make it an oblate spheroid, so the rotation about the axis with maximum moment of inertia is interesting because the rotation sets which axis has the maximum moment of inertia. There seems to be a loop of causality. This could be stable or unstable and I don't know enough to work out which.

Additionally, the fluid core is magnetically active, and there are further forces as a consequence. Oh, and there's the movement of the two bulges in the oceans... the tides caused by the moon (and lesser ones due to other bodies...) So now the lunar orbit gets thrown into the mix.

It's left me wanting a tennis racquet.

Back to radio, soldering and flux. Liquid flux is sticky-messy enough in a nice reliable gravitational field. I'm not sure I'd want to go soldering in zero gravity and releasing little particles of spatter to float around. Solder particles are conductive and flux is chemically active. Nice!. Murphy says they will move to the place of maximum mischief.

Needle bottles of liquid flux may not be desirable in orbit.

David

Re: Rosin flux needle bottle users
 

Odd as it sounds I use an aerosol flux can, with gentle pressure I can deliver very small drops of flux from the tube. The tube is clear and I can see the drop arriving, the drops are separated by the propellant gas.

Re: Rosin flux needle bottle users
 

I have read that it is the moon that prevents the earth from flipping. Our moon is the largest in relation to its planet in the solar system. Earth and the moon are effectively linked by the gravitational attraction between them and this acts to stabilise the axial tilt.
Venus has no moon and has flipped in the past so that it rotates retrograde.

Peter

Re: Rosin flux needle bottle users
 

I have a similar little flat sided little bottle which has my surface mount flux. It's rather sticky and a pain to get off anywhere too. It has a brush applicator which is useful. I have it permanently stood in a larger high sided glass jar. It might have been an old paste jar or similar and is about half as high as the bottle. That way the bottle cannot fall over and if liquid ever ran down the bottle it would collect in the jar.

Re: Rosin flux needle bottle users
 

I love my needle bottle. Would struggle without it .:thumbsup:

Re: Rosin flux needle bottle users
 

I like gel flux better.

Re: Rosin flux needle bottle users
 

I see it has ribbing too, so perhaps its form is a survival of a long-established convention for substances "not to be taken" to come in flattened bottles with tactile surfaces easily recognised in dim light and by blind folk once they knew the implied warning. I've picked up several 1920s/30s glass examples at a nearby bottle dump: Jeyes Fluid, Sanizal etc..

Paul