Who's Got Ceramic Balls

[Bogstandard]

I corresponded with Jan Ridders about his test tube stirlings.

He advised against glass marbles as they very easily shatter when warmed up.

He told me that he is using, to very good effect, ceramic balls that are used in tumbling and grinding machines. They should be somewhere around 13mm diameter.

He had difficulty obtaining the ones he has, so I need to ask the question.

Does anyone know where they can be obtained from in small quantities?

It seems like the min order is about 25kgs, and rather expensive in that quantity, a kilo would last a lifetime.

Or does anyone know where to obtain the old style clay marbles?


John

 

[Brass_Machine]

John,

I have been looking myself. Please let me know if you find some.

Eric

 

[rickharris]

Why not use large dia ballbearings? they are easily available.

 

[Bogstandard]

Rick,

I have already tried them, the weight of just one did a great job of turning them into a straight, open ended tube, they knock the roundy ends off rather efficiently.

I had this discussion with Jan and he suggested I put wire wool in as a buffer, but I can see that, over time, compressing to a solid, and again, I will be making straight thru tubes.

I have thought about casting a silicone rubber buffer to fit into the bottom of the tube to act as a soft stop. But I don't know how it will stand up to constant heat. I suppose the only way is to suck it and see (try it out).

Someone out there must have come across this problem and solved it.
Maybe a coiled spring would work.
All suggestions greatly accepted.

Thanks for the suggestion anyway, it is nice to know that people are trying to help.


John

 

[Tin Falcon]

Brass machine:
Mcmaster Carr has them in a couple of different grades a 1/2 ball (12.7 mm) will run between $ 4.00 and $13 each. IIRC they are pretty close to where you live.
Bogs: If you ask BM nice he might be willing to pick up what you need and send it over the pond. For a price of course.
another source is smallparts.com
Tin

 

[ronm]

Sorry, but this reminds me of a character I used to work with...in school, he had a couple of ball bearings & rolled them down the aisle when the teacher was writing on the board. When the teacher asked, "All right, who has the steel balls?", he piped up, "Superman!!"...that was good for a trip to the principal's office...

 

[Bogstandard]

Thanks for that Tin.

I am being a bit cheeky at the moment, I have contacted a couple of manufacturers in the main producing country, China.

I am attempying to get them to send me a 1 kilo sample for free.

If you don't ask, you don't get.

I will see if being cheeky gets me anywhere.

Knowing my luck, I will end up with a container sitting outside my house, and a bill for ten squillion pounds.

If that happens I will send a few to BM, wrapped up in the bill.

John

 

[SandyC]

Rick,

I have already tried them, the weight of just one did a great job of turning them into a straight, open ended tube, they knock the roundy ends off rather efficiently.

I had this discussion with Jan and he suggested I put wire wool in as a buffer, but I can see that, over time, compressing to a solid, and again, I will be making straight thru tubes.

I have thought about casting a silicone rubber buffer to fit into the bottom of the tube to act as a soft stop. But I don't know how it will stand up to constant heat. I suppose the only way is to suck it and see (try it out).

Someone out there must have come across this problem and solved it.
Maybe a coiled spring would work.
All suggestions greatly accepted.

Thanks for the suggestion anyway, it is nice to know that people are trying to help.


John

Hi guys,

John,........... these people may be able to help.

The following companies manufacture and supply Ceramic balls in the UK.

Precision Ball and Gauge Co.
www.precisionball.co.uk

The Technical Glass Company.
www.technicalglass.co.uk

Dejay Distribution Ltd.
www.dejaydistribution.co.uk

Direct Bearings.
www.directbearings.co.uk

This latter one will definitely supply loose balls, and Dejay usually will supply small quantities, the rest may well be prepared to send you some samples…worth asking.


In the USA.... another source is Ortech Advanced Ceramics.
www.ortechceramics.com

They have an on-line store and list single balls in both Zirconia Oxide and Silicone Nitride in 12.7mm and 13mm respectively.

They would dispatch to the UK, however, shipping costs may well rule them out.

That is, unless one of the USA guys can buy them for you and ship them over (small packet gift ) as a favour... costs covered by you of course. ;D ;D

Hope you find something.

Best regards.

SandyC

 

[Bogstandard]

Just had a message back from a Chinese chap called Jack.

He is willing to send me a 1 kilo sample of either 1/2" or 13mm for the cost of postage.

I have asked him how much that will be, if it comes back at less than $50, I am on to a winner.

How many balls can you get out of 1 kilo? I suspect a hundred at least.

John

BTW, Thanks for the info Sandy, came up trumps again. If the Chinese connection fails, I have already had a look at Dejay, as they supply some nice hollow balls, just depends if they explode if heated.

 

[Tin Falcon]

Bogs by my calculations it would be more like 250 balls in a kilo.
the volume of a sphere is pi x d cubed / 6 the density of alumina oxide ceramic is .139 lbs/cu inch. 1 lb = ..45359 kilos I come up with 4 grams per ball .
Tin

 

[Bogstandard]

FOR SALE

200 ceramic balls for Stirling engines, only $2 each, postage extra.






Got to make a living somehow.

Just joking of course, haven't got them yet.

John

 

[DICKEYBIRD]

"Who's Got Ceramic Balls?"

President Tug Benson (played by Lloyd Bridges) in the Movie Hot Shots Part Deux.

I think all his body parts were blown off "in the big war" and replaced with aluminum/titanium/whatever-um parts so surely he had ceramic balls! ;D

If you haven't seen the movie, make a point to rent it. It's a hoot.

 

[AKViking]

I'd google Rio Grande Jewelry supply or Kingsley North. Both carry tumbling and lapidary supplies. I know they carry ceramic tumbling media. Not sure about ball shapes or sizes but neither require tax numbers/business licenses/accounts to order.

Chris in Ketchikan, AK

 

[ed miles]

John, search around your neck of the woods for Machine Tool Spindle repair shops. They should have bearings with ceramic balls in the scrap bin. In many cases where the spindle has a quad set of bearings in it, only one bearing has failed but they replace the whole set. This means you can find lots of good balls for your purpose. Once you get hold of some I can tell you how to get them apart without damaging the balls.

Ed

 

[Cedge]

John
Why not add a small coil spring in the end of the tube to absorb the shock?

Steve

 

[Bogstandard]

Steve,
Fast asleep and brain in neutral again.

Someone out there must have come across this problem and solved it.
Maybe a coiled spring would work.
All suggestions greatly accepted.

Thanks for the suggestion anyway, it is nice to know that people are trying to help.


John

We'll have to get you to the vet, and quick.

John

 

[Cedge]

John
I don't do too badly considering that I have flashbacks instead of memories of my youth...(evil grin). I'll work on my reading comprehension skills this week....LOL

Steve

 

[Bogstandard]

it looks like the chinese connection has collapsed, ever since i asked how much and how to pay everything has gone quiet. might be he was trying to make a fast buck behind his bosses back, and is now floating down the yangtse, bottom up.

so i will now try some of sandy's connections.

john

 

[shred]

I think a leaf spring might look nice, depending on the arrangement

If you can locate a friendly glassblower, they could make you some borosilicate glass (aka: Pyrex) marbles. Those can take considerable thermal shock without cracking and could come in about any color or pattern desired.

 

[GailInNM]

With no disrespect to Jan's opinion, there are marbles and then there are marbles. As Shred mentioned borosilicate marbles would work well. They are made for, but are just as hard to find.

For another project here, I have some marbles made for use as ammo in elastic power slingshots. They obviously have a fair impact resistance as they are intended for reuse. For fun, while following this thread, I did some crude thermal stress tests on a few of them. I heated them from cold for about 20 seconds with propane torch and the dumped them in water where they sizzled for about 5 seconds. I repeated this several times with no failure. Then I heated one to a good glow and dumped it onto a heavy steel plate and pushed down on it with a big chunk of brass to flatten it to about 1/3 of it's original diameter. I figured that should induce some good residual stresses. After cooling, I flung it against the concrete floor a few times and it remained intact. I then heated briefly with the propane torch at full blast with out problem. I also measured a few at between 0.496 inch and 0.501 inch with a couple of thousands "runout" on each one.

I know this is a crude set of tests, but I suspect they would be far more likely to cause failure than the heating-cooling cycle in the engine.

So you might want to experiment a little with marbles before discounting them. The ones I used are made by and sold under the Trumark name and are available in retail stores in the US and I think Germany. Google "Trumark slingshots". They have retail packages of 75 marbles for US$3.75 locally and sell bulk for under US$5 per pound in thier online store. They list 168 marbles per pound.