bogateer

Okay...here's a trivial question of obscurity but my curiousity has gotten the better or me. On the older metal reed valves...why were they coated with beryllium, a [now] known toxic metal?

Thanks,

Rob

ptulmer

My Feedback: (5)

Take two and call me in the morning.


(if you don't call, we'll have the answer!)

indoorff

My Feedback: (2)

I do not think they were coated in beryllium, the reeds were a copper-beryllium alloy. This gives it much more spring than just a copper reed valve would have, and more durable. I do not think copper-beryllium alloy is highly toxic, unless you were to sand it or weld it or something like that. Beryillium on its own is highly toxic, causing a nasty type of cancer (berylliosis).

Chris

combatpigg

My Feedback: (3)

The job that the reed has to do is mind boggling, bounce back in forth in some cases up to 500 times per second, and creating a fairly decent seal. at that rate of speed, there is way more time spent in transition than there is time spent actually seated against the intake opening. I would think that either hard, thin plastic, or stainless steel would be the best materials for the job. I have heard about carbon reeds, but don't know how well they apply to our tiny engines.

mylamo

My Feedback: (1)

I hope I don't get any cancer from shooting an air
rifle,the old Benjamins used to tout a beryllium barrel

burtcs

bogateer: It probably had to do with corrosion resistance.

but:

First for safety's sake don't lick the copper-beryllium reed valve and just to be sure, keep them out of your mouth
altogether. This is especially hazardous when the engine is running.

I've got a beryllium alloy nipple in a Whitworth muzzle loader and the most dangerous thing that comes out of that thing is the 560 grain slug which is lead.

HTH - Steve B.

KidEpoxy

berylliosis

no fair
why did they give such a funny name to something so not-funny

BMatthews

Nothing to do with corrosion resistance. Everything to do with springyness and fatigue resistance.

indoorff

My Feedback: (2)

just for those curious about history.....

Beryllium, when made into extremely thin sheets, was found to have the property of being very transparant to certain types of radiation. This was handy in scientific apparatus which had to be sealed from contaminants in the air around, but still had to let as much radiation through as possible. When the scientist who were using the apparatusses started dieing, Beryllium exposure was found to be the cause.


Chris

vicman

My Feedback: (10)

The big concern comes from working it. Grinding, machining, and especially polishing. I have made many parts and continue to do so for the aero industry that requires a few of Beryllium's characteristics. We always wore special safety garments for finish grinding and polishing of embossments.

culver

I had been wondering why the reeds have changed to teflon, now I know. Reminds me of my first squadron in the navy (f-14's) that had beryllium in the brake pads, you had to suit up in tyvek with gloves and a respirator to ward off the dust, then pitch it all in a hazmat drum when finished. Thank god they switched to carbon brakes real quick.

Tim Wiltse-RCU

Culver,

The "plastic" reeds were made from nylon, plastic, whatever not teflon. Davis Diesel sells teflon reeds. They are pretty pricey but they work very very well. Of course now the current Cox reed is stainless steel.

LAter,
tim

andrew b

Sounds strange, that they were playing with radioactive materials and they started dying from radiation poisoning, maybe it was REALLY transparent!
Beryllium is used as a springing agent in copper leaf springs and a hardening agent in "Beryl bearings", a type of bronze.
I have found BC in all types of relays and switchgear, the only time I have seen a health waring was with some large power transistors that used Beryllium Oxide as a heat conductor. It solders really easily and is often used for battery terminals and brush holders in small electric motors.

vicman

My Feedback: (10)

Not aware of it being HOT. If I recall correctly it causes a form of brain cancer that can be traced only to people with one thing in common - working with Beryllium.
I think I even saw one of those late night class action lawsuit ads for people who may have been exposed. I just laughed had a fourth round of CC and went back to applying CA and Kicker to my model with blue foam wing cores I cut with a hot wire. Before using my drill press with gloves on and bandsawing a prop to the correct length for balance.[sm=bananahead.gif] I don't smoke though, those things will kill ya.

pbunn

My Feedback: (1)

Beryllium is a sligtly radioactive element and main use is in spring type electrical conductors. It makes copper very springy when mixed with it. Brush Wellman is the US manufacturer of most beryllium copper.

Beryllium oxide is used in RF power transistors and ICs as a ceramic heat conductor. It is dangerous in a powder form and these devises should never be ground or drilled.

Elemental beryllium is used as a neutron reflector in nuclear bombs and does an excellent job in increasing yield. If a critical mass is enclosed in a beryllium case, the yeild of the weapon rises substantially. The old gun type bombs (Hiroshima type) had more than double the yield when the tube was lined with beryllium.

BobHH

My Feedback: (18)

Isn't that the stuff the Doc makes you drink when they check your plumbing? I don't feel s good!!!

Bob Harris

uliner

My Feedback: (2)

Elemental beryllium is very dangerous and a known cancer causing agent.

Copper beryllium alloy is safe and is used in many places. Many electrical connectors like the serial port in your PC use small amounts of copper beryllium. The dust of beryllium alloys is not healrhy to inhale

Beryllium is used in nuclear reactors and warheads because it has a low cross section for absorption of neutron (they mostly pass right through). It is very hard, has a high melting point and is non magnetic.

http://en.wikipedia.org/wiki/Beryllium


I got to go to Brush-Wellman once and worked on their machines. They insisted on a chest x-ray and a blood test before I could go into the plant.



Dave

lukesp

Barium, I would think

mylamo

My Feedback: (1)

Barite and cillium = ?