speedo face repair

[Piper]

ON the UC mark 2 we're working on the speedometer face is really badly rusted. I haven't done anything to it yet to see if there is something salvageable. My first thought is some CLR with gentle rubbing to see if we can get to what's beneath. I'd really like to clean this up as you can see some numbers on the face where the rust isn't too bad.

If it needs to be repainted etc, what's the best way to go?

Cameron

[kevin powles]

Hi, If I were you I would leave the speedo face well alone !. I work in a Nuclear Power Station and took a Mk2 speedo to work the other week to make up an outer ring to mount it to the instrument facia. On leaving radiological controlled areas we routinly put stuff in a small articles monitor (SAM), I put the speedo in with my tools, the messgae from the SAM was to contact the Health Physics department immediately, What you have here is a gauge painted with RADIUM paint, highly radioactive. The radium was mixed into a paint with a phosphorescent agent that emitted light after absorbing the radiation from radium's decay process. Radium and its progeny are a part of the natural uranium decay chain but have been concentrated from its natural state for this use. Radium (and its progeny) emit alpha, beta, and gamma radiation. All of the alpha radiation and most of the beta radiation is stopped by the glass cover of the instrument. The gamma radiation passes through the glass and is easily detected by most radiation meters. Leave it well alone !. If you have a Mk1 speedo gauge these do not contain Radium. If you need a Mk2 gauge I have a couple of new old stock ones here in near mint condition which i will trade for carrier parts.

[Keith Webb]

Scary stuff. Read a fascinating story about it here on the Damn interesting site (which is full of very interesting stories).
Here's an excerpt:

In 1922, a bank teller named Grace Fryer became concerned when her teeth began to loosen and fall out for no discernible reason. Her troubles were compounded when her jaw became swollen and inflamed, so she sought the assistance of a doctor in diagnosing the inexplicable symptoms. Using a primitive X-ray machine, the physician discovered serious bone decay, the likes of which he had never seen. Her jawbone was honeycombed with small holes, in a random pattern reminiscent of moth-eaten fabric.

As a series of doctors attempted to solve Grace's mysterious ailment, similar cases began to appear throughout her hometown of New Jersey. One dentist in particular took notice of the unusually high number of deteriorated jawbones among local women, and it took very little investigation to discover a common thread; all of the women had been employed by the same watch-painting factory at one time or another.

[Mike K]

And various WW2 wireless sets use the stuff too. It's used on the dials and knobs . Watch out for the 122 set Aust. of 1945 vintage.

Older watches from the 1940's and 50's is another source.

Mike

[Rob Beale]

Leave it undisturbed.

Alpha particles are the most damaging as they have high Ionising ability which damages cells. Fortunately they have the least penetrating ability and a sheet of paper, or our skin will stop them. Problems arise when they are ingested.

Beta particles are more penetrating, but less ionising. A sheet of thin aluminium will stop them.

Gamma rays are just energy, very high penetration, (several cm of lead) but very low ionising ability.

Those girls used to shape the paint brush tips with their lips!

Rob

[jeff davis]

I have used equal parts Vinigar and cooking mollassis works great to remove rust on delicate parts leaves the paint intacked and leaves clean water it washes up with water.
Jeff (non radio active}