How to fix your clock part 2: the second hand is stuck!
A bedroom wall clock with five minute and quarter hour intervals was what we wanted.It had to be easy to read from the bed.
Most of the paint used on modern clocks will not last for a full night.We have come a long way from the days when zinc sulphide was activated with radium or tritium.It is now possible to get 'glow in the dark' powders based on rare earth doped strontium aluminate which do not need radioactivity.The green one has the best staying power and will emit light for twenty four hours after being activated by natural or artificial light.The old style zinc sulphide is very similar to the 'glow in the dark' powder.
Due to their coarse nature, the powders are hard to apply and grinding impairs the light emitting property.The article shows how they can be applied in situ with cheap nail varnish which is dissolved in an acetone/amyl acetate solvent and is very similar to the 'dope' used by model aircraft enthusiasts many years ago.
There is a previous 'ible here where some of the techniques used in this article were worked up.
It is cheap and widely available on eBay and Amazon.The green variety has the longest persistence and the ability to emit light for 24 hours after charging.Alpha Industries Incorporated produced the material used here.
This is a case where the cheapest is the best.The acetone/amyl acetate solvent is used to make nail varnish.The cheap artist brushes can help.
There are a lot of clocks.If the hands are behind a glass, we need to know that we can get behind it to work.It's not easy to tell when the clock is on display in a shop.The clock needs to be cheap so that disasters are not disastrous.Simple hands with a large surface area will make the job much simpler.In our case, the project was for bedroom use so silence in operation was vital--this can be the source of some anguish as in our example where one partner can hear a pin drop three floors down.The other is not hearing.
Our clock is a compromise and can be seen in the picture above.The clock is twelve inches in diameter and can be easily read from fifteen feet away.It is not loud in operation.The hands are out in the open and can be worked on without the clock mechanism being removed.The hour hand must not foul the minute hand above as it rotates because of the free space between the two hands.There is an eighth of an inch clearance with this clock.
We will deal with the case where your clock has simple hands in the next four steps.The powder can be applied directly.
There is a cheap clock in the picture.The hands are made from brass and can be treated.
The clock should be placed in a tray.nylons and tights are not going to be attacked by nail varnish.
In the picture above, you can see how a sheet of card in two parts has been gently slid under the hands to protect the face and allow for the collection of excess powder.
The bottle of nail varnish has a brush in it.To create a 'pool' without it overflowing, take a full brush of varnish and paint it on to the hands.
Before the varnish is gone, spoon 'glow in the dark' powder liberally over the hands, allowing the excess to overflow on to the card below.Allow it to dry for several hours.
The excess of 'glow in the dark' powder should be used to withdraw the card.The excess of 'glow in the dark' powder can be collected by Invert the clock over a large sheet of paper.The excess powder should be saved for further use.You should have a cushion of nail varnish and powder on your hands.Give the hands a final coat of nail varnish to consolidate your work.
The nocturnal effect on the right can be seen in the left hand part of the picture.
The last four steps show how easy it is to find a clock with simple hands.
These hands are not promising for our purpose.They are ornate and lack the surface area to take much 'glow in the dark' powder.The decision was made to glue the strips to the hands.
The plastic sheet that formed the top of a box of Christmas cards can be seen in the left hand side of the picture.The material is probably a type of plastic.
The right hand side of the picture shows the strips that were cut from the plastic to make the arms.
It was found in the project that nail varnish does not make a permanent bond to PET and that our cushion of luminous powder can be lifted with vigorous rubbing.My use of super glue and subsequent varnishing means that the hands made here will probably last for the purposes of this project in the long term but those starting the project from scratch might do well to use a material such as cartridge paper.It's important not to build up the thickness to the extent where the two hands foul each other.
Two rows of four pellets were placed on a card in a metal tray and flattened to the same height with a thick straight edge.The two strips were stuck to the pellets by the left hand side of the picture.
The right hand side of the picture shows how the strips were coated with nail varnish and an excess of Luminous powder was spooned on before being left to dry.
Remove the excess powder from a sheet of paper.A coat of nail varnish is needed to consolidate the Luminous layer.
One way of applying the hand patches is shown in the picture above.The clock face in the upper part of the picture has a patch on it.The A4 printer paper was carefully slid under the minute hand.We can now press down on the hand with no damage to the mechanism, because the pad has just enough A4 sheets.
The clock hand can now be decorated with a small amount of nail varnish at each end.Take a tube of superglue and apply it under the edges of the patch at various points along the length.The glue will get under the patch because of capillary action.Allow to dry and then apply nail varnish to the hand.
I decided to put one set of markers at the quarter hour positions and another at five minute intervals.
The 'glow in the dark' stickers can be found here.The quarter hour markers and simple round sticky pads were used for the triangular markers.The basic pads which are sold for furniture protection can be found in do-it-yourself and pound shops.
In the picture above, we can see how our pads and cut down double sided sticky pads have been anointed with nail varnish and then covered with an excess of 'glow in the dark powder'.
They are ready for use after the removal of excess powder and the application of a final coat of varnish.
The rear of the sticker can be peeled and placed on the clock.The triangular ones are used at the quarter hour positions.The circular ones are placed where the other interval points are.The process of moving the stickers can be accomplished by using wooden cocktail sticks.
It came as a revelation to us that a large luminous clock can be used in the bedroom and yet it is not easily available to purchase ready made.
The approach has been flexible enough to allow for individual variations, so this article should show how to judge if a given clock is suitable for this treatment.
It is possible to replace the whole movement of a noisy clock with a non-ticking version.For useful advice see: There are many clock movement suppliers.
Three months ago on Step 14.
Hello!There are two little LEDs on the hour and minute hands of the table clock.The clock is working without a time delay.There is a seperate power supply for the LEDs by two cells.The switch on the clock's head can be used to turn on or off the lights.For nearly 5 months, if LEDs are kept on, they give glow.We can see the time in darkness with the clock's utility.
3 months ago
That looks very effective and must be worthy of an 'Instructable'.Thanks for showing us.
On Step 14 a year ago.
You could save yourself a lot of trouble by removing the hands and installing them again.If you re- install them with both hands pointing to 12 o'clock, they will line up properly and you can adjust as needed.
1 year ago
Thanks for the feedback.Although I have run into trouble with small clocks, we can put it down to fat fingers!A radio controlled movement can be reset to 12 o'clock but many will find it unsuitable for bedroom use.
1 year ago
2 years ago.
I had to stop the clock because of the crucked needles that got jammed into each other.
I never have to change it's battery because it has temperature,humidity, internet and battery.
3 years ago
3 years ago
Many products fall into this category because they are based on zinc sulphide without radioisotope activation.If you expose them to a bright light but fail to deliver after an hour or so, they are very impressive.
You will find an underlying theme of disappointment with the luminosity in the reviews from those who have purchased the alarm clocks that are widely and cheaply available.
The green variety of rare earth doped strontium aluminate glows all night after it's activated, and perhaps it is the coarse nature of the product that stops its wider application.
I have never used clear duct tape, but I see that it is available.It might be a good idea to lay some out on a surface that can be peeled and then spread some 'glow in the dark' powder around the central area.Put another layer of tape on top of your powder.You can deploy elsewhere if you peel off your sandwich.