Compasses and alcohol

Aren’t these compasses (typically American ones) nick named the Whiskey Compass?
If on a flight and the compass leaks you can refill it from your hip flask.

came across this story from the book ‘They Shall Not Pass Unseen’ by Ivan Southall
http://www.n461.com/n461_story.html
regarding the Sunderland Ju88 dogfight
“Incendiary bullets ripped up the cockpit. Walkers compass blew up and sprayed him with blazing alcohol. Liquid fire splashed across the bridge and poured down the companionway into the bow compartment. ”

wonder how many pilots got burns from compass fires

[ATTACH=CONFIG]218155[/ATTACH][ATTACH=CONFIG]218156[/ATTACH]Finished my redo on my P8. Refilled with alcohol, white plastic rod replacing the pointers and a re-paint of the body etc. Moving on now to one of my P11’s.

There is no need to grind off anything in the bowl, since the radium is a powder, held inside sealed (at each end) glass tubes. The tubes are “glued” to the spider with alcohol-resistant paint (the same as that in the bowl itself.) Getting the spider out of the bowl is the tricky part, since it needs a B.A. spanner (either 6 or 8, can’t remember which,) bent at right angles, and a light touch.
The jewel post is B.A. threaded and screwed into a crossbar in the bottom of the bowl; it is then held in place by a locking nut, which, preferably, should not be unscrewed.
At the top of the post is a cone, which is split, and forced apart by the action of a second nut, as it is screwed up the post; this needs to be screwed back down the post, to free the spider.
Use the angled spanner to screw it back down again, and, with a little gentle persuasion, the spider should come off the top of the jewel post.
If the correct method of using paint to attach the tubes has been utilised, it’s a simple matter to remove them by dissolving the paint with a paintbrush laden with white spirit. Of course, if they’ve been damaged (or you damage them,) all bets are off.
The grid ring is the most hazardous item, since the paint is likely to have turned to dust, and some of that will have found its way onto the bowl’s glass, giving you the chance to breathe it in before you start work on the bowl; talk to Sirs of Kent, who build, and rebuild, these compasses, and follow their advice.
Before you do anything, of course, the most sensible course would be to run a Geiger counter over them, remembering that the glass will always act as a barrier to the rays; looking at the condition of the paint in that pair, in your photo, it looks in far better condition than any 70-year-old radium paint that I’ve seen, so there might be a possibility that they’ve already been worked on, and the paint replaced by fluorescent type.
If you’re ever anywhere near High Wycombe, talk to Pandect Instrument Laboratories, who have a Geiger counter, and will run it over the instruments, if you ask nicely.:D

I’ve always used kerosene.

Thanks Stan. Do you have a link for Spruce and Spec?

Jet A1 is also a good substitute and I have used Vodka (straight) for many years without any problems. Of course the correct compass fluid available from Spruce and Spec is the most desireable.

Thanks Dave. I’ll check it out.
John

Hope that helps a little.

Great post and thread.
Type 5/17 has radium in it (AP 802 1922), dry 5/17 should be treated as if dust contains deadly biological agent.
I have P2, P3 and P4-11, waiting to devise safe handling method. Currently stored in vented safe as radium decay creates radon gas, an unhappy gas.

Filling compass with water (or high water content gin) will setup electrochemical corrosion – brass case will act as cathode to cadmium and steel component anode. Insides will turn to mush. If it is for display, perhaps leave it dry. Drink the gin.

Thinking of this safe handling method :

Tank filled with clear, water miscible oil, tank has sump to clear sediment.
Open compass under liquid bath – no airborne dust hazard.
Use air powered dentist drill to grind off radium components.
Radium Specific Gravity is 5, oil is 0.8, radium will settle to bottom.
Alcohol with micro radium particles will bind with water miscible oil, allowing full float sink separation of radium solids over time.
Proper disposal of sump sediment via medical imaging radioactive waste disposal.

Should set this up with govt grant as a Health initiative before govt spends ten times as much confiscating my and your instruments.
Original technical manuals are unsuitable as they do not envisage dealing with near century old radium binding components.
Not an issue then, leaving a legacy of passivity now. If senior members are nonplussed, why should you be ? Asbestos, anybody ?
A love of history should not expose you to a dismaying danger.

Get together, pool your resources and set up a local, govt endorsed, safe handling method.

Hi there,

There is a Kelvin Hughes overhaul manual for the P11 compass available for download here:http://www.dsgaviation.co.uk/page5.htm

Regards

Dave

Hi Paddy. I’m starting on my P8 fix-up tonight. I think I have everything I need on hand except for a new top glass which I’ll have cut. I just hope mine turns out as well as yours did. 🙂
John

[ATTACH=CONFIG]217795[/ATTACH][ATTACH=CONFIG]217794[/ATTACH]Hi Edgar,
Yes, this does help. Now if I can find some replacement glass for the top I might be able to fix it up nice. I just picked up a tube of silicone windshield and glass sealer which should work fine for the bottom glass as long as the alcohol doesn’t affect it. The top ring and “O” ring, minus any glass look okay. It would be great to get hold of a schematic.

John

Wow! Thanks Paddy. That will be a big help for sure. Much appreciated!
John

Initially “P” compasses were filled with a 90%:10% mixture of industrial alcohol (aka IMS 99) and distilled water; eventually it became 100% alcohol. Being industrial alcohol it is (and tastes) nothing like booze, and is, in fact, poisonous.
On the “spider” mechanism glass tubes are “glued” (with ordinary compass paint.) The 1940s versions had radium powder inside the tubes, which glows in the dark; post-war this was replaced by fluorescent powder, which needs a special light to make it glow; compasses with this modification should have an “M” added to their serial number, but that’s no guarantee. A good rule of thumb is to visually inspect the paint in the tubes, and on the cardinal points; if it’s brown, with black specks, it’s a fair bet that it’s radium-based, but don’t assume otherwise if the paint looks good. A Geiger counter is the only safe check.
Hidden from view, in the dome of the spider, is a pivot, which has a hardened chrome tip, but I wouldn’t like to hazard a guess as to how water might affect it.
The pivot fits into a depression in a sapphire “jewel,” which is held in triangular top to the “compass post,” and is free to rotate; it is usually considered (now) safest to store the compass upside-down, so that the pivot and jewel are not in constant contact, since the jewel can chip, and become useless.
Below the mechanism, in the base of the main bowl, is a flexible piece of corrugated metal, which takes up the difference in volume, caused by the effect, on the liquid, of height and temperature variations. During rebuilds, the liquid has to be de-aerated, to lessen the amount of this movement. As well as de-aerating the fluid, it’s normal practice to immerse the filler plug, at the same time, in some more liquid, and give it the same treatment, since the fibre seal is porous, and can trap air bubbles, which have a nasty habit of appearing at inopportune times.
The seal, under the bowl’s glass, is normally rubber, as found in “O” rings, and was 1/8″, but now 3mm; getting the seal the right size (usually, now, done by bevel cuts and super-glue,) and ensuring that it’s exactly in the right place, under the retaining bezel, can be a nightmare. Some compasses have been sealed with a form of two-part mastic, which is a real pain to remove.
The internal paint is a special compass type, which, once having contained the compass fluid, should never be allowed to dry out, since it’s prone to crack, and flake off, necessitating a repaint; this seems more prevalent with the white paint in landing compasses, less so with the black.
Hope that helps a little.

Go to this page

http://www.skyfield.demon.co.uk/

scroll down and click the download at the end of the P8 text
I think this will help you quite a bit
HTH.
Paddy

I sure appreciate your feedback. Your P8 REALLY looks good. I can’t tell for sure but does it have a glass over the top? Mine only has one glass below the two cross pieces. My P11’s have two glass covers.

the P8 should have glass that rotates with the compass degree ring and another which is the seal that keeps the fluid in. basically the lid for the fluid bowl.
Be aware that the danger with these things is not the radioactivity by being near to them, its the radioactive dust given off that you can breath in. The red paint on N/S/E/W for example is radioactive and dusts very easily if you scratch it to remove it for example. As are the glass vials that are the small white tubes on the compass rose/pointer.

I sure appreciate your feedback. Your P8 REALLY looks good. I can’t tell for sure but does it have a glass over the top? Mine only has one glass below the two cross pieces. My P11’s have two glass covers.

Hi John
I used a 50/50 mix of distilled water and what you call surgical spirits in the USA or Isopropanol over here in the UK.
I did the compass above with this mix and its still as clear and clean as it was in Nov 2011.
One word of warning is the mix can strip some water based paints or acrylics so i was careful to use an oil based paint inside the bowl and let it go off for a week or two in a warm place.
HTH 🙂

PS I used a bathroom mastic from the diy shop to seal the glass to the bowl. Chose the right colour and use very sparingly as it squeezes out as you tighten the screws and can make a mess on the inside of the glass if you use to much. Consider a paper gasket and a very thin smear of mastic ?

I’m awfully late here but I just today found this thread about re-filling compasses. Lately I have been collecting P series compasses. Right now I have three, two P11’s and one P8. One of the P11’s and the P8 have no liquid in them. I would like to refill them both with the appropriate liquid and also, if possible, replace the seals. Can someone here recommend a proper liquid that is easily available and maybe a source for new seals? I am in the US by the way.
Thanks in advance!!

John