Liquid filled gauges

[Guest De Soto Frank]

Bill,<P>Two different "fluids" come to mind; one is a "glycerine" solution, the other involves "mineral oil"(like you get from the drug store).<P>As to what will be "benign" to the lettering on the "rose", test carefully on the back side?<P>Better yet, if this is a marine compass, perhaps a marine museum might be able to suggest what was origanally used in the compass?<BR>It must have been a commonly available item way back when.<P>Perhaps the folks who restore old mahogany speed boats might have an answer?

[Guest]

Modern liquid filled gauges are filled with heavy silicone oil, the fluid is benign and won't attack any kind of paint so I would think it is safe to use with your rare item.

[Guest]

Chuck ~ Based on some experience in the late '40s with marine compasses, I am not sure that "heavy" silicone oil will allow the proper free movement of the compass card.<P>I could be wrong, but I seem to recall that alcohol or a fluid containing alcohol was used. <P>But then I am not an expert, so I could be wrong. <P>BillP ~ Do not use my input without checking with someone who really knows something about liquid filled compasses of that era.<BR>~ hvs

[Guest]

BillP, Dow Corning makes silicone fluids that range from thinner than water to grease. If you find a viscosity that you would like you can consult their product datasheets at this site. Silicone oils will not degrade when exposed to sunlight like conventional oils would and are perfectly clear, it would be a good HOT RODDING trick to apply to your compass.<BR> <A HREF="http://www.dowcorning.com/" TARGET=_blank>http://www.dowcorning.com/</A> <P>I do hope you are not thinking of showing your replica, HVS seems to have an aversion to anything non authentic. If he judges your plane he would be tasting the fluid in your compass.

[Guest]

Sorry Chuck, but I don't do airplanes anymore. Even in my flying days in the USAF back in the '50s I didn't judge them.<P>And yes you are quite correct, I am a stickler for authenticity when JUDGING antique cars. If a person doesn't want to preserve the historical accuracy of a motor vehicle, that is his/her business. Like you say, it's a free country. ~ hvs

[Guest Randy Berger]

Bill, McMaster-Carr has glycerine-filled gauges which are refillable so they must carry the glycerine also. Below is copy from their catalog.<BR>• Refillable glycerin-filled gauges dampen needle vibration; allow more accurate gauge readings <A HREF="http://www.mcmaster.com/" TARGET=_blank>http://www.mcmaster.com/</A> and then search for fluid-filled gauges. Hope this helps.<BR>

[Guest]

A friend of mine is building a replica WWI fighter plane. For use on those foggy days returning from the front, he has obtained an old (small) marine compass. It resides in a canister and is mounted on gimbals. There is a plug/port in the body of the compass, presumably to add liquid. The compass is now dry, and the undamped indicator is too mobile to provide a good reading in the jittery aircraft. <BR>So, what is the recommended fluid, one that will effectively damp and also not dissolve the lettering on the rose?

[Ron Green]

I have heard of people buying a inexpensive liquid compass(s) at Pep Boys or some other auto related store and draining the fluid out of them for there old car compasses. They worked fine, however it could be a different story using this process for a airplane. Just a thought. Good luck and let us know how you make out.

[Guest stude8]

I know a guy who is a Xerox copier machine service tech. He drains silicon toner fluids routinely and has used them as BRAKE FLUID! Its good stuff, can't beat the price and has worked for years according to him.

[Guest leadfoot]

stude8 -<BR>What will your Xerox guy be thinking when he stomps on the brake pedal at 60 mph and the "paper jam" flashing light comes on? Probably "Oh S@!#"!

[Guest stude8]

Well I like to stay behind him in traffic but it seems to have worked well for 10 years at least.