---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 05/04/12: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:19 AM - Re: AeroElectric-List Digest: 4 Msgs - 05/03/12 (kent@cybermesa.com) 2. 07:19 AM - Re: AeroElectric-List Digest: 4 Msgs - 05/03/12 (kent@cybermesa.com) 3. 07:19 AM - Re: AeroElectric-List Digest: 4 Msgs - 05/03/12 (kent@cybermesa.com) 4. 10:19 AM - Re: OS Wig-Wag Project (Robert L. Nuckolls, III) 5. 10:47 AM - Some folks really good at what they do. . . (Robert L. Nuckolls, III) 6. 10:51 AM - Re: OS Wig-Wag Project (gregmchugh) 7. 11:27 PM - Re: Secrets Techniques (John Loram) ________________________________ Message 1 _____________________________________ Time: 07:19:00 AM PST US Subject: AeroElectric-List: Re: AeroElectric-List Digest: 4 Msgs - 05/03/12 From: kent@cybermesa.com O Sent from my Verizon Wireless BlackBerry -----Original Message----- From: AeroElectric-List Digest Server Sender: owner-aeroelectric-list-server@matronics.com * ================================================= Online Versions of Today's List Digest Archive ================================================= Today's complete AeroElectric-List Digest can also be found in either of the two Web Links listed below. The .html file includes the Digest formatted in HTML for viewing with a web browser and features Hyperlinked Indexes and Message Navigation. The .txt file includes the plain ASCII version of the AeroElectric-List Digest and can be viewed with a generic text editor such as Notepad or with a web browser. HTML Version: http://www.matronics.com/digest/digestview.php?Style=82701&View=html&Chapter 12-05-03&Archive=AeroElectric Text Version: http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chapter 12-05-03&Archive=AeroElectric =============================================== EMail Version of Today's List Digest Archive =============================================== ---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 05/03/12: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:08 AM - Re: Aluminum bronze - conductivity (Stuart Hutchison) 2. 06:28 AM - Re: Aluminum bronze - conductivity (Robert L. Nuckolls, III) 3. 07:30 AM - Re: Hour meter ground (Richard Girard) 4. 08:19 AM - Re: Aluminum bronze - conductivity (Eric M. Jones) ________________________________ Message 1 _____________________________________ Time: 01:08:04 AM PST US From: "Stuart Hutchison" Subject: RE: AeroElectric-List: Aluminum bronze - conductivity Thanks guys. I've made lots of aluminum and stainless parts for underwater photography and yes, the galvanic corrosion between them can be brutal immersed in an electrolyte liek sea water. Ultra Tef-Gel from B&C Specialty helps, but I suppose aluminum adjoining stainless is very common at the firewall and doesn't seem to present too many problems without an electrolyte ... I could be wrong, but that area stays pretty dry and I haven't witnessed much corrosion at the firewall on aircraft. I'm less worried about the aluminium bronze oxidising - a gas tight seal is obviously important because all the usual metal options oxidise, but there must be tens of thousands of aircraft with ground wires bonded direct to aluminium. I guess I'll just use di-electric grease to keep the air out at the point where the stud meets with the firewall, or perhaps make a phenolic bush to insulate it from the stainless, then bond the stud to a substantial part of the aluminum structure on the inside (such as an engine mounting bolt). Kind regards, Stu F1 Rocket VH-FLY http://www.mykitlog.com/RockFLY www.teamrocketaircraft.com _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Henador Titzoff Sent: Thursday, May 03, 2012 1:11 AM Subject: Re: AeroElectric-List: Aluminum bronze - conductivity With copper and aluminum, it's bound to be extremely low resistance, but the aluminum will corrode on the surface to form alumina, which may interfere with good connections. Why not send that puppy off to Eric at Perihelion Design to get it copper plated? Or better yet, why not go with copper bar? It's relatively cheap and known good material. Beats ripping out something that didn't work that well. Henador Titzoff _____ From: "Robert L. Nuckolls, III" Sent: Wednesday, May 2, 2012 10:18 AM Subject: Re: AeroElectric-List: Aluminum bronze - conductivity At 05:33 AM 5/2/2012, you wrote: G'day Bob, Do you reckon aluminum bronze is suitable to be used in place of brass for the main firewall ground ? It has plenty of copper in it, but are there any known nasties when it's used adjoining stainless steel - I'd like to turn a custom large-flanged firewall passthrough for the engine ground. Hmmmm . . . I have no reason to believe it's any worse. Brass isn't the greatest of conductors but the way we use it (large cross-sections and/or short lengths) the electrical resistance doesn't raise concerns. I don't know any specifics about its reactivity with other metals but I think anything against stainless is pretty low risk . . . Perhaps others on the List have experience foundations from which to advise you further . . . Bob . . . href="http://www.matronics.com/Navigator?AeroElectric-List">http://w====== ________________________________ Message 2 _____________________________________ Time: 06:28:09 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Aluminum bronze - conductivity At 03:06 AM 5/3/2012, you wrote: Thanks guys. I've made lots of aluminum and stainless parts for underwater photography and yes, the galvanic corrosion between them can be brutal immersed in an electrolyte liek sea water. Ultra Tef-Gel from B&C Specialty helps, but I suppose aluminum adjoining stainless is very common at the firewall and doesn't seem to present too many problems without an electrolyte ... I could be wrong, but that area stays pretty dry and I haven't witnessed much corrosion at the firewall on aircraft. Agreed. I'm less worried about the aluminium bronze oxidising - a gas tight seal is obviously important because all the usual metal options oxidise, but there must be tens of thousands of aircraft with ground wires bonded direct to aluminium. The legacy process involves putting a tin-plated copper terminal down on a brightly buffed area of aluminum and applying lots of pressure with the attach hardware. The surface areas in gas-tight contact are, as you suggest, not subject to environmental stresses. The outside of the joint can get pretty cruddy with age without having the connection go bad. I guess I'll just use di-electric grease to keep the air out at the point where the stud meets with the firewall, or perhaps make a phenolic bush to insulate it from the stainless, then bond the stud to a substantial part of the aluminum structure on the inside (such as an engine mounting bolt). I think clean, grease and lots of pressure are key. Additional bonding is not useful. Bob . . . ________________________________ Message 3 _____________________________________ Time: 07:30:58 AM PST US Subject: Re: AeroElectric-List: Hour meter ground From: Richard Girard On Wed, May 2, 2012 at 11:13 PM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > The tach has its own signal wire. None of the Rotax wiring diagrams for the various regulators has an AC > going to ground. As pointed out, the note on the drawing for the hour meter says if one of > the AC feed wires is grounded that wire is used for pin 5 on the meter. > Otherwise the two AC wires feed the meter and it makes no difference which > goes to the meter connections. Rick > At 02:46 PM 5/2/2012, you wrote: > >> Bob, Yes, as you can see they show one side of the AC leg going to ground. >> >> Rick >> > > Hmmm . . . separate winding for the tachometer. Your > AC power to the rectifier/regulator cannot be grounded > on one side so that you can have full-wave rectification. > This tach coil is a very low power source. Do you have > an electronic tach reading this output too? In any case, > exactly where it grounds (if at all) is of little > consequence. These two systems are neither potential > antagonists nor victims. Does your tach wiring call out > grounding of one side of the signal wire? > > > Bob . . . > > -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ________________________________ Message 4 _____________________________________ Time: 08:19:01 AM PST US Subject: AeroElectric-List: Re: Aluminum bronze - conductivity From: "Eric M. Jones" > Why not send that puppy off to Eric at Perihelion Design to get it copper plated?...Henador The copper clad aluminum I sell is not plated. This wouldn't be good, plating always has pinholes and wears off. The Super-CCA I sell is "clad" which is a process where copper and aluminum are fused together. 10% of the diameter of the crossection is actually copper. Copperweld Inc., historically made lots of different stuff clad with copper by this process. It is important to know that there is a long history of aluminum wiring problems, but essentially NO HISTORY of CCA problems. The wire behaves very much like copper Some notes of metals: 1) In many applications the conductivity of the metal is less important than the surface reactivity with atmospheric oxygen (or in the case of titanium only, with nitrogen). Impure aluminum oxide is the same as sapphire or corundum and is quite insulating. Copper oxide looks bad but still conducts electricity well. Same for silver. It can turn black and conduct well. Stainless steel, nickel, chrome and aluminum looks great initially but turns into an insulator. This usually happens slowly. Battery contacts made of stainless steel were once the bane of cheap electronics. 2) See: http://aerospacedefense.thomasnet.com/Asset/MIL-F-14072.pdf Finishes for Ground Based Electronic Equipment. There is probably an aircraft-version of this but it is all the same chemistry. 3) Gold has zero reactivity with the atmosphere. Gold is only a fairly- good conductor but is great for low voltage electrical contacts. Silver is the best conductor followed by copper, then aluminum. 4) Aluminum has over TWICE the conductivity per unit mass of any other metal. So learning how to use it can save weight. The electrical power industry uses far more aluminum than copper outside the home. Aluminum wiring in houses (that used electrical plugs and switches designed for copper) were retrofitted by adding a short pigtail of copper with special grease in a wirenut or crimp connector. 5) Galvanic corrosion depends on the Electrode potential in the electro-chemical series AND presence of an electrolyte--saltwater perhaps but water will do. If you put dissimilar metals together, but keep them air-tight and dry, there is no problem. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=372337#372337 Attachments: http://forums.matronics.com//files/copper_cables_aluminum_cables_579.pdf ________________________________ Message 2 _____________________________________ Time: 07:19:00 AM PST US Subject: AeroElectric-List: Re: AeroElectric-List Digest: 4 Msgs - 05/03/12 From: kent@cybermesa.com O Sent from my Verizon Wireless BlackBerry -----Original Message----- From: AeroElectric-List Digest Server Sender: owner-aeroelectric-list-server@matronics.com * ================================================= Online Versions of Today's List Digest Archive ================================================= Today's complete AeroElectric-List Digest can also be found in either of the two Web Links listed below. The .html file includes the Digest formatted in HTML for viewing with a web browser and features Hyperlinked Indexes and Message Navigation. The .txt file includes the plain ASCII version of the AeroElectric-List Digest and can be viewed with a generic text editor such as Notepad or with a web browser. HTML Version: http://www.matronics.com/digest/digestview.php?Style=82701&View=html&Chapter 12-05-03&Archive=AeroElectric Text Version: http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chapter 12-05-03&Archive=AeroElectric =============================================== EMail Version of Today's List Digest Archive =============================================== ---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 05/03/12: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:08 AM - Re: Aluminum bronze - conductivity (Stuart Hutchison) 2. 06:28 AM - Re: Aluminum bronze - conductivity (Robert L. Nuckolls, III) 3. 07:30 AM - Re: Hour meter ground (Richard Girard) 4. 08:19 AM - Re: Aluminum bronze - conductivity (Eric M. Jones) ________________________________ Message 1 _____________________________________ Time: 01:08:04 AM PST US From: "Stuart Hutchison" Subject: RE: AeroElectric-List: Aluminum bronze - conductivity Thanks guys. I've made lots of aluminum and stainless parts for underwater photography and yes, the galvanic corrosion between them can be brutal immersed in an electrolyte liek sea water. Ultra Tef-Gel from B&C Specialty helps, but I suppose aluminum adjoining stainless is very common at the firewall and doesn't seem to present too many problems without an electrolyte ... I could be wrong, but that area stays pretty dry and I haven't witnessed much corrosion at the firewall on aircraft. I'm less worried about the aluminium bronze oxidising - a gas tight seal is obviously important because all the usual metal options oxidise, but there must be tens of thousands of aircraft with ground wires bonded direct to aluminium. I guess I'll just use di-electric grease to keep the air out at the point where the stud meets with the firewall, or perhaps make a phenolic bush to insulate it from the stainless, then bond the stud to a substantial part of the aluminum structure on the inside (such as an engine mounting bolt). Kind regards, Stu F1 Rocket VH-FLY http://www.mykitlog.com/RockFLY www.teamrocketaircraft.com _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Henador Titzoff Sent: Thursday, May 03, 2012 1:11 AM Subject: Re: AeroElectric-List: Aluminum bronze - conductivity With copper and aluminum, it's bound to be extremely low resistance, but the aluminum will corrode on the surface to form alumina, which may interfere with good connections. Why not send that puppy off to Eric at Perihelion Design to get it copper plated? Or better yet, why not go with copper bar? It's relatively cheap and known good material. Beats ripping out something that didn't work that well. Henador Titzoff _____ From: "Robert L. Nuckolls, III" Sent: Wednesday, May 2, 2012 10:18 AM Subject: Re: AeroElectric-List: Aluminum bronze - conductivity At 05:33 AM 5/2/2012, you wrote: G'day Bob, Do you reckon aluminum bronze is suitable to be used in place of brass for the main firewall ground ? It has plenty of copper in it, but are there any known nasties when it's used adjoining stainless steel - I'd like to turn a custom large-flanged firewall passthrough for the engine ground. Hmmmm . . . I have no reason to believe it's any worse. Brass isn't the greatest of conductors but the way we use it (large cross-sections and/or short lengths) the electrical resistance doesn't raise concerns. I don't know any specifics about its reactivity with other metals but I think anything against stainless is pretty low risk . . . Perhaps others on the List have experience foundations from which to advise you further . . . Bob . . . href="http://www.matronics.com/Navigator?AeroElectric-List">http://w====== ________________________________ Message 2 _____________________________________ Time: 06:28:09 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Aluminum bronze - conductivity At 03:06 AM 5/3/2012, you wrote: Thanks guys. I've made lots of aluminum and stainless parts for underwater photography and yes, the galvanic corrosion between them can be brutal immersed in an electrolyte liek sea water. Ultra Tef-Gel from B&C Specialty helps, but I suppose aluminum adjoining stainless is very common at the firewall and doesn't seem to present too many problems without an electrolyte ... I could be wrong, but that area stays pretty dry and I haven't witnessed much corrosion at the firewall on aircraft. Agreed. I'm less worried about the aluminium bronze oxidising - a gas tight seal is obviously important because all the usual metal options oxidise, but there must be tens of thousands of aircraft with ground wires bonded direct to aluminium. The legacy process involves putting a tin-plated copper terminal down on a brightly buffed area of aluminum and applying lots of pressure with the attach hardware. The surface areas in gas-tight contact are, as you suggest, not subject to environmental stresses. The outside of the joint can get pretty cruddy with age without having the connection go bad. I guess I'll just use di-electric grease to keep the air out at the point where the stud meets with the firewall, or perhaps make a phenolic bush to insulate it from the stainless, then bond the stud to a substantial part of the aluminum structure on the inside (such as an engine mounting bolt). I think clean, grease and lots of pressure are key. Additional bonding is not useful. Bob . . . ________________________________ Message 3 _____________________________________ Time: 07:30:58 AM PST US Subject: Re: AeroElectric-List: Hour meter ground From: Richard Girard On Wed, May 2, 2012 at 11:13 PM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > The tach has its own signal wire. None of the Rotax wiring diagrams for the various regulators has an AC > going to ground. As pointed out, the note on the drawing for the hour meter says if one of > the AC feed wires is grounded that wire is used for pin 5 on the meter. > Otherwise the two AC wires feed the meter and it makes no difference which > goes to the meter connections. Rick > At 02:46 PM 5/2/2012, you wrote: > >> Bob, Yes, as you can see they show one side of the AC leg going to ground. >> >> Rick >> > > Hmmm . . . separate winding for the tachometer. Your > AC power to the rectifier/regulator cannot be grounded > on one side so that you can have full-wave rectification. > This tach coil is a very low power source. Do you have > an electronic tach reading this output too? In any case, > exactly where it grounds (if at all) is of little > consequence. These two systems are neither potential > antagonists nor victims. Does your tach wiring call out > grounding of one side of the signal wire? > > > Bob . . . > > -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ________________________________ Message 4 _____________________________________ Time: 08:19:01 AM PST US Subject: AeroElectric-List: Re: Aluminum bronze - conductivity From: "Eric M. Jones" > Why not send that puppy off to Eric at Perihelion Design to get it copper plated?...Henador The copper clad aluminum I sell is not plated. This wouldn't be good, plating always has pinholes and wears off. The Super-CCA I sell is "clad" which is a process where copper and aluminum are fused together. 10% of the diameter of the crossection is actually copper. Copperweld Inc., historically made lots of different stuff clad with copper by this process. It is important to know that there is a long history of aluminum wiring problems, but essentially NO HISTORY of CCA problems. The wire behaves very much like copper Some notes of metals: 1) In many applications the conductivity of the metal is less important than the surface reactivity with atmospheric oxygen (or in the case of titanium only, with nitrogen). Impure aluminum oxide is the same as sapphire or corundum and is quite insulating. Copper oxide looks bad but still conducts electricity well. Same for silver. It can turn black and conduct well. Stainless steel, nickel, chrome and aluminum looks great initially but turns into an insulator. This usually happens slowly. Battery contacts made of stainless steel were once the bane of cheap electronics. 2) See: http://aerospacedefense.thomasnet.com/Asset/MIL-F-14072.pdf Finishes for Ground Based Electronic Equipment. There is probably an aircraft-version of this but it is all the same chemistry. 3) Gold has zero reactivity with the atmosphere. Gold is only a fairly- good conductor but is great for low voltage electrical contacts. Silver is the best conductor followed by copper, then aluminum. 4) Aluminum has over TWICE the conductivity per unit mass of any other metal. So learning how to use it can save weight. The electrical power industry uses far more aluminum than copper outside the home. Aluminum wiring in houses (that used electrical plugs and switches designed for copper) were retrofitted by adding a short pigtail of copper with special grease in a wirenut or crimp connector. 5) Galvanic corrosion depends on the Electrode potential in the electro-chemical series AND presence of an electrolyte--saltwater perhaps but water will do. If you put dissimilar metals together, but keep them air-tight and dry, there is no problem. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=372337#372337 Attachments: http://forums.matronics.com//files/copper_cables_aluminum_cables_579.pdf ________________________________ Message 3 _____________________________________ Time: 07:19:02 AM PST US Subject: AeroElectric-List: Re: AeroElectric-List Digest: 4 Msgs - 05/03/12 From: kent@cybermesa.com O Sent from my Verizon Wireless BlackBerry -----Original Message----- From: AeroElectric-List Digest Server Sender: owner-aeroelectric-list-server@matronics.com * ================================================= Online Versions of Today's List Digest Archive ================================================= Today's complete AeroElectric-List Digest can also be found in either of the two Web Links listed below. The .html file includes the Digest formatted in HTML for viewing with a web browser and features Hyperlinked Indexes and Message Navigation. The .txt file includes the plain ASCII version of the AeroElectric-List Digest and can be viewed with a generic text editor such as Notepad or with a web browser. HTML Version: http://www.matronics.com/digest/digestview.php?Style=82701&View=html&Chapter 12-05-03&Archive=AeroElectric Text Version: http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chapter 12-05-03&Archive=AeroElectric =============================================== EMail Version of Today's List Digest Archive =============================================== ---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 05/03/12: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:08 AM - Re: Aluminum bronze - conductivity (Stuart Hutchison) 2. 06:28 AM - Re: Aluminum bronze - conductivity (Robert L. Nuckolls, III) 3. 07:30 AM - Re: Hour meter ground (Richard Girard) 4. 08:19 AM - Re: Aluminum bronze - conductivity (Eric M. Jones) ________________________________ Message 1 _____________________________________ Time: 01:08:04 AM PST US From: "Stuart Hutchison" Subject: RE: AeroElectric-List: Aluminum bronze - conductivity Thanks guys. I've made lots of aluminum and stainless parts for underwater photography and yes, the galvanic corrosion between them can be brutal immersed in an electrolyte liek sea water. Ultra Tef-Gel from B&C Specialty helps, but I suppose aluminum adjoining stainless is very common at the firewall and doesn't seem to present too many problems without an electrolyte ... I could be wrong, but that area stays pretty dry and I haven't witnessed much corrosion at the firewall on aircraft. I'm less worried about the aluminium bronze oxidising - a gas tight seal is obviously important because all the usual metal options oxidise, but there must be tens of thousands of aircraft with ground wires bonded direct to aluminium. I guess I'll just use di-electric grease to keep the air out at the point where the stud meets with the firewall, or perhaps make a phenolic bush to insulate it from the stainless, then bond the stud to a substantial part of the aluminum structure on the inside (such as an engine mounting bolt). Kind regards, Stu F1 Rocket VH-FLY http://www.mykitlog.com/RockFLY www.teamrocketaircraft.com _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Henador Titzoff Sent: Thursday, May 03, 2012 1:11 AM Subject: Re: AeroElectric-List: Aluminum bronze - conductivity With copper and aluminum, it's bound to be extremely low resistance, but the aluminum will corrode on the surface to form alumina, which may interfere with good connections. Why not send that puppy off to Eric at Perihelion Design to get it copper plated? Or better yet, why not go with copper bar? It's relatively cheap and known good material. Beats ripping out something that didn't work that well. Henador Titzoff _____ From: "Robert L. Nuckolls, III" Sent: Wednesday, May 2, 2012 10:18 AM Subject: Re: AeroElectric-List: Aluminum bronze - conductivity At 05:33 AM 5/2/2012, you wrote: G'day Bob, Do you reckon aluminum bronze is suitable to be used in place of brass for the main firewall ground ? It has plenty of copper in it, but are there any known nasties when it's used adjoining stainless steel - I'd like to turn a custom large-flanged firewall passthrough for the engine ground. Hmmmm . . . I have no reason to believe it's any worse. Brass isn't the greatest of conductors but the way we use it (large cross-sections and/or short lengths) the electrical resistance doesn't raise concerns. I don't know any specifics about its reactivity with other metals but I think anything against stainless is pretty low risk . . . Perhaps others on the List have experience foundations from which to advise you further . . . Bob . . . href="http://www.matronics.com/Navigator?AeroElectric-List">http://w====== ________________________________ Message 2 _____________________________________ Time: 06:28:09 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Aluminum bronze - conductivity At 03:06 AM 5/3/2012, you wrote: Thanks guys. I've made lots of aluminum and stainless parts for underwater photography and yes, the galvanic corrosion between them can be brutal immersed in an electrolyte liek sea water. Ultra Tef-Gel from B&C Specialty helps, but I suppose aluminum adjoining stainless is very common at the firewall and doesn't seem to present too many problems without an electrolyte ... I could be wrong, but that area stays pretty dry and I haven't witnessed much corrosion at the firewall on aircraft. Agreed. I'm less worried about the aluminium bronze oxidising - a gas tight seal is obviously important because all the usual metal options oxidise, but there must be tens of thousands of aircraft with ground wires bonded direct to aluminium. The legacy process involves putting a tin-plated copper terminal down on a brightly buffed area of aluminum and applying lots of pressure with the attach hardware. The surface areas in gas-tight contact are, as you suggest, not subject to environmental stresses. The outside of the joint can get pretty cruddy with age without having the connection go bad. I guess I'll just use di-electric grease to keep the air out at the point where the stud meets with the firewall, or perhaps make a phenolic bush to insulate it from the stainless, then bond the stud to a substantial part of the aluminum structure on the inside (such as an engine mounting bolt). I think clean, grease and lots of pressure are key. Additional bonding is not useful. Bob . . . ________________________________ Message 3 _____________________________________ Time: 07:30:58 AM PST US Subject: Re: AeroElectric-List: Hour meter ground From: Richard Girard On Wed, May 2, 2012 at 11:13 PM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > The tach has its own signal wire. None of the Rotax wiring diagrams for the various regulators has an AC > going to ground. As pointed out, the note on the drawing for the hour meter says if one of > the AC feed wires is grounded that wire is used for pin 5 on the meter. > Otherwise the two AC wires feed the meter and it makes no difference which > goes to the meter connections. Rick > At 02:46 PM 5/2/2012, you wrote: > >> Bob, Yes, as you can see they show one side of the AC leg going to ground. >> >> Rick >> > > Hmmm . . . separate winding for the tachometer. Your > AC power to the rectifier/regulator cannot be grounded > on one side so that you can have full-wave rectification. > This tach coil is a very low power source. Do you have > an electronic tach reading this output too? In any case, > exactly where it grounds (if at all) is of little > consequence. These two systems are neither potential > antagonists nor victims. Does your tach wiring call out > grounding of one side of the signal wire? > > > Bob . . . > > -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ________________________________ Message 4 _____________________________________ Time: 08:19:01 AM PST US Subject: AeroElectric-List: Re: Aluminum bronze - conductivity From: "Eric M. Jones" > Why not send that puppy off to Eric at Perihelion Design to get it copper plated?...Henador The copper clad aluminum I sell is not plated. This wouldn't be good, plating always has pinholes and wears off. The Super-CCA I sell is "clad" which is a process where copper and aluminum are fused together. 10% of the diameter of the crossection is actually copper. Copperweld Inc., historically made lots of different stuff clad with copper by this process. It is important to know that there is a long history of aluminum wiring problems, but essentially NO HISTORY of CCA problems. The wire behaves very much like copper Some notes of metals: 1) In many applications the conductivity of the metal is less important than the surface reactivity with atmospheric oxygen (or in the case of titanium only, with nitrogen). Impure aluminum oxide is the same as sapphire or corundum and is quite insulating. Copper oxide looks bad but still conducts electricity well. Same for silver. It can turn black and conduct well. Stainless steel, nickel, chrome and aluminum looks great initially but turns into an insulator. This usually happens slowly. Battery contacts made of stainless steel were once the bane of cheap electronics. 2) See: http://aerospacedefense.thomasnet.com/Asset/MIL-F-14072.pdf Finishes for Ground Based Electronic Equipment. There is probably an aircraft-version of this but it is all the same chemistry. 3) Gold has zero reactivity with the atmosphere. Gold is only a fairly- good conductor but is great for low voltage electrical contacts. Silver is the best conductor followed by copper, then aluminum. 4) Aluminum has over TWICE the conductivity per unit mass of any other metal. So learning how to use it can save weight. The electrical power industry uses far more aluminum than copper outside the home. Aluminum wiring in houses (that used electrical plugs and switches designed for copper) were retrofitted by adding a short pigtail of copper with special grease in a wirenut or crimp connector. 5) Galvanic corrosion depends on the Electrode potential in the electro-chemical series AND presence of an electrolyte--saltwater perhaps but water will do. If you put dissimilar metals together, but keep them air-tight and dry, there is no problem. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=372337#372337 Attachments: http://forums.matronics.com//files/copper_cables_aluminum_cables_579.pdf ________________________________ Message 4 _____________________________________ Time: 10:19:43 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: OS Wig-Wag Project The boards are here and I've stuffed some of the parts. Thought I'd ordered the IRF6201 hex-fets but that slipped under the rug. Those are on order and should be here Monday. May have the development articles ready to mail then. How many folks are herding bytes for this board configuration and need hardware? I need mailing addresses. Bob . . . ________________________________ Message 5 _____________________________________ Time: 10:47:35 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Some folks really good at what they do. . . I ordered the wig-wag hex-fets from Digikey and in less than 60 minutes, I got an e-mail with a tracking number. Bob . . . ________________________________ Message 6 _____________________________________ Time: 10:51:42 AM PST US Subject: AeroElectric-List: Re: OS Wig-Wag Project From: "gregmchugh" Bob, Send one out to me, please... I will test the current software and if it checks out I will flash some PIC12F683 chips and send them out to you. If there is anyone else who is getting one of the initial boards and would like a flashed micro let me know. Greg McHugh 4201 N Willoway Estates Ct Bloomfield Hills, MI 48302 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=372397#372397 ________________________________ Message 7 _____________________________________ Time: 11:27:49 PM PST US From: "John Loram" Subject: RE: AeroElectric-List: Secrets Techniques I knew there must be a tool for this!!! http://www.aircraftspruce.com/catalog/topages/twiststrip.php And look at today's special price at the bottom of the page!!! ;-) -john- can you believe it! I stumbled on it while looking for unshielded tefzel insulated twisted pair (which I'm still looking for). _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John Loram Sent: Sunday, April 29, 2012 4:31 PM Subject: RE: AeroElectric-List: Secrets Techniques Well, that works like a charm!... I've spent so many years trying not to melt the insulation that I was not taking full advantage of the properties of Tefzel. I've encountered solder sleeves in the past, but never appreciate their purpose. onward and upward (someday), -john- _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Thursday, April 19, 2012 9:39 PM Subject: Re: AeroElectric-List: Secrets Techniques At 11:12 PM 4/19/2012, you wrote: Sixty years I've been doing this! Built all my own ham radio gear as a teenager in the 50's, got a EE degree from a prestigious university, spent my adult life as a development engineer designing medical and laboratory instruments. You'd think I could strip a multiconductor shield Tefzel insulated cable in my sleep, but it's a bit@h! I make a mess of the shield when I try to remove the Tefzel. What is the secret trick to it! The secret is go ahead and 'trash' the shield. I have a bunch of 22AWG, 3-conductor shielded that a common Stripmaster more-or-less strips the outer jacket and probably 80% of the shield strands. Then I use a solder-sleeve to put a neat pigtail on the damaged shielding. There are normally no currents flowing in the shield. If your grounding pig-tail gets good electrical connection with only one of of the strands, you're good to go. More than likely you can get good connection with 10% or more of the shield stranding. The neat thing is that the pigtail under heat shrink covers the carnage. I'll see if I can dig some of the stuff up and do a comic-book series of pictures on the process tomorrow. Bob . . . href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matro nics.com/Navigator?AeroElectric-List href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.