Mag Switch

[Larry Lyons]

Re: Mag Switch

There is a very good write-up in the March 2004 Taylorcraft owner's club newsletter that gives in detail how to take an A7 mag switch apart,test,clean, and reassemble it with illustrations. If anyone wants a copy I would be glad to send them one. I will be leaving Friday 18'th and be back the 25'th so anyone needs one in that time I will send it when I get back.
Buell

I must try again; I have the exact switch shown in the earlier pics. However the copper bus bar that swings across the back on the outside has failed (cracked). The rest of the switch looks to be in good condition. I carefully opened the case and all looks good in there too. This bar is riveted on both ends so I am looking for guidance rebuilding, either by me or someone else. After watching the prices they are bringing on EBay I will try to fix first, as there is no guarantee that what is for sale on there is any better.
Larry

[Hank Jarrett]

Re: Mag Switch

I have rebuilt several of these mag switches and it is really easy. The main problem seems to be that the tabs that hold the back on fatigue and break off. You can't rebuild them for ever. That said (I'm going to sound like a broken record here) DON'T TRASH THE REALLY BAD ONES!!! They are the ones we can hide a modern switch inside. Don't do it till it just CAN'T be rebuilt any more, but it isn't very hard. One thing I WOULDN'T do is solder the key in. First the key is annealed by the heat and will break easier, second the heat will warp the lever if you aren't really careful. I used a really thick E-Poxy on mine and it now resides in my 41 panel. Looks great and now I can pull the key out.
Another thing I have for my plane is a jumper cable that I can clip to my Mags and to the engine. I am paranoid about a kid getting inside and turning the mag switch, followed by one of the fly-in knuckleheads who leans on props. I just HATE getting blood on my plane!
Hank

[Larry Lyons]

Re: Mag Switch

Hank as I have not and can not find the newsletter article I have a question. Have you ever drilled out the rivets on the back plate to replace anything mounted there? I have mine apart and it looks good inside except for the broken copper connection on the outside of the switch. What would you or anyone else recommend; 1. drill out the rivets and replace the copper circuit; 2. drill out the rivets and silver solder the copper back together then rivet it back together; 3. Go the, replace with a keyed mag switch combined into my A-7 that would still look great? On EBay the keyed switch is bringing under $30 but an A-9 without the bat. location just brought $315 yesterday!
Larry

[Buell Powell]

Re: Mag Switch

Hi Larry,
I will be glad to send you a copy and anyone else that needs one. If you want either send me a PM with your mailing address or call @830-935-2294.
Buell

[Hank Jarrett]

Re: Mag Switch

Larry,
I never had one with the brass (or copper, didn't look that close) runners on the back cracked. The one I put the Bendix in had been in water and was a mass of rusted trash. Nothing inside was even identifiable, but the faceplate and lever were repairable with some bead blasting, priming, filling and hand painting. The pits in the face plate were almost pitted through. When they get THAT bad, they are good candidates for the Bendix "Guts Transplant".
If I were going to repair the cracked land I would only do it if I could solder a jumper across that I was willing to bet my life on (you may be doing just that). If it is the land that shorts out a mag, you could put a second switch in parallel and accomplish what I do with the jumper. If the soldered wire fails you could still kill the mag with the security switch. Remember to reach under the panel and flip the security switch after shutdown anyway. You now have 2 independent shorts to the mags and if someone DOES turn your mags on the engine still won't start.
I may have to add the security switch to mine. The jumper is a PITA.
Hank

[Larry Lyons]

Re: Mag Switch

Hi Larry,
I will be glad to send you a copy and anyone else that needs one. If you want either send me a PM with your mailing address or call @830-935-2294.
Buell

Buell, thank you for the newsletter. I am going to silver solder another copper bar on top of the existing bar. The only question is; will the fiber backing panel withstand the heat. I will be very careful and if successful I will have a great switch, if not I will still have a shell for rebuilding it in to a modern keyed type but it will look completely original. Larry

[Hank Jarrett]

Re: Mag Switch

Larry, try taking the switch and jumper to a good jewelry repair. They should have the tools and equipment to solder or weld it without damaging the back plate. If they can weld and solder jewelry it should be a snap to do this.
Hank

[Larry Lyons]

Re: Mag Switch

Good thought Hank, I have the new piece made up. I used a penny for stock. I was going to try tinning it tonight but am missing the soldering iron. It is at work so will wait till tomorrow to get it. To lazy to go get it tonight. LOL
Larry

[Hank Jarrett]

Re: Mag Switch

Don't tell them you used a penny! It's illegal to destroy coins for the metal in them.
Just another whacko law to worry about.
Hank

[Larry Lyons]

Re: Mag Switch

Yea they had to stop exporting pennies because the raw material alone is worth somewhere between 1.24 and 1.48 cents apiece on the open market right now. They would go over seas and be smelted down and the raw material resold back to us. Also, just a touch to the belt sander and the copper was gone! LOL All I have left is a chunk of zink (white metal).
Larry

[Larry Lyons]

Re: Mag Switch

OK an update; I have my switch rebuilt, ready for repaint! I cleaned everything inside ( it was all in good shape), greased the rotating parts with silicone grease, silver soldered a jumper on the broken bus bar, put it back together. Thank you Buell, for the newsletter I had already done exactly what was described in the letter but felt much better. After thinking about it, I went to my business and retrieved an old soldering iron off the wall of legend. An old solid copper bar on a steel rod with a wood handle. The kind you use a torch to heat up, it worked perfectly. By using the old soldering iron I could put a lot of heat in to the bus bar quickly. I had already cleaned, tinned, and sort of stuck the repair in place. All I had to do was get everything hot enough to make the solder flow, no cleaning, no acid at this point, no additional solder needed. Worked nice, no cold joint, everything looks good. Be aware that I know what a good solder joint looks like, that is critical, I think! Larry

[ricky]

Re: Mag Switch

Can you use a 3" mag switch instead of 2 ",I have the key one it look crappy,
friend have 3 inch switch, Ricky

[Leenicklas]

Re: Mag Switch

If you still have the article on repairing mag switch, I would appreciate your sending it to me. Lee Nicklas 4021 E. 88th St, tulsa, OK 74137 and/or [email protected]. Would be glad to pay any reasonable cost.

[Buell Powell]

Re: Mag Switch

Lee--I wanted to post these but had to make them small to upload so I just e-mailed them to you also.

[Leenicklas]

Re: Mag Switch

Thank you very much, Buell. Lee Nicklas