MTFCA Forum

I recently purchased a Atwater-Kent Model K coil-switch box. Sadly it doesn't work. I would like to try repairing it but like model T coils it is full
of tar/ bitumen. I have removed tar from Ford coils with a screw drive( but I have a idea what is in a Ford coil ) I have no idea what is in a
Atwater - Kent coil or where it is. Do any of you have a method for removing the tar by heating it up & how do you do it?
Thanks. Craig.

By Erik Barrett in Auburn Ca. on Monday, September 17, 2018 - 09:43 pm:

Put them in the freezer overnight and the tar becomes brittle. You can chip it out with a small hammer and chisel.

https://www.mtfca.com/discus/messages/8 ... 1537338755

If only Hugh Jass was still on line. He could tell you about Bitumen’s properties.

Since you don’t know what is inside it you might try taking it to your doctor office and get it xray of it.
Did that one time with a piece of electronics equipment at a plant to see how to take it apart. Dan

I think trying to chip it out will break something. What is the melting point of the tar? Since it was poured in at one time without damaging the components, you should be able to melt it out using the same degree of heat. Set your oven for the minimum melting temperature of the tar, set the box on wooden blocks at a tilt in an old bowl and allow it to melt out into the bowl. That way, when you have repaired it, you can reheat it and pour the same amount back in. If you don’t know what temperature to use, start at 150 degrees F. If it doesn’t melt at that, go up in 5 degree increments until it starts to melt. It would help to have a visual thermometer in the oven to monitor. Jim Patrick

Just be sure to bake your coil while the lady of the house is away shopping and leave the doors open to air out the house!

Mack. As an old Model T guy, my wife expects behavior like that from me, so I didn’t even think to warn against that. LOL. Jim Patrick.

Use your gas grill outside. don't need the tar smell inside

Tried the Bar-B-Q idea @ 150 degrees no movement was noticed. I kept increasing the heat a little at a time. The tar started to move @ 500
degrees. but did not melt all of the tar out. It did how ever destroy the wood, the connections & the bake-a-lite parts & melt out all of the
solder leaving the coil a complete loss. Good news is I have 1lb 10 OZs of high temp tar/bitumem for sale if you rebuild coils. & the high
tension coil wire cover that I didn't leave on the coil for a Atwater Kent model K 2 coil. & can know show others where everything in the coil
box is if you want to dig the tar out with a screwdriver. Somedays this hobby is not as much fun as others. Craig.

Craig,
I use a paint stripper with a funnel to meld the tar out of the model T coils. Just pay attention not burning the wood on the sides.

Good luck
Andre
Belgium