Guys, is pine tar the product used inside the coils?
Looking to buy some instead of reusing the old tar but want to make sure I'm buying the right stuff. I can get 1kg of Stockholm Tar which is pine tar in a tub.
The closest modern "Tar" is Type III Steep Roofing Tar.
Visit a roofing contractor Paul. Take along a coil to show them what you're doing with the tar. They might be more inclined to help you.
Good plan there Garnet, thanks for that. I might also visit our local council depot and speak to the road crew. They use tar to repair the road.
A bit hard to do in Australia, we don't use any tar products on a roof.
I recently helped a friend who was restoring a 1902 Rambler and wanted to get the coil working that came with it. I used a heat gun to melt the potting compound and can say for sure that it was pine resin/tar. I don't know if that was used in the Ford ignition coils but I think it would work as well as anything provided you have easy access to it. I drained the pitch from my friend's coil into a cheap, small no stick pan and re heated it and put it back in the coil after repairs with out any trouble.
Stockholm tar (pine tar) is a preservative coating for wood and rope and is not used in coils.
"Type III Steep Roofing Tar" is the American classification for a high melting point tar which is what you need in the Model T coil. A low melting point can lead to trouble as the coil warms during use, and if your coils live on the cylinder head (Improved Car) then you really really must have the high melt temp tar.
I have no idea what it might be called in a land down under.
Only thing I ever used pine tar for was to smear on a hog or calf after I cut them(neutered). KGB
It is also good for horse hooves, soap, and cheating in baseball.
Here is some technical data on asphalt material available in the US: http://www.owenscorning.com/trumbull/products/built-up-roofing-asphalts/trulo-ma x/
Physical Requirements - ASTM D312-00
Type (Softening Pt Range°F) (Flash Pt °F)
I (135-151) (500)
II (158-176) (500)
III (185-205) (500)
IV (210-225) (500)
From personal experience I found I could easily pour the type III at 250°F, you certainly don't want to overheat it, the fumes increase with temp and there's a huge safety issue.
I have no relations to/with Owens Corning or the ASTM. jb
As Frank (from Aus) said, above, we don't use roofing tar here in Aus. Makes it difficult to get. But thank you all for the info you have given me, it's all been useful.
I'll find a way!
The stuff in the 02 Rambler coil was positively pine resin. It was the hardness and texture of hard candy when cool and smelled like a Christmas tree when I was heating it and while it was in a pourable state. It actually caught on fire briefly while being removed and smelled like pine when it burns. It would make brittle little strings as it cooled while I was trying to pour it out of the box.. I'll bet if you went out to the woods and collected pitch off the side of pine trees and heated it, it would melt and be pourable enough to use as potting compound in a coil. Another option to hold things in place would be hot glue from a glue gun. I don't think you would be able to re melt that to work on the coil later though.
It would not be a good idea to use hot glue, or expanding foam, or RTV, or any of the other make do stuff that I have heard of being used. Your best bet is to re use the tar from the coil. If you do not have enough tar from your coil, then there is no problem. Just find some T coils that have open secondaries or trashed cases, or whatever would make them unsuitable for rebuild and dig the tar out of them. Put it in a pot and melt it down and you have just what you need.
Paul, maybe you could just find a few more coils to use the "tar" out of..If you keep all the fragments you may only need a bit more...That way it would be the right stuff anyway. As an old roofer that worked with the old style hot built up roofs with the "kettle of hot" on flat roofs in northern Michigan, I can see why it went away. We called that "tar" a # 3 steep bitumin in the old days...Not much of that used anymore up here, maybe for a repair. Jim Derocher, AuGres, Michigan
Using glue, is not the way you should do it.
As Steve said, just re use the old tar from the coils, it is the right stuff. If not enough take take from the coils that are to far gone to be rebuild.