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kimber
United Kingdom
1529 Posts |
 Posted - 24/11/2004 : 22:24:39
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Anyone who has ever dismantled an original firewall-mounted Triple-M starter switch will know that it relies on a piece of thin insulation material, which in the case of my car has deteriorated beyond use.
Has anyone had a similar problem and if so where did they source suitable material? Its a bit like very stiff grey card about 1.0 mm thick. I suspect it has a degree of heat resistance. I've seen similar stuff inside electric motors. I've seen it various colours e.g. grey, brown or terracotta, like the stuff fibre washers are made of. May even be the same stuff? Any ideas? |
Edited by - kimber on 24/11/2004 22:25:19 |
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LewPalmer
USA
3243 Posts |
Posted - 24/11/2004 : 23:33:31
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Sure. I've replaced these insulators, the wrap inside the inspection band of dynamos, and any number of other items with plain old heavy gasket material. Here in the US we have some that is gray and I believe is asbestos-like. At least it seems to have pretty good insulating properties.
Trace the old piece onto s piece of this material, bend to shape, and you're good to go. For extra electrical and moisture insulation properties, you can use a coat of shellac or clear varnish.
Cheers,
Lew Palmer
Registrar, NAMMMR |
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kimber
United Kingdom
1529 Posts |
Posted - 25/11/2004 : 06:59:16
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| Lew, Thanks for the response. I had considered using thick gasket paper and may well do so given that you have used it successfully. I'm still interested to know what the original stuff was and if it's still obtainable. |
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rbm
United Kingdom
141 Posts |
Posted - 25/11/2004 : 09:02:46
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I think that the insulator was made of a phenolic type material, in slightly later lucas items (40's) tufnol was used this is a phenolic fabric reinforced material which has very high dilectric strength and insulating properties, but more importantly has very very low moisture absorption.
tufnol is still available in sheets of .4, 2, 4, 10, 12, 16, 20 and 25 mm thick.
Richard |
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LewPalmer
USA
3243 Posts |
Posted - 02/12/2004 : 01:36:30
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I'd love to have some of the newer material, but remember that very high dielectric strength is not necessary as the voltage (electrical pressure) is never above 14 or so volts. In most applications in our cars, durability is more important than electrical insulating qualities.
Cheers,
Lew Palmer
Registrar, NAMMMR |
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kimber
United Kingdom
1529 Posts |
Posted - 02/12/2004 : 14:22:44
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OK. The stuff is called Paxolin. They still make it and use it inside electric motors. I got some from my local electric motor rewind place. It is identical (texture/pliabilty/thickness/colour) to the original. It was a bit fiddly to cut to fit inside the starter switch, but I managed it with careful use of a Stanley knife. It will cut with strong pair of scissors. Fortunately, enough remained of the old one to provide a template. If anyone needs a template, I can copy it and give a 'link' from here.
Apparently, 'Paxolin' offers good heat resistance, which is probably just as well as the old one was somewhat 'fried'. It is actually a very important component. It is all that separates the copper terminals inside the switch from the body of the switch (i.e. earth) and if that insulation fails you have a dead short between the main battery lead and the chassis. Not ideal.
The same stuff is used across the back of the switch forming a protective insulating bridge between the connection terminals. |
Edited by - kimber on 02/12/2004 14:26:06 |
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talbot
United Kingdom
718 Posts |
Posted - 19/05/2008 : 20:03:13
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If heat isn't a problem the black plastic that one gallon engine oil containers are made from is a very good material for electrical insulators. I recently recently used some to make. the insulator that fits under the brush cover band on the dynamo.
Cheers
Jan T |
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Frank van Dalen
Netherlands
28 Posts |
Posted - 20/05/2008 : 14:02:35
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I bought a "rebuilt" starter switch a few years ago which produced a strange smell one day shortly after I installed it. As I opened the bonnet I saw it was on fire - well just a little flame, but bad enough to scare the #@$#$& out of me! The copper terminals had cut through the insulation and caused a short circuit. I fixed it using gasket paper, so far it is OK. It's worth making sure you get this right, otherwise it could potentially destroy your car!
Frank van Dalen
J2 4138
email@frankvandalen.net |
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Terry Andrews
United Kingdom
546 Posts |
Posted - 20/05/2008 : 18:19:29
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Hi Guys,
I have restored quite a few of starter switches which are very crude!!! The one from Bill Abbot had welded the insides together. I cannot remember exactly, but I know I modified the plunger pin as there is a possibility of this shorting out particularly if one of the copper segments brakes off in side. The fibre stuff is not 'Paxolin' which is a lot harder. We used this red and grey fibre insulation a lot in the old electro-mechanical telephone exchanges. I salvaged some when we went electronic. Andrew, send me a SAE and I will send you some to do the job.
Regardsąą Terry
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kimber
United Kingdom
1529 Posts |
Posted - 20/05/2008 : 23:15:07
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| Terry, the stuff I obtained from a company locally who specialise in electric motor repair was called Paxolin and worked fine in my starter switch. Looked just like the stuff I took out. It was a bit tough to cut, but by no means impossible. It has heat resistant properties.Many thanks for the offer of help though. |
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