Hi all
My Kriesler 11-104 had a small piece of asbestos (roughly 7x3 cm) stapled to a piece of cardboard to shield the power transformer from the heat from the 6V4 rectifier. So I removed this, carefully, but now I probably need something in its place to shield the PT. I was thinking maybe a piece of thinnish plywood. Does anyone think this would be a bad idea (ie fire hazard?). Or perhaps there is some 21st century material I could use for the same purpose. Any thoughts? Cheers.

I wouldn't use wood, especially plywood as its outer layers are usually hoop pine which is a softwood and thus would ignite easily. Modern fibro, or CFC as it is known in the building trade, would work providing it doesn't touch the valve and you can get a piece thin enough to maintain an air gap.

Fibro, if you can get a thin sheet, or dont bother at all if the radio wont be regularly used. Coat the asbestos with a mix of wood glue and water then contact your council for disposal options.

ben

One has always got to be careful in old Radio's. There are several with Asbestos heat shields and some with wire wound resistors wound on an Asbestos core.

If that becomes flaky it will spread through out the set. A vacuum cleaner is not a safe method of removing it, nor is a brush. Both stir up particulates and its dust & a respirator is an absolute must. In most cases I initially paint the sheet stuff (no spraying or compressed air) with PVA glue & that binds it: Similar to above.

If you use any metal that has magnetic properties, there is such a thing as too close to the transformer. That also applies to replacing speakers with ones with huge ceramic magnets.

Marc

Thanks for the replies. I'll try to get some CFC. I removed the old asbestos by soaking it with cooking oil first, that way I don't have water dripping on my chassis, and triple bagging it. I still have to find the appropriate way to dispose of it though

Some waste transfer stations will take asbestos though not all do. Your council's website should have more information.

For a replacement, a piece cut from a silicone rubber kitchen heat pad.

Better than risking heat damage to the cabinet finish.

Thanks Ian...good suggestion. I got one of those silicone mats, which is rated to 250 degrees C. It should fit well. The reason for the asbestos was to shield the power transformer from the radiant heat from the rectifier tube.

I own and restored a Rockola Jukebox from 1960 that was made in Australia by the Goddard Novelty Co. The lamp ballast for the fluorescent light is mounted on the inside of the wooden cabinet with a sheet of asbestos between the lamp ballast and the wood. I have been very careful not to disturb the asbestos and so far I have left it alone as it would be a fire hazard to remove it and I am not sure of what would be a safe modern alternative material to use as a heat shield.

The reality is if the asbestos is in good nick and there's no chance of it being disturbed whilst operating the equipment it should be safe to leave in place. Iron core ballasts do get hot to touch whilst in operation so it does need to be insulated from the timber. If you do really want the asbestos out then it is easy enough to replace the ballast with an electronic one - they run cooler and ensure the lamp runs at its rated power and not 3 x the rated power via the heat losses in the older ballasts. These provide a slightly brighter light that is free of mains flicker because the frequency of the power running through the lamp is much higher.

Thanks Brad. The original ballast still works well and the asbestos mat is in good condition so I might leave it alone unless the ballast fails and requires replacing at some point in the future.
Regards, Sam

I recall seeing a sign on a brick wall in a university building (I won;t say which one). It read:

Behind this wall there is asbestos.
If you drill a hole in this wall you will disturb the fibres

So don't.

Very pragmatic approach. But I wonder if the building is still there......

Many institutional and government buildings still contain asbestos and indeed all fibro houses built before about 1984 will also contain asbestos.Old cars that are seldom used will still have blue brake pads/shoes and the seal between the exhaust manifold and engine pipe will also be asbestos.

There's more of it around than people realise, though at the same time the rule of thumb still applies - if the asbestos is covered and not disturbed it can't hurt anyone. EG: a steam pipe that is lagged with asbestos and is completely taped up is quite harmless unless someone breaks the seal.

The other thing is, there's plenty of other materials around that are just as deadly and most are based on ceramic fibres. Batts are made of the stuff and it is used to reinforce CFC sheeting - the modern fibro. Even concrete dust is bad, even when it is wet down.

Plenty of asbestos still present in house and commercial building fuse boxes, too.

Dunno when they stopped using asbestos board in those.