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Hot Section Insulation
I'm surprised at the angst about finding appropriate insulation for exhaust hot sections. MMI sells just the thing - give Don and Brenda some business in appreciation for their services to us Afourians.
I used the MMI woven glass tape on our Tartan 30 exhaust which runs within two inches of the plywood mid-ship bulkhead for about 18 inches (as well as within inches of most of the important electrical wiring on the boat). Being a "belt-and-suspenders" engineer, I used two layer of the wrap, and the resulting surface temperature is low enough that the tape can be touched (briefly) during operation. If you get the MMI product, discard the supplied clamps which are worse than useless: use SS worm clamps instead. The insulation will smoke for the first few hours, but not to worry.
An alternative for the very wary is molded magnesite insulation which comes as two half-cylinders which are clamped around the metal pipe. If you want to go that route (and I don't know why you would want to unless you had an installation where the hot section runs very close to a flammable surface), a few minutes on Google will find you a local supplier.
Any glass wool insulating product is something I would keep as far from my A4as possible, preferably not on the boat at all. It's not good for machinery, it's not good for skin, and it's not good for the lungs.
The advice that we have already heard on asbestos is good. Asbestos, particularly long-fibered white asbestos as was most common in North American insulation products, is innocuous unless you snort the dry dust into your lungs. Keep it wet, and it won't fly around. It's not poisonous, nor is it carcinogenic in the chemical sense. However, those tiny fibers (blue asbestos is tinier, hence worse) stick in the lungs and cause irritation which can become cancerous, particlarly when chemical carcinogins (e.g. tobacco tars) are present. This mechanism may also apply to finer-fibered grades of glass wool.
I'm surprised at the angst about finding appropriate insulation for exhaust hot sections. MMI sells just the thing - give Don and Brenda some business in appreciation for their services to us Afourians.
I used the MMI woven glass tape on our Tartan 30 exhaust which runs within two inches of the plywood mid-ship bulkhead for about 18 inches (as well as within inches of most of the important electrical wiring on the boat). Being a "belt-and-suspenders" engineer, I used two layer of the wrap, and the resulting surface temperature is low enough that the tape can be touched (briefly) during operation. If you get the MMI product, discard the supplied clamps which are worse than useless: use SS worm clamps instead. The insulation will smoke for the first few hours, but not to worry.
An alternative for the very wary is molded magnesite insulation which comes as two half-cylinders which are clamped around the metal pipe. If you want to go that route (and I don't know why you would want to unless you had an installation where the hot section runs very close to a flammable surface), a few minutes on Google will find you a local supplier.
Any glass wool insulating product is something I would keep as far from my A4as possible, preferably not on the boat at all. It's not good for machinery, it's not good for skin, and it's not good for the lungs.
The advice that we have already heard on asbestos is good. Asbestos, particularly long-fibered white asbestos as was most common in North American insulation products, is innocuous unless you snort the dry dust into your lungs. Keep it wet, and it won't fly around. It's not poisonous, nor is it carcinogenic in the chemical sense. However, those tiny fibers (blue asbestos is tinier, hence worse) stick in the lungs and cause irritation which can become cancerous, particlarly when chemical carcinogins (e.g. tobacco tars) are present. This mechanism may also apply to finer-fibered grades of glass wool.
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