Exhaust Wrap/Repair

I seem to have developed a leak in my dry exhaust. I'm looking for advice on how I should go about the repair. I suspect the wrap should be cut back either side of the leak area, the pipe repaired and then the wrap restablished. Suggestions on method? The wrap is "hard", reminds me of the cast I once had; what is this? I've only found "dry" wraps that must be secured with bands or wire. Thanks for any advice --

Cut the insulation back carefully, WEAR A MASK, you don't want to breath in the
dust/fibers from it.

The old wrappings were asbestos. To get the hard surface they brushed waterglass
on them. The smell of it curing by exhaust heat was vile.
I coated them with a mixture of flour and water, smelled like baking bread.

I think newer wrapping are available without the asbestos,

Ted

When I bought our current boat the exhaust was not wrapped before the water was injected so it would hit over 600 degrees. I wrapped it with some header wrap for cars. It was easy and I used stainless steel zip ties. Cost around $15 per engine. I agree that your old wrap probably has asbestos in it. Be careful taking it off. Wet it down with water in a spray bottle as you take it off. Wear a respirator and try to contain any dust. I used Ledaut 2”x50’ titamium exhaust wrap from Amazon.

Roses Marine in Gloucester, Mass. sells the F/G wrap like that and "Chill seal" (or they used to). Your plan to cut it back and rewrap is good if you can repair the underlying exhaust leak. Chill seal is like the old boiler compound that used formerly. Call Roses, they will hook you up and send you whatever you need.
Marine exhaust Systems of Alabama may have a similar product.

It looks like there might be a join there, you will probably find that the pipe has disintegrated, prepare to change more than just the wrap. A level run like that is a perfect moisture trap.

Wet it down and use a shop vac to suck the dust and bits. Replace it with fiberglass/foil backed wrap with 100 mile an hour tape. Easiest.

From an expert at many levels in the marine industry...


"Cut away old insulation and clean pipe. Judging by the appearance, a weld has corroded internally and may not be repairable. I would carefully inspect entire exhaust run.

Wrap first with 2 or 3 layers of stainless steel mesh: http://www.firesleevetec.com/html/2015/Fitting_0325/143.html

Wrap with Temp Mat or equivalent to obtain desired thickness, do not compress tightly: https://www.gltproducts.com/products/temp-mat-19866

Wrap with a coatable material such as what appears to be used in the photo: http://www.textiletechnologies.co.uk/fire-retardant-mesh.html or what is known as a
re-wettable" cloth:

https://www.buyinsulationproductstore.com/blog/how-to-encapsulate-asbestos-pipe-with-rewettable-lagging-cloth/

Coat with Chil-Seal CP-50A MV1 to obtain hard, smooth, washable finish: http://metrosupplycollc.com/insulation-mastic.html"

Asbestos hasn't been used legally in the US for at least 40 years. An old steamship may have asbestos. Last time I saw it being used was on a steamship overhaul in 1968. If the pipe is very wasted you may need new pipe.You can't weld or braze rust and have it last. Don't use galvanized pipe.

I know in the late 70s I put a new furnace in our house and bought asbestos wrap to put around the flue because I couldn’t get enough clearance between the flue and some framing. At the time it was readily available and we didn’t know the problems it could cause. So if the boat was built in that timeframe it could have asbestos. I don’t remember if the OP said what year it was built or not.

Comodave said:

I know in the late 70s I put a new furnace in our house and bought asbestos wrap to put around the flue because I couldn’t get enough clearance between the flue and some framing. At the time it was readily available and we didn’t know the problems it could cause. So if the boat was built in that timeframe it could have asbestos. I don’t remember if the OP said what year it was built or not.

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His ID calls it a "1985" trawler.

I don’t recognize the brand boat, if it was built in Taiwan then no telling if they were using asbestos or not in 1985. So I would take care just in case.

Thank You for the Exhaust Advice

Gentlemen, thank you for your expert advice. Some additional information: the exhaust is 4" steel pipe at the header and where welded to the muffler above the house. The insulation is 1" thick all around. The boat was built/launched in 1985 by Zirlott, a builder on the West Fowl River just above Dauphine Island Alabama.

Were you able to make repairs and replace the exhaust wrap material?

I have not begun the repairs as yet.

jbishop said:

I have not begun the repairs as yet.

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Good luck.