What's in YOUR muffler???

[ewengstrom]

That rebuild is outstanding!!! You may want to relocate that muffler on deck....seems a shame to hide it under the bathroom sink.
Seriously though, the finish looks like gelcoat, and I do like the idea of the reinforcing fillets for added strength at the joints.

[derekb]

I wrapped the new tubes myself. I purchased some 32mm outside diameter PVC pipe from the local hardware store, wrapped it with PVC film as a release layer, then wrapped about 8 layers of 300 gsm 0/90 fibreglass cloth around the pipe. I soaked the fibreglass with West System 105 epoxy before wrapping. I placed the soaked fibreglass on a flat surface and rolled the tube from one end, squeezing out as much resin as possible as I rolled. Then I wrapped the wet tube with peel ply, again squeezing out as much resin as possible. After curing the PVC tube came out easily. I sanded the outside of the tubes down to the correct diameter using a disk sander and using the 32mm PVC pipe as a mandrel on which to spin the wound tube.

I glued the new tubes back into the muffler body with thickened epoxy and built up a large radius fillet to strengthen the joint.

I did consider wrapping the fibreglass tubes around an aluminium tube and leaving the aluminium tube in place as an anti-crush sleeve (as suggested by Ken K in another thread), but I decided that the difference in CTE between the aluminium and the fibreglass may cause problems over the next 20 years.

The repaired muffler was painted with one-pack epoxy paint (also from the local hardware store, Bunnings - equivalent to Home Depot).

Tube lengths were as listed on the Catalina Direct website:



Here's another shot of the repaired muffler, alongside its new mounting plate. The mounting plate bearers have not yet been trimmed to size, they need to be cut to match the angle of the inside of the hull...


IMG_1425resize by Derek Buckmaster, on Flickr

[lazybone]

Nice shop porn

[KWKloeber]

Outstanding Derek

Did you slice open the body and do any work on the bottom seam, or just handle the inzie/outzie from above?

I've thought (dreamt) that if I had decided to repair mine (the 2nd time) I'd take it apart to clean up the inside and "float" a good resin fillet around inside after reassembling it.

ken

[derekb]

Ken, I was tempted to slice off the bottom and give the muffler a thorough overhaul, but I decided not to go that route. The new tubes were inserted from the top.

To repair the leak in the bottom edge seam, I just machined out a groove (around 1/8" wide by 1/2" deep by 3" long) where the split seam was visible (it looked like a surface scratch, but the leak-test showed it was more than that) and filled it again with unfilled West System 105 epoxy.

[derekb]

OK, enough of the shop-work... time to get this muffler into the boat.

(Eric, if I mounted this on the deck it would make everything else look "tired and worn"!...  )

Here are a couple of pictures of the repaired muffler and the new mounting base placed in position to check everything before gluing. This shows why it is difficult to get the muffler out via the aft double-bed opening: even though it looks like there is lots of room, the two pipes are already protruding above the bottom of aft bed molding. And you have to lift the muffler up by about half an inch to clear the mounting plate. So tilting it forward doesn't give you enough room to clear the pipes under the aft bunk molding. At least that was the case on my boat... as Stu says, there are a lot differences boat-to-boat...

The view from under the aft bed, looking forward:


IMG_1496resize by Derek Buckmaster, on Flickr

And the view into the head basin cabinet, looking aft:

IMG_1490resize by Derek Buckmaster, on Flickr

I decided to attach the muffler to the base with a super-large hose clamp (cut in half), rather than the 4 screws in the corners.