400 CM Build

[bwalker]

I like your idea of decreasing how loud the saw is.
Another idea I had to accomplish this is to make a sandwhich of the front cover and sheet of perf plate with fiberglass insulation between the two. Held in place by some thread studs welded to the front cover.

The perf plate I am talking about.

 

[Duane(Pa)]

I have a different model saw with a pipe outlet on a cat muffler. I really don’t think there is a catalyst, but rather a perf plate. I can see the plate glowing bright red through the piped outlet. Only mention bc I think you will toast any packing in short order.

 

[EFSM]

The perf plate I am talking about.
View attachment 481911

Robin/makita and I think Redmax used to do something similar on their trimmer mufflers. Most of the inside of the muffler was covered in insulation with something that looked like expanded metal holding it on. I don’t know how much it proved, but every little bit helps.

 

[bwalker]

I have a different model saw with a pipe outlet on a cat muffler. I really don’t think there is a catalyst, but rather a perf plate. I can see the plate glowing bright red through the piped outlet. Only mention bc I think you will toast any packing in short order.

That perf plate is coated with catalyst.

The fiberglass packing made for the purpose won't burn. Its used in motor cycle exhausts.

 

[drf256]

I like your idea of decreasing how loud the saw is.
Another idea I had to accomplish this is to make a sandwhich of the front cover and sheet of perf plate with fiberglass insulation between the two. Held in place by some thread studs welded to the front cover.

Hmm. Like an old glass pack muffler. Interesting

 

[Duane(Pa)]

Nothing louder IIRC

 

[bwalker]

Hmm. Like an old glass pack muffler. Interesting

Exactly, with the exception of the flow hitting the cover in a perpendicular manner vs parallel for a glass pack.
I think a set up like this would absorb a fair bit of noise.