| Author |
Message |
Mark Radius (24.247.233.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 13, 2002 - 8:52 pm: | |
Well, the reconstruction of my MC-9 is well under way. The interior wall cavities are foamed, the ceiling panels are back in place, and I am ready to install the plywood on the walls. One thing I need to do is insulate over the engine compartment inside the coach. I was going to do this with just sprayfoam, but I was advised that I would be much happier if I put down a layer of lead first, then the foam. In fact several experienced converters mentioned that. What do you folks think of that idea? How thick should the lead be? What is the best way to fasten it to the walls? And where does one find "sheet lead"? I know, I know... so many questions. But I have yet to ask a question that someone in this group can't answer! What a valuable resource!
Thanks again for the help!!
MR |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, July 13, 2002 - 9:04 pm: | |
Lead's a great idea and it works really well. The best thing you can do with it is to sandwich it between two softer materials...makes what's known as an "impedance mismatch" that does not transfer sound efficiently. The best commercial stuff is two layers of flexible foam with a lead sheet sandwiched between, or two layers of fiberglass with the lead between like the stuff Scott used for his genset. The sheet thickness you want to find is 1/64th. Commercially it's availiable at 1/32 for the roofing trade. Otherwise a quick google search under "lead sheet" will find you some suppliers.
I did it a bit differently- there's a place called B-quiet that sells an organic polymer material that they call "Extreme" that's cheaper and less toxic than lead, but acts about the same.. about 1/16" thick with gooey stickum on one side. I put down foam carpet pad on my floor, then a layer of the stuff, then the carpet. Makes a nice soft surface to walk on and really cuts the sound. You can find it on ebay if you search "Dynamat". The guy that sells stuff he calls "deathmetal" has a great product that's lots cheaper than "Extreme" but the same stuff basically. I used it on the floor and layered it on my plywood walls too... deadns em up quite well.
Cheers
Gary |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, July 14, 2002 - 12:01 am: | |
http://www.b-quiet.com/lcomp.html |
FAST FRED (65.56.24.6)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, July 14, 2002 - 6:09 am: | |
At time the local scrap yards have sheet lead .
If rolled down with a linoleum roller , you can rent one , it gets very flat in the coach floor after a bit if rolling.
Cover it with your choice of flooring.
At a minimum , covering just the engine compartment on the coach side will silence the mechanicals a bit.
To silence a gen set is much harder as traps for the noise is needed. Traps are 90deg changes in direction the noise can't easily follow.
FAST FRED |
Jim Ashworth (Jimnh) (172.159.34.88)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, July 14, 2002 - 6:17 pm: | |
No one here has mentioned that lead is heavy. Keep in mind that, at this stage, the bus is a bowling alley that is also an echo chamber. Once you get the bed in and the back cabinets in, full with shirt, pants, etc. that will cut the noise enormously. As originally converted, the floor of my bus was lined with lead up to the kitchen area. It was quiet as could be. No engine sound, no road sound whatsoever. There were a couple of disadvantages to this. One was the bus was 1500# over GVW and the suspension needed all of the 130psi that the compressor would put out and even then it would NOT raise the front to the specified ride height. The other disadvantage was that I could not hear anything going wrong with the engine even if I wanted to. Couldn't hear anything right with it either. Sort of like the gensets that are TOTALLY soundproofed so you need to touch the exhaust to know it is running. That thing could be on the verge of loosing a waterpump or alternator and you wouldn't have a clue. My point is, normal construction will cut the noise by 80% and you might be wise not to cut it more. Most mechanical stuff will usally make some unusual noise prior to failure. Caught early enough, a little failure will not turn into a catastrophic failure.
Jim |
FAST FRED (63.208.87.224)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, July 15, 2002 - 5:18 am: | |
This is a great point for systems that are vital.
On our coach the water pump is Hard mounted ,
so you can hear it run.
Should a problem happen we would have a chance at hearing the water supply leaving.
This is an old sail boat trick ,
as empty tanks half way to Hawaii could be nasty!
FAST FRED |
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