I hope this bit of info helps some of you and it applies to anything old
and noisy.
This vehicle in question is a '78 VW Westfalia camper. I'm finishing a
general freshening up - that has taken 2 years this Easter - which includes
trying to update a few things - the upholstery, interior lighting, noise
level at 60 mph, and handling (with sway bars).
I started a hunt for a way to quieten it down. VW's are pretty noisy
sometimes of course.
The search naturally led to Dynamat but the cost was way to high for my
budget to support enough material to do this bus which has lots of floor.
JC Whitney had their version of Dynamat as a reduced cost but still high.
My objectives were to lower the noise inside the van:
1) cheaply
2) effectively
3) not create a rust problem (the VW can do that on it's own)
4) I wanted something that I could get locally (in our small town)
Dynamat fails #1, the silvered faced sheets of jute that Lowe's sells
locally fail #2 as their isn't enough material (thickness) there.
Carpet underlayment fails #3 I guess and so may industrial neoprene (also a
reasonable cost).
The various OEM guys use a thick tar paper material much like Dynamat on
the fire walls and some parts of the floors. All that LOWE's has to offer
was thin tar paper - which would require may layers of glue and paper to
build enough mass to be effective.
A fellow once posted to one of the VW lists that there are two basic ways
to dampen the noise a car makes - absorb it (upholstery, carpet, etc) so
there isn't much to reflect, or dampen the vibration of the metal panels of
the bodywork. The OEM guys use a combination of both obviously using the
tar paper panels and jute. I'll do the same with my asphalt material on the
floors and foam on the vertical surfaces all - and I mean all of the other
surfaces upholstered - roof too (all except the cabinets).
Finally I started talking to local roofers - specifically ones that worked
on commercial flat roofs. One very helpful fellow here in middle TN took
the time to show me the materials he uses which were mostly as you can
imagine, the standard thin tar papers.
However he showed me a roll of modified polymer+bitchum - that is 180 mls
(maybe a lower number slightly) versus the thin regular tar paper stuff.
Imagine comparing sliced American cheese to newspaper.
He showed me how it had a face which when heated with a Propane torch would
get sticky and could be layered to any thickness. It looks like three
layers would gain you 1/2" or so. The heat required seems to far exceed the
temps of a hot car in the summer.
It will also require a torch to really get this stuff contoured to any
curves your floor might have. I left the roll of material in the back of my
CR-V for two days (other things to do) and noticed no smell despite the
fact the car got 70 degrees one day (inside) and feel confident that any
very hot days my bus might see would only create a small stink inside that
would fade with time.
My plan is to lay this material directly on the floor with glue and heat
and then top it with any layers I might need and then top it (and glued)
with the silvered jute material from LOWE'S to keep the black
bitchum/polymer junk where it belongs. This will be topped with carpet and
etc.
A roll 3 feet by 45 feet cost me $42. The opposite side of the material is
similar to regular tar paper but not prone to tearing - in fact you
couldn't if you tried.
It weighs about 50 lbs for the whole roll.
He questioned me to the exact trade name of the stuff in the magazines
(Dynamat) and told me he was sure that Dynamat was a 'John Mansfield Co'
trademark and was generally used (as I understood it - our conversation was
held during a hard rain under a tin roofed pavilion) for walk mats in
roofing - sections of flat tar roofing with a thicker membrane suitable for
foot traffic (maintenance people). It was also cheap and very similar to
what I purchased - naturally he had my stuff in stock and didn't have the
raw Dynamat though he said he could get it if I wanted to wait a few days.
So looks like the magazine guys are making a fortune off of folks willing
to pay retail price for Dynamat. My version won't have peel and stick glue,
so I'll have to use spray can glue I think, but I am very excited about a
successful hunt!
Hope this helps some of you out there.
Two successes this week - another fellow on the Type 2 (VW) list sent me
the recipe for Waxoyl (another item sold in small quanities through the
catalogs) - anyone know where I can buy candle wax or bee's wax in bulk?
I'm getting a good education from you GOOD folks!
CHRIS in Tennessee
scmills@tntech.edu
ICQ: 5944649
'78 VW Westfalia (maybe some CIS injection,Corvair, turbos --- maybe I'm
just dreaming.....)
'65 Beetle (Type IV powered)
'99 CR-V 5 speed
'49 Chevy 3100 Pickup
'81 Honda CB900C
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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