Hapy Cab Gets Quiet

In my last post about noise containment, I posted about getting the main living area floor noise controlled with Heat Wave Jute and MLV. Before that, I posted about the application of the constrained layered dampener (CLD) on the ceiling and easily-accessed exposed steel (See Noise Control Update). There has been a lot of foundational work and many posts leading up to this next step. I removed the drop ceiling. I ran the rough electrical for the luxury items like accessory plugs, dome lights, etc (See Ceiling Wiring Rough In). I found and resolved holes from the old Westfalia pop-top. I removed the old shelf, designed and installed a new one (See New Cab Shelf). So finally, today, I will focus on getting the cab area practically noise controlled.

 

Cab Floor Prep

cab floor, nose quieted

Many years ago, I applied something CLD-like to the floor of the cab after addressing the rust with naval jelly and rust encapsulator (see Rust Never Sleeps). That post was so long ago, it pre-dated my now-common efforts to identify the products I am using, but I am fairly sure it was B-Quiet. Regardless, the stuff available in 2007 may not be as effective as the stuff available now. I suspect the old B-Quiet has since been reformulated to have more Butyl and less asphalt. So, I started working on removing that old stuff. It did not want to let go, and in some cases it left a sticky mess behind. I found that I was most effective at removing it when I cut 2" squares into the foil topper and removed a square at a time. For the spots where tacky goop remained, simple scraping worked a little, running the grinder was ineffective, and multiple passes of Goof-Off was moderately effective. After multiple rounds with Goof-Off, scraping was much more effective, and I was able to get most of the asphalt-y sticky off the floor. Still, the effort to remove that old stuff took most of a weekend.

With the old stuff gone I discovered that I needed to address rust in the floor again. Long ago, I abandoned Naval Jelly to get rid of rust, believing that it just is not as effective as the converters currently on the market. Perhaps, it was user error, but I followed the instructions. Anyway, this floor had been worked on with the Naval Jelly before I changed and it showed. I like Eastwood stuff, after trying and abandoning others. It is a simple spray-on product that I then spread around with a gloved hand to make sure it gets everywhere. It dries with a thin shell that could be painted on top of, but Eastwood recommends their encapsulator (of course) on top. I thought about adding another layer of paint, but decided it was unnecessary and left the floor "top coated" with the black Rust Encapsulator.

Cab Floor Noise Contain

Once the cab floor was rust treated, I applied some fresh CLD. Even the Noico was an improvement on what was there before. Before I started, the floor still had a fairly noticeable "ting" when smacked with the roller. Perhaps part of the reason the B-Quiet was not as effective was because it was trying to adhere to rust, not to steel and converted rust. Similar to the cab ceiling, I did the larger panels with the ResoNix, and did a few smaller areas with some leftover Noico. I had not previously applied anything to the walk-through, but that got CLD this time.

I used the rubber mat as a template for the next 2 layers: Heat Wave Jute and the Mass Loaded Vinyl (MLV). I under-sized the front edge so the kick panel/card that runs along that leading edge can seat against the floor later. Then, I did the walk-though floor with Heat Wave and MLV, following its basic rectangle shape.

 

Cab Doors Contained

door Mega Zorbe'd

The amount of prep work needed in the doors was not as extreme as the floor, but there were some needed steps. There was some surface rust down along the bottom and in the spots where the different metal bits intersect. After the rust was addressed and some Rustoleum was applied, it was ready to go. The steel also had some of that B-Quiet, but it seemed much more effective in the door than it was on the floor. I only removed the pieces that came off easily. Oddly, the passenger door stuff came off with little effort and the driver side stuff would not budge. So, the driver door was pretty much left alone (just CLD'd one section) and the passenger door got a full replacement treatment. Thinking about how much material I have on-hand, and how small an area I needed to solve, I used the Noico. While I test-tapped each door, I noticed both doors had a rattle that I traced to loose fasteners on the window mechanisms and door latches. A couple of passes of tighten-loosen-tighten eliminated those rattles.

 

Unlike the floor, I used Mega Zorbe in the doors. This stuff is so easy to work with. It is self-adhesive, so you figure out exactly what size you need, cut it, test fit it and when you're ready, you peel the paper off the back and stick it on. Of course, clean the surface really well first. The self-sticky is super-sticky, so I suggest the first time you play with it you apply it in areas which won't be seen until you get the hang of it. I got the 1/2" thick Zorbe, and it easily fit against the outer door skin without impacting the action of the window. If I have material left at the end of this project, I may apply some to the side of the door card that fits into the door cavity for more sound absorption. 

 

Nose Noise Contain

original Styrofoam

Most of the metal on the inside of the nose is inaccessible or at least very hard to get to. The pedals make getting to that lower section difficult, but not as difficult as the area behind the dash, especially on the driver side. Accordingly, I did not get very complete coverage of the inside of the nose with CLD. Before I could start, the bus originally delivered with some foam stuff glued to the lower section (below the mid-point). This stuff looks like old Styrofoam cooler material, and made a mess similar to a broken cooler with those little white dots everywhere. It was very thin, so I doubt it did much. Once removed, shop-vac'd and surface-cleaned, I used ResoNix, hoping to maximize the vibration deadening from covering such a small percentage of the total surface. I removed the windshield washer bottle and successfully fit a full one-foot-square sheet of ResoNix on the nose in that area. I cut a second square, fitting material up behind the glove box and onto the big metal airbox on the passenger side. On the driver side, access was even more limited. I was unable to fit a full uncut square directly in front of the pedals, but I was able to get a pair of rectangles applied there. I consumed the rest of that sheet plus another, getting coverage above the running light (beside the headlight) as well as onto the airbox. It is hard to know how much those sections will help, but I used the higher quality ResoNix, so maybe it will matter. Because of the foil topper, I figured putting CLD anywhere near the fuse-box would be a bad idea, so the whole upper left side is CLD-free.

I had originally intended to use the Jute inside the nose, but I changed my mind after wrestling CLD in there. First, the Jute needs adhesive to stick. Second, it is stiffer than the Mega-Zorbe. Third, the foil on the Jute is electrically conductive, so, like the CLD, we do not want it near the fuse box or electric controls. So, while we would have probably appreciated the temperature management of the Jute, there is no way I could have constructed a thermal wall in there. This is all about absorbing sound, and inside the nose can't be seen nor felt. So, I used and will continue to harvest for use, trimmings from other applications of the Mega-Zorbe and patch-work my way to sound control on the driver side. On the passenger side, I was able to place a single sheet of Mega Zorbe in pieces. The driver side was very difficult to get to, and handling the super-sticky self-adhere was not working out too well. I was able to get some larger cuts (maybe 4 inches by 8 inches) along the lower section, but that was about it. As I generate trimmings around the rest of the bus, I will return to the nose to add more.

Cab Ceiling

Mega Zorb'd ceiling

After all the efforts in previous postings, from the rough-in electrical to the mounting of the luggage tub and the shelf, I was finally ready to do the cab ceiling. Recall that the drop ceiling has been removed, the old shelf came down, and the original 1972 Westfalia supporting superstructure was removed. I used a combination of ResoNix and Noico for vibration control, thinking that an extra pound was worth minimizing the noise closest to my head. Similar to the doors, I used the Mega Zorbe on the ceiling. I covered the ceiling from lip to lip, front edge to the cross support. Simply sitting in the seat with that single layer of 1/2" foam was incredibly quiet just sitting in the driveway with the engine off. It is quieter inside the bus than outside. If I utter words, they are simply gobbled up by the noise control material in a more pronounced way than a gentle wind takes your words outside. I had originally planned for a second layer, and still may before applying a true headliner, but it will not be because I need more sound taken out of the air. It will depend more by how to contour the ceiling and remaining steel so the transitions are smooth. I will sit with it as-is for a little while, as I do other areas, to see how I feel about it. I may get some basic automotive foam if I need to add something. I don't have the headliner material yet anyway. Seriously, this bus is getting crazy quiet.

Under the Seats

view of the under-seats

Moving on to the seats, I used the Heat Wave and MLV combination again. Consider the little compartments along the inner edge of the seats. These compartments accepted 6-inch wide, 26-inch long Heat Wave on the floor. Against the wheel wells, another 26-inch long 5-inch tall stretch of Jute was set. Then, I got to thinking about the MLV. Consider, the access is very limited and the side of the wheel well is vertical. Simply brushing or spraying on contact adhesive was not viable. I cut 2 sheets of MLV for each compartment, with a combined overall average length of 25 inches each (d-side shorter, p-side longer), but 12 inches wide. Dealing with a half-length, I rolled it up and stuffed it through the access hole, unrolling the 12-inch width in place. So, the bottom edge is against the inner edge where it meets the floor, and the MLV runs up along the side of the wheel well with the top edge roughly against the ceiling. I set the second sheet in similarly, and with an overlap, the compartments are covered.... mostly. The driver-side compartment has the brake reservoir and tubing, so I was not able to get as deep. Hence, the shorter length of MLV. Still, I knew this was not going to be 100% sealed/covered. This is about as good as I could have expected without putting MLV around the outside of the entire seat pedestal, but that would have intruded into the limited walk-through space, for what I think would be little improvement. I accept that the MLV may not stay in place long-term. Since there will be a card on the walk-through side, I can access it and check up on it periodically. Being honest, I probably won't. If I have left over MLV, maybe I will figure out a way to put it inside the walk-thru card. We'll see.

Other than the little compartment, the under-seat space was controlled rather simply. I put one piece of both Heat Wave and MLV under each seat, running from the outer edge of the little compartment (under the seats) to the door's edge. To fit, I cut a channel around the outer seat runner. I thought about lifting the seats, but decided that having an additional 1/2" of squishy lift was not desirable; having some noise travel through the rails was an acceptable tradeoff. After the seat compartment efforts, we are no longer looking at 95% containment anyway. Between the inner seat rail and the inner edge, I set another section of Heat Wave, covering up the remaining bits of steel. This final section was not rectangular since the seat pedestal is not exactly square, but it rests above the little compartment, so MLV was unnecessary. The Heat Wave, however, will allow the carpet to lay flat.

Wrap It Up

Once installed, I taped all of the MLV bits together. Why? Audiophiles suggest that the MLV works best when it hasn't any breaks in it. I know there are breaks under the seat rails and inside the little compartment, so the tape may not be as effective. Still, the metaphor I have read is that the seams are like slightly cracked windows in your house, letting in the noise of your neighbor mowing their lawn. If the window is completely closed the noise is much more contained. So, having lots of open seams is like lots of cracked windows, versus a couple around the seat rails. Since I have not been taking noise measurements along the way, I cannot say whether the patchwork MLV will help meaningfully more than just the CLD and Heat Wave. The sound experts swear by this stuff though.

At this point, I have the floor completely noise contained, from rear hatch to the front nose. We have CLD to contain the vibration, Heat Wave to absorb some of the sound that makes it through and MLV to block most of whatever remains. Since most of the noise comes from the engine, drivetrain and wheels, the work to date should have addressed most of the problem. I am continuing down the noise elimination path, though. I will be applying Mega Zorbe onto the rear ceiling, adding some deadener between the 2 rear ceilings, and solving for the slider and mid-bus driver-side wall. I feel that I have turned an important corner, however.

That's it for today. Thanks, as always, for following along-