I showed some images of some of the prototype parts a concocted to get a sense of the challenge associated with making them on the previous page. Working with 8020, creating internal fabric panels, laying down a Marmoleum , etc. There's a lot of finish surface square footage in the van. Some parts are going to be a challenge. One thing to our advantage is the fact that our grey paint will look good in the small remaining van interior not covered by some other skin.
We received the Crypton Horizon in 'Natural' fabric the other day along with some headliner. It looks like a good product: stain and fire resistant, etc.
Earlier, we prototyped the wall panels. I really want to see how insulating and making these panels will play out. The rear doors won't have anything running through them such as plumbing or electrical, so we can insulate -> vapor barrier -> panel these doors here in the near future as a way to learn about how that process will go. It might inform how we proceed with earlier 'rough' steps such as how to run the wiring, etc. I always like to find a safe way to get a few steps down the road before I commit.
I spent a little time thinking about the roof vent install as well, pulling the parts out of the box. We will be installing two vent fans on the roof.
The fore vent will be much easier because there isn't any ribbing to have to work around. The back one will be a little more tricky due to unavoidable ribs. Luckily, someone else described how he handled this situation, so I'll at least have a point of reference. I'm glad to have spent some time thinking about this; I think my brain is wrapped around how that will work so I can concentrate at the next task at hand.
EDIT: I later learned about some shims that make this a lot easier.
Installing the Floor
The lucky recipients of some spring sunshine here in Portland, we took advantage by putting in the floor. I'm basically copy-catting almost exactly what a great poster on the sprinter forum specified in his rig with the exception that he re-installed the factory floor. We can't re-use the floor because the marmoleum sheet needs a good smooth layer for the mastic. Here's what we will be doing:
- fill the valleys with 1/4" minicell closed cell foam
- put a continuous layer of 1/4" minicell over the entire floor
- lay down 3/8" of A1 baltic birch
- send some screws up from under the van to lock the ply subfloor in place, getting rid of the wavy-gravy
- adhere a single sheet of marmoleum.
Unfortunately, putting in the floor entails pulling the battery out. Eventually, I'll have to pull the entire electrical panel off to insulate behind it, but that's a project for another day.
There's three deeper channels that needed to get furred out prior to insulating. I glued some ply strips in place, holding them down with some iron.
We made a little mosaic out of minicell to fill in the valleys, consolidating the floor to one height. Then we put a 1/4" sheet over it all. Moving front to back we installed the top sheet of foam, then the subfloor ply, helping ensure it all says put until we screw it down.
Using the old factory floor as a template, we cut the birch ply to shape, when we had all the ply in place, I used self-tapping screws from under the van to lock the ply to the van and make a nice stable floor. The screws came up through the ply about a quarter inch. I used a grinder to cut the tips off below the ply top to ensure they can't poke through. Some wood filler fixed up those crescents nicely, readying us for the final floor install.
Here's an image showing the final buildup. Minicell in the channels, a full layer of minicell on top of that, then 3/8" A1 birch ply. The Marmoleum finish floor is about 3/16" thick for a final floor buildup of about an inch.
With the subfloor in, we then used the factory floor again as a template to cut out the marmoleum sheet. I've never worked with this product before--it was a nasty surprise to learn how fragile it is. It is very, very easy to buckle the sheet when moving it. Any decent crease causes the material to fail, literally breaking apart! My guess is that once the floor is applied, it's durable, but during install, it's like handling nitroglycerin filled eggshells. EDIT: the floor seems pretty bomber after it's glued down.
We carefully and stressfully rolled the sheet in the van for a rough fit, shaping a couple of tight spots. Then we turned right around and removed the sheet, carefully re-rolling it. We want to do all the rough work we can (which unfortunately isn't all that much more) prior to the final sheet install. Since everything will be set down on the final floor, it won't be but a few days before we glue it down, but we might save ourselves a few scuffs. While I'm really happy to have a single sheet down for the floor, there's not very much that is going to show in the end. Just a few square feet of finish floor will be walked on, but it certainly simplifies things to have floor a consistent thickness througout. Moreover, there's less of a chance of a spill getting under the floor and onto the van substrate when the finish floor is one piece. We plan on running a latex bead on the sides wherever we can to basically make the floor water tight. Did I mention I'm paranoid of uncontrolled water?
we applied some stair nose and transition trim which came out ok. The stair nose will come back up when the galley cab goes down, then we will put it down for real with some countersunk screws.
With the subfloor down and the electrical in place, it's a lot easier to set stuff down to confirm it's all going to work the way we want it to from the initial drawings. This is one advantage when you build it yourself: you can prototype, check, and address your design. One big surprise is how our placement for the hot water heater needed to change. Luckily it wasn't that big of a deal to move it a few feet behind the drivers seat.
The white box at the rear is a 25 gallon fresh water tank. The pump will be behind it on the left. The cardboard box on the left demarcates the end of the galley counter run. The range top and sink will go there. The 10 (edit: we changed to a 6) gallon hot water heater is on the edge of the frame to the right. I was thinking of putting it to the left, but there's no way that will work. Where it sits now is just about the only place it could possibly work. Word to the wise: if you are designing your own buildout and plan a hot water heater, it will be one of the first things you will want to figure out. There are many limitations on where it can go. Another issue: the outside of the sprinter is not flat at all, but our hot water heater really wants to mate with a flat exterior. I've decided that I'm not going to stress this one: I'm going to have Van Specialties install it. This will be another example of choosing my time and nerves over my money!
If you are thinking of your own custom buildout and have the luxury of having some money to pay others to do some work, I think it's well worth it. A full buildout such as ours is a LOT of work. Nothing that I'm having done by a vendor is totally beyond my capacity; it's more about the amount of stress I can take an the trade of between time and money. So, for, example, I know if I really sat and thought about it, I could come up with a way to put the hot water heater in myself that would work well. But I have so much work to do just getting the bed platform up to snuff I'd rather pay someone else to install the hot water heater--it's not going to be fun for me at all to do, and it's a discrete task that can be handed off to someone else.
It's also time to get more concrete with my wiring runs, so put some tape indicators to help keep my stuff straight when I start running the circuits and hot water. I'll only be able to do the drivers side of the van until the 8020 bed platform gets built, because the right side water lines and all the electrical runs will run under the bed. I'll be spending a fair amount of time going over my runs set down in tape to make sure I've really got it sussed in. The yellow extension cord is the 120v outlets. We've run one through the wall forward, terminating just behind the drivers seat. The outlet pictured will become a junction box. Another line will run from that box across the van under the bed platform to a position on the galley wall.
The drivers side 12v runs could go in, so I spent an hour running those. We used some split loom tubing to wrap those runs together so they are out of the way for the insulation batt and to generally keep things tidy. The split loom also serves a really important service by ensuring that as the vehicle rolls its many miles down the road that the vibration doesn't eventually saw through the electrical wire shielding as they touch the sharp sheet metal edges. I'll tighten down the cable ties once we are sure we are good to go with all the wiring, pulling the wiring up tight to the frame.
We are using thinsulate batting for insulation, followed by relflectix with metal tape as a vapor barrier. The thinsulate works as a mass loader, decreasing the metal resonance (a fancy way of saying sound deadening). Many choose to apply mass loaded vinyl to achieve this--word on the street is that thinsulate gives the same results
The thinsulate comes in a big roll. It's going to be an effort to cut it up and feed it into all the little channels. There's tons of them in the van. We are starting on the rear doors since there's nothing getting routed through them. Basically all the grey metal you see there has thinsulate threaded through it, attached with spray adhesive.
Then all the holes in the door are covered with reflectix and metal tape to ensure a vapor barrier:
After insulating both doors, I'm impressed with the decrease in noise. Slamming these doors results in a deadening 'thunk' instead of the 'briiiiiiiiiiiiing' prior to insulation. The thinsulate seems to really work well as a mass loader/vibration dampener on the sheet metal. I look forward to how the van sounds after the insulation is complete.
Planning out the Structural
I'm going to build the structural components out of 8020 extruded aluminum. We are ready for the largest section of the interior structure, the bed platform. Once that's in place, I'll route the water tubing and electrical from side to side. This is a much better option then routing all that stuff overhead in the ceiling. I've had a rough sketch of this for a long time, but I needed to make the materials order, so I finally sat down and created a cut sheet
We decided to take the van back to the liner shop that put the floor liner down to apply plastic coating to the ribs. He couldn't use his normal 'hot' applied formula because of the massive amount of wax applied by Mercedes. This product supposedly will stick (how, I'm not sure). We are really concerned about the external trim clip inserts weeping. On the outside of the van, a belt of plastic 'shopping cart protector' is clipped to the van via holes. You can see the plastic insert clips in the picture below. These clips can leak. This would mean water getting in and potentially pooling on the bottom. A sure recipe for rust. We carefully siliconed the inserts, but are also taking the paranoid step of having the plastic liner applied. As you can see below, it runs over the holes, also hopefully sealing them.
Then it was time to put down the finish floor. This was a pretty straightforward job of applying glue with a trowel, laying down the floor (carefully as not to split it!), then rolling over it with a hundred pound roller. This went off without a hitch. With that down, we can now start installing the internal framing. The biggest component to this is the bed platform, which takes up half the van. With this down, we can then run the electrical and plumbing across the van underneath this structure.
Installing Some Structure
I made a slight mistake going with 1" 8020 bar stock. It's really not beefy enough. Moreover, there isn't really enough metal to do some of the connections we want to do (i.e using some self tapping screws). We can make it work, but it's sort of a pain. Additionally, it takes quite a bit longer to built with 8020 than I expected. Since any 90 degree joint is screwed, you gotta tap for that screw head, which is time consuming. The 1" 8020 takes a 1/4 - 20 screw tap, which is a little two thin to just reef on--I broke two taps in the bars before I learned the proper technique of constantly backing out a half turn while only cutting about 1/8 of the way around. This requires a *lot* of twisting with the tap, which is surprisingly difficult on the hand and elbows considering the volume.
Prior to building the bed platform, we covered the wheel wells in Thinsulate, using Goralla Tape to keep in in place. These will also eventually get covered with a plywood box. Supposedly, this is a great help in keeping road noise down, in addition to adding some R-value.
Next, I built the fame that will span from side to side. The bed will sit on top of this, but it will only be 54" wide, leaving about sixteen inches on the driver side for a closet.
We used some nutserts to bolt this to the sides of the van. Between the 8020 bars and the van, I applied a little spacer of minicell so we don't have a metal-to-metal connection.
As you can see, we are building a kneewall so the horizontal span is strong enough to hold the bed. We will also apply some ply to the kneewall, which will stiffen it up significantly, in addition to some other bracing. Like I mentioned, 1" bar is too small. We can make it work, but I'd rather of had it overbuilt. On the positive side the lack of metal in the 1" stock compared to 1.5" means the platform will not be very heavy--maybe like 150 pounds max when the plywood goes on.
With the bed platform in, we can start getting the electric and (eventually) the water lines across the van. We plan on using the van this coming weekend for a trip out to Smith Rock in central Oregon so I wanted to get the Espar air heater powered up. I ran that line and a couple of others on the passenger side through some split loom. The water lines will basically follow the same path as well.
I'm not sure how I'll get these 12v DC lines all tidy, but I'll figure out some way to sort out this cable gore. For the moment, it's bothersome but innocuous to leave these wild octopi flailing in the breeze.
Adding the plywood to the 8020 structure dramatically changes the feel of the van, suddenly transforming it from a big cavern to something much closer to what it will feel like when done