New Build Begins- 2021 CV 515

[2 bikes 2 brown dogs]

I used LoctitePL3X to adhere the sheets of 1/2 to the tops of the 'planks' (top of steel corrugations and top of XPS trapezoids in the valleys). Just before that a did put a bean of Great stuff foam in the gaps between the sides of the 2" foam and the sides of the steel corrugations because, why not. On that note I also made a little test piece of XPS to XPS with Great Stuff. In case you ever need to put those together it sets up damn fast and is super strong but you get less than a minute to put you pieces together and clamp it down.
With the roof insulation done it was time to apply the EPDM and this turned out to be the most difficult compatibility issue of all. I actually still do not know if it will be successful as it hasn't cured completely after 10 days.
Most EPDM kits sold for RV roofing come with a water based acrylic adhesive that can be rolled on. It looks like Elmer's Glue and Kilz Primer had a baby. I joke because I have to make light of a really frustrating situation. All my reading of MSD sheets on the adhesive along with installation instructions from different EPDM manufacturers made my layering choice seem acceptable. I found a lot of commercial applications where EPDM was glued to XPS, referred to as "fully adhered", with out mechanical fasteners and is what made me decide on this in the first place.
At the perimeter steel I used DAP Weldwood contact cement to adhere the rubber to the steel. Just before that was applied though you could still grab the edge off the rubber and 'peel' the membrane away from the insulation boards. My best guess is the problem has something to do with the XPS not being porous or at least porous enough to bond. I don't think having an airtight steel layer below is helping the curing process by any means but to suggest I'm less than thrilled is an understatement.
That was about a week ago. In a few more days I'll have some other equipment bolted down and I'll do a test drive under an overpass with a friend standing above. If the EPDM doesn't act as a huge balloon I wont start ripping stuff apart. My original plan intends to use a 3M double sided tape to adhere the aluminum sheets to the frame and in the case of the roof it would be taped to the EPDM. If the rubber isn't working under suction forces I'll have to rivet the roof aluminum down to the steel deck. Drilling holes through all three layers of waterproofing will be a sad admission of planning failure but I cant have my solar array and the aluminum it's attached to sucked off the truck so my fingers are crossed the test drive goes well. If anyone has some knowledge or experience with XPS to EPDM with water based acrylic being a bad idea I'd like to hear about it as I don't want a successful test drive to give me a false sense of security.

 

[jeg920]

How did it go... did it hold?

 

[2 bikes 2 brown dogs]

EPDM didn't flutter or balloon as far as the camera could capture. I'm going to stay with the plan and tape the roof down to the EPDM.
For what it's worth some of the tools I used like the roller handle got the adhesive on them. A month later it was extremely pliable, like really soft rubber. Ide test some other acrylics next time for a stiffer cure/set.
Some other distractions have pushed the start of that work until after the holiday.

 

[BBD]

Very cool build - thanks for sharing!
Any issues / modifications required to fit those wheels / tires?
Did the larger tires limit your turning radius, or they clear the springs / steering arm?
How's it going on the habitat build?

 

[2 bikes 2 brown dogs]

BBD, the only issues regarding wheel fit was cutting the rear outer edges of the aftermarket bumpers back to clear the fully rotated tire. Both the front and rear did have a 3" body lift but that wasnt for steering related clearances. It worth noting that the upfitter that did the wheel and bumper work noted they had worked on more than a few off the CV515's and that the turning radius (steer angle is actually what he referenced) was well less than OEM specs. He noted there were bump stops installed but couldn't get feedback from GM or International on what else those might be protecting and recommended leaving them in.

 

[2 bikes 2 brown dogs]

The build out is moving along but darn slow. I spent the last two weeks of July bending and taping the wall panels on. Got it back to the house and have been working on the roof and wall openings. I have to say the panels do look great. The thickness of the 0.063 sheets makes for a dead flat plane. I've got lots of 40" spans between internal supports and even at highway speeds there is barely a shimmy to the material. Short story is i think it will withstand a few more limb smacks and bumps before they actually leave a mark. There are some down sides though. I haven't installed the vertical corner guards yet and and the roof panel laps are discussed below along with some of the other 'hurdles' for others to consider.

 

[2 bikes 2 brown dogs]

Once a bend is added to the panel the stiffness of the edge introduces water issues at the laps. Note the panels are installed from the rear towards the front. Also the wall panel has a lap up and under the roof sheets. The roof panels are like C shapes and have 3" flaps that run down the wall face.
The bent material is so stiff that as the forward/upper panel laps over the rear/lower panel the high edge keeps going away from the flat plane. Like a little ramp.
My wall seams were based on aligning with some of the existing windows and door jambs (see the photo of the door). I though less added verticals at seams and super clean factory cut long seams. Because the panels were so stiff and wanted to stay high it took about 8" of over run for the panel to come back to the flat plane.
I didn't align my roof seams with my wall seams so this problem of 'lift of' is exacerbated when a roof joint lands close to a wall joint.
Without rambling too much if I did it again tomorrow I would definitely not have let the wall panels bend up onto the roof. I don't think I would have even bent the roof panels flap down the wall either (still on the fence if I could have made that work). Doing flat panels and capping the top edge with a corner guard would have been far more watertight. Keep it simple stupid applies. I'm now putting a case of Sika 221 around all the top corner seams and capping it with a huge corner guard ....and crossing my fingers.

 

[2 bikes 2 brown dogs]

On a past note the EPDM does have good adhesion to the XPS insulation. There are three openings (RTU, fan and skylight). From the inside of the habitat I had to remove the XPS to expose the underside of the EPDM then cut that to get to the aluminum panel. It was a ********** to separate the insulation from the rubber. It stuck!

 

[Quirky]

Hi 2 Bikes 2 Brown dogs, Can I ask you who the upfitter was who did the work on the chassis body, kelderman suspension, bumper and wheels upgrade? I too have the 4x4 CV 515 chassis with a Nexus Rebel 30R camper body built on it. We like to roam the beaches and as a stock vehicle, the camper body is too low to the ground. I was thinking the Kelderman upgrade and larger tires would get me the additional clearance I need. Love your build out! Thank you for your time.

 

[Sixinarow]

Awesome! I almost bought the Chevy version in the LT trim but even that was lacking what I wanted, bells and whistles-wise. Looking great so far!

 

[tyke123]

Great build! Is it possible you could share the Make/model of front bumper you used?

 

[2 bikes 2 brown dogs]

The front bumper and skid plates were provided and installed by Skeeter Brush Trucks out of Hillsboro, TX. They just referred to it as "Big Truck Bumper" if I recall. No kidding
It was done along with the wheel and front suspension work. I'm not sure if they sell it stand alone but it's worth asking. It's awesome. The winch compartment is a nice little touch that keeps it a little sheltered and works well with the front swing for engine access.

 

[dbhost]

Holy cheez whiz Batman! I never knew IH / Navistar was building a truck / cab / chassis using a GM cab. At least that LOOKS like a Chevy cab...

That is a lot of truck!

 

[2 bikes 2 brown dogs]

We spent the most of August waiting for rain to do leak test drives and the pin hole drips in the roof were elusive but we caulked the last one and weather stripped the rear door by labor day. It didn't rain for another 30 days so we finally drove 200 miles to catch some of Ian's rain bands and got the green light on dried-in. The caulked wall seams don't look awful but a corner cap of diamond plate 25 gauge will still go on as a corner guard to act as lipstick.

 

[2 bikes 2 brown dogs]