Modern Off-road Trailer Build

[Onajourney]

I would reconsider the OSB.

[mhnudi]

I would reconsider the OSB.

I don’t really see any issues with how I have it used in this application. It’s outdoor rated osb and will be well sealed on all edges, and then covered by the walls and additional sealant on top of that. The top of it will be completely covered by waterproof marine vinyl flooring. Most the time I see people having issues with OSB they have tried to use it as a flooring material where some portion of it is exposed to the elements (like the bottom of their trailer).

[mhnudi]

Had a nice delivery today, the under-carriage LPG tank came which will be mounted in the area where the timbren cross-member support bar is located, approximately in line with the axle. This was purchased from gowesty.com and is a 3.3 lb LPG tanks (https://gowesty.com/products/lpg-tank-with-regulator?_pos=3&_sid=a6d11a821&_ss=r). It’s designed as a part replacement for vintage volkswagen buses so it’s nice and low profile and doesn’t eat into the ground clearance of the trailer that much. It will sit slightly above where the lowest point will be, which will be the water tanks.



This will be getting installed along with this NashFuel remote fill kit (https://www.ebay.com/itm/180405827194?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=RxTioHAgSLC&sssrc=2349624&ssuid=Gz56BiojTFK&var=&widget_ver=artemis&media=COPY) which will allow for fill and venting from the side of the trailer.

[lfhoward]

I have one of those! They rock! You will love it. The low profile makes them almost disappear under the trailer. Be sure you install it somewhere that you have good access to fill it.

Mine is dated 1986 and comes from a Westfalia Vanagon. It’s 3.2 gallon capacity, slightly smaller than yours.





What propane appliances will it fuel? Mine is permanently connected via copper line to my Propex heater, but I also put in a Coleman port to be able to attach a rubber line to my camp stove.

[mhnudi]

I have one of those! They rock! You will love it. The low profile makes them almost disappear under the trailer. Be sure you install it somewhere that you have good access to fill it.

Mine is dated 1986 and comes from a Westfalia Vanagon. It’s 3.2 gallon capacity, slightly smaller than yours.

What propane appliances will it fuel? Mine is permanently connected via copper line to my Propex heater, but I also put in a Coleman port to be able to attach a rubber line to my camp stove.

Looks great! I was happy when it came in seeing the low profile of it. It’s just big enough for our needs but won’t hang down much below the timbren support bar.

In my case, it’s going to be mounted right under the center of the trailer, but I am installing a remote fill kit which will be mounted on one of the trailer sides for easy fill/venting.

In terms of appliances, this will go to the combi heat/water heater. This unit can be powered entirely by electric, entirely by propane, or a combination of the two. The other “appliance” will be a propane quick connect in the kitchen area for an optional connection to a propane stove. The goal is to have enough batteries to just use an induction cooktop, but we would like to have the option of a propane stove if needed. The same idea for the heat, where we will likely primarily power by electric or combination and use the propane as a backup system when needed. I am intending to have direct copper connections to both of these attachments/ports on the trailer since I don’t plan to have any additional appliances using propane.

[mhnudi]

Last night I finished installing the huber zip system liquid flashing to all of the edges of the flooring and base structure. This stuff took a while to put on but seems like it’s a nice sealed edge when testing it a bit this morning.



Up next I will be installing the marine vinyl flooring, but I first have to cut out the holes required for the floor mount air conditioning unit.

[mhnudi]

Little change of plans and decided to go ahead with installation of the propane tank. First I went ahead and welded a simple bracket that I could bolt to the frame and then have bolts in the 4 corners to mount to the tank



Gave it a good coat of primer and black paint and had to get a little creative with hanging it in the garage to let it dry overnight:



Next I decided to get the main hoses for the remote fill kit installed so I didn’t have to mess with these after the tank is installed. These fittings were a bear to get on, but definitely have no question that they are secure after all that work.



And the finished product. Took a little fumbling around to get it mounted up there and the bolts torqued, but glad to have one more thing put on the trailer.

[lfhoward]

The tank looks very secure (4 bolts to the frame) and ground clearance is still good. Since the tank diameter is 6 inches, it looks like you have 10 or 12 inches from the skid plate to the ground, which should be plenty offroad. Nice work!

What is your 4x4 tow vehicle, and is it lifted?

[mhnudi]

The tank looks very secure (4 bolts to the frame) and ground clearance is still good. Since the tank diameter is 6 inches, it looks like you have 10 or 12 inches from the skid plate to the ground, which should be plenty offroad. Nice work!

What is your 4x4 tow vehicle, and is it lifted?

The 4 bolts is definitely overkill, but I was trying to avoid a center bolt through the main bar going through the trailer because that’s where the tail light wire runs though. It would be a bad day if I cut those wires at this point, lol.

I didn’t measure yet but I think there is right around 11” of clearance. I drive a non-lifted F-150 so I think the trailer will end up with just a bit more clearance than the truck, but I will have to verify. We don’t intend to do much heavy off-roaring with the trailer, but did want the timbren suspension to help with bumpy gravel roads, etc.

[mhnudi]

On this weekend’s agenda was getting the floor cutouts for the air conditioning unit planned and cut through the floor. The planned order of operations was to cut the holes, installed the flooring, and then seal + install aluminum flashing around the opens to seal off the hole.

The air conditioning unit as well as the combination heater/water heater unit were both ordered from the Chinese company Nanfeng Automobile Group (https://www.auto-parkingheater.com/). Communication for my orders was really easy, payment was via PayPal, and shipping came via FedEx in 3-4 days after ordering each time. The AC unit is 120v, but we don’t intend to use it much unless we are in a location connector to shore power. The combination heater/water heater unit is either 120v or propane, or a combination of the two together. Time will tell how the units perform but the packaging was good and came will all the accessories you would need, so it looks promising.



The front of the unit will effectively be where the camper wall segregates the sleeping area from the utility area/kitchen, but leaves about 90” of open floor space between this and the front of the trailer.



The flooring is a marine vinyl flooring with a ¼” foam under layer to add a bit of padding between the plywood and the top surface. At this stage was just rough cutting out the panels and getting ready for glueing. This particular flooring is the “textures” line from Overton’s that I found on my local craigslist ads.



Lots of glueing, using marine flooring adhesive here




After rolling the entire surface to flatten out the flooring, found every heavy object we had around the house to weigh down the edges while the glue dried:


And the finished flooring. We probably could have done this after installing the walls, but it seemed easier to me to just cut away strips are things were added vs. trying to piece-part this in after the fact.


After doing the flashing for the AC unit openings, it’ll finally be time to starting going vertical and working on the walls. My plan is to start with the side walls and then build out the galley/utility area first, before moving on to the remaining walls and roof.

[mhnudi]

Before I started installing the aluminum flashing, I lined the entire cutout for each of the holes with butyl-based tape:



The flashing was done with the thing 4x4x8” pieces they sell at lowes in the roofing section. It was a bit tedious to cut them all to fit. To attach them, the top and bottom surfaces of the flashing were mounted with VHB tape to the flooring as well as the ACM paneling on the bottom of the trailer. I took the picture before doing this, but for the 2” diameter cutout, after putting a thin plate on the top and bottom, I had another piece of aluminum go through the hole on the edge, which I then cut and taped down to seal off that penetration. This is where the AC drains from, so there will be another hose to take the condensate down below the base of the trailer



And finally, glad to see that the AC still fits after the tape and aluminum. I am going to be leaving this mounted moving forward since the location of the AC unit was going to decide the placement of the walls.

[mhnudi]

Made a bit more progress over the last few days. Firstly was getting the remote fill kit for the propane tank mounted to the frame. Some of the fittings that came with the Nash Fuel kit were not ideal (like the right angle fitting on both sides of the fill line) but it worked out. After this picture I used some hose clamps to secure both hoses to the frame.


Decided to revisit the overall shape of the trailer before moving onto the walls end ended up going with just flat sides in the end. This will simplify things and cut down on the weight, although giving up a bit of insulation.


Next was to start joining the three pieces of plywood needed for each side of the main wall. I went with a tongue and groove bit to make the joints. Here I added a top rail to the router table in order to keep the pieces aligned with the table face, and also correct for any bow in the plywood as it was cut.


The groove was relatively shallow, but deep enough for the glue to grab on and not too deep where the plywood could splinter out easily while moving things around preparing for gluing.


While the board extensions were drying, I clamped two scrap pieces on both sides to help ensure that the faces were aligned.


A bit of geometric info in case anyone down the road is interested:




I didn’t grab pictures of this, but I repeated the process again of joining the plywood on the short edge to give a total board length of around 60”x115”. In a perfect world I would have just bought a 5x10’ sheet of plywood, but I gave up after calling all the local suppliers I knew of in the area and couldn’t find anyone that offered it. After this, I laid out everything on the board and started cutting things out with the track saw, repeated for the second wall. I did a dry fit and everything is lining up well with the trailer.


The doors from Teardrop Trailer Parts will be here this weekend and I’ll go ahead and get the door cutouts done next. These main walls were done with ¾” plywood, but I’m planning to use ½” and ¼” plywood for the rest of the walls and roof.

[mhnudi]

For today’s progress, my wife and I proceeded with getting the first of the walls installed. To start off, we built the boxes that will sit over the wheels. These will protrude into the main cabin, and will eventually be sealed and covered in aluminum on the exterior side, prior to installing the fender.

First thing we did was went around the edges and installed a butyl tape to connect the liquid flashing that was previously installed and the ACM panels.



Then, each piece of wood that was installed was capped off on the bottom with zip flashing tape prior to install. I’ll go back through later on and caulk in any of the screw holes. I plan to use this flashing tape for all of the exterior plywood seams prior to the aluminum sheeting and trim.



The sides of the wheel well complete, I plan to cap it with thinner plywood but didn’t have any on hand.



Next I needed to make a template for the doors, which was 26”x36” with a 4.75” radius corner. I used my shaper origin for this to make a template for a flush trim router bit. Not pictured, but after cutting out the template, I laid it out on the doors, marked the location and did a rough cutout with the jigsaw. This template was then clamped back onto the side walls and used a flush trim bit to finish cutting out the hole.



Added some more zip tape to the base of the right side wall and then got it installed. It is screwed along the edges into the base frame, as well as into the wheel well assembly for some vertical support ahead of the rest of the structure.




Next I’m going to start building out some of the interior divider walls and structures before adding the opposite side wall. I’m hoping this makes things go a little faster as I’m not trying to work sandwiched inside the trailer.

[chopperwalker]

I've been eyeing the Shaper Origin since before it released. What a great use case. Any reason why you didn't just use it on the door opening itself?

[mhnudi]

I've been eyeing the Shaper Origin since before it released. What a great use case. Any reason why you didn't just use it on the door opening itself?

It’s a great little tool and I get a lot of use out of it. I find it’s best for template routing projects. The main reason why I didn’t just use it on the door directly was to save a bit of time. It’s easier to do one really clean pass with the shaper on a thin piece of stock than it is to do probably 3-4 passes on each door I would have to cut out. If I was just cutting out one door I would probably just do it all with the shaper, but for me it’s just a bit faster to do the cutout once on a scrap piece, and then jigsaw and route out the door cutouts for the other side.