Sorting out loose ends for a new foamie, all input welcome

[peeler]

Hey everyone

I recently joined, I live beachside in Ormond Beach, Florida, and am putting the pieces together for a camper build.

My original shape and layout before finding this forum, turned out to be very very close to "Woodie's Camper - Lightweight Standie", build thread here: http://tnttt.com/viewtopic.php?f=50&t=63630

Same basic design and layout, only a couple differences. I'm using the IronTon 5x8 trailer from Northern Tool, and plan to have an exterior size of 6' Wide x 10'6" long (including the nose) so I'll have a bit of overhang in my floor.


I've got a grip on the basics of the PMF method, and I've done fiberglass work before so that shouldn't be too hard.

But there's things I'm still figuring out, so I made this thread to post questions in.


The first thing I'm looking to finalize on is my sandwich floor, i'm leaning towards framing with 2"x2" pine, and sandwiched with ohhh maybe 3/8" or 1/2" plywood on top and bottom, with foam board filling the gaps, all glued together with titebond. And PMF over top and bottom, and eventually bolted down to the trailer frame with several big bolts. I'm looking for input on the floor construction, total overhang (past the metal frame) will be around 6" on each side, and 15" overhang at the rear. I also considered using 1"x2" and or 1"x3" for the floor framing, but I'm on the fence about whether that will get me enough strength for that 15" overhang at the rear. Looks like there's no need to overbuild this, but also I don't want it to end up bowing. I am not planning on having the drop section of floor as Woody's Camper has, just one solid block of floor. Input on 1"x2" vs 2"x2" framing, and thickness of plywood would be super cool.

[peeler]

Basic initial concept, subject to a bit of massage on final dimensions. *updated image*

[peeler]

I also need to decide on wall and ceiling thickness.

3/4" foam board is readily available here, so the 2 easiest options I see are:

(1) 3/4" thick foam wall and or ceiling, with PMF both inside and out
(2) 1.5" thick foam wall made by sandwiching 2 sheets of 3/4" foam board together, with PMF both inside and out.
(3) a mix of both thicknesses (example: 1.5" thick main walls, 3/4" thick walls on sides of trolley top)

The general idea is to have that small, roughly 4 foot-ish section in the back tall enough to stand, and the rest progressively dropping down in the front.

I have built all sorts of stuff, lots of furniture, and done basic framing etc so I'm pretty OK with building. That being said, this is my first camper build. I've wanted to build one for years now. I do not have welding tools.

I've tossed around the idea of building the whole camper shell as a single unit before mounting it to the trailer (mocking up along the way to ensure things are level, and fit). I haven't figured out all of the benefits / drawback to doing it that way, versus building it in place, on the trailer.

I want to build this one as lightweight as possible, and at the same time I want it to be strong. Aerodynamics are not a top priority, we're planning to use this one for hopping around mostly within the state here, and we prefer the slow and easy routes over interstates when possible.

[KCStudly]

Have you done any mock-ups or models taking into consideration the turning circle of your tow vehicle (TV)? The way you show your overhang at the front being wider towards the front of the tongue gives me a little concern about the two vehicles colliding; especially when backing to maneuver.

For a standy the 3/8 or even 1/2 inch ply may be justified on the top. If weight is a big concern it might be worth the effort to go lighter on the sides where you won't be walking. On the bottom you can go much lighter.

To give you an idea, I have been building my cabin on a temporary wooden build cradle that does not extend all the way to the back floor xmbr and is only about half as wide as the cabin. My floor frame is 2x2 cedar perimeter and at the 2 xmbrs where there are plywood seams, 1x2 xmbrs on edge in between, 1-1/2 inch foam infill, and only 5mm ply skins top and bottom. Every surface is glued.

During construction I left the front wall and roof off for as long as I could while finishing the cabinets frames and interior so that I could step up inside and walk around. I did put a waster piece of ply down to walk around on, but that eventually came out, too. In the galley I can't tell you how many times I have stepped up in there to work on the back of the roof, shelves, hatch hardware, etc. Mind you I didn't dance around and dance a jig, but I can tell you, IMO you just don't need that heavy a thickness, at least not on the bottom or wherever there will not be heavy foot traffic.

[TheOtherSean]

The vintage standy plans here on this site tended to use about 1/2" plywood by itself for a floor. I'd guess you could go 3/8" safely enough if using sandwich construction, but I am certainly no expert.

3/8" - Wanderbug
1/2" - Li'l Guy, Wander Pup, Terra Cruiser, Roamabout
5/8" - Popup, Mechanix Illustrated Vacation Trailer
3/4" - Trail Scout

[peeler]

Have you done any mock-ups or models taking into consideration the turning circle of your tow vehicle (TV)? The way you show your overhang at the front being wider towards the front of the tongue gives me a little concern about the two vehicles colliding; especially when backing to maneuver.

For a standy the 3/8 or even 1/2 inch ply may be justified on the top. If weight is a big concern it might be worth the effort to go lighter on the sides where you won't be walking. On the bottom you can go much lighter.

To give you an idea, I have been building my cabin on a temporary wooden build cradle that does not extend all the way to the back floor xmbr and is only about half as wide as the cabin. My floor frame is 2x2 cedar perimeter and at the 2 xmbrs where there are plywood seams, 1x2 xmbrs on edge in between, 1-1/2 inch foam infill, and only 5mm ply skins top and bottom. Every surface is glued.

During construction I left the front wall and roof off for as long as I could while finishing the cabinets frames and interior so that I could step up inside and walk around. I did put a waster piece of ply down to walk around on, but that eventually came out, too. In the galley I can't tell you how many times I have stepped up in there to work on the back of the roof, shelves, hatch hardware, etc. Mind you I didn't dance around and dance a jig, but I can tell you, IMO you just don't need that heavy a thickness, at least not on the bottom or wherever there will not be heavy foot traffic.

Thanks for the input! I did sketch the camper hooked to our tow vehicle, and cut them out and do some turns with it, and it seemed fine for all forward driving and turns. Backing up seemed to be OK but needed to be watched. That sketch test was also done with a 48" wide nose, versus the now sketched 54" wide nose, so I need to revisit that. I really should look at making some adjustments to bring that nose back in to 48", and everything else flowing together.

I think 2x2 and 1x2 for floor framing (1.5" sandwich) sounds good, I like the idea of going thinner on the plywood where we won't be walking, and doing the walkway thicker. I wonder how thin I can go on the bottom ply, maybe 1/4"-ish? The PMF wrap with 10 ounce canvas will surely add strength (and thickness) all around.

[KCStudly]

I finished the top of my floor with stain and poly, so I can't speak to the addition of canvas. I know canvas was a common flooring material for area rugs back in the olden days, but maybe something more intended should be used in a standy.

How about using the 1/4 inch all over then just adding some of that laminate snap together stuff (Pergo, etc.) over the traffic areas? A lot of people have found small left over quantities at places like Restore and HFH.

[peeler]

I did another sketch up. The camper is 6" shorter, trailer 3" shorter. I reduced the rear overhang to 12". The nose was moved back 3" from the trailer coupler, and narrowed to 48".

[peeler]

How about using the 1/4 inch all over then just adding some of that laminate snap together stuff (Pergo, etc.) over the traffic areas? A lot of people have found small left over quantities at places like Restore and HFH.

I like it

[GPW]

Me too !!!

[peeler]

Me too !!!

The build threads are super helpful. We really dig that FoamStream!

[peeler]

I am weighing the possibility again of using 1x2 / 1x3 to frame the floor. The revised plan only has 12" of overhang at the rear, and the only spot i can see that could give any issue is right there in the middle of the rear floor, where the door is. The walls and ceiling and all will be light, I think I could reinforce that section of floor under the door from underneath.

So that would make the floor sandwich go something like.... 3/4" foam and 1"x2" / 1"x3" framing in the middle, 1/4" ply top and bottom, reinforce the walkway with a second layer of 1/4" ply or wood flooring glued down, and PMF wrap top and bottom.

[GPW]

The further apart you put those 1/4” ply skins , the stronger the structure will be ... just sayin' ...

[peeler]

The further apart you put those 1/4” ply skins , the stronger the structure will be ... just sayin' ...

Indeed. A lot of bouncing and bumping when in tow. And everything sits on that floor, one way or another. Perhaps it would be better to stick with a 1.5" gap between them. It's not a large increase in weight, or height.

[GPW]

The foam is the lightest element in a trailer build , so feel free to use it as thick as you like ... remember the old adage , “Twice as thick is EIGHT times as strong “ .... True when it comes to bending/flexing properties ...