Wheels

The plan now is to move the frame to a place where I can work on it indoors for a while to get things weather proof. To this end I need wheels. 

I found heavy duty wheels with a 20mm axle hole. Brackets for these were fabricated using a 20mmm mild steel rod.

An R clip will hold the wheel onto the axle. 

On board

With the frame on board it was off to the supplier for the timber for the walls floor and roof. 

Demounting system

I looked at various ways of supporting the camper to move it onto and off of the trck bed. There are some very sexy and expensive ways of doing this around. I happened a kit of four legs and a jack for about 200 pounds from Edwards Trailers. 

The legs have two hooks at the base to carry the weight and a lug at the top for stability. I created suitable brackets for these. 

These brackets are removeable. It is worth pointing out that I envisage that removing the camper will be a seasonal and not a daily event; I don't envisage removing it 'on-tour'. Part of the plan, of course, is for the vehicle and camper to be transportable in a shipping container. This plan envisages de-mounting the camper onto wheels, hitching the truck and camper together and driving both into the container. 

With the stands all attached the scaffolding was dismantled and the truck (gingerly) reversed beneath it. 

Completing the frame

The frame was moved from the back of the truck onto the scaffolding base for completion off a level base. 

Central floor support added and underside painted

Frame turned over and first corner post being positioned

Positioning the roof support frame work onto the corner posts. Small sections of steel were welded at the underside of the roof frame at each corner. These dropped into the top of the corner posts and simplified the positioning job (by one man).

Roof frame in position 

Laminate Floor

Laminated Floor strength test.

Following a bit of research into floor construction I decided to experiment with the creation of a laminate floor panel based on ply/expanded foam/ply laters. 

Adhesive used was Screwfix no-nonsense expanding (solvent free) sticky foam. Mid later 30mm XPS styrofoam. These layers were glued, pressed together under weights and allowed to dry overnight.

Top surface 12mm of softwood plywood. 30mm XPS styrofoam, bottom surface 4mm plywood

Output is light, strong and inflexible. The beams here are at 750mm centres and there is no flexing under my weight.

I have spent the past week on the construction of the camper base and roof frame. 

The camper frame sits on top of the frame on the base of the van and the steels match the postion of those on the base. The steels are mainly 40mm x 40mm square mild steel tube with 3mm wall thickness. The back front and sides of the camper base are 80mm x 40mm 3mm rectangular tube. There is quite a lot of guess work in this but I think that I have struck a reasonable balance between strength and weight. I have had to think of the twisting that might occur as the camper unit is demounted.

I have experimented with creating a laminated floor base on 4mm Ply, 30mm XPS styrofoam and 12mm ply. I have stuck these three layers together with an expanding foam glue. This has produced a (very) surprisingly light and strong composite board which will support my weight without flexing between rafters at 800mm centres. On the basis of this I plan to construct both the floor and walls on this principle. XPS is expensive so I have done some further experimenting with PIR (Kingspan) board. I was not sure how the glue would work with the foil face on these boards. It turns out that the glue works fine so I have settled for this. The PIR board is 40mm thick. This is thicker than the average caravan wall so limits the choise of windows. I have opted for Seitz S4 windows which can cope with this wall tickness. 

On of the reasons for making the camper demountable is to enable use of the vehicle for other uses when not on holiday. Such as.....

I used the base as a template for making the roof frame. Once complete this was moved the my scaffolding workspace. I have built this as a stand on which I will build the camper. This keeps the van free for other work and means that I can work from a platform whch is level so the spirit level can be used. Once the roof frame was welded on the truck it was transferred to the scaffolding, turned over and the welds completed to the underside. 

Today I received delivery of the steel for the camper frame.