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Project Rhocaravan


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This week has mostly consisted of stripping the trailer down to the chassis so we can start the build proper. We were careful removing anything we could sell on Ebay and by putting low start prices on item, we actually sold everything we wanted to and got about £70 back.


The things we kept were the cooker / sink unit, cupboards and a few edge trims. Once the main cover and fold out framework was removed, the trailer looked like this






At the front, you can see the cooker / sink unit which hinges up in to position.


The body is thin steel panels on a steel and wooden framework. It's all fairly light duty but clearly up to the job. It was held together with rivets, bolts to the chassis and the wooden frames and panels were stapled together.


Here's the back end with the door removed, the inner steel frames can be seen. As these aren't going to be any use they were left out for the scrap man, together with the outer panels.




With all the panels removed and the carpet stripped off, this is the bare trailer.




You can see the plastic inner arches that will need to be boxed in under the seats.


This is the other stuff we kept, the old timber framework, some thick and thin plywood, some cupboards panels and the door. Some of this may be useful so we can afford to hang on to it for now.




The real work can start now. the first job is to extend the chassis - currently it's 2.1m long and it needs to be 2.4m so we need to add an extra foot somewhere?

Edited by richyb66
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Yes the plan is to add the 300mm at the front end so it's supported by the A frame. The chassis has 2 side rails plus two additional longitudinal rails about 500mm inboards either side.


If I extended the rear of the chassis, I'd need to extend all 4 rails which is may be trickier so by extending the front, I can just extend the side rails and the A frame can provide the extra support. The front end of the trailer will house the cooker / sink area so it's not as if we'll be jumping all over it.


Once the chassis is extended, the axle won't be in the middle so I'm going to also move the whole A frame forwards 300mm (and maintain space for the storage box) as well as moving the axle forwards 150mm to keep it in the middle of the floor area. The A frame and axle are bolted on so I'm hoping this will be fairly straightforward.

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One of my biggest areas of concern is the windows and door. As we need custom sizes for both, we've either got to make everything from scratch or try and modify existing parts. The original plan was to make the window and door frames from aluminium extrusions cut and bent to shape and to add some sort of seal section around the profiles.


Thinking that we might be able to use extrusions from existing static caravan windows, a few weeks ago we took a trip to a caravan breakers in Colwyn Bay to see what sort of things were available. On arriving, we found that they only dealt in tourers but they had a few vans available for breaking and were happy for us to have a good root around.


This proved to be very useful as we were able to see how the caravans were put together and what materials were used. The main walls are just a foam core with an aluminium skin on the outside and decorative wood board on the inside. The window apertures are lined with a wooden frame and have a rubber U section seal stapled around the inside of the hole. The outside of the seal has a bubble seal that the window closes on to.


We'd already calculated how much seal and extrusion we needed to make all our windows and we removed about 7 window seals by pulling out the staples. In addition to the seals, we also got some lengths of the extrusion that goes across the top of the windows and forms a hinge for the window.


A door and frame was the next on the shopping list. By getting the whole unit complete, we'd get all the seals as well and it would just need reducing in height (the width would remain the same to give us a chance of fitting through it). Whilst we were there, we also picked up a few window catches and cupboard hinge stays.


In all it took us around 3 hours to get everything, the trickiest part being the removal of some of the fixing screws that were corroded. We wanted to remove the extrusions without damaging them as they'll mostly be visible and we don't want to do lots of refinishing on them.Some of the seals had been re-sealed at some point with a non setting mastic which would need to be removed. Although this proved very time consuming, all the window seals cleaned up ok and would be re-usable. No pictures of the window parts yet, we'll show them later when we start to use them.


Total spend for everything was £70 which I thought was very reasonable, they'd quoted me £40 for the door and frame and took an age to work the final price out, during which I was expecting a much higher price.


This weekend we started to look at the door - the caravan door is 1700mm high but we need to reduce this to 1100mm meaning 600mm out of the frame and 300mm out of each half of the door.


Here's the door and frame assembly and the frame on it's own






Shortening the frame involved pulling off the door seal and then removing the 2 screws each side that secured the threshold piece. The seal across the bottom was badly damage but as the frame is less than 600 wide, we could use an off-cut of the side seal to replace it once the frame was cut down.




The frame was marked out to remove 600mm and then carefully cut with a hacksaw before being re-assembled. Like most things on a caravan, the frame is as floppy as anything when removed from the body so we put a couple of wooden straps across it to make sure the width was constant all the way up the frame. The section of frame we removed contained one hinge, we drilled out the rivets and re-positioned the hinge on the frame to become the lower hinge on the upper door.


Moving on to the door, the upper and lower halves are a 20mm foam core skinned either side with thin aluminium sheet. The outer skin has pressed flutes in it which we don't want, so for now we will just cut the doors to size and then reskin them in flat aluminium later. Around the outside of the doors are aluminium extrusions, screwed at the corners and in several places, there's some additional aluminium stiffeners to support the door catches




The lower door was shortened first followed by the upper, which had a large window in it. We probably won't have a window so just cut the door out to maintain the catch position and we'll transfer the measurements across when we re-skin it. The skins easily detach from the core so we've got the option to use the old cores (and use the off-cut from the lower to fill the window hole in the upper).




Here's the finished door and frame, it seems to open and close OK, we just need to re-fit the handle and latches. We'll use it in this state to build up the sideframes and re-skin the doors at the end.




Here's the frame and hinge detail, together with the seals between the upper and lower door. Should keep the weather out OK and far simpler than making a door and frame from scratch. It's also very light.



Edited by richyb66
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Underfloor storage is already being considered but I dont think its going to be practical as a means of increasing headroom. In addition to the 2 longitudinals that run under the floor, forwards of the axle theres a brake actuating rod that runs down the centre and the A Frame and rear of the axle has the spare wheel stored. It would be possible to move the brake rod but this would only allow around 150mm of floor drop before the ground clearance becomes compromised. I stood the door frame up on the chassis last night and the top is around 1500mm above ground level (up to my chin when Im standing outside) so creating sufficient space inside to stand would also require a significant increase in roof height which would spoil the proportions. We'd need to increase the length to make it look right and effectively end up with something the size of a small caravan.

Were not particularly bothered about being able to stand up because were trying to make everything useable from a seated position. The CAD model Ive done seems to show that its possible but once weve extended the chassis, we'll draw the layout full size in chalk on the wooden floor to see what it looks like.

A toilet could be stored inside for transport but its not high on the planning list at the moment. We want to concentrate initially on the function of a tent but in a better package somewhere to sleep, eat and cook and develop it from there depending on the space available.

Edited by richyb66
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This weekend we made a start on lengthening the chassis. We don't have the channel section yet but we could begin with moving the A frame. First job was to remove the wooden floor and separate the wheel boxes. These were held to the floor with a screw a each corner and loads of staples. The screws came out easy enough but the staples took a bit more persuasion and we had to be careful not to damage the wheel boxes because they need to be reused.




They look to be vacuum formed rather than injection molded - the small number they make probably doesn't make an injection tool cost effective.


This is the bare chassis - actually 3 longitudinals in addition to the main rails not 2.Rod for the brakes down the middle and the spare wheel underslung at the back.




We unbolted the front stabiliser legs and re-drilled the rear fixing holes 300mm forwards on the chassis. This will give us an idea where the front of the chassis will finish.




The A frame bolts to the inner longit on this metal plate. The plate needed to be removed from the chassis as the axle has to occupy this space when moved forwards. The A frame was unbolted here, together with the 2 bolts either side that attach the axle beam to the chassis. The welds holding the plates to the chassis were carefully ground away so the plates could be re-positioned.




Jackie set to on the axle with a stripping disc on the angle grinder while I continued with the chassis mods,




The A frame was also un-bolted from the front of the chassis. I marked off 300mm from the mounting plates on the A frame and clamped a piece of wood across so I had something to line up against the front of the chassis.




The galvanising was ground off the chassis where the mounting plates were to be welded back on and once the welding was complete, the area was sprayed with cold galv paint.






At the front of the existing chassis, I welded 2 additional mounting plates to the A Frame to give extra support.



Edited by richyb66
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The axle cleaned up really well, it was mostly surface rust. The backplates were also cleaned before everything was sprayed first with cold galv paint






then the centre beam was painted with black stonechip






the back plates and trailing arms were painted satin black (hidden inside the poly bags) and the drums / hubs will be stripped off the axle once it's back on the chassis and then cleaned and painted.

Edited by richyb66
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55 metres of 25mm aluminium tube ordered ready for making the body framework. Gaz got some galvanised steel folded up for the front chassis extension and we should get that welded in next week ready to start laying out the side frames.

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Extending the chassis was a quick evening's work. Gaz got me 2 pieces of channel 300mm long and a third piece 1500mm long (the width of the trailer. The short pieces needed a bit of trimming so they'd butt up to the current side frames before they were clamped in to position. I used the long channel to ensure the top surface was level and clamped a big spirit level along the side face.




Once the new piece was tacked in to place, the clamps were removed and it was finish welded. As the metal is galvanised, the coating has to be disked off with the angle grinder before welding. I'm using a gasless MIG welder which is now 30 years old but it's still a decent bit of kit if it's used correctly.


The 2 side extension pieces were welded on first and then the front part was added afterwards. It sat perfectly on the A frame and once it was all welded in place, the holes for the bolts were drilled through. Final job was a wire brush over the welded areas and a few coats of paint.




Here's the finished chassis - now 2400mm long as required.




Today the aluminium tube and connectors arrived. Most of the tube is 2500mm lengths (14 of them) but there's also 4 lengths of 5000mm (same length as the garage).




Here are a selection of the tube connectors



Edited by richyb66
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I'd already prepared a CAD model of the side frames and these were drawn out full size on an 8' x 4' sheet of hardboard. The tube could then be cut to length and laid out on the template to ensure it's all square and flat.




The roof and front and back end of the frames will be curved so we'll need to make separate templates for these together with some wooden formers that'll be used to shape the tube around. It's the same technique I used when making my hardtop frame and with some care, smooth bends can be achieved.


For now I just knocked a few lengths of tube together with some connectors to see how robust the system is.




So far so good, another session in the garage tomorrow night should see most of the right hand side frame completed. The front half of the frames are identical but for the back half, the left hand side has a door and the right hand side has a window.

Edited by richyb66
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