New and Improved Camper Box Build - Ver 2.0

[Heifer Boy]

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Welcome to the new and improved “Camper Box Build – Ver 2.0”.

All the photos for this build can be found in my PhotoBucket Album at http://s1101.photobucket.com/albums/g423/Heifer-Boy/Camper Build Ver 2/?start=all. Just a few have been added to these posts.

If you have seen my previous attempt at a camper lid for my ute http://www.expeditionportal.com/forum/showthread.php?t=55247 you will know all the requirements I had and the positives and negatives of that experience. It's what brought me to design and make this current camper.

Prelude – RIP Camper Lid Ver 1.0

The first thing I did was tear apart the old lid to see what a few years worth of offroad abuse and living outside full time did to it. It wasn't pretty. There was water seepage and rotting had started and all the galvanised exterior wood screws has started rusting. The construction adhesive I used came apart fairly easily on all the joints with only some laminations hanging on and breaking with a very loud pop!! All the joints failed at the glue and not the plywood which is the sign of a glue not designed for building a camper with. The only real positive was the self adhesive foam seal used around the joint between the lid and the tub. It was in excellent condition and didn't let in any water after all those vibrations and weather.

So that definitely put that camper experiment to rest as there was no rebuilding it. It did us well for a while but time to move on to bigger and better things.

Stage One - Research

Because I wanted to something that would be waterproof and dust proof I first thought of just enlarging a ute tool box to my dimensions and fitting it out inside with drawers etc. I couldn't understand why all the slide-ons I had seen had steel frames with either steel sheet or alloy sheet attached. Surely a 3mm checker plate alloy box would be strong enough. No!!! Further research showed many people had thought the same and how many alloy tool boxes had cracked after thousands of kilometres of corrugations in the outback. A steel box wasn't going to happen because it would weigh more than my truck and a framed box wouldn't work because I would just lose too much space on the inside (remember I have a tub, not a tray). What to do...

My search took me to exotic materials way out of my price range and back again before finally landing on all the hundreds of wooden boat building websites, teardrop camper websites and expedition trailer websites. These taught me the wonders of epoxy glues, waterproofing and encapsulation ideas. Building methods utilising lamination, stitch and glue and fibreglassing to easily build things strong, light and tough. I had my building method and I could do it myself. If it was good enough for a T-Van it was good enough for me!!!

Stage Two - Testing

So I read and read and read but I still couldn't get away from the idea of “12mm ply with screws holding it together” so I needed to do some tests. I got a sample epoxy kit from BoteCote (great Aussie company in QLD) and some bits of ply to play with and away I went. With the exception of boats, most wooden camper and teardrop builds use a frame but I wanted to build a torsion box slide-on design so I needed to test simple butt joints.

First I glued and screwed three 12mm ply dado'ed butt joints with PVA glue (white glue), PU glue (yellow polyurethane) and epoxy mixed to a glue, waited a couple of days, removed the screws and broke the joints with the following results.

• 1. The PVA glue was like tearing paper - very easy.
  2. The PU glue was tougher but still broke at the glue joint. It fills the gaps well but only with foam which has no strength.
  3. The epoxy glue took a bit more force to break than the PU but this time the ply was the weakest link instead of the glue joint. All the gaps were filled well and it pulled the ply apart. Perfect.

These were the expected results but it's nice to see it for yourself. So epoxy it is!!!

Next I made another joint out of 12mm ply and epoxied and screwed the corner. When dry I removed the screws and filleted the inside of the joint with a thickened mix of epoxy and filler. This adds enormously to the strength of the joint and provides a radius for the fibreglass tape to fit around. I also routered the outside edge and then laminated on some fibreglass tape inside and out. The result is a corner joint I cannot break!!! I've clamped it to a bench and hauled on it, hit it was a hammer, hit with a 4lb hammer and jumped on with my 80kgs. Nothing, Nada, Bubkiss!!! It is one hugely strong joint!!!

Then I thought “they build kayaks and racing dingies out of 4mm ply” so I couldn't see why a camper needed to be out of 12mm. So I repeated the test with 9mm ply and this time only fibreglassed the outside joint. The result was exactly the same. One hugely strong joint I still haven't broken!!!

The last test was durability. I painted 9mm ply with fibreglass matt and epoxy on one piece and just epoxy only on the other piece. I want to find out how much the epoxy only and the epoxy with fibreglass strengthened the ply and what impact resistance it had. When clamped to a bench it was easy to snap a piece of ply with no epoxy at all but it took my full weight to break the one coated in epoxy only. But I had to stand on the piece with fibreglass in it to break that!!! I then hit the remains with a hammer to test impact resistance, twice flat and twice with the edge of the hammer. The epoxy only piece dented with a loud pop and the epoxy cracked like plastic (which it is). The piece with the fibreglass barely dented when hit with the corner of the hammer and I can't find where I hit it with the flat!!! It added a lot of impact and flexibility strength overall.

The end result of all this is a easy build process that should be light and strong. So the plan is -

• 1. The camper to be built with a mixture of 12mm and 9mm exterior grade ply.
  2. Epoxy glue all corners. Clamp screws to be removed afterwards.
  3. Fillet all inside corner joints.
  4. Coat interior with penetrating epoxy for waterproofness.
  5. Fibreglass all exterior surfaces and joints for waterproofness and strength.
  6. Paint exterior.

cont/

 

[Heifer Boy]

/cont

Stage Three – The Design

I've had the design in my head in various materials for over a year so I had to get it down on paper – literally!!! Some of the corners and voids I couldn't “see” in my head or in drawings so I built a little model out of paper and sticky tape and this made it so much easier to think about what was good and bad about the design. Highly recommended. I never took a photo of it but I do have this Sketch Up drawing instead.

Overall it's a fair bit higher than Ver 1.0 because we now have a roof rack for an awning and with the tent on the camper it will be the same height as this. It gives us a lot of extra space above the storage drawer and fridge and I put in some side doors for access. I tried some other ideas but came back to the K.I.S.S principle. This solves most “what if” ideas – as does a little paper model!!

The basic layout is the same as Ver 1.0. Fridge, jerry can and storage down the RH side and kitchen box and storage on the LH side. The RH “wing” will house the water pump, the hoses and some power points for the fridge etc. The LH “wing” will be left open to allow extra width for a removable kitchen box on the slide. The floor will slide on runners into the ute tub and the roof will have some internal supporting alloy cross members to bolt the tent to. The floor and centre panel (the spine) are 12mm with the rest being 9mm. Doors and door frames are laminated for strength.

Here's a couple of bad SketchUp drawings but you will get the idea -

Stage Four – The Trolley

The idea is that the camper box is removable but instead of having wind up legs I have gone with a trolley idea. It is the same height as my tailgate and I will just slide it on and off the ute as required. The trolley is on casters to move it around for storage and it makes a perfect workbench to build the thing on in the first place.

Stage Five – Initial Layout

I picked up some sheets of 12mm and 9mm exterior B-B A-Bond ply. I didn't need marine ply as it's not a boat and won't be submerged and it costs twice as much. But A-Bond glue is important so it won't rot and there are less voids in exterior grade too. It's much, much better quality than the stuff from Bunnings I built Ver 1.0 out of. You can feel the weight in it because it's so solid, it doesn't warp much and it has a nice finish too. There was a mix up at the supplier so I ended up with A-A marine grade 12mm sheets for the price of the exterior stuff. Score!!!

The first thing to do was mark out the floor and laminate on an extension. A lot of the big panels in this build are larger than the 1200mm width the sheets come in which is a pain so I have to add on extensions to the floor and roof and watch my wastage. I routered out a 100mm x 6mm lap joint in both pieces and epoxied glued them together. Then I could finalise the actual dimensions that would fit in the tub and start cutting some of the walls. Everything was dependent on the floor being accurate.

The next critical part was the centre panel which is the spine of the whole camper box. This is also 12mm for strength and I have set this into a dado cut into the floor, roof and the back wall to give extra surface area for glue. This piece has the most work in it as it has dado's running along it's length at 2 different heights to support the middle floors, holes cut in it for fridge ventilation and rebates along the top edge for the alloy cross members under the roof. The front needed to be shaped for the door too. The RH wall is high to clear the fridge and the panel has a hole cut in it for additional access to the water and power in the RH wing. There is a dado cut along it for a middle floor section too. The rest of the walls are easy and are just the height of the ute tub.

I've clamped bits and pieces together before to get the layout right but now it was finally time to screw some of it together. I have all the pieces in place for the first build up.

I pre-drilled pilot holes around the edges because I was going to be screwing into thin 9mm ply and didn't want to split anything. I used 6g 18mm self drill needle point wood screws with a Tri coating so they screw in really easily and I can bed down the screws with control. It makes it easy to get things lined up and I didn't split one bit of ply. Yay!!! The screws are just placed at random to hold the timber as these will only be used for clamping the epoxied joint and will be removed once the epoxy is dry.

It's nice to see it all come up so well so far. I'm a happy boy!!!

Next up - Epoxy Gluing 101. See ya next time.

HB

 

[Deleted member 9101]

I like it. I grew up on the coast (Florida) most of my life where fiberglass covering plywood reign's supreme. Its amazing how strong and durable it can be if laid up properly!

 

[LandCruiserPhil]

Looks like a great start! I'm Subscribed for the final.
What kind of joints are you using for the corners?

 

[pods8]

The first thing to do was mark out the floor and laminate on an extension. A lot of the big panels in this build are larger than the 1200mm width the sheets come in which is a pain so I have to add on extensions to the floor and roof and watch my wastage. I routered out a 100mm x 6mm lap joint in both pieces and epoxied glued them together. Then I could finalise the actual dimensions that would fit in the tub and start cutting some of the walls. Everything was dependent on the floor being accurate.

A scarf joint is the ideal way to join them but harder to do, however I don't think you're going to pushing your panels to the point that the stress concentration would be an issue. I know you said you're glassing the one side, you could consider a strip of glass over the joint on the inside to really make sure you never have an issue.

Good build, this one will be far far stronger and much more water resistant.

On your fillets what filler are you using with the epoxy?

 

[Heifer Boy]

Thanks for the responses guys. It's nice to see some people take an interest in what I'm doing and the support will help with the build.

What kind of joints are you using for the corners?

Just normal butt joints for most of it with a dado routered into the panels for the centre spine. Based on my tests these will be well strong enough for my purposes.

A scarf joint is the ideal way to join them but harder to do...

On your fillets what filler are you using with the epoxy?

A scarf joint is the proper way for sure but I'm not that good a woodworker. The lap joint was easy and it was only for the last 100mm and has 3 support walls attached and 4 runners underneath. It will be fine.

I'm using BoteCote epoxy (Aussie made) so I'm using there filler compound for everything. The fillet sets rock hard and I don't need it to be (too) beautiful as it will just be inside the camper box. I've read about lightweight microspheres etc but I'm not using them. BoteCote have a great book available with tons of info and I'm following that.

 

[pods8]

I'm using BoteCote epoxy (Aussie made) so I'm using there filler compound for everything. The fillet sets rock hard and I don't need it to be (too) beautiful as it will just be inside the camper box. I've read about lightweight microspheres etc but I'm not using them. BoteCote have a great book available with tons of info and I'm following that.

I was just passively curious what the kind of filler you were using was, looking up boat coat it sounds like boat coat does fillers blends for the service rather than individual components (like our US west system products). FYI, you wouldn't want to use microspheres for this as they don't make a structural fillet verse wood flour, cotton flock, milled glass, etc.

This is be burly verse the version 1 that's for sure!

 

[Heifer Boy]

FYI, you wouldn't want to use microspheres for this as they don't make a structural fillet verse wood flour, cotton flock, milled glass, etc.

This is be burly verse the version 1 that's for sure!

BoteCotes filler is a wood flour I think and although they do a 'high strength' version I think the standard mixed to the right consistency will be fine. The 9mm test piece I made had a fillet was way to runny and it's still as strong as. I'm getting better at measuring and mixing.

She'll be strong alright but I think only around 150kgs (330lbs). That's the plan anyway...

 

[Heifer Boy]

Stage Six – Glue Time

So after getting all screwed together and making sure I had nothing else to do to the panels I just pulled it apart again. But not before I had a quick test fit in the back of the ute. I think it's going to look all right. Not to big, not to small, just right.

It was time to glue so I made sure I had everything ready to go. I'm new to this “mixing epoxy and using it before it gels” idea so I made sure I had thought about the routine and had everything ready. It was pretty easy once I got the hang of it and got the consistency of the filler right. I was pre-coating the joint with epoxy and then adding the filler to the rest of the pot and laying this down while the pre-coat was still wet. Besides being a bit messy and wasteful with stirrers and pots etc, once the joint is together cleaning it up is easy and you end up with a really tidy joint.

The next day it was time to fillet all the inside joints. The BoteCote book said make a fillet about 2-2.5 times radius of the thickness of the timber. I'm using 9mm ply so I made up a coving stick about 40mm in diameter and it worked well. Getting the mix of the fillet right was a bit harder. Some came up a bit dry which stuck well to the vertical corners but was hard to cove neatly. I really concentrated on the mix later and seemed to get it right but then the last batch I though was perfect has slumped in the corners. So I will have to sand back a bit and re-coat later. It's just a couple of joints and it's only aesthetic but I will probably fix them up anyway otherwise I'll know and it will bug me. Already the camper is getting a lot stiffer and there's no horizontal panels yet. I'm a happy boy!!!

Thanks for looking.
HB

 

[Harald Hansen]

Very nice write-up! Subscribed!

Mathias Wandell's excellent woodworking site has tests of different kinds of joints and different kinds of glue. Well worth a look for those interested in wood construction.

 

[Deleted member 9101]

Wow.. that thing is going to be a tank when you are done!!!

 

[The Swiss]

Very interesting. Really like the way you conducted all your material tests, very informative.

 

[Heifer Boy]

Thanks for the feedback guys. It's a learning experiance but I'm really enjoying it.

Wow.. that thing is going to be a tank when you are done!!!

I hope so...but a light weight tank!! If you have ever been on some of our Outback roads for weeks on end you would have some idea why things have to be so strong over here. Everything, and I mean EVERYTHING, rattles and shakes loose. This is why I was interested in building without mechanical fastners. There should be a little bit of flex in it too which will help. Too rigid and it might crack. Ask me again in a few years time...

 

[Deleted member 9101]

I hope so...but a light weight tank!! If you have ever been on some of our Outback roads for weeks on end you would have some idea why things have to be so strong over here. Everything, and I mean EVERYTHING, rattles and shakes loose. This is why I was interested in building without mechanical fasteners. There should be a little bit of flex in it too which will help. Too rigid and it might crack. Ask me again in a few years time...

I know for boats around here (mullet and shrimping) they usually brace the inside of corners with a 1 x 2 or 2 x 2 and glue them.. then when the glue has set they fiberglass the crap out of the. They beat the crap out if them for years with no real problems.. so I am sure the way you are building will be perfect for the "out back".

From my limited experience, I see your only real problem being "flex". Of you can eliminate that you should have no problems.

 

[Heifer Boy]

Stage Seven – Front Wall and Door Frame

This is the first of 3 door frames to be made up but is a little different to the side doors. It’s the largest door and also the front wall of the camper box. Because my storage drawer slides will run on the floor of the camper, the front wall doesn’t have a bottom surround so it was pretty tricky cutting and trimming the thin 3-sided frame. The frame is 2 pieces of ply with the outside being 12mm and the inside 9mm and the inside piece is 15mm smaller all around to create the door jamb.

After a lot of test fitting these 2 pieces were laminated together, glued to the front of the side walls and held it in place with temporary screws. I had to be careful when I was moving them around until they were laminated as they flexed all over the place. The frame is only 40mm thick!! There is a tiny connection tab at the top of the centre panel but overall the frame has very little support until the middle floors and top section go in. It’s pretty solid though and will strengthen up once I fillet it. The corners have a rabbet joint with the side walls formed by the 2 pieces ply so there is plenty of glue surface for bonding.

I’m also thinking of adding additional support down the RH side to support the door. The wall is 21mm thick already but the door will be about 1100mm x 800mm and hinged from the side so an extra strip of ply epoxied inside for strength might be a good idea. I’ll take a look at this tomorrow too.

Remember, more photos in PhotoBucket (link in first post) and see you next time. Thanks for looking.