Tuesday 3 July 2012

Building A Teardrop Trailer

It was the spring of 2004 and I stumbled upon a fairly old trailer project that was quite popular in california and various states in the US. The trailer is called a Teardrop and many DIY builders got excited about them when popular mechanics released an issue about it back in the 1950's.  I spent a few weeks reading up about them and I knew I wanted to try building one.  I started my Teardrop project in early April (just before easter I believe) in the hopes to have it built and ready to go for that summer's camping season.

The plans for most teardrop's call for 3 standard issue 4x8 foot plywood sheets on all sides giving you approximately enough room for a double bed on wheels essentially.  The first thing i had to do was find a basic schematic on the web and enlarge it onto paper that i could trace out onto my first sheet of plywood.   Many places on the web will sell you plans for building a Teardrop Trailer but I was totally going to just custom build it on my own.  I merely used any low resolution schematic i could find and sized it up to actual size and traced it in photoshop to create my basic side form.  At that point I printed off an inkjet version on transparency paper and borrowed a projector to sketch it full size on a roll of drafting paper.

Once I had my basic shape on paper it was pretty easy to lay it down on the plywood and get it transferred to the wood.  I wasn't terribly worried accuracy because I knew i was going to be jigsawing it out and belt-sanding it down to a more solid clean shape after. Once I got the first side of the trailer cut to shape I used it as a stencil to cut the 2nd wall,  then its just a matter of C-clamping them together so you can belt sand both sides of the trailer simultaneously and keeping them exactly the same.  The sanding process wasn't too long when you have a belt sander, I'd say it took maybe 20 minutes tops.

Once I had both walls sanded to where i wanted them I figured I might as well sketch out where i thought the door should go.  It was pretty rough, and as you can see in my 3rd image here I initially made it a little small at first, so i just moved it down a little extra to be level with what i expected my mattress height would be.

Once the two sides where finished with doors cut  the next step was to assemble the basic shell of the cabin. We used two 8 foot pieces of bed framing (L shaped) to attach the sides to the floor sheet of plywood.

The ribbing of the roof was next which was made up of 2x1's which were strong enough to stabilize everything and yet small enough to save precious interior cabin space.

I have to tell you how incredible bed framing was for this project,  its incredibly plentiful and cheap. If you ever see anyone throwing away old beds at their curb I highly recommend grabbing the framing.   Even though we did purchase special steel for building the actual trailer frame itself,  we did use a ton of scrap bed framing for many parts of this trailer.

I propped up my old Chevy Chevette rims up to the outside of the cabin just to visualize how it was gonna look eventually.  I had long scrapped my beloved Chevette maybe 7 years before this project began but I had kept the old wheels and this was the perfect project to use them for.

teardrop trailer frame
Now that the cabin was fairly stable in its initial form we focused on building the actual frame of the trailer.  This is where the purchased steel came into play in leu of the bed framing.  I had sourced the steel that we would need from a place called Mississauga Steelmart,  and i think it cost me about 250 bucks roughly at the time.  We used a Miter Saw to cut all our sides to length and we left the 8 foot side pieces extra long in order to cut and bend the tongue portion.

teardrop trailer frame weld
The trick behind the tongue is you just use a power grinder to essentially score the bend edge then use whatever leverage you have to bend the metal to the angle you want. The 2nd image on the left closely illustrates the score area which we later welded closed to seal and strengthen.

There I am in the old garage..  good times.

teardrop trailer frame
Okay here we can see the tongue coming together but not welded at this point because its easier to get our other support pieces in without the tongue secured (its a pretty heavy piece of steel).

I had decided early on that I wanted to modify your average teardrop plan by adding a transformable table inside the cabin that would allow you to convert the bed into benches and have your feet hang down a trap door area in the event of a major camping storm and you wanted to eat or play cards or whatever inside while it pours outside.

This is why you can see this rectangular framing happening here.  This was the portion of the cabin we had designated as the trap door,  the wood flooring in this area would lift up and act as the table itelf mounted by an adjustable pole.

teardrop trailer frame with axel
You'll notice the trap door area is using
bed framing which looks different from
the purchased steel.
The next step was finding our trailer axel, and the real tricky bit was that because I already had wheels I wanted to use, I needed to find something that worked with the existing bolt patterns of the rims.   This is where I nearly got derailed from using my old cool chrome rims since most current era cars in 2004 mostly were using struts on cars that seemed compatible with my rims.

I did luck out however, as I discovered that Toyota Tercels seemed to be the very last era of cars that had a single solid 1 piece axel that still had the matching bolt pattern that was on my Chevette. I ended up miraculously finding a few junkyards that actually still had early 90's Toyota Tercel parts (which i wouldn't have believed in 2004) but we managed to score a complete axel from a scrap yard in Milton.

Some of you might be wondering why I didn't try and find a Chevette axel to begin with, since the wheels came of a Chevette...  well firstly at the time 1980s era Chevette's were very much extinct,  but secondly the Chevette was a rear wheel drive vehicle believe it or not so they didn't have the kind of rear axel that would have worked anyways..  Thank you Toyota you saved this project.

teardrop trailer frame with springs
A closer look at the Tercel Axel and springs.
Attaching the axel with leaf springs to the frame was no big issue here, we used a pair of U bolts per side and we picked up the springs at princess auto.
With the frame welded up and wheels bolted on we lifted up the cabin (which was still relatively light at this point) and mounted it onto the frame.  It was only going to be temporary since we still had to prime and paint the frame, but it was going to help us move along with the build.

Putting the cabin in place allowed us to mark and cut the trap door out of the floor and allow us to visualize how it was gonna fit and feel.  Here you can see Cat and I checking out the vibe.

In retrospect I would say the overall feel was slightly cramped since climbing out or into the trailer with the table in place was a bit clumbsy, but it worked well enough and its a nice extra transformable feature that most Teardrop's don't even consider.
The wheel well is only propped up to give the
illusion of being installed.
The rear galley door is definitely the hardest part of any teardrop build as far as i'm concerned, they are really finicky to get snug and sealed but if you take your time, don't rush and don't panic everything will work out fine.

In the picture to the left you can see that we started it by cutting two thin pieces of plywood at the same curve as the side walls and the approximate thickness of what your finished door will be..  I'd think our door was close to 2 inches thick.  We used C-clamps to hold the pieces in place so i could belt sand them flush with the side walls.

The C-clamps remained as we carried the 2x1 ribbing down the backside of the trailer which would then makeup the ribbing of the rear galley door itself (this is illustrated in the top 2 images) you can see how the door shell takes shape in the 2nd image after the ribbing is in place,  but its a long way from being done let me tell you..   I hated every minute of making that galley door.

We left the door in its current state when the ribbing was finished and decided to focus on installing the interior 1/8th inch ceiling material which was a super thin flexible wood easily purchased at any home depot in the same 4x8 sheets they sell everything else at.

Just before installing the interior ceiling
Installing it was relatively straight foward,  it just took a lot of wrestling with its flexible nature..  We had to have one person pushing against the ribbing while the other was inside the cabin pushing hard against the ribbing and then hammering in finishing nails into the 2x1's to keep it in place.

Here we see the interior roofing material installed.
 What ends up happening with a 4x8 sheet of the roof materials is that it doesn't fully make it all the way to the galley door as you would want, so you end up having to cut a small extension piece near the back door.  (i'll discuss this later since you can't visualize it with these photos)

With the ceiling now installed we decided to tackle the roof vent next. I sourced a nice one at an RV shop in Milton called John's RV and I think it cost me about 50 bucks for a basic model that didn't have any fan or anything.
We started by adding two support ribs at the top in the approximate area we were planning to put the vent, then added further supports to complete the wooden framing around the vent hole. We later subdivided it even further to accommodate two 10 watt solar panels i was planning to install into the roof on either side.

Cutting the vent area was nothing, a jigsaw made short work of it, but it was important to go slowly since the vibrations could potentially pull the wood through the finishing nails that were securing it to the ribbing. We fitted the vent just temporarily for visualizing since we still had the entire outer roof to install.

The next phase of the build was getting started on covering the outside of the trailer with metal,  the vast majority of teardrops you see online are sort of airstream looking aluminum pods which is what attracts most people too them i'm sure.  The metal was probably one of the first problems I had to investigate even before thinking about tackling this project because if the metal was crazy expensive then there wouldn't really be any sense in trying to pull this project off.

This is where working in the print industry at the time paid off.   I was working for a pre-press film house at the time as a photo retoucher and I got to thinking that old used press plates might be a cheap way to cover the trailer.   Press plates are used in the printing process for many things and what usually happens is that advertisements for say a bus shelter are etched onto thin aluminum plates that are pretty big which act as a stamp of sorts when ink is placed on them which then transfers onto paper (its more technical then that really, but i'll just leave it at that for now).  Typically press plates are matt finished on one side after they've been etched but the back side of them is perfectly clean shiny aluminum,  now;  after a press plate is used for its intended print run they are generally piled up in a corner of a printing shop and then eventually picked up to be recycled for future re-use. 
I decided to ask one of our sales rep's if he knew of any press places that might be willing to let me have 4 or 5 used up sheets and as it turned out he was good friends with a shop who were in fact more than willing to let me snag however many i needed.  This was the opportunity that allowed me to even consider attempting this project to begin with as raw aluminum seemed pretty pricey to me when i was shopping around for it.  I used about 4 sheets of transit shelter sized printing plates which were maybe slightly smaller than 4 x 8 feet.  How do you apply this stuff?  We used rubber cement..  just glob on large amounts of it and try and keep it even (i highly recommend you do this in ample ventilation as well as masks because as you can imagine its powerful).  I cut the basic side shape out with lots of overhang to begin with then stuck down onto the wood.
Now because our sheets were slightly smaller than 4 x 8 we had a seam to contend with that we wanted to keep water tight.   One full sheet of this metal only covered about 75% of the full side length of 8 feet, so we had to create a fold that the two sheets folded into each other that we screwed down tight onto the wood.  This was the end result of covering our first side.
Once we had a handle on what adhering the metal was gonna be like,  we decided to move onwards with priming and painting the trailer frame since that process was going to take up a good portion of the garage.  There was still lots to do with the cabin in its current state such as running electrical wires up the roof through the ribbing for lights and solar panels etc and we could accomplish that stuff quickly while the frame was drying.

We had to rig up an A frame support out of 2x4's that we could hang the frame from to make painting all sides of it easy.  It didn't take too much time, but definitely not stuff you consider as part of the process of building something like this.

I primed it using a few home depot spray cans but decided it was best to paint it silver with a proper air compressor mix of paint,  since you can cover more ground quicker.  Painting is always one of the most satisfying parts of these jobs for me since in a very short period of time you can see such drastic results.

With the frame painted and drying I flipped back to the cabin to get electrical wires run for the interior dome lights and the solar panels which would charge the 12volt deep cycle battery which I was going to put in a utility box located on the tongue area.

The cables were fed directly through the ribbing in the roof which only required some small drilling, I just used thin gauge speaker wire to power the dome lights.

Once I had my cables in place it was time to insulate!  I decided to use styrofoam for insulation which was cheap and easy to cut and work with and so piece by piece ribbing by ribbing we inserted our styrofoam slices into each compartment

In my initial plans I had imagined building a special heating area under the galley kitchen where i could have a bucket that I could toss hot rocks into that had been sitting in the camp fire for a while,  and have a vent that would lead into the sleeping area,  this never really came to fruition though and was ultimately left on the design room floor. Insulation was in place,  everything was snug;  it was time to close up the roof and for that we decided to use masonite..  now some of you might be wondering why on earth would you choose such a crappy piece of fake wood for something as important as the roof of your trailer?  well let me tell you,  i don't know why either because it was it wasn't easy to install..

I mean every skateboarding half pipe in the world is practically made of this stuff so how could it not work well for this dome shaped trailer... that sort of looks like an inverted half pipe?  I'll tell you how,  first of all counter-sinking screws in this material sucks,  it was waaaay to easy to drill the counter-sink hole to the point of becoming structurally useless so we had to fix quite a few of our mounts.  Fortunately the more screws you throw at something there's a good chance it will eventually accept its curved mounted fate.  
You can see in the 2nd picture where we brought the electrical cables out from within the cabin roof in preparation for where our utility box was going to reside.

The 3rd image gives you a better idea of what happens with our standard 4x8 sheets of roofing materials when we install them,  it ends up leaving us about a foot short from making it to the galley door seam where the roof would end, thus;  in each case we would have to create a small one foot patch on both the inside and the outside to complete the shell.  Not a huge deal, but still I ended up having a bit of a warping seam on the inside of the trailer on the ceiling at that area above the cupboards..  it took a couple years mind you,  but it happened none the less.
It was time to seal up the masonite roof with more of our prepress printing plate aluminum sheets. There was no way to avoid a seam in the roof since the sheets were not long enough to go from back to front, so we decided to place the seam directly in front of our vent, it felt like the least visible area when standing on the ground looking at it. The seam itself was done the same way we approached the side seams where we fold the edges of our 2 sheets and then interlock them together for a water tight seal.

Just a liberal amount of contact cement and laid it down on top of the masonite ensuring to leave an even amount of overhang on both sides. I'll discuss the overhang in the next post. Once the aluminum roof was secure and dry I drilled a starter hole in the vent hole as well as in the two pockets where the solar panels were to be placed, then used metal cutting shears to cut the holes out completely as I had done with the side doors before the masonite went on.

The cut holes didn't have to be clean and perfect since both the panels and vent would be loosely fit then filled with a water tight caulking later.
We were now ready to permanently mount the top vent, this was something i wanted to be super diligent about because this was one of the major items in the roof that could potentially lead to future leaks if it wasn't done properly.

You can see how rough my cuts were in
the aluminum for the solar panels
I was having visions of uneven caulking and tons of excess silicone to scrape off all the edges and possibly open up leak points but that was not the case at all..   Its very easy to purchase a standard vent installation kit which is made up of butyl tape and screws.  We applied our strips of butyl tape to the bottom side of the vent keeping it even and clean around all edges then simply peeled off the protective layer from the second side of the tape in order to press it down to mount.  We finished off with screwing it down into our wooden framing through the butyl tape.

My next task was to start cleaning up all the rough cuts in the aluminum as well as the edge overlap of excess aluminum on the roof. The solar panel compartments were as easy as 4 cuts in each corner then fold down the overlapping metal. The aluminum is very stiff and doesn't require any glueing to remain in place after bending.

The roof overlap was had to be handled a bit more differently, because the of the trailers curve you can't just hammer down the edges to get a smooth clean fold. The roof edges will be covered with a nice water tight trim later on so the aluminum didn't need to be perfect it just had to be nice and flush with the body. What we did was trim the overlap every inch to cut it into many small pieces so that each piece could fold on its own angle and remain flush.

Once I had the entire length of the trailers roof overlap cut into pieces it was just a matter of trimming each cut a little bit further so that none of the small pieces overlapped each other when folded in the steeper curved areas near the front end of the cabin.

The rear door that covers the galley area was coming together without too many problems except that the actual fit just overall felt a bit sloppy. The further along we went with the door I was starting to realize that the radius of the door was slightly straighter than the trailer and I think it was happening when we started skinning the inside and outside with wood. The 8th inch plywood and masonite skins were putting pressure on the sides and reducing the curve ever so slightly. As we started adding the weather stripping and positioning it on the back of the trailer i had concerns about how water tight this door was gonna end up. The styrofoam insulation snugged into the sections without any issue and adding the inner and outer skin's was pretty much the same as how we did the cabin of the trailer only more manageable since the pieces were smaller that we were working with.

I'm going to take a second here and speak from the perspective of someone who used the trailer for a couple years and explain what happened with this door and why you see a steel bracing shown in the first photo in one of the top most wood compartments. Essentially over time the hydraulic arm that raised and lowered the door started to strip from its mount on the door itself, there was so much tension and pressure on the door being held upright and so much weight from the door all focused onto such a small area that we realized that we had reinforce the inner area with steel in order to secure the hydraulic arm to withstand the amount of pressure the door was constantly under.

Our next step was to start staining the interior wood to a nice dark rosewood colour. We chose a brand of stain by Minwax and went with a Red Mahogany colour to give it a deep rich feel. The 236mL can's cost about 8 dollars and we only used 1 can to complete the job. We used standard brushes to paint it on and it took only about a half hour to do 1 full coat of the cabin, it wasn't all that messy we'd just brush on a wet layer let it sit for a few minutes and then wipe the area with a paper towel to pickup the excess.

In total we did 3 to 4 coats to reach the desired darkness we were looking for. We didnt' really leave much drying time since by the time we'd finish a single coat it was long enough for us to come around and start at the beginning again.

I had a good idea of exactly how i wanted the mattresses to behave in this trailer from very early on in the planning stages since I just wanted to replicate what a lot of camper dinette benches have done for years, which is convert from a dinette into a bed and in our case it was more about going the opposite way, from bed to couches. I looked around a bunch of local foam shops in Mississauga and ended up choosing a place called K N K Foam on Dixie and Britannia.

They were tucked away in a small industrial complex and looked to be a wholesale foam supplier for major furniture shops, but they didn't seem to have any problems dealing with me directly. They were able to cut me 4 pieces of foam that i could use for my benches / bed and only cost me like 50 bucks. Since then I've visited them again for a different camper project so If you're in the area and are looking to do something similar I highly recommend them so go check them out.

The foam was a very nice fit and everything was coming together pretty well. My mother in-law helped us out by sewing us covers for the foam that just zippered on and they really turned out great. We ended up having just enough room to fit a water tank and a decent size cooler into the back galley area under what would soon become our kitchen counter.

the Solar panels I used for this project were by todays standards quite low powered coming in at a whopping 5 watts each giving me 10 watts charging power,  but at the time they weren't incredibly cheap either.  I would probably put like 40 watts these days,  but regardless, it was neat to have.  Installing them into the roof was pretty straight forward as I had pre-measured and built the pockets to be pretty snug when the panels slipped in.  I had them intentionally raised above the roofline just so there'd be no risk of water pooling etc during rain storms,  and I used some heavy duty black silicone to seal them into place.

Overall I'd say the panels were a great addition,  but as mentioned earlier the more wattage you can give the better.  I did many tests over the couple years i tripped with this teardrop and I typically found that 10 watts of charging power usually only gave me like 10 extra minutes of interior light power,  so on a day-to-day basis it really doesn't help you much but where they really helped was when you left the trailer for a few weeks in-between trips.   I was leaving this trailer in an open field when not in use so it was always exposed to plenty of sunlight so battery maintenance was great,  just don't expect panels of this caliber to help you top-up a dead battery over the course of one sunny day on a long trip.

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