I stumbled upon the world of teardrops about a year ago when I saw a picture of one in a miata.net forum and then found my way to this forum. Owning several Miatas, nearing retirement and looking for a cheap way to travel around the country, and being handy with woodworking I decided to build one.
I spent the winter lurking in the forum, and decided to build one based on Mike Schneider’s ultralight plans in the Member Designs forum:
My design and build critera were:
- Keep it light so I could tow it behind a Miata (I also own a CRV that I use to tow things with)
- Keep it simple – optimize for build ease
- Keep it cheap – try to build it for less than $2000
- Take my time and do it right – I didn’t want to have to build a second one to get it right
- Make it so my wife will like it and come on trips in it with me
- Complete it over the summer so I could use it for a mid-October music festival
As it turned out, I lost my job in early June, so all systems were go to work on this project. I spent that month gathering parts and materials and started building the second week in July. Much of what I needed I got from Harbor Freight, Northern Tool, etrailer.com, and a local RV parts store. I kept a spreadsheet with the cost and weight of everything I ordered or bought to also keep track of what had or had not arrived yet. If people want I’ll add a post with links to what I got from where…
I finished by the end of September with some days off for other commitments, hurricanes, etc. I’ll do a day-by-day journal below with pictures.
I made a few changes to Mike’s design:
- I made it 5 feet wide instead of 4. This was a big concession to the wife but I’m glad I did it. The inside is quite roomy and fits a queen size memory foam mattress pad. The wider kitchen area now is much more useful and the additional storage space is good too.
- I used 5/8in. marine plywood for the walls instead of building a frame and covering it with 1/4in ply. I calculated this only cost me an additional 25 pounds but saved me hours of woodwork and about $125 in materials. It especially saved me a lot of work building a curved frame around the profile edge that I did not want to get into. I did keep the bottom trim piece which was a nice design element and was useful for running and hiding the running light wiring.
- I changed the radiuses of the front and rear bottoms slightly to give me an extra 2-3 inches room on both ends. This allowed my tall wife to sleep with her legs straight and made the rear storage area much more usable.
- I changed the shape of the door to make it wider to more easily swing your legs getting in and out, and to make it easier to install all the door edge mouldings (less corners)
- I changed the cabinetry a little so that the bedroom has a place for a flat panel TV if wanted and two small compartments, while the kitchen has a single large opening into which we could put a microwave or toaster-oven if needed. At the moment that is where the camp stove gets transported
- I decided to install a ceiling and insulate the roof since what I came up with didn’t add hardly any weight
- I used marine plywood for the floor (3/4in) and walls (5/8in). – solid (no voids) and waterproof. Because there is no frame, it was especially important that the floor be stiff and strong as it essentially is the frame
- I did not use any tar or goop on the underside of the floor. Just multiple coats of spar urethane
- I bought a torsion axle de-tuned to 1400 lbs instead of the usual springs and axle. Very clean and easy to mount, and rides well
- All the non-ply wood is poplar, which is a strong light hardwood that is as easy to work as pine. It is cheaper and lighter than oak or maple. All joists, frame pieces, and hatch ribs are 1x2 poplar
- Titebond III was used for all bare wood to wood gluing, and GE Silicone II caulk used for all other glueing (with screws) and caulking
- I didn’t stain any of the wood. I just urethaned the poplar and marine mahogany plywood and it came out looking great. One of the advantages of the marine plywood is that even the bad side is covered with the same wood as the good side (as are all the inside plys), so it looks pretty good as well. At the recommendation of another builder I used Minwax Spar Urethane for all exterior surfaces (multiple coats) and just used fast drying water based Polycrylic urethane for all interior finished surfaces
- I used a roll-up bamboo shade for the ceiling – lightweight and attractive, although it was not cheap (~$50 at Lowes or HD, I don’t remember which)
- For insulation I used two pieces of 1/2in foam sheets to achieve 1 inch of insulation. This made it easier to address the curvature, and I could run wiring between the sheets of foam
- I found some lightweight corrugated plastic panels and Home Depot that I used between the front-most ceilling “joists” as a headboard we can lean against without fear of breaking the bamboo. I also intend to use it for the underside of the hatch Because the exterior walls are not skinned I used Kreg screws to attach the roof joists and cabinet frames to them
- I chose to put self-stick vinyl floor tiles on my countertop instead of dealing with laminates, since I had hatch doors to work around. If I ever need to I can replace any single tile, or replace them all if I want a new look
- All the interior ply surfaces for the cabinets, countertop, and hatch skin are 1/4in luan plywood (non-marine)
- I splurged for a small yellow-top deep cycle Optima battery placed in the storage compartment behind the axle. It’s a D75/25, gives 48 amp hours with 100 reserve minutes, and weighs only 37.8 pounds
- To save time and insure it would look professional when I was done I ordered crank-out windows, hurricane hinge, and all my aluminum mouldings from Grant Whipp at Li’l Bear Tagalongs. Grant was great to work with and answered a lot of questions for me
- I predrilled all screw and screwnail holes in the edges of the wall plywood to insure that the fasteners went in straight and that they wouldn’t split or push out the plywood. With marine plywood I may not have needed to do this, but I wanted to play it safe
So how did it come out?
The finished trailer weighs in at 720 pounds with the memory foam, battery, and camp stove. Tongue weight is only 65 pounds which which means I can easily lift it up and move it around by hand, and the Miata should have no trouble towing it. I’m happy with the tradeoffs I made
The final cost of all parts and materials is a bit shy of $4000. Much of the additional weight and some of the additional cost is due to going with a 5 foot wide trailer. The floor alone cost almost twice as much as a 4x8 sheet to get a piece 5 foot wide (which was also 10 feet long instead of
.At the end of the day it took me twice as long and cost twice as much as I had originally thought it would. If I were doing it again I figure I could trim 20-40% off of both now that I know what I’m doing. But it was a learning experience, I took my time, and I didn’t make any critical mistakes that I couldn’t recover from.
I did learn some big lessons that I’ll share with everyone here so maybe it will help you avoid some of the issues I had, and would have saved me time and cost (of re-doing things) had I known. I’ll put what I think are the most important ones first:
- In general, whenever a curve is involved your calculations and measurements will be wrong. Always cut or order material larger than you think you need and trim it to fit after dry fitting
- Dry fit every piece or assembly before gluing it in place
- VERY IMPORTANT: store your aluminum dry and indoors if you will not be using it shortly after receiving it. If water and condensation gets between packed aluminum sheets that are touching they will discolor, become etched, and get white deposits all over them that cannot be removed
- Cut the hatch frame (not the skin) 1/4in shorter at the top (at the hinge) and bottom (that rests on the counter) to allow for spacing at the hinge and other things that seem to affect how it fits. You can always put weather-stripping and/or rubber/plastic bumpers on the bottom of the hatch frame to take up any extra space. Likewise leave 1/4in space on the sides of the hatch frame (not the skin) outer ribs and the wall
- For a perfect hatch fit, cut hatch plywood skin a little wider than needed, and after mounting on hatch frame and fit in the teardrop, mark the trailer edge and trim the excess off
- When applying edge moulding along a curve do not work too far ahead of where you are. Just drill, glue, and screw 2-3 holes at a time. Otherwise things won’t line up as the molding tightly follows the curve after being attached
- Measure your floor dimensions up front – don’t assume it’s the exact dimension you ordered. My 60in. wide marine ply turned out to be 59 7/8 inches. I had to trim down a number of pieces I had already cut
- When you make a trip to the hardware or big-box store buy twice as many screws, glue, etc. as you think you’ll need and return any you don’t use when you’re done
- Check any hidden wiring for continuity and shorts early on when they can be replaced if needed without having to remove too much and re-do a lot of work
- Apply finish to the exterior walls & trim after it is mounted on the floor, not before. This will allow you to use Titebond to more strongly glue wood-to-wood pieces
- When gluing to vertical surfaces (such as cabinet faces) glue the piece being attached and then apply it to the wall. If glue is first applied to the wall it will drip all over before you can attach the other piece (don’t ask me how I know this…)
- Do not wipe up spilled drops of glue. Let them dry and then use a chisel to dislodge them, otherwise they will prevent stain and sealer from penetrating as the surrounding wood and it will look awful. This is a standard woodworker “trick”
- Mark all pieces as D (for driver) or P (for passenger) sides, instead of R and L so there’s no confusion relative to which way you are standing
- For exterior walls (for woody designs), if using spar urethane varnish thin it first with mineral spirits and apply multiple lighter coats. Otherwise the finish will be blotchy where brushed sections overlap. The effect may be exaggerated if applying the finish in the sun (where it dries more quickly and tends to thicken up). You’ll see this on the underside of my floor in the pictures below, and on the sides if you look closely
- The 4x8 rolling work platform that I could roll in and out of my garage and provided a flat surface for drawing and measuring on worked great
- Measure twice, cut once. Or measure three times…
- For larger aluminum cuts, .040 aluminum is easier cut with a sabre saw with a metal blade than tin snips or aviation shears
- To draw up walls, etc. to the piece being attached, drill holes large enough so the screw threads don’t bind
- If you are building a trailer wider than 4ft, consider getting a trailer to haul materials if you don’t have a big pickup or flat bed truck at your disposal
- Get a power or compressed air caulk gun – I got this idea from someone else on this forum
- Practice being proficient cutting curves with a sabre saw if you need to
- You can never have too many clamps
And now, the journal and pictures…
