Build Journal: All Aluminum Bare Bones Tiny Travel Trailer

[ssuuki19]

Got road blocked - today I pre-fit and cleaned the RV door, but didn't have enough butyl tape, 3/16" rivets, or sealant on hand. I found a different butyl tape in town but its wider like almost an inch wide - the stuff I was using was 1/2" wide which fit the flanges on the windows perfectly. I'd have to do a 65 mile run just to get more of the same tape, so prob going to use the wider stuff and figure out a way to work it into the flanges. The rivets... unfortunately can't find any 3/16" .250" grip alum alum rivets in town either, both stores are sold out so they won't come in until earliest monday afternoon. So I'm putting that part of the project on hold for now.
Next up after the RV door is mounting the cargo door w/ piano hinge, and I believe a feasible mounting, and frame sealing approach has been found, but it also requires the same rivets, so its research for the next day and a half. Maybe its a good thing to have to wait as both these doors are so important to be waterproof - perhaps I may learn one or two more things before committing to the install.

[ssuuki19]

Did the Dexter door today - dunno if it was beginners luck or maybe that a $650 door installs itself (got it for 300 cash, minor shipping dmg, and that screen tear for those wish great vision). Anywho I did just the same as I did with the windows, but with the wider butyl tape that wasn't as smushy, and I put a lot more sealant - a whole canister - a fat double bead with more at the corners to really guarantee the seal, as I knew this was a one time chance on the install. And I knew if something went wrong, prob a whole day just to re-work.
My approach after test fitting the door, grinding, test fitting, etc. after about ten test fits I was ready to commit today (the rivets finally showed up). So I tacked in one rivet on the hinge side about 3/4 of the way up - I found that to be the best spot to 'hang the door', although it was fully resting on the the 1" square tube aluminum frame at the bottom (with butyl tape and a generous amount of sealant just beside it). Then I did the two rivets immediately beside the latch (on the left) to force them into place, and then from there I opened and slammed the door every few rivets (to make sure I didn't rivet it stuck shut) until all 45 or so were done. The hinge side of the door caught mostly rivets right into the 1" tube - this is very good news to me, as it will be locked in there damn good. The left side, non-hinge side of the door most of the rivets just went into the skin - 16 ga aluminum. The bottom rivets went right into the middle of the 1" tube, all of them, and the top rivets went just into the skin. [Edit: this requires explanation - I fit the frame to the door so close, that all the rivets were catching the 'outside'. Had I fit the frame looser, the door would have caught all the rivets. About 12 rivets will be re-done with .375 grip to re-work the mistake which is, really, not a big deal, structurally, even with the mistake]
So the afterthoughts are that it worked really well, I've never done a door before, but this one gave me few hassles. Its a dang full size RV door!! Hilarious. So glad I did it, I'm gonna get some laughs out there in the field. Here are the pics:

Dexter door fully open (umm... is that a full size RV door there?!?)

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screen door closed

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and fully closed RV door - its awesome so far i've slammed it about 30 times

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[ssuuki19]

So no pics today, the piano hinge wants to be installed, but it is on deck. I learned a lesson today, I used this brown 'packing tape' to tape up the cargo door (the lack thereof) spot and when it was removed today it left some crud behind. So a good lesson learned. No big deal, but if you are tarping a load to protect it from rain, use the 'green tape' not the 'brown tape'.
The cargo door piano hinge will be installed soon. But I am a master procrastinator. Beginner fabricator. I'm much better at the former.

[ssuuki19]

Today it rained.. first time in a long time. I tarped up the insulation panels, and was working on the cargo door hinge. I have been painstakingly working through installing this piano hinge and cargo door. So far I got the fitment I'm looking for, but I have to 'shave down the cargo door aka plasma cutter and lots of grinding. Was going to make it lighter anyways by thinning down the width of all the 1/4" aluminum flat bar its made out of. Soo much grinding on this door! I learn as I go its looking like the fitment is going to be great. I remembered that if I shave down the door where it connects a little too much I can make the space up with sealing strips or similar product. This would be the secondary seal, the primary seal is going to be two aluminum angle frames within that opening that mate up to each other.. to be started very soon.
In the first picture the roof line got finalized during my first attempt at 'grinding a straight line' using the hinge as the ruler, and a 0.9mm red sharpie. Then I proceeded to grind off all the red doing it in three passes. It worked out really well! That's the straightest line I've ever done freehand with the grinder. In the first picture the left side is actually popping up a bit, so if you hold it down the line it looks like 1/2mm accurracy and shores up to the piano hinge very well. I am very happy with that, and glad that although this part of the build is going really slowly, my confidence in the install is increasing as I go along. Great news for such a weird door. Here are the pics:

practice fit of 3" wide .061" aluminum cargo door piano hinge

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hinge is upside down and wedged between the roof skin and 1" tube aluminum (to be riveted) [Edit: the hinge was too tightly fit, it was backed out 5/16"]

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birds eye view of the hinge

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[ssuuki19]

Today, for the first time, the reverse of the cabin loading was done. Didn't take pictures of the sequence this time, but the first picture shows 2 of the 4 attachment points to off load the cabin 'beer keg out of pickup box' style. Hook up to the trailer, unhook the boat winch carabiner from the front (doh!), tie off the cabin to something(s), and floor it!... just kidding I did it slowly because it was the first time. [Edit: this requires explanation - its better to the frame to floor the car rather than do it slowly which puts un-necessary strains on the frame] The offloading proceeded as expected with no problems, the little cars clutch has plenty enough jerk to get past that initial friction.
I used two climbing ropes to tie the cabin off to a shelf in the garage, and the front door handle of the house (hey I had to get creative here!), and this setup worked fine, but I only attached the ropes to 2 of the connectors at the back instead of all 4 and I noticed as expected that I was pushing those connectors too much and one of them bent a bit, they are only rated for 150lbs each... I hammered the connector back to square with a punch, and next time I'll try it with all 4 connectors and I'm sure that will prevent too much load being put on a single point. In the field I would use two ropes to tie off to two trees, and load balance all 4 tie downs using idler pulleys and/or block&tackle style rope threading.
Other than that today I grinded the cargo door (hereon-in referred to as the 'clamshell') down until all grinding is done, with some rework required to fill some holes and one more grind session. You can see its a weird looking door, its a stepped square pyramid as I had to bring some sci-fi geek to the design, as thats kindof my signature style. The reason why I chose this design for the clamshell is its the only way I could figure out how to make the door aerodynamic without using complex curves as I am new to working with aluminum. So I chose to work with flatbar and do all the panels separately in 2D and then weld them all together. I sent the sketchup drawing to the supplier to cut all the skin panels, just like with the cabin, and as a result they are perfect. All this effort isn't really for the increased volume in the cabin (although thats where my head will be sleeping), its for the reduced drag ratio this door will cause to the entire trailer. This should help to stabilize the trailer when semis pass me, but also it should sway less and improve mileage significantly over a flat backed door. It better.. hehe, can't wait to take it out for a rip.. should happen soon hopefully next 2 weeks! [Edit: no, no, it does not happen in two weeks, of course predictions are as good as rolling dice sometimes] Happy friday, gentlemen & ladies! Here are the pics:

these are the 150lb tie down spots at the rear of the cabin (4 of them)

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for those confused this is how the clamshell mounts (and how when raised 90 degrees its an umbrella)

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[ssuuki19]

Today I did some re-work. After looking over the rivets that missed the 1x1 square tube aluminum on the door, (aka the ones where the drill migrated to the outside of the tube) I just knew after looking at them more than three times that I had to make them better. So 5 .250" grip rivets were drilled out and replaced with 5 .375" grip rivets. Aaahhh now I feel better

Also the cargo door frame will be finished next week, and apparently 80 feet of L-track are to be installed in this prototype by my estimations. I won't bother you with the number of permutations of tie downs with 80 feet of L-track, but its a large number. You see this is a prototype so I must 'overdo' certain things.. and under-do certain other things.. and by prototype I mean it will never actually be what it should be, but by pushing the boundaries of how it gets to its stable condition, the actual version could be easily made from this one.

Edit: I forgot to show the pictures of the acoustic insulation.. on it.

[ssuuki19]

No pics, nothing to show yet. Got a soldering iron and practiced on some 12-2 wire. My first one was the best go figure... there really is something to beginners luck because the second and third weren't as good.. not totally new to soldering but never got proficient at it.. until now. Now I'm studying and taking the learning seriously. All my first three joins were satisfactory, but I'm gonna get some flux and practice some more, I think the flux might help the heat transfer to the top of the wire. 12 gauge is pretty thick to soldier, its for the 12V send from the cars lighter socket (temporary, a just for now approach), and for the ground wire for all the trailer and cabin lighting for the roads. All the runs will be done in 14, except for that dedicated 12V send and the ground. This will end up in a Pollack 6 pin connector, if I go with electric brakes in the future I'll have to drop one of the redundant grounds.
80 feet of L-track and accessories on its way from Illinois. Ouch that's expensive with the exchange and no discount. Oh well, suck it up I say, gotta commit some times. I won't regret 80 feet.. lets just say that was cut down from 96 feet. There's a mounting hole every inch so that's 960 mounting holes in the trailer, none on the floor or ceiling, just horizontal rails top to bottom on the walls (all the L-track is horizontally mounted [Edit: correction - 4 pieces were mounted vertically for ease of installation and minimizing scrap.. see below somewhere]). Only 900 spots to tie in anything one desires. I got a wack of ratchet straps, ring mounts, and threaded mounts, I had to guess on that and overdo the accessories. Everything in the cabin will be connecting to the L-track.
Weld session teed up for tomorrow morning to get that clam-shell ready to be mounted. Time to connect it to the cabin and make this thing one giant step closer to going on an overnight camping trip with the temporary LED wiring harness I fabbed up with crimp connectors last year.
I went off to another part of the forum to discuss the alignment of the half-axles on the trailer. They have 0 toe, so at the recommendation of Dancam I'm going to buy some hub shims, and learn how to install and adjust them, to give the half-axles 1/16th" toe-in.
[Edit: gonna wait to load up the frame to 800lbs and re-check the alignment to see if it toes in under load...]

[dancam]

Hey, just be aware the lighter socket and wires going to it on most cars cant handle more than 10 amps continuous or 15 amps for 20 or 30min. They are fused bigger than they can handle for sporadic and short use.
Ive been super busy, just got home and its almost 10.30 :/ but i will update what i said on the wheel alignment thread. Sorry i didnt get back to you on that earlier.

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[ssuuki19]

No prob on that ^ and I am with you on the 10A I was just researching this myself. I happen to have the amazing (aka not so amazing but good enough) Roadpro 12V car vacuum cleaner (looks like a hand-held vac with a re-useable bag and it has a furniture attachment) I use in my truck all the time and it maxxes out 12V sockets.. I think its 10A but it has an inline fuse in the cord for 20A. When I vacuum with it which is usually 5-6 mins after I'm done the cord is very warm and slinky, and the cord looks like 14 to me, not 12, so its probably pushing its boundaries. I'm using this vacuum as my DC test device as the farther the wire run, the lower the rpm the vacuum can hit so I can judge how the power delivery will be to the sockets in the trailer (2 of them to start) by the sound of the vacuum. Also when you start the car the rpm's on the vacuum jump up a bit too. Also the wire I'm using is 12-2 heavy jacket threaded speaker wire rated for 300V and 10A, it might even be thicker than the wire in the guts of the car, I wonder if they would run the aux dc socket with 14.. I'll know soon enough..

[dancam]

No prob on that ^ and I am with you on the 10A I was just researching this myself. I happen to have the amazing (aka not so amazing but good enough) Roadpro 12V car vacuum cleaner I use in my truck all the time and it maxxes out 12V sockets.. I think its 10A but it has an inline fuse in the cord for 20A. When I vacuum with it which is usually 5-6 mins after I'm done the cord is very warm and slinky. I'm using this as my test device as the farther the wire run, the lower the rpm the vacuum can hit so I can judge how the power delivery will be to the sockets in the trailer (2 of them to start) by the sound of the vacuum. Also when you start the car the rpm's on the vacuum jump up a bit too. Also the wire I'm using is heavy jacket threaded speaker wire rated for 300V and 10A, it might even be thicker than the wire in the guts of the car, I wonder if they would run the aux dc socket with 14.. I'll know soon enough..

On my car for the cig lighter it was like 10awg from the battery to fusebox. But from fusebox to lighter socket it was like 18 or 20awg. Melted it and it runs in a wiring harness so it melted other wires and shorted them to. Had to rewire a ton of stuff. Going right from the battery is pretty simple and worth it i think.
Also 7 pin trailer connecters are more common than 6. Easier to find adapeters to flat 4. You can get 9 pin connecters but i went with 7 pin and another heavy duty 6 pin for more power wires, another ground and my 120v wires.

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[ssuuki19]

Going right from the battery is pretty simple and worth it i think.

Ok, but it bypasses the key. Just a thought, could I take the key signal from the cig lighter and pipe it to the direct connection to the battery so that the key has to be on to work? Thats all I need to start. Melted wiring harness risk should be avoided. At 10 amps and 12 volts the vacuum would be pulling 120 watts of power. Even this amount of power is a lot for the setup, and in fact its the maximum for now. I bought a 12V kettle and it will boil half a liter of water in about 75 minutes. At first this seemed like a pain, but after I got used to setting an alarm and turning it on, then going back to sleep for 75 mins, and voila.. my morning coffee! And the Pollack connector is beefy. Its just as good as the 7, but smaller gauge it can only take up to 12 gauge wire which is fine for my setup, or horse trailers which is where it derived from.

[ssuuki19]

Today the welding was a complete success. I did a weld session, then took the piece elsewhere to grind the heck out of it for over an hour.. got most it done, but left some half done b/c I had to do another session of welding and get the argon bottle back to the store. The spoolgun had 035 wire in it, so I ran that spool out, and then tried some 030 wire. I like the 030 wire waaaay better. It smokes less, lays down better, and you can hold the gun farther away, plus as I noticed after it grinds like two times faster (so its a softer metal alloy I assume). Now I'm learning, hah! So the downside of 030 is that it wants to jump to the tip more so I jammed 4 tips in a matter of ten minutes when I first started with it. The 035 never once jammed a tip, I could always spin it off and it would dislodge before the threads let loose. The 030 doesn't do this it breaks or just won't let go. Luckily I had 8 used tips from my 035 sessions last year, and low and behold, although they were needing re-work for re-use with 035, they worked just fine with the 030! So from now on, I am going to learn with 030 wire mostly and when I get better I'll migrate to the 035.
I wanted to give the neighbours a break so I didn't finish all the grinding, I decided to stop and do the rest tomorrow. Its pretty loud, and the frikin' cargo door is reverberating and making all these hilarious tonal sounds as I grind it, one time it sounded like a person moaning, it rings through harmonic frequencies as I grind down, and other times the whole thing started to ring like a bell! Fun stuff, welding and grinding. Getting better at it, I was able to lay down pretty good caterpillar lines free-hand today, but mostly I use my right hand to brace and only do a few inches at a time. I'd overheat the welder if I went any faster, which isn't a big deal you just have to take a break and then it works fine after, that happened to me last year once when I cranked up the amperage and wire speed to see how fast it could do 1/4" aluminum t joints.
So since its not grinded, no pics. Tomorrow afternoon I will show the insulation and the clamshell.
Can't wait for that L-track shipping from Illinois.. wonder what duty I'm gonna have to pay on it to clear customs.. soon to find out it ships monday. Over and out.

[ssuuki19]

Did a grind session on the clamshell today, then a final inspection where JB Weld Quickset (6min) was used to fill in all the remaining little holes that a MIG welder is overkill for - thats what the dark brown/black is that you see in the pics. Tomorrow a final grind session will be done, and the clamshell will be tacked in with rivets. Still don't know what the best process is.. I'll have to make it up as I go thats why I want a good monday morning start to ensure it gets completed. Both the JB weld and the sikka seal grind off well I've found. So here's 2 pics of the 'close to final' clamshell frame:

this shape should help minimize airflow separation and magnitude of the reverse pressure gradient at the rear of trailer improving drag ratio significantly

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clamshell oriented properly leaning against the wall

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[ssuuki19]

Did the final grind, jb weld, grind today, it went very well. Unfortunately I have to cut the whole perimeter of the door down by 1/2" or so, and I only got 2 of the 4 cuts done before my time deadline, and the shade in the area was elapsed (the 4 cuts are 18ft of 1/4" aluminum with a grinder and 90 degree cutting disk). So one more session should have this clamshell tack riveted onto the cabin. Soo much work - the reason why is that the skin panels for this door - two triangles and 6 trapezoids were all cut to fit from the same drawing, and they all fit really, really well, I should be able to get this thing pretty much seamless which is to me, within half a millimiter or a millimeter. When all is said and done perhaps a tig welder will want to do some signature work on the panel lines, I'm not planning on covering them.

[ssuuki19]

Well its all downhill from here on - the clamshell install went very well. I am very glad to not rush a first bespoke door such as this..
It took the whole day, a bit of rework, and I was off by half a millimeter here or there, but it doesn't matter. The point is the door fits, its skewed by the tiniest bit thats why the ratchet strap is on it. Gonna leave it to gravity settle and heat and cool in the sun for a week or so and keep ratcheting it square as the hours go by. I'm sure with a bit of over-tension and riveting the panels on, I'll get her square on.
To tack in the clamshell, 6 rivets were used on the roof/cabin side and 8 were used on the hanging clamshell side. Notable points are that the door is short by a quarter of an inch. And I'm glad. Offloading and onloading the cabin I don't want that door anywhere close to catching. A notable second point is that the upside down hinge fit in there so well, I think the second seal (as I was calling it) will be so good it will be water resistant to a great degree even without the primary seal, which will get all that other water that happens to make it through.
I was reading another build yesterday and one thing that touched me how the guy said that the build was emotionally and physically painful. I can so agree with that statement. But its moments like this, where my gut tells me its all downhill from here on... this is good news to me Here are the pics:

the clamshell (no its not the front its the rear)

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this will show you how the clamshell attempts to direct the airflow

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this side shows it shoring up to within 1/4" which is all around, for upcoming gasket/weatherseal

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