Learning to build a 5x8 square drop

[DesertApprentice]

DrewsBrews, thanks for the encouragement! The overall goal sounds very simple: just build a teardrop trailer Then details come in, every bolt position matters. I'm going to have the wheels on the frame as quickly as I can. Then it's big (real) task of building the cabin.

[DesertApprentice]

It has been a long time. It has been an extraordinary learning experience for me every step of the way!! From overall design to a simple screw size selection, I posted many questions here, I watched numerous youtube videos. I want to thank everyone here for your help and encouragement!

I'm still long way from being done. I wanted to post some update here. The photos also show the major steps and the lessons learned. some lingering questions still haunt me even to date.

0. Overall camper dimensions
Frame: 5x8
Cabin: 5x8-8" (plywood extends 8" beyond the frame at the back)
Exterior cabin height: from frame metal to the roof (external) ~53.5".
Interior cabin height: ~49"
Ground to the top of the frame (including 2" frame tubing): ~21".

1 - Timbren suspension:

I selected 1-ton Heavy Duty ASR1THDS09, because it has the a longer spindle for big tires. A few things to pay attention: if you use off-roading tires, double check the tire clearance to the frame! I welded the assembly to the frame. If you decide to weld it on, don't weld all the way around. I hope I didn't burn that rubber too bad, fingers crossed I won't have problems down the road.

2 - Hub-brake

I also selected the compatible hub/brake 94550PR. Beware when they say the hub fits Jeep JL/JK wheels. The only thing this hub "fits" JK/JL wheel is the 5x5 (5x127) bolt pattern. My JL OEM wheels do NOT fit on the hub at all! Also the hub size is 65mm, good luck finding any hub-centric wheels for that. I see my wheel cambers are way off. I still need to address that yet. No regret selecting Timbren though. They do have good customer support.
Another scary story: since it was my first time ever worked on trailer hub, i forgot I need to put in the cotter pins for the castle nuts I dragged the trailer a few times across the town searching for the right wheels for the trailer. I noticed my tires were wobbling badly. I found out the castle nuts were loose. After checking the instruction again, I found out about the cotter pins! An angle must have been watching me.

3 - Tongue
,
only thing worth noting, I selected 50 degree for the triangle. I don't know there is any science with the angle, it appears to be very common with trailers.

4 - POR-15

I believe POR-15 is good stuff. If I do it again, I may select a simpler solution. I followed that 3-step process for POR-15. I'm not sure if that's even necessary for clean steel. Also, beware, you still have to apply UV protection coating where POR-15 is exposed to the Sun.

5 - Brake controller

I selected Curt Echo wireless controller.

6 - Floor build



I used 10 carriage bolts fastened the floor to the frame (i pre-welded some gussets to receive those bolts).
I have 2x4 sandwiched between two 1/2" plywoods with 1.5" insulation filling the middle. It is heavy!

7 - Side walls cut-out dry-fit


8 - tire selection

I ended up using two 37" tires. I know it is ridiculous the tires take half the size of the whole camper. The advantage is I can share the same spare tire with my Jeep. I struggled trying to design a good spot for the tiny off-roading camper to carry a spare tire.

9 - Next steps: here I am. A lot needs be done!
I don't have a detailed design. So I'm designing (changing) it as I go.
I plan to first finish the exterior walls and skin the outside with aluminum. This way, I can use the camper as I'm building the interior. I understand the challenges I'll face working inside the enclosed camper. I hope I'm not making a huge mistake. I'm counting on the full size hatch gate to make it a bit easier for me.

[KCStudly]

One thing to look out for when using large tires is galley counter height vs floor height. Most kitchen counters are 32-36 inches above the floor (flat ground). As the trailer deck gets higher the space under the counter gets shorter. If you want to keep your cooler/fridge under there you need to account for the height of the cooler, added height of sliding tray (if used... recommended), the thickness of the counter and any face frame or trim supporting the edge of said counter.

If you run out of room one solution could be to do a split level counter. Build the smaller section over the cooler up to make room, but have the remainder down lower at a more comfortable working height. Also consider the lost storage space.

[DesertApprentice]

After nearly 10 month hiatus due to some emergency, I'm back working on the trailer again. Here are the latest photos





Everything was made up as i go, no detailed plan.
Next steps, I'll add one board to sit on the bulkhead as shelve bases for both galley and cabin. then i'll add insulation and electrical. I got a couple questions, hope to get some expert advice here:

For special devices, such as fan and frig, brake, signal lights etc, i'll use the wire gauge per device requirements.
1. For lights (LED), I see people buying a spool of wire and just tape each end with colors. Is that a good idea?
2. What gauge I should pre-wire for all lights?, i suppose I can go 16 or 14 AWG, then if I buy a spool, i may select 14 or 12 AWG for all LED lights.
3. Is it ok to use copper coated aluminum wires? not sure if I should stick to copper wire only.
4. For those LED lights with changing colors, do i need to prewire those things any differently? It appears the light colors are controlled by the remote, no control wire is used.
Thank you so much!

[tony.latham]

1. For lights (LED), I see people buying a spool of wire and just tape each end with colors. Is that a good idea?
2. What gauge I should pre-wire for all lights?, i suppose I can go 16 or 14 AWG, then if I buy a spool, i may select 14 or 12 AWG for all LED lights.
3. Is it ok to use copper coated aluminum wires? not sure if I should stick to copper wire only.

If you buy a two-wire color-coded cable, life will be easy.



16 AWG multi-stranded copper is fine for LED's (and your fan), 12 AWG is gross overkill. I used 14 AWG because it's what I found. Don't use copper-coated aluminum. It has reduced conductivity and is more likely to break.

Get a roll of this stuff:

https://www.amazon.com/gp/product/B074DMPH8P/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

Tony

[KCStudly]

Multi strand copper wire, or "automotive" wire is preferred over solid strand wire. Solid strand, like Romex house wire, is not meant to flex repeatedly or vibrate and can fracture. Whereas stranded wire... the finer the strands the better... will live a very long time going "over the road". Tinned wire is "the cat's meow" if money is no object; it won't corrode in harsh conditions. LEDs have very little draw and could probably get away with smaller wire (larger gauge numbers). Search for capacity or voltage drop tables for recommend gauge sizes for the load and length of wire.

[Onajourney]

18 Gauge is fine for most applications in a trailer build. It's good for up to 14 amp or 170 watts. To put some perspective on it, MaxxFan Delux draws 5 amp or 60watts, LED puck lights draw .2 amps, typical fridge about 70 watts. I actually can't think of anything that would need anything larger than 18 gauge IMO.

[DesertApprentice]

Tony, KC and Onajourney, thank you all for the great info! Will hear the advice and get the better quality wires.

[DesertApprentice]

I want to add a side door on the tongue box. I have some basic idea. I would like to see how others have done it.
Are there instructions (examples) on how to build a small water tight door?
Thanks in advance!

[tony.latham]

Are there instructions (examples) on how to build a small water tight door?

Here are the details on door seals from my book. It should work equally well for a tongue box.





Tony

[DesertApprentice]

Here are the details on door seals from my book. It should work equally well for a tongue box.

..
Tony

Thank you so much!

[DesertApprentice]

Another basic question, after i adding insulation, I'll use 1/8 birch ply for interiors. Is leaving the ply untreated too crazy an idea? what would be an easier alternative? I never did any wood work before. I binge watched youtube about stain vs varnish. I couldn't come to a conclusion what to do.
I want the least exotic option (lazy, cough, cough), i also would like to reduce the condensation.
Thanks!

[tony.latham]

Is leaving the ply untreated too crazy an idea?

It's not crazy, but not a good idea. Two humans put off a lot of moisture. I strongly recommend two or three coats of Minwax oil-based poly. And do it before you install it.





Tony

[DesertApprentice]

It's not crazy, but not a good idea. Two humans put off a lot of moisture. I strongly recommend two or three coats of Minwax oil-based poly. And do it before you install it.
...

Super, will do it as you recommended!

[DesertApprentice]

a picture is worth a thousand words

wiring diagram.png (129.49 KiB) Viewed 926 times

For sanity, does this picture look right? Let me know anyone sees any problems.
1) all 3-watt lights share the same 14 awg wire circuit,I suppose it's OK?
2) dedicated 14 awg for the cigaret usb combo charger,https://www.amazon.com/dp/B08GX4Z9NB?psc=1&ref=ppx_yo2ov_dt_b_product_details, is that necessary?
3) I'm thinking using a SOK 12v 100ah LiFePo4 battery. I have not designed the charging. I suppose that's independent of this part of the wiring, am I right?
Thank you!