Gary's Square Drop

[*Inside]

Well - it's 2021 and it's time for me to start seriously planning if I want to finish my trailer by the end of April so I can take it places in early summer

Step 1 (Custom Trailer):

• 59" x 95" trailer base
• 2x2", 1/8" wall thickness tubing
• 205-75-15 Tires (This seems to be a common size according to etrailer)
• #9 Dexter Torflex Axle @ 1500lbs (if I can find this..)

1-trailer.JPG (52.17 KiB) Viewed 895 times

Question 1: Do I need any cross members to support the floor in the center?

Step 2 (Floor Sandwich consisting of):

• Floor: 59.25 x 95.5" x 1/4" marine plywood cut from a 5x10" sh
• 1x4" exterior blocking
• 1x2" interior blocking
• 3/4" insulation
• Some sort of 1/4" plywood on top

2-floor.JPG (58.7 KiB) Viewed 892 times

Question 2: What should the bottom be coated in? I've seen roughly 100 different answers from tar, to paint, to fiberglass. I'm trying to stay away from fiberglass

Step 3 (Wall sandwich):

• Exterior: 1/8" baltic birch
• Skeleton: 3/4" ACX Plywood with 3/4" insulation
• Interior: 1/8" baltic birch ply

The skeletonization is not shown yet since I haven't figured out what the galley or interior cabinet work will look like.

3-wall.JPG (54.77 KiB) Viewed 892 times

Step 4 (Ceiling):

• Interior (not shown) 1/8" baltic birch ply
• Skeleton: 1 x 2 poplar w/ 1 1/2" insulation
• Exterior: 1/8" baltic birch ply

Step 5: Rear hatch:

Question 3: I am not sure what to do here. I want a 4.5-5 wide by 2.5-3 top open door. Any suggestions on what people have done in the past? I've browsed an awful lot of posts, but details have been light regarding the hinges and seals that people have used.

Step 6 (Skin): Not shown
But - planning on painted aluminum sheeting. 0.040" on all sides.

[tony.latham]

#9 Dexter Torflex Axle @ 1500lbs (if I can find this..)

They are all special order. I order mine direct from Dexter.

Do I need any cross members to support the floor in the center?

Your floor design will be remarkably stiff. I use two strips of 3/4" ply for my floors set with the grain vertically for stiffness.



The gussets are temporary to keep it together until one side is sheathed. The plywood is to support the heavy stuff in the galley. The outer floor frame is made from 1 x 6s since my bolt attachment points are about 3 1/2" in.

The Torflex axle will stiffen up the frame. I add a piece of angle under the galley since I put a battery, water jug, and cooler back there. That's a lot of weight.

What should the bottom be coated in?

I believe in using something that soaks into the wood and cures for this. You can't beat epoxy for this and I don't see any reason to use fiberglass. Several coats of back-to-back thinned polyurethane will also do it.

If you want to set a trap for dinosaurs, you might go with a tar-based roofing product like they used to use --and some still use. (That's humor, BTW for you guys that use Henry's.)

Skeleton: 1 x 2 poplar w/ 1 1/2" insulation

I live and camp in the Rockies and think you are overdoing it on the wall insulation. I build with 3/4" in the walls and 2" in the ceiling. It's plenty. I also use 3/4" CDX plywood for the skeleton because it is a lot quicker and adds flexibility for hardpoints (drawer sliders, gas strut attachment points, hooks etc. You can screw both together and gang cut them. That wall thickness may also cause issues if you are buying commercial doors. (Check with the manufacturer.)

Floor: 59.25 x 95.5" x 1/4" marine plywood cut from a 5x10" sh

You don't need marine plywood on the bottom. Do a proper job of sealing it and you'll need to include your camper in your will. I use 1/4" underlayment. It's cheaper than AC and built for wet environments. But any exterior plywod will work fine.

I think you can find the Dexter order form here:
http://www.dexterpartsonline.com/page/465305582

Good luck with your build.



Tony

[Pmullen503]

........
You don't need marine plywood on the bottom. Do a proper job of sealing it and you'll need to include your camper in your will. I use 1/4" underlayment. It's cheaper than AC and built for wet environments. But any exterior plywod will work fine......


Tony

You have to be careful about some underlayment products. I used Revolution plywood underlayment and it is definitely NOT waterproof! It delaminated and rotted under PMF after a few years. I had to rout out the bad areas, replace it with birch plywood (coated with "the Mix" and recover it with canvas and TB3.

I recommend tossing a scrap of whatever you use in a bucket of water for a week to see if it's truly waterproof. Real exterior plywood won't delaminate.

[tony.latham]

You have to be careful about some underlayment products.

I'm sure you're spot on with real-world experience. The underlayment plywood I use isn't waterproof either so I hope I didn't imply that. It's certified by the APA for moist environments. It won't delaminate if it gets wet.

But that's why I advocate for a sealant that soaks in and plasticizes the wood. No water. No delamination or rot. And no dinosaur bones in the tar.

Sometimes I feel gifted to live three hours from the nearest Home Depot or Lowes and have to buy from a real lumberyard. Sometimes.

Tony

[*Inside]

Thanks for the feedback Tony!

One more question about the frame/tongue. I'm using your removable tongue design. How far does the "central" member go into receiver hitch?

Removable trailed tongue based on Tony Latham's designs.

1-1 trailer tongue.JPG (89.5 KiB) Viewed 781 times

I've ordered the wheels, axle, jack, and coupler for the frame. Decided to go with the flexride 1400lb axle since for some reason I thought they were cheaper than Dexter (I was wrong), but they appear to be about the same price once side mount hanger brackets + shipping is calculated. Unfortunately the local assembler is out of one of the parts to make the 2,000lb axles so I have to wait a few weeks. He told me that after a 20 minute conversation and right after he'd taken the CC# info!

Flexride Axle:$343 + Brackets:$20 + $70 shipping (local Texas assembler) = $433

Dexter Axle: $275 + Brackets $60 + $140 shipping (Bend Trailers) = $475

I severely underestimated how much it costs to get something welded! I'm getting quotes that run about $800-1200 to weld together the frame as shown if I provide all the parts. One of my coworkers can weld and said he'd do it for cheaper... so hopefully that works out!

[tony.latham]

I'm using your removable tongue design. How far does the "central" member go into receiver hitch?

I think it's about ten inches on the inside of the tube.

Tony

[rjgimp]

You have to be careful about some underlayment products. I used Revolution plywood underlayment and it is definitely NOT waterproof! It delaminated and rotted under PMF after a few years. I had to rout out the bad areas, replace it with birch plywood coated with "the Mix" and recover it with canvas and TB3.

Had you properly treated the Revolution plywood with the Mix? If not, why? Perhaps I'm misunderstanding but it sounds like you installed it as-is. If you consider the birch a superior product why did you feel a need to use the mix on it in the repairs?

[MickinOz]

Patriot timber products say in their FAQ's that Revolution Ply is for interior use only.