Frame and Chassis question from a nob

[scoutleader]

Ok bear with me this might be a bit long. My question is why do most people build the trailer out of metal then build the frame out of wood? What would be the problem with frame and trailer made out of metal and the two welded together. I think you could use something like a 2x2 or 2x4 square tubing. That would allow me to use metal for the roof and free up even more weight. My problem with using the current 4x8 frame is I need room for 2 adults and one 8 year old girl. My wife is a bit claustrophobic so I will build just a big square. Thanks in advance.
Danny

[doug hodder]

You can do anything you want. There are no rules, be innovative in your design and use of materials. Tubing/steel however is way up in price now and you can do it in wood a lot cheaper than using tubing. If you are thinking of 2x2 or 2x4 tubing on the body walls...that's way too much! I also think everyone overbuilds a frame and that you can get by with some really thin wall material and still build something that will work and be much lighter. Just my opinion. Doug

[scoutleader]

Well I have access to some nice 2x3 rectangle tubing that I can get for free if I will go get it. I need the TT to be light since the wifes small SUV will be the tow car for long trips and it has a 1200 lb weight limit and I don't want to push it to hard. My Jeep will tow up to 5000 lbs but she wont ride in it for more than a couple hour trip. Just because it has 270k on it she freaks out. But only 40k on the motor and drive train. I will camp with access to bathroom and shower onsite so no need for one in the trailer.
I would rather not cook inside the trailer so just need the place for a queen bed for wife and I and maybe a fold down bunk for the kid. Just a place to store cloths and stuff. Then when I go trout fishing in the winter I wont have to sleep in a tent on the cold ground to chase those browns.

[angib]

Do you think metal is light? If so, think again. Here are some weights for 2"x3" rectangular tube is various thicknesses:
2"x3"x14g (0.083") - 2.7 lb/ft
2"x3"x11g (~1/8") - 3.9 lb/ft
2"x3"x3/16" - 5.6 lb/ft

For comparison, most people use 1"x2" wood framing which is about 0.6 lb/ft (depends on the type of wood a bit) and even if it's 'overdone' with 2"x2" wood framing, that's only 1.1 lb/ft.

The right size for metal framing would be somewhere around 3/4"x3/4", so it would be no thinner than 1x wood framing and then you have to work out how to insulate it - wood is a half-decent insulator on its own, which metal isn't.

Andrew

[jeep_bluetj]

My TinyTentTrailer was mainly framed in steel. (body mostly .75x.75, just like was mentioned, chassis was 1.5x.75, 1.5x1.5 and some big 1.5x3 for the framerails)

It weighs alot. I have little else in it, so it was ok. But a 5x8 TD would be real heavy framed in steel, unless you were really good at using 16ga and sheet to build a monocoque structure.

The other main reason to build in wood is it's just plain easier, faster, cheaper, and waaaaay more forgiving of mistakes.

My next trailer will still have some steel frame (my offroad requirements dictate a heavier frame than most TD's) but much less than the first one.