Frame made of steel tube....miter ends or leave open?

[greasywheats]

I am about to have a chassis built for my TD and gave my welder a plan that shows a 2"x2" tube chassis, with cross members made of angle. In my plan I had the four corners mitered so that the frame will be sealed. He is suggesting that I do not do that ("based on his experience building thousands of trailers") and suggests that I leave the ends open. The reasoning being that if water gets into the frame (say from any bolt holes I might drill into etc...) and the water freezes in the tube, it will explode the frame. I have a couple problems with this.... how do you have both side of each frame member stay open, wouldn't 2 of the four members have to be sealed as they butt into the next member? Second, if there is a hole for water to get in, isn't there a hole for it to get out...and if I manage to get that much water in the chassis, I'm doing something that I shouldn't! Anyone have any recommendations? Another point is that I intend to have the sidewalls and front/back extend to cover the trailer chassis, so this could cause problems having a good seal there....Any input is welcome!!
ThanXs much!

[SteveH]

greasywheats,

I can see where there are "issues" with doing it either way, but I seriously doubt you would ever get so much water inside the tubing to have it split from freezing. The real issue in my mind would be corrosion (rust) forming on the inside and rusting thru. Granted it would take a while, and is just one of the things to deal with when using tubing. Sounds to me like he doesn't want to build it with mitered and sealed joints, but that's just me.

[Cutterpup]

I used 2 x2 tube but wished I had used 2x3 channel. Lighter and once welded just as stiff as tubing. Pop-up campers use this and they are heavier than teardrops. One big advantange is the open sides so you can run wires and even water lines if so inclined. Where the axle is attached that section needs to be boxed.

Dan

[greasywheats]

Where the axle is attached that section needs to be boxed.

Dan

Not sure what you mean by the section where the axles are attached needs to be boxed...you mean a piece of steel needs to be welded to the inside of the channel to form a box, or piece of tube steel where the axle attaches?

[Cutterpup]

Really it up to you which way you do it. Of course if you have 1/8 sheet steel just weld it into place but if all you have is some channel left over reverse it and weld that in to box it.

Dan

[norm perkiss]

Greasy,
I had a frame made about 20 years ago. It is all 2x2 square tubing including the tounge, all ends welded closed. It was for hauling ATVs. I bolted the plywood deck directly onto the 2x2 frame. Some water did get inside the frame, I can hear it after the winter rains.

Bottom line, some rust but no burst tubing or any other problems. If you had mounting tabs or some angle welded on, you wouldn't need to drill into the 2x2.

If you are having Mike built it, he coats the frame with something like "asphault paint". It takes a couple of days or longer to set up, but coats very well. I agree with a post above, that he wants to build it his way. The cross pieces on my Tear frame are 2x2, though the ends are not completly sealed.
Norm

[JunkMan]

I mitered my corners instead of leaving the ends open. I have built a couple of trailers like this and never had one freeze and bust. I have had some water get in, and I worry a little about rust from the inside. I plan to check this trailer over and see if I can find where the water is getting in, and weld up the holes before I bolt the body on permanantly. Of course water may still seep in through the holes where the body bolts thru the frame. I'll probably run a bead of caulk around the bolt heads to seal them (on the underside of the trailer where it can't bee seen).

The main reason I see not to miter the corners, is that is a pain in the butt getting the angles right! My chop saw isn't real accurate, when I set it up, the blade always seems to drift a little and make my cuts off a little. Not a real problem, just have a bit of a gap to fill sometimes.

[bledsoe3]

Greasy,
If you had mounting tabs or some angle welded on, you wouldn't need to drill into the 2x2.Norm

Look here. http://www.tnttt.com/gallery/image.php?image_id=1993 You can see the "tabs" Norm is refering to on mine. I spaced 10 of them around the frame to bolt the floor to. Jim

[madjack]

...double or triple dittos to what Powderburn just said...it's a strength issue in my mind, if you are gonna butt weld use channel or angle
madjack

[SteveH]

if you are gonna butt weld use channel or angle

I built my frame out of angle, and mitered the corners. Agree it makes a stronger joint, and it just plane makes it prettier.

[Cutterpup]

Here we go again lets build a frame so strong that if we put 10,000 capacity axles on the frame it still would not bend. 2x2 1/8 inch tube is overkill for a frame.

We collectively build trailers that weigh in anywhere from 300 lbs to 1200 lbs and as amateurs well meaning amateurs we over build. You know the old saying well if one will do it lets make sure and add two more just to be safe.


Before building any frame get some knowledge about how trailers are made go to a dealer and LOOK at the frame with a ruler in hand and see just what is there. You won't find 2x2 tubing used for trailer in the 2000 lbs or less capacity.

With gas prices only going up do we need to haul around 50 to 100 lbs of useless dead weight all the time?

Dan

[McTeardrops]

I had an open-ended tube trailer rust through and fail, so I pay more attention than most. I miter cut the ends, and use tabs to avoid having to drill into the tubing. I weld on a nut at a high point and pour in some oil to protect the tubes' interior.

[Shrug53]

I used 2 x2 tube but wished I had used 2x3 channel. Lighter and once welded just as stiff as tubing. Pop-up campers use this and they are heavier than teardrops. One big advantange is the open sides so you can run wires and even water lines if so inclined. Where the axle is attached that section needs to be boxed.

Dan

I am inclined to agree with cutterpup. This is exactly how car frames were made all the way in to the 30's. They seem to hold up just fine. My father-in-law runs a 1928 channel frame on his Ford roadster and has never had a problem with it. I think some people really get carried away with frame strength here. I have had auto transport trailers that were not as heavy duty as some of the trailers folks talk about here.

The "Jim Dandy" trailer weighs 2200 lbs. and it uses the big 2x2 stuff, just for the main frame and the cross pieces are 1.5x1.5 angle iron.

Anyway, just my perspective from a car builders point of view.

[angib]

I used 2x3 by 1/16 tubing on my teardrop trailor because its off-road.Half as thick as the 1/8 (2x2)inch tubing but stronger.I bet its lighter too.

2" x 2" x 1/8" tube - Z = 0.51 in3, weight = 3.05 lb/ft
2" x 3" x 1/16" tube - Z = 0.51 in3, weight = 2.04 lb/ft

So exactly the same strength, but one third less weight. However I've not seen 2x3 tube listed with 1/16" wall - is it 0.083" (about 1/12")?

2" x 3" x 0.083" tube - Z = 0.65 in3, weight = 2.67 lb/ft

That would be a quarter stronger than 2x2 and a little over 10% lighter.

Andrew

[Shrug53]

Andrew - soooooper genius!