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Steel spars

PostPosted: Fri Mar 23, 2012 6:55 am
by Forrest747
I am starting to help a friend finish his basement and he is using steel wall supports instead of 2X4's. they have cut outs for wires and such and i have also been thinking about the weekender wondering if i have anything to contribute to the revisit.

So the cutting of these supports is pretty easy and they are light so i was thinking i wonder if they would do well as roof spars, help cut down on the weight and be a good place to attach roof. just a thought in my head.

Re: Steel spars

PostPosted: Fri Mar 23, 2012 8:10 am
by Shadow Catcher
You are building an airplane and I have long advocated the use of light weight alternatives. Compass Rose uses 1X 1.5 X 0.060 aluminum and is strong enough to hold my weight (not inconsiderable). So by all means if it is less weight, go for it, but steel rusts.

Re: Steel spars

PostPosted: Fri Mar 23, 2012 10:19 am
by GuitarPhotog
My entire trailer is built of welded 1" X 1" angle iron uprights with 1" X 1/2" u-channel spars as roof spars. The angle iron frame is just tack welded together, but is skinned with 0.050 aluminum riveted in place.

The skin riveted to the light-weight frame is what has given this trailer the rigidity and strength to survive 65 years on the road, without a leak, weighing in at under 800 lbs (dry).

As so many here are fond of saying "build it like an airplane, not a tank!"

<Chas>

Re: Steel spars

PostPosted: Fri Mar 23, 2012 4:41 pm
by KCStudly
While the steel studs are very light compared to their equivalent lumber counterparts, and they are galvanized for corrosion resistance, I suspect that you will find that they are still foot for foot heavier than say 1x2 poplar or fir. Also, the more common sizes are much deeper in section than what would be required, taking up valuable interior space.

Many people with metal super structures have commented that temperatures telegraph through their roofs/walls at the spars/studs where it is difficult to isolate the interior skins adequately.

Just my thoughts and part of the reason I have chosen to build in foam with some wood (Foamie Hybrid).

Re: Steel spars

PostPosted: Fri Mar 23, 2012 5:47 pm
by Forrest747
not sure i had a clear though on this use of the material. so thought i would ask.

Re: Steel spars

PostPosted: Wed Mar 28, 2012 5:43 pm
by 2bits
I was thinkig about this approach for my new TT build. when I was talking to a trailer repair place sourcing some sheet alumunim and the guy said he could sell me some Z posts also and I was like "what's a Z post" and it is the framing that cargo trailers use. Better quality trailers use a Hat post (Same shape as a stop sign post). I was just thinking it works for a cargo trailer, why couldn't I use the same method for a teardrop shape in a standy.

So... .050 aluminum for the sides for rigidity, Z or H posts for side wall framing spaced 16" on center, insulate since you have the open space anyway, and then pannelling or stained wood to skin the interior. I was thinking the fake wainscoating pannelling that you stain yourself might be nice. I don't think that would be overbuilt. My question would be the roof. Possibly use the same exact contruction? I would prefer welded construction since dealing with metal, I want to get a welder anyway.

Re: Steel spars

PostPosted: Wed Mar 28, 2012 5:53 pm
by mikeschn
Got a picture of a z post? Maybe that's what I've been looking for!!!

Mike...

Re: Steel spars

PostPosted: Wed Mar 28, 2012 6:04 pm
by Forrest747

Re: Steel spars

PostPosted: Wed Mar 28, 2012 6:29 pm
by mikeschn
Interesting...

Do you have a snapshot of it being used in a Cargo trailer?

Mike...

Re: Steel spars

PostPosted: Wed Mar 28, 2012 8:33 pm
by 2bits
I saw a cargo trailer today and REALLY wanted to stop off and take a peek haha. I plan on visiting a dealership this weekend and trying to find one without the interior walls. I did like that it already had mounting holes drilled in them. drill from inside out and rivet away...

Z posts are considered inferior, and Hat posts better and square tubing best, but this isn't a cargo trailer so when I see them myself in person I will make my own call.

I'll take pics!

Re: Steel spars

PostPosted: Thu Mar 29, 2012 2:19 pm
by Forrest747
89915

Here are a HAT post and a Z post, with the top being a HAT Post. I was also reading that Z post tend to lose thier rigidity over time

Re: Steel spars

PostPosted: Fri Mar 30, 2012 8:27 am
by aggie79
One of the ideas I've kicked around in my head is to use minimal framing of lightweight 1" square aluminum tubing. The tubing would be connected with nylon connectors: http://www.brunnerent.com/Tools/Portfolio/frontend/itemlist.asp?type=2&size=0&lngDisplay=2&strMetaTag .

The exterior sidewall and floor skins would be aluminum composite panels such as alumalite or alucobond. They would be bonded to the aluminum framing using VHB tape and perhaps riveted at the perimeter where they would be covered with trim. The roof exterior would be standard aluminum. The voids in the framing would be filled with 1" insulation

The interior finishes would be plastic laminate, aluminum composite, FRP, and/or pre-finished paneling.

My 2 cents worth.

Re: Steel spars

PostPosted: Fri Mar 30, 2012 10:15 am
by GuitarPhotog
I think you'll go broke buying 1" square aluminum tubing and the connectors. Both are very pricy.

<Chas>

Re: Steel spars

PostPosted: Fri Mar 30, 2012 7:01 pm
by 2bits
Something like this Tom?

Image

Re: Steel spars

PostPosted: Fri Mar 30, 2012 8:23 pm
by mikeschn
2bits wrote:Something like this Tom?

Image


Thats a good picture Thomas.

I've been wondering if that would be a reasonable approach and haven't really had a chance to visualize it yet. That a good visualization!!!

I'm guessing that's steel. Any idea what the size of the tubing is? 3/4 * 3/4 * 1/16?

Mike...