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Old 09-11-2016, 07:10 PM   #1
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Metal Framing: Builds, suggestions, and ideas

Hi all,

I feel silly cluttering our forums with silly questions such as these but I wanted to talk about metal framing: basic structural engineering, and probe your opinions and expertise on angle iron vs square tubing. I recall reading a few builds which used metal framing, but apparently I didn't save them, aside from the broccoli bus build. Also this topic doesn't seem to come up often outside of the builds where they occur. From what I understand metal framing can be advantageous if done properly because it is lighter, smaller, and potentially longer lasting.

1. Does anyone have any links to any builds where people use metal framing?

2. What are our opinions on basic structural engineering with metal framing? From what I understand, triangles are good, lots of squares/cubes are good, and the sheeting adds to the general structural integrity. I think it's also good to add a buffer between the framework and the bus to reduce rattling?

3. Angle Iron vs square tubing. I plan to follow aaronsb's approach of using 16 gauge 1" square tubing. From what I read, square tubing's advantage over angle iron is that it will handle twisting torque better than angle iron, however the inside is vulnerable to rust due to it's hollow nature. I suppose it's good to note that the best price I've found on 16 gauge 1" tubing seems to be around 0.70/ft.

I know there's a lot of great fabricators on this board so I look forward to all of your opinions! And please share some builds if you have any saved with metal framing, thank you!
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Old 09-12-2016, 01:09 AM   #2
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If it helps - if there is enough moisture for a long enough time to cause the square tubing to become structurally deficient, I've got other huge problems like mushrooms growing out of the floor and black mold everywhere. Either that or the rest of the vehicle is rusted out from long term salt exposure.

If corrosion still bothers you, drill small ports and spray some cavity wax in the tubes after everything is welded and painted, which will make it basically last forever in the controlled environment of a bus.

You also have the option of cold spray galvanizing things too.

From what I've encountered, any simple welded square tube assembly seems to be much more robust than a similarly sized/complicated assembly made from wood.



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Originally Posted by TAOLIK View Post
Hi all,

I feel silly cluttering our forums with silly questions such as these but I wanted to talk about metal framing: basic structural engineering, and probe your opinions and expertise on angle iron vs square tubing. I recall reading a few builds which used metal framing, but apparently I didn't save them, aside from the broccoli bus build. Also this topic doesn't seem to come up often outside of the builds where they occur. From what I understand metal framing can be advantageous if done properly because it is lighter, smaller, and potentially longer lasting.

1. Does anyone have any links to any builds where people use metal framing?

2. What are our opinions on basic structural engineering with metal framing? From what I understand, triangles are good, lots of squares/cubes are good, and the sheeting adds to the general structural integrity. I think it's also good to add a buffer between the framework and the bus to reduce rattling?

3. Angle Iron vs square tubing. I plan to follow aaronsb's approach of using 16 gauge 1" square tubing. From what I read, square tubing's advantage over angle iron is that it will handle twisting torque better than angle iron, however the inside is vulnerable to rust due to it's hollow nature. I suppose it's good to note that the best price I've found on 16 gauge 1" tubing seems to be around 0.70/ft.

I know there's a lot of great fabricators on this board so I look forward to all of your opinions! And please share some builds if you have any saved with metal framing, thank you!
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Old 09-12-2016, 07:28 AM   #3
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MMMMMmmmmm Shroooms from a bus floor.
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Old 09-12-2016, 06:51 PM   #4
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Originally Posted by aaronsb View Post
If it helps - if there is enough moisture for a long enough time to cause the square tubing to become structurally deficient, I've got other huge problems like mushrooms growing out of the floor and black mold everywhere. Either that or the rest of the vehicle is rusted out from long term salt exposure.

If corrosion still bothers you, drill small ports and spray some cavity wax in the tubes after everything is welded and painted, which will make it basically last forever in the controlled environment of a bus.

You also have the option of cold spray galvanizing things too.

From what I've encountered, any simple welded square tube assembly seems to be much more robust than a similarly sized/complicated assembly made from wood.
Thank you Aaron, it very much helps! I couldn't imagine why there would be a lot of moisture in the bus but that's definitely good to know. Do you have this mushroom problem in your bus or other projects? After reading through your build, I've become a big fan of cold galv spray, and use it anytime I see exposed bare metal. I was planning to paint my interior framing comparable to how you painted your double folding bed frame. But maybe that's not necessary? Thanks for your response, and pardon my excessive directed attention towards your build.
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Old 09-12-2016, 07:14 PM   #5
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I used sch 40 steel piping for anything heavy duty I needed and 16-guage sheetmetal studs for all of my framing and boxed them together when I needed solid metal on both sides of my walls. Sorry I turned the studs width ways to make my walls 1-1/2" thick and with a little effort two studs face to face will lock together therefore making a 1-1/2"x3-1/2" stud out of sheetmetal studs.
I used the piping because it was scraps that I deal with daily.
The cold galvanized spray paint is good but don't try to paint over existing paint that isn't galvanized? The xylene and toluene in the paint is what makes it eat into the metal and if you paint over paint it is still trying to find metal so bubbles,cracks,runs,mess in any paint you paint over will have to be cleaned and done again.
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Old 09-12-2016, 07:42 PM   #6
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Thank you Jolly, lately you've been humoring all my threads with your great input and experience.

Your cold galv explanation is very helpful and makes a lot of sense. Since I plan to paint over my bus later I'm not too worried, but it's very good to know especially when it comes to interior work on the bus.
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Old 09-15-2016, 03:19 AM   #7
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No shrooms, just saying the level of persistent moisture required to rust tube framework from the inside out would be excessive, and cause lots of other issues with the existing structure.


Quote:
Originally Posted by TAOLIK View Post
Thank you Aaron, it very much helps! I couldn't imagine why there would be a lot of moisture in the bus but that's definitely good to know. Do you have this mushroom problem in your bus or other projects? After reading through your build, I've become a big fan of cold galv spray, and use it anytime I see exposed bare metal. I was planning to paint my interior framing comparable to how you painted your double folding bed frame. But maybe that's not necessary? Thanks for your response, and pardon my excessive directed attention towards your build.
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Old 09-15-2016, 11:27 AM   #8
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Check youtube for a guy using metal studs to frame his shuttle bus. He has several episodes. I liked it because metal studs are galvanized and very light weight.
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Old 09-15-2016, 11:49 AM   #9
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when you use a lot of metal is it clangy when you drive the bus?

not that school busses arent clangy and rattley already stock..

-Christopher
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Old 09-15-2016, 11:49 AM   #10
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Any measurable temperature differential between inside and out will create condensation. Very often...a LOT of it. Hot sun on exterior metal combined with "conditioned air" on the inside...or...snow on the roof with heated air inside...either will produce a surprising amount of moisture. Propane heaters are notorious for making metal ceilings rain indoors under the right (or is it wrong) conditions.
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Old 09-18-2016, 12:17 AM   #11
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Originally Posted by leadsled01 View Post
Check youtube for a guy using metal studs to frame his shuttle bus. He has several episodes. I liked it because metal studs are galvanized and very light weight.
Thank you! I learned the critical vocabulary word I was looking for-"studs", I have spent weeks trying to figure out why I couldn't find what I was looking for now I have found a lot of nice leads. Perhaps the guy you were talking about was "FixItWithMike" on youtube, you

After using this same search term with google via "site:skoolie studs", I then re-discovered The Great White Buffalo Thread. Where he does all his framing with steel studs which starts on page 4.

I also came across some funny threads where Nat condemned the poster for not using the search function properly. However I did find some good stuff which I wanted to copy pasta here.

Quote:
Originally Posted by aaronsb View Post
I've found that steel studs (like the kinds you would use in a commercial building or other fixed structure) are not optimal for a vehicle like a bus. They take up too much space given their size and application.

It would be more apt to think of metal studs as formed sheet metal channels (since that's what they are) and are structurally strong in specific ways that force you to construct your interior parts on a bus in a specific way that isn't always optimal.

The 2x4 (and smaller) wood construction that you see in skoolies is more versatile to constructing the shapes and parts that need to fit than the steel studs simply because they can be combined and used in nearly any orientation.

After evaluating steel stud, 2x4, plywood, and other media, I personally settled on 1"x1"x0.065" thick cold roll square tubing. With a welder I can quickly assemble small frame pieces and attach mounting flanges cut from 1/8" flat bar stock.

I can also use nut-serts in the square tubing, which let me build large assemblies that can be deconstructed and reassembled for installation, maintenance, and plain changing my mind about something.

Per linear foot, 1" square steel tubing has a much higher modulus of elasticity, lower weight, and takes up less space than both wood or sheet steel box (steel stud) construction.

To go even further in optimization, a panel formed from fiberglass or sheetmetal would probably be stronger in-situ, but the specialized construction techniques, and planning requirements for building those components is far more effort than bolting or welding together some square tubing.
One of my favorite things I learned from this quote is regarding "nutserts", I will look into these later and possibly report back into this thread.

Quote:
Originally Posted by cadillackid View Post
when you use a lot of metal is it clangy when you drive the bus?

not that school busses arent clangy and rattley already stock..

-Christopher
YES! I wanted to bring this matter up, would it be practical to put in some cheap foam or rubber between the metal and the floor/walls to dampen some rattling and sound? Would anyone have experience with something like this? Conceptually it makes sense to me, it may also increase insulation values somewhat? Maybe.

This now brings more questions to mind, but makes me think the following. Maybe I should do cabinets with the studs and appliances with steel tubing? Or maybe I'll do everything with steel tubing. I guess I should take a welding class first and decide how long until I am capable of welding together the steel tubing as desired. Anyway at this point I'm rambling so I'll shut myself down here. Thanks again all, your input is awesome.
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Old 09-19-2016, 01:45 AM   #12
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Nutserts are super awesome! To ensure success use them in shear applications as much as possible.

I tested some nutserts in a tension rig (bottle jack) and I stripped the threads on the bolt and dimpled 1/8 steel plate - the insert did not release from the hole.

I have tons of steel and nutserts and everything is very solid - thud, not clang.

Quote:
Originally Posted by TAOLIK View Post
Thank you! I learned the critical vocabulary word I was looking for-"studs", I have spent weeks trying to figure out why I couldn't find what I was looking for now I have found a lot of nice leads. Perhaps the guy you were talking about was "FixItWithMike" on youtube, you

After using this same search term with google via "site:skoolie studs", I then re-discovered The Great White Buffalo Thread. Where he does all his framing with steel studs which starts on page 4.

I also came across some funny threads where Nat condemned the poster for not using the search function properly. However I did find some good stuff which I wanted to copy pasta here.



One of my favorite things I learned from this quote is regarding "nutserts", I will look into these later and possibly report back into this thread.



YES! I wanted to bring this matter up, would it be practical to put in some cheap foam or rubber between the metal and the floor/walls to dampen some rattling and sound? Would anyone have experience with something like this? Conceptually it makes sense to me, it may also increase insulation values somewhat? Maybe.

This now brings more questions to mind, but makes me think the following. Maybe I should do cabinets with the studs and appliances with steel tubing? Or maybe I'll do everything with steel tubing. I guess I should take a welding class first and decide how long until I am capable of welding together the steel tubing as desired. Anyway at this point I'm rambling so I'll shut myself down here. Thanks again all, your input is awesome.
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Old 09-20-2016, 03:56 PM   #13
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*googles shear applications*

So I'm shy to clarify but what do we mean by shear applications?
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Old 09-20-2016, 04:40 PM   #14
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You can purchase them in 2 1/2" studs also
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Old 09-20-2016, 05:48 PM   #15
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Quote:
Originally Posted by TAOLIK View Post
*googles shear applications*

So I'm shy to clarify but what do we mean by shear applications?
Press the palms of your hands together. If a bolt is now drilled through both palms as they move in opposite directions, that bolt would be in shear.
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Old 09-20-2016, 06:52 PM   #16
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Example for discussion. If you put a bolt through a piece of metal where there lower metal has to support the upper metal and then the two foot piece(roof raise ) bolted have to support the roof raise roof? Then your shear weight is on the lower bolts.( with of the structure is on the lower bolts? Your upper bolts will might give up before the lowers?
Bolts are yugoes. Rivets are better and welding is solid.
Shear weight is two pieces fastened together with several methods and each method is tested to there shear point which means until they break?
Shear test.
A 1" steel plate vertical concreted in with a 10"x10" x10" X 1" piece of angle bolted with 1/4" home improvement bolt test at 150' the same piece with solid rivets test at 250',with grade 8 bolts 5000' ,with a solid weld joint 10,000
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Old 09-20-2016, 07:16 PM   #17
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clangy....

Quote:
Originally Posted by cadillackid View Post
when you use a lot of metal is it clangy when you drive the bus?

not that school busses arent clangy and rattley already stock..

-Christopher

Its a bus... Noise is a part of the experience! (that what I tell myself anyways). I have metal file cabinets for storage, and a Stainless Steel countertop on and between them. As of now, still rather noisy. I'm not sure how they will hold up to twisting and vibration either.... I plan to glue carpet or sound deadening foam to the bottoms and backs just for sound reasons.
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Old 09-20-2016, 08:34 PM   #18
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an open propane or natural gas flame indoors produces a TON of moisture...

ever notice houses that have gas or propane heating systems all that white steam that comes off the flue? all moisture that would be Inside your bus if you use a portable propane heater...

if you run a heat exchanger you will lose a little bit of the heat produced by the flame but also exhaust that moisture...

the ultra high efficiency furnaces like the one in my house with a 3 stage heat exchanger condense that moisutre inside the exchanger and gain a lot of extra heat from it.. its entirely possiuble to build your own high efficiency heat exchanger..

-Christopher
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Old 09-21-2016, 05:44 PM   #19
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I'd recommend metal studs.

It's more expensive than wood but so much easier to work with.... at least for me as I'm neither a framer nor a carpenter. It was so easy to make the radius up at the ceiling.

There are no rattles (none from the metal studs) and no foam or any sort of thermal break between the studs and the bus walls.

If I had to do it over again I would go with the same gauge metal but probably just a 1" stud and track if there is such a thing. (The track is the bottom and top "stud" that has a different profile to allow the "studs" to snap into place.)

Metal is the way to go....
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Old 09-21-2016, 06:54 PM   #20
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This isn't the best video in the world, but gets the idea of what you can do with a simple tube bender. I have a cheap one with dies for square tube. It's a little tricky to make a progressive curve like a bus roof but it's just a matter of measuring off some points with a sharpie pen and turning the crank.

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