out of the box tube bending ideas

[frankendat]

It has been a bit since I Ratsuned, my house needed more winter prep than usual and I planned out a way to get it finished by the end of November, at least my time management skills are consistent. 
 

I rebuild my tarp/carport/canopy thing in the backyard about every six years and that time has come again. I've been using a tarp canopy thing since 2000 and each rebuild try to add an improvement.
 

My tarp structures have no problems holding a snow load for a while, but I still "bump the tent" after heavy snows, so the tarp releases the snow. The canopy fittings create a roof angle of 30 degrees. If I bend "open" the fittings to 40 degrees, more snow should shed and less bumping will be required. My original plan was to bend open the fittings to 45 degrees, but the amount of trouble bending this fittings, has lowered expectations. 
 

There are not many forums I would post a custom question, because of the need to start at ground zero and prove consideration of an assload of details. I realize increasing fitting angle changes dimensions of the structure and I have new poles. I realize heating and bending fittings weakens the metal and I have incorporated two methods of reinforcement. I have been using one of these "temporary" (no building permit needed) for over two decades and have them sorted, but I have chronic better disease. ( That was good, what would be better)
 

What I am after from the Ratsun DIY coalition. Backyard techniques for bending tube. I went to local metal shops and muffler shops and they wouldn't touch it. I do not have a tube bender. I have tried heating the tube with MAPP gas and bending by hand and heating the tube with MAPP gas, inserting longer tubes in the fitting and in the receiver hitch on my truck. Most of a can of MAPP gas and 2 hours and I bent one fitting about 5 degrees.(There are 12 fittings that need to go 10 degrees)

Aside from the receiver hitch on the truck, I have a square steel pole in the ground in the back yard and there is a small hitch welded to the back of my Sentra, those are the only things I can think of that will hold fast if subjected to great pulling or pushing force. I have a couple bottle jacks and a couple handymans, a pile of chain and some tow straps. Any of that parlay into a force multiplier for bending?
 

This is not the kit I purchased, but mine is similar. It provides a look at the type of fittings that I am trying to bend. https://www.ebay.com/itm/154451745631?hash=item23f60a9b5f:g:6T8AAOSw~Ghj5uIl&amdata=enc%3AAQAIAAAA8NIhjzsbBXFDjfnodxlOkMkAfN3WxqfadUsDIh9NRfS04UdHbRrQ6ofT6Zs3IvrhjvkhLpOlbB8xlBSlw30al85RYlCV6wcStr4EAELQGdjjS3LaLXIj%2FS%2BJJROMd5oweh7Zh%2FpYjNsik4BCvKKUn8AUO5ckfgNo0vGJk012HvCIICcosOHO52lVFGL73mG5EQCpBggYJ1%2BBRYBopSBDxMKOpIC49uSjuhnJ2D87K4QEwg1uAE7GJETfDm%2B6qwRp53mRjzg6UHn1xBLv%2BrgVe7BZVLADrC6zfgNGc5%2FKMdaHFm6KSKHrI%2F6JoLaFXezUAA%3D%3D|tkp%3ABk9SR_b_0emIYw

 

[bottomwatcher]

Got a mig welder? I would pie cut with a death wheel and weld it back together. A lot more control without overbending or crimping.

[frankendat]

Thank you. I will think on that, it is a solution that I had not considered and those are exactly what I seek. I have a mig. 

[frankendat]

10 minutes ago, bottomwatcher said:

Got a mig welder? I would pie cut with a death wheel and weld it back together. A lot more control without overbending or crimping.

And I have a double death wheel. There is only one wheel but I always rip off the guards (because they get in the way) 

[datzenmike]

 

I assume you want the peak angle more acute? more pointy? Then the tip angle should be made smaller not bent more open?

[jagman]

If you want them to be consistent build a jig to 1 make sure your angle is right and  2 to  clamp the piece for your welding.

[ratpatrol66]

You are in Boise so access to materials should be easy. I don't know who your local metal house is. Everett Steel is my friend here in NW WA. 

They should have everything you need in different sizes, you just need a welder 

[frankendat]

5 hours ago, datzenmike said:

 

I assume you want the peak angle more acute? more pointy? Then the tip angle should be made smaller not bent more open?

I thought the same thing until I started playing with the angles. Then again, I could be wrong. Check this out https://www.omnicalculator.com/math/right-triangle-side-angle
 

Currently, the tent is 10ft wide. I am going to open it to 14ft. I think of the tent in two sections, the base and the peak. The base consisting of the walls and lower supports and the peak consisting of the rafters and upper supports. (The two sections share the top rail of the wall, which is the base rail for the peak). The peak is then one large triangle that  can be divided into connecting right triangles. Using the calculator in the link for reference, each right triangle,(creating the peak) angle A, side A, and side C will be the same (mirrored), side B and angle B will be double.

14ft wide peak is two 7ft right triangles (back to back). I originally went for 45 degree angles (12/12 pitch on the chart) because it is steep, easy to find with a square, and the height of the peak is half the base. Additionally, I found a great deal on 1-3/8 galvanized fence top rail in 7ft and 7ft 4 inch lengths. 

Returning to the calculator: Side A 84in, Side B 84in, angle A and angle B 45 degree (Total peak section will be 84in center and 168in base) There will be additional supports. The walls of the base will be 7ft or 7ft 4 inch, for a total tent height of 14ft (base+peak) which would be nice symmetry and make good use of my materials.(length of the tent will be three 7ft sections)

 

There are a number of details I am still working on, but the basic seems sorted. The tent fittings arrived with a                    30 degree angle, a 45 degree angle is more "open" farther apart (makes the peak more pointy) . Or am I misreading my angle finder and screwing this up?

[frankendat]

2 hours ago, ratpatrol66 said:

You are in Boise so access to materials should be easy. I don't know who your local metal house is. Everett Steel is my friend here in NW WA. 

They should have everything you need in different sizes, you just need a welder 

Finding the right stuff has been a  challenge, but it has nothing to do with local metal house. It is late, I will update at a future date

[thisismatt]

That 120° is from the vertical, but from the horizontal it is 30° as you say (90°+30°=120°). 45° would be a 135° (90°+45°) corner to the vertical and you would need a 90° peak...the three corners of a triangle have to add up to 180°.  I think you can get the 90° fitting that looks like an axis, not sure about 135°

[frankendat]

12 hours ago, ratpatrol66 said:

You are in Boise so access to materials should be easy. I don't know who your local metal house is. Everett Steel is my friend here in NW WA. 

They should have everything you need in different sizes, you just need a welder 

My appointment cancelled this morning, so I have a sec. It is not a very unique story, I seem to relearn the differences between tube and pipe, nominal and actual, every time I have to build something out of pipe or tube. The canopy fittings are mostly 1.5 inch actual OD, except the last three I bought as replacements are 1.66 OD which is a pipe size. (they were labeled as 1.5 inch canopy fittings) Then I have a bunch of 1.25 OD from earlier versions of the tent, which I will use as "inner" tubes to increase strength, as the rafters are increasing in length. I found that 1.5 pvc tail piece pipe will fit inside 1-3/8 tube filling the gap between 1.25 inner pipe and the inner diameter of the 1-3/8 tube. The pvc tail pieces conform to neither pipe nor tube sizing charts but they work. I found them by taking my box of tube and pipe to a plumbing store and trying different combinations. The canopy fittings, that are 1.66 OD will be reinforced with chain link fence pipe sleeves. 

[frankendat]

9 hours ago, thisismatt said:

That 120° is from the vertical, but from the horizontal it is 30° as you say (90°+30°=120°). 45° would be a 135° (90°+45°) corner to the vertical and you would need a 90° peak...the three corners of a triangle have to add up to 180°.  I think you can get the 90° fitting that looks like an axis, not sure about 135°

So, move the bottom corners 15 degrees more open, like I am attempting, but the top triangle corner will need to be "closed" 15 degrees on each side to make a 90 degree "more pointy" peak. Yes?

[frankendat]

9 hours ago, thisismatt said:

That 120° is from the vertical, but from the horizontal it is 30° as you say (90°+30°=120°). 45° would be a 135° (90°+45°) corner to the vertical and you would need a 90° peak...the three corners of a triangle have to add up to 180°.  I think you can get the 90° fitting that looks like an axis, not sure about 135°

Something that is a scrape in my thoughts, looking at the ebay canopy kit link and my original canopy fittings, the peak fitting and the bottom corner fittings look identical (there might be a slight variation). If I continue opening my bottom corner fittings to 45 degrees and closing the peak to 90 degrees. Will not the peak fittings and bottom corner fittings look very different from each other? 

[frankendat]

I have found a couple of videos on bending by pie cutting, but only a few that use the "not completely cut through the pipe method like this one

Using this method to bend a canopy fitting 15 degrees should not require an abundance of slits, but how many and how wide? If I use this method, of slits rather than individual pieces to bend my already bent tube, will the formula used by those constructing bends out of individual angled sections provide the angle, width and number of cutout slits necessary to accomplish a 15 degree modification?

[datzenmike]

They don't have to be pies. Just slit most of the way though in 2 or 3 places and inch apart (so not an abrupt kink) and pull closed and check against a jig, add more as needed.

 

 

To get this straight '62 Chevy II bumper to match the tail gate curve I made 5 slits, closed them and welded them up.

[bottomwatcher]

5 hours ago, frankendat said:

I have found a couple of videos on bending by pie cutting, but only a few that use the "not completely cut through the pipe method like this one

Using this method to bend a canopy fitting 15 degrees should not require an abundance of slits, but how many and how wide? If I use this method, of slits rather than individual pieces to bend my already bent tube, will the formula used by those constructing bends out of individual angled sections provide the angle, width and number of cutout slits necessary to accomplish a 15 degree modification?

I used this method on my KA swap. This guy did a straight 90 but if you offset your cuts you can really make a "unique" exhaust pipe. 

[thisismatt]

The 120° fittings make a triangle because only 30° makes up the angle from horizontal. 30° left + 30° right + 120° peak = 180°. Opening up the shoulders to 135° gives you 45° from horizontal...45° + 45° + 90° = 180°. So yes, they will look very different...no other way about it

[frankendat]

I located a tube coping calculator online, that produces templates. I made a few, but they are complicated and do not inspire confidence. I am going with making a jig and cutting slits in the fitting: cut a slit, check the bend, cut a slit, until angle is achieved. Neither as slick nor as quick as a coping cut, but I will not worry about screwing up a fitting (I don't have spares and they are not sold local)

[frankendat]

17 hours ago, thisismatt said:

The 120° fittings make a triangle because only 30° makes up the angle from horizontal. 30° left + 30° right + 120° peak = 180°. Opening up the shoulders to 135° gives you 45° from horizontal...45° + 45° + 90° = 180°. So yes, they will look very different...no other way about it

I understand. My concern arose because the 30 degree fittings (sides and peak) are almost interchangeable. I had to mark the peak fitting to avoid confusing it with the others.(The peak and side fittings might be exactly the same, but they came separately packed, so I keep them separate.) There is no worry mistaking a 45 degree fitting for a 90.