Bending Aluminium I Beam for Trailer, How i done it! manufacturers will go broke

[Fed]

Gazza have a look at the boat build threads on Jumpy's website he knocks out trailers like sausages.
Ask questions & adapt to suit your needs.
I take it this is in preparation for the Baron?
The site is pretty dead but there's still a lot of pictures.

[Noelm]

Jumpys website??

[Fed]

Sorry Noel, Dogcatcher, JumpusGoodarus, Angelo etc.
Cast your mind back sportsfish & fishnet days.

[Noelm]

OH, how could I forget? they were the days.

[Fed]

I'm sure Gazza was around then but now you've got me thinking it might have been a different Gazza, even our Gazza here is a couple of other Gazzas I think.

[gazza2006au]

Thanks Rayken i will look for some now

Fed yeah its for the Baron looking to build anew trailer in a few months not sure i to go with steel and get it gal or alloy trailer, the steel gal will be costing $1000 alone plus the material i can build the alloy trailer for cheaper but just not sure about the bends

i need a 20 degree bend to attach to the drawbar, half of trailer width frame will be around 90cm so i am possibly thinking 2x 10 degree bends in than 2x 10 degree bends just before the drawbar so the i beam runs up along the drawbar and i can run bolts strait thru the 3 pieces of metal

done some stick welding yesterday trying to teach my self how to stick weld and made a little die out of some 70x40mm RHS the die worked but where i had welded the cuts the welds protrude and it creased the i beam right on the weld when i put it into the hydraulic press, i may refine the design or scratch it

[Fed]

Cut, shut & gusset where you want the bends, I'll send you a PM.

[gazza2006au]

Yeah I'm thinking of grinding down the welds along the face of the die than running some 4-5mm flat bar around the radius o the die and possibly weld some flat bar across the sides for support

here are the beds the bend to the right is the original 19.1 degree bend which fractured, the bend on the let is using the die unsure of angle will have to check but that to fractured from the welds protruding from the die as it only fractured right on the opposite side of the welds

i still have another length of the same aluminium plus i have two shorter lengths about 1m long to keep testing

found some of that dye or checking cracks in metal once i decide on alloy or steel i will grab some its not cheap

[Noelm]

I don't profess to know much about bending aluminium and cracking, and I am just kind of thinking, that if at 19* you get visible cracks, then surely at 16* there must be at minimum some weakening of the metal? As I said, I don't know, and am really just pulling stuff out of my bum, but......

[Noelm]

Be interested to know what the material costs, I am toying with the idea of either getting my trailer regalvanised, or building a new one from aluminium, my trailer would be a breeze, because there is no bends, (cat trailer) even though it might look neater with a bend at the front maybe.

[gazza2006au]

Hey Noel its not an actual crack as in a hair line crack, at 19.1 degrees u see tiny 3mm 4mm long creases in aluminium going along the length and right on the opposite side of the bend they are so tiny its hard to get a picture it needs to be a camera with macro shots to be able to see it and even to the naked eye u need the day light to shine on the area to see it reflect itsmore of a crease rather than a crack but if i used that dye mentioned it will stand out like dogs balls

the normal aluminium has a matt finish so when u see the creases they are obvious because they all run in the same direction and is no longer a matt finish rather a grainy finish

the initial bend at 16 degrees had no creases at all it looked really good so i think 2 bends at 10 degrees each might be a far better option of getting to 20 degrees rather than one single bend

[gazza2006au]

I went thru my settings on the Samsung camera i had something called "selective focus" for taking pictures no further than 50cm away its like macro shot on a camera

here this picture clearly shows the over bend/stress in the aluminium this was the bend from the die

it may be ok for small sub 4.5 meter tinnies but or my 5.5 meter glass boat that will weigh around 1500kg i don't think it would settle my nerves knowing the trailer has these stress marks

[frank100]

Gazza try annealing the ally before bending, after bending slightly (how much I don't know you may have to trial & error, but I'd suggest 10deg) anneal and bend again & so on. When you anneal ally you won't know it unless you have a heap of test equipment (ductility, hardness etc) you won't see it or feel it but from memory you affect the grain size - annealing they get bigger, work hardening they get smaller hopefully someone else can provide more info - & knows what their talking about unlike myself). Anyway anneal- work - anneal (repeat).
To anneal ally we used to use white soap (Velvet ?) rub on outside of proposed bend, heat the inside with low temp. flame (propane ) until soap browns or just starts to burn, let the ally cool in air (no quench ), make the first bend. Anneal & repeat till done. As I said it was a long time ago that I did metal work so none of the above should be taken as being written by an expert.
Frank
PS
Serve with celery garnish (for those foodies who may be reading this)

[Jason Green]

IMHO I think you are better calling someone like bendpro and talking to them about what you want to do and asking them what material they would suggest you use
You are trying to bend a material that is really not designed to be bent as it is a structural alloy and is not very flexible
The molecular structure of it is very fine grained and without the correct environment and furnaces to preheat and post heat it during bending you will change the structure to some thing that could shatter one day and wreck your boat or cause something a heck of a lot worse
That’s just my two cents worth don’t know a lot about ally but do know a little about steel



Sent from my iPhone using Ausfish forums

[gazza2006au]

Frank yeah i have read about using the soap i thought about using soot from a candle to test it i may give that a try on the next piece

Hey Jason i looked at a few online manufacturers and they use the same 6061 t6 treated i beams that are available to the public i also looked into getting the i beam annealed than i do the bending than get it heat treated again the thing is companies dont like to reheat extruded aluminium as its almost impossible to stop the piece warping so i really think the shops are just annealing there own jobs and letting it self harden