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BenM78
26th Aug 2009, 07:44 PM
I need an ultralight trailer to carry my 10' tinny down to the creek. Lifting it onto the roof of the patrol is giving me grief so time for a trailer :)

I was originally going to use 40x40x2 RHS but local steel dealer has 8m lengths of 50x50x1.6 RHS which has 25% more steel content but (obviously) thinner wall. Would this material still be ok? Max load would be around 100-150kg PLUS trailer.

Any thoughts?

Edit, the Gal 50x50x1.6 x 8m is $42!!

Calm
26th Aug 2009, 08:44 PM
Have you thought of using flat steel on its edge instead of square.

There is no strength in the top and bottom bit all the strength is in the upright peice. Flat just needs to be braced a bit.

I made a tandem car trailer out of 1/4 inch flat top & bottom and mudguard material (about 9 inches high) to make a "I beam" like semi trailers use. Strong and light.

Cheers

pipeclay
26th Aug 2009, 08:52 PM
Are you making this for Normal H/Way use or just for Private property.

BenM78
26th Aug 2009, 10:02 PM
Use will be light around town type stuff just going to local boat ramps. Never more than 10km and never on the highway. Will have all required lights etc and be registered.

Will just add too, 40x40x2 has equal steel content to 50x50x1.6, not less as I wrote in my OP.

graemet
26th Aug 2009, 10:27 PM
Why not consider Lysaght cold rolled C sections. http://www.lysaght.com/go/product/lysaght-cold-formed-sections . I have used these successfully for lightweight boat trailers, and an 8x6 camper trailer. Load tables are readily available to allow you to calculate the required sizes. They are light enough to gas weld or stick weld with a light electrode. Mate these with a tubular beam axle and springs from a wrecker and you have a very strong unit, easily manhandled around your yard or across the waterfront park, no need for a ramp. you can have the whole frame hotdipped galvanised for an indefinite life.
Cheers
Graeme

soundman
26th Aug 2009, 11:36 PM
I have been dragging around a box trailer made of 40 x40 x 3 angle for decades......its carried considerable loads.......* back when the QLD main roads asked us all to provide details of our trailers.....I weiged it using bathroom scales.

the big advantage of angle is that it is managable to weld where RHS starts getting thin and requires better skill.

the secret with angle is proper bracing and not relying on a single member.

if you realy want to keep the weight down and the strength up strat thinking about web truss type structures.........you used to see quite a few boat trailers like that in the past.

have you looked at the various fold up trailers on the market....there aint much to em.

grab your calipers and probe a few production trailers & I think you will get a surprise.


cheers

catbuilder
5th Sep 2009, 11:22 PM
My Tinnie trailer is made out of 50x25x2.5 with a 50x50x2.5mm single drawbar, is professionally made and plenty strong, have done a few fishing trips since buying the boat last year, without any dramas.

I think the drawbar is where you might need something more like what I've got.

Regards Matt

soundman
5th Sep 2009, 11:51 PM
50 x 50 x 2.5 is a pretty sweet section.....I think it is the lightest it commonly comes in 50x50, and is only 25% heavier than 50 x 25 x 2.5......its only twice the weight of 25x25x50 but a hell of a lot stronger.

50 x 50 matches up realy well with spring hangers and roller hardware & stuff

and you can even get a stuff it up the pipe tow hitch from trigg bro's

you'd rely have to work hard or spend $$$ to build a lighter functional trailer than out of that section.

cheers

BenM78
6th Sep 2009, 08:31 PM
I bought a couple of lengths of the 50x50x1.6 and then drove around a couple of the creek ramps and took a bunch of photos of the other trailers there. Have drawn it all up and am getting a freight quote for the single axle kit from Marshall Engineering. Should have an operational trailer for less than $350!

soundman
6th Sep 2009, 08:51 PM
ooooo.... 1.6... my steel shop doesn't stock that.

cheers