So I was getting a bit bored lately so I decided to try my hand at making a Alu Roof Rack.... So like we all do I sketched one up on a piece of paper and away I went... Here is were I am so far it just needs legs which I am getting made at the moment thanks to some kind help Marinus, Thanks again Marinus for the Leg Design.... Although I have changed them slightly to a quick release setup..... hahaha which I think will work better for me.. I have used a "toggle latch or throw over latch" never know the name?? which I drilled the m6 thread out and tapped it to a m8. then welded on the feet. I also pop riveted the latch on with stainless steel pop rivets. Only disadvantage is if ever in the bush and a pop rivet brakes, I will have to knock it out and replace it with a bolt....
Now with regards to the frame I think, like all true South Africans I might have Slightly over Designed the Strength of it a little bit. But hey you can never be to tuff hey??
I used 38mm tubing with a wall thickness of 3,18mm top and bottom with the struts being 60mm x 6mm thick flat bar and 1,5mm check plate on the front... The Cross struts are 25mm x 50mm x2mm which were tested by a friend of +/- 100kg and they did not brake... 
So I think they will work!! I am now just going to polish it up nicely and then off to the powder coaters. I have found a powder coater in Kempton park that is Cheap. so I will be trying them out.... will keep you up to date on there work...
but here is some pictures of how far I am.. you will see a box on the side that is a DIY awning that I will make a post later off....
