# Forum Home Renovation Metalwork & Welding  Joining some aluminium hollow rectangle bar

## Led

Hi, I'm looking to make a frame of sorts out of aluminium, 30 x 50 mm rectangle bar in 3m thickness.
It would be one horizontal with two verticals coming up off it about 250mm apart. All about 600mm
lengths, this then fixed to timber at the 4 ends of all the bars.
 What would be the best way to join the two verticals to the horizontal bar so the fronts all sit flush with each other?
 It's going to have about 15 kilos mounted on it, fixed to both the horizontal and vertical bars. 
Mending plates and a few small bolts maybe? 
Thanks for any advice.
Cheers.

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## ringtail

Difficult without welding. Angle brackets with rivets will work but won't be very strong. Bolts will work bit you won't be able to tighten them without crushing the ally. What's the frame for ?

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## Led

Hi Ringtail,
for a rangehood. It's about 13.5Kg but rounded to 15.
Trying to avoid closing in a window space. Can't do an island one becase of solar 
on the roof directly above and no cavity to vent through.
Might have to get a steel frame welded by someone instead.
Thanks for the reply.

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## Marc

if you want to join square or rectangular tubing with bolts without crushing it, you have to drill one side hole big enough to put the head of the bolt and the socket to tighten it through. the other side hole is the normal size for the bolt. This will not give you a flat H frame though.

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## Led

HI Marc,
yeah I was hoping ro keep it all flush. I could do it with timber but I can't work metal. 
There's a stainless welding/fabrication place in my area might have to see what they could 
knock up. 
Thanks

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## ringtail

I would go to the stainless guys. SS RHS is pricey in bigger sections. Try and rework the design to use common "bench size" sections like 30x30x1.6 which is more than strong enough.

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## Pulse

bunnings has ally box section with plastic joiners, might be strong enough.  
Sent from my iPhone using Tapatalk

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## Led

I had a look at the square tube and plastic joiners but heat could be an issue.
I'll have a chat to the stainless guys near our place or try to find someone local
who can do the welds for me. Could be done in square gal steel tube as well.
Thanks for the suggestion 
of the 30mm, that would work for the fixings I need.
Cheers.

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## Marc

Any panel beater would be able to weld RHS for you

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## PlatypusGardens

So If I read your description correctly, you're making a 3-sided square without a top, so to speak?
(Or, a square "U" when looking at it from the front) 
And you need to join the lower corners?   *[EDIT] 
Just read it again and realised I got it all wrong...* 
You're doing something like this, yeh?      
Anyway, this might help someone else with something, so...  
You can get different kinds of internal brackets and bracing for aluminium frame, such as the ones they use for screen doors and windows.   
I think these will fit inside 30x50mm   
Or something like this.          :Smilie:

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## Marc

Hi PG, I think the OP is concerned with strength ... by the way like your new si.........zzzzz  :Smilie:

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## PlatypusGardens

> Hi PG, I think the OP is concerned with strength ...

  
Yeh getting something welded up would probably he the go    :Smilie:

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## Led

Hi Platypus, yep the drawing you did is what I was trying to do. I trying to only have one horizontal but am rethinking things to have two 
horizontals, as there are 2 spots the main body is fixed to which will need more strength. If I do it that way the verticals will only be holding
the ducting and cover so won't need near the strength they would to hold the main unit. 
Rather that try to hide the single horizontal I'm rethinking the approach to use two horizontals and make a feature of them instead.
Thanks for the advice all.
Cheers.

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## phild01

> You're doing something like this, yeh?

  Does the cracked screen make the lines go fuzzy :Smilie:

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## PlatypusGardens

> Does the cracked screen make the lines go fuzzy

  I actually googled "symbols" and found one I could crop.
As it was pretty small I had to zoom in on it.   :Wink 1:

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