Welding Growbed Stands

KudaPucat

VeggieBoy wrote:

JJ & KP - regarding the stands, I may give RHS a go next time - because it would certainly make things a little easier not having to stuff around with the corner cuts required for angle. One of my issues with RHS is that my welder is just a 130amp cigweld turbo compact. I expect I would blow holes in anything thin, so need to use thicker stuff. One disadvantage for me with RHS is that I can't weld both sides of the metal (if you know what I mean). I have quite a bit of 40mm 3mm thick RHS in my shed that I was originally going to use for legs and some other things but changed my mind. May as well give it a go for my next bed - provided I can get a decent weld on it as the piece I am working with gets bigger (another problem I have with just having a 130 amp welder Sad. If anyone wants to discuss this stuff further - we can take it to a welding thread (might be able to make use our metal work teacher friends :-))

VB,
As Steve mentioned, you often have multiple taps on your welder (I am assuming it's an old wire-wound heavy thing and not switchmode)
Are you sure there's nowhere to change down from 130A?

I use an old large wire wound welder and weld RHS quite often. To begin with I blew holes in stuff ALL the time!
The stuff I have available is no where near 3mm wall thickness either.

Regarding your worry about not welding the inside, a bead on the outside will penetrate 3mm with ease, so welding both sides would be superfluous.
Welding on 3 sides will be absolutely plenty, depending on the stress directions 2 sides imho is plenty sometimes.

So practise, practise, practise...
Don't let it get too hot, so stop often
Use the smallest rods you can.
Practise the angle for your weld, this will throw the material from the rod, and not throw material off your work.

Hope this helps.

veggie boy

KP - goes down to 50 - but at low amps seems to be pretty hit and miss. Have done most of my welding at higher amps so will have a play a bit more at lower amps sometime, but is not really an issue for what I need to do here. Since I have 3mm stuff that is gettign in the way all the time (is 7 mteres long - so sits across most of the length of the shed and is at the front just behing roller doors) then I may as well use it. My bigger issue will be getting enough heat into the work once it gets bigger (ie I have put a lot of it together). I generally leave the work out in the sun before attempting this - and that helps a bit. Then I just crank up the welder and go for it. Welds will generally be a little less pretty at that point - but I will probably get them to hold okay.

veggie boy

Hey Steve - you used your Tig for anything but the plasma cutter yet?

KudaPucat

My driveway where I am putting my growbeds is not flat or level.
So each leg of my stand will need to be a different length, and the angle between leg and concrete driveway is different.

Any ideas for making these easily? I was thinking some kind of adjustable feet, so they can sit evenly on the concrete.

As for getting the right height I'll weld the frames off site, and then add the legs when they're in position and cut the tops off after. It's the swivel feet I'm concerned about, as I'm worried about the contact area between foot and concrete.

I think I'm rambling... did that make sense?

RupertofOZ

Probably too expensive to buy... but maybe you could duplicate something like these Kuda... even has measurements :wink:

http://www.blythenterprises.com.au/adjustable_feet.htm

KudaPucat

Roz...
Seems I didn't explain myself... I can fix vertical height, by cutting after I weld.
My issue is with the contact between ground and leg. The simplest design, is to cut the leg on an angle. But because all the angles are different I don't want to do this, it'll be too hard.

So I want a pivoting foot. like a separate foot with a connecting pin.
I'm looking for a simple yet easy to implement design.
I can make them, just scared I'll make it too fancy or complicated and it'll cost me time and may not function as required. :-)

RupertofOZ

Gotcha Kuda... maybe something like those in the link but with a ball and cup type coupling??

Edited :

Have another look at the link Kuda.... they do have a swivelling ball joint on the bottom connecting into the pad.... :wink:

KudaPucat

Yeah, that's like something I'd try and do... Trying for less complex, and easier to manufacture from scrap.

TimC

I suppose this is a good place to show off these....

Me, NicholasC and JeffJ made 6 of these up last monday.....

They are made out of 40x40x2.5mm Dual Galv Steel. They were designed to support a fair bit of weight.

All the pieces were cut first and the edges ground to improve welding. We estimated each stand represents three man hours of work.

Welding was done using a regular gas assisted mIG welder. It took about 25 mins to weld up. All edges were welded except for the top edges on the cross braces. After welding we grinded them all back and painted on some cold-gal to protect from rust.

Not bad for a days work.... And yes, they are all perfectly level....

RupertofOZ

Nice work lads

veggie boy

Are any of you using gravel in your beds. If so - I'll be interested to see if you have enough cross braces to support the bottom of the bed and elimate sagging.

A professional welding aquaintance encouraged me to do bracing also from bottom of legs to top of legs - if you know what I mean. On my first stand I only did one brace on each side, but it was when he saw this that he suggested that I should do 2 - thereby forming an X on each side.

veggie boy

Thsi might explain what I mean http://www.backyardaquaponics.com/forum ... 270#101270

TimC

The outside edges of the stands are 5cm in from all sides of the the GB so it gives extra support there...

I hope to have Hydroton in my system... If not I built them strong enough to support gravel...

KudaPucat

Small bracing bands would be useful if legs were high. I'm not worried as I only have 300mm long legs max, and 0mm at the other end.
But I may do it. It wont get in the way, and would be suitably over-engineered to my liking :-)
The reason your engineer suggested a cross formation, rather than diagonal, is because your legs aren't joined at the bottom.
using the tube you have is definitely over--engineered, as they are not required for compression, only tension.

I currently have a treated pine stand. it has a bottom support every 650mm or so. My bed does not sag.

As for the feet I have currently designed, they look like this.
Anybody got a better, easier design? less cutting etc?

TimC

I would just use those rubber/firm plastic feet that plug into the metal tubing. I am sure you can cut or mold them the get the right angle.

I am just concerned that you have a lot of weight resting on the one bolt...

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Welding Growbed Stands

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