Help butt welding frame for coffee cart - 30x30x3mm RHS

Hi All,

I am very much a novice welder but love getting my hands dirty.

1. I am making a coffee cart that utilises 30x30x3mm painted RHS as the frame.
2. The cart will be 1200w x 700m D x 900m H
3. It will be skinned in Plywood
4. It will have castor wheels
5. I will be using Gasless MIG for the process.
6. I have cut the RHS for Butt joints.

I am wondering how to best weld the joints where the curve on the edge of the tube is. I am thinking it will be a multiple pass process. Put the first weld into the bottom of the joint then run a second pass over the top. Or is it ok just to use the first pass?

I have looked around for examples but they are hard to find. Is there a particular name for the joint that I should be searching for - that might help me find more info.

Single pass is more than sufficient. Have a practice on some scrap beforehand to get the settings right before you do the actual cart.

Many types of E71T-11 self shielded flux core 'gasless' wire is single pass only...
So if you crack a weld on a trolley carrying a $10K coffee machine/generator/battery-inverter setup, don't say we didn't warn ya!

You say it is a coffee cart that is going to be skinned in plywood.

Don't weld those open curved surfaces if they will be covered.
It is a coffee cart and will carry bugger all. Too many newbies are convinced all joints need to be fully welded,ground and then polished.

It comes under "fitness for purpose".
Sure! Fully weld maybe if its a support gantry for an Apollo rocket launch pad. However more weld deposit than necessary does NOT equate with the strongest possible joint on every occasion.

Some easy layed fillet beads across the 90 degree corners will carry far more weight than your cart will ever be required to support.

As a new welder trying to bridge an open gap such as those radiused edges will bring you grief in the form of slag holes , burn through and heat distortion of the frame. The screw up fairy is waiting ready to pounce.

If there are joints open to view and they have to look good under paint , then fill this problem gap with plastibond or builders bog and sand off.

Good luck with your project.

Grahame

Skinning it with plywood will also add a lot of strength.
Save yourself some grinding by not welding any joints on the outside where the plywood is going on for this job.

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Quote:

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Originally Posted by mote

1. I will be using Gasless MIG for the process.
2. I have cut the RHS for Butt joints.

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What weld sequence shall you use to avoid distortion ?

The frame will need to be square so that all four castor wheels will touch the ground at once.

Grahame

On a light frame like this the concrete is usually my square up, lol.
Anything heavier I'll tack braces it to save distortion.

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Bevel the edges to save some post weld grinding. You also don’t need 3mm wall. 1.6 is plenty, and quite a bit cheaper as well as lighter. As already mentioned, get your hand in on the off cuts first. Single pass weld.
I build furniture to order, I use a TIG almost exclusively now for these types of jobs, and I mitre the joints. I have a rabid dislike of seeing open box section on the corners of a frame, just doesn’t look particularly pro to me, regardless of whether it’s covered or not.

Quote:

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Originally Posted by racingtadpole

I have a rabid dislike of seeing open box section on the corners of a frame, just doesn’t look particularly pro to me, regardless of whether it’s covered or not.

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Oh come on tadpole. That's what those black plastic push-on endcaps are for!

[emoji16]

Simon

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Quote:

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Originally Posted by simonl

Oh come on tadpole. That's what those black plastic push-on endcaps are for!

[emoji16]

Simon

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BAHAHAHAHAHAHAHAHAHAHAHAHA!!!!
That's funny!!
I did use them once on a gate frame for a dog run!!

I have a pathological hatred of tread plate too.. the only place that should be seen is in the floor of a trailer, or on the treads of an industrial stair case in a petrochem plant.

:q

Quote:

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Originally Posted by racingtadpole

I have a pathological hatred of tread plate too.. the only place that should be seen is in the floor of a trailer.

:q

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Sorry, butI hate trailers with treadplate floors. So impractical when you want to shovel out some soil or crushed rock etc.

It's like having a 4x4 with low profile tyres!

They look great to people who don't actually use them!



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Quote:

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Originally Posted by simonl

Sorry, butI hate trailers with treadplate floors. So impractical when you want to shovel out some soil or crushed rock etc.

It's like having a 4x4 with low profile tyres!

They look great to people who don't actually use them!



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If you have a tilt trailer, no shovelling required...:U
Just to clarify, my Amarok has chromed 22” spinners on it... Exactly why does one need a kanga jack, four max tracks, a shovel, two jerrycans and a permanently seized into the tow bar recovery adapter to go to the local shopping centre?

That would more than likely depend on the location of the nearest shopping centre.