Thread: Like a hole burning through my retirement funds. Stick welder question.

Dear Forum.,

I'm a retired engineer, who needs to build a trade trailer for my grand son.

I have attached a JPG image of the design.

As you can see there is approx 32 welds, and there are three frames. Approx 96 welds.

I was hoping someone out there could point me in the right general direction.

The material has to be 1.6mm Galvanised SQUARE RHS Steel as its lighter, and budget blows out with anything thicker.

COuld someone comment if I am going down the right track.

1. WELDER OPTION

• The welding machine applies the two-transistor single-ended forward converter inversion technique. The switching tube applies IGBT (insulated Gate Bipolar Transistor). The whole machine produces high working frequency. With its advanced design concept, reasonable construction, lightweight, ease of use, portability, elegant appearance, easy ARC forming, good welding features, beautiful welding seam, optimum handling, strong resistance against mains voltage fluctuation, this machine can be applied for welding anywhere and is your first choice of modern welding tool.
• input power voltage (V) : AC240V±10% 1 ph 50/60HZ
• Rated input current(A) : 22A
• NO-load voltage(V) : 80
• Output voltage(V) : 22V
• Output current range(A) : 5-120
• Protection class : IP21
• Efficiency(%) : 85
• Rated Duty cycle(%) : 120A@20%,50A@100%
• No-load power(W) : 30
• Power factor cos : 0.93
• Arc Current: 5A-120A
• Pulse Frequency: 60HZ
• Pilot Arc Current: 30A
• ARC welder: inverter
• MMA welding machine: dc

OR
Rossi Arc200 DC Inverter Welder

• 240V 50Hz (15A Plug)
• No-Load Voltage 72V
• Output Current Range 5-200 Amps
• Efficiency 85%
• IP21 protection class
• Duty Cycle 35% @ 200A / 60% @ 160A / 100% @ 120A
• No-load Power 40W
• Power Factor COS 0.93
• Generator Recommended 5.5kVA

2. STICK OPTION
I was hoping to use CIG Satincraft 2.0mm or BOSS GEMINI 12 WELDING 2mm ELECTRODES

Considering Im a novice, but loads of time to perfect techniques (which I hope to do eventually)

MY QUESTIONS

How does the no load power effect decision to buy a welder, expecially for 1.6mm Galv square
Can these welders be DC electrode set on positive current ) As from forum post here
Do I require a particular stick for a particular metal, and where would I find the chart?
Is there a good chart, which matches stick welder to material?
Whats would be the optimum distance between the two square joints?

Thanks in advance.
Long time reader
Joe Runner Snr.

A couple of suggestions - post your trailer design here:
TRAILERS & OTHER FABRICATED STUFF

That's where the DIY trailer people live, including experts who know VSB1 backwards (the Federal rules regarding trailer design). They'll help ensure you build the most functional trailer in the most practical manner that'll ultimately pass inspection.

Secondly, 1.6mm section with stick is brave, particularly if you're a beginner welder. I'd be burning a kilo or five of rods practising on thicker material before venturing into that territory. With stick, there is no definitive "lookup table" for amps, you go by the range suggested on the packet, and only through experience by practice, trial and error do you learn how hot you need to run.

Thirdly, if you're considering Satincraft, look at Kobelco RB26 rods - similar results at lower cost.

Finally, the only small inverter I'd recommend is the BOC Smootharc 130 - it has a very solid rep. There may be other capable machines, but I haven't seen anything remotely close to the number of endorsements this machine has received.

Hi Joe,

Have a read of some of the threads I've started. I also do a lot of work with 1.6mm and 2.0mm section, also with a stick welder. E.g.:

http://www.woodworkforums.com/f160/p...i-rods-124022/
http://www.woodworkforums.com/f160/a...chines-134757/

and a few others.

It's a steep learning curve for sure. Not easy, this thin stuff. I've standardised now on those Kobe RB26 rods that Rusty mentioned. Same welder too.

You could read and learn for a week off this forum, there's lots of information if you search. Things that have helped me include:

- a Miller auto helmet. Expensive but worth every cent. Works outdoors too.
- learning that I should use a scratch pad clamped near my welds.
- practice, practice, practice.
- doing everything in the flat position if possible.
- how important fitting is, particularly with this thin stuff.
- experimenting with DCEN and DCEP.
- that I should use a fan.
- to use my ears.
- to pay attention to angles and the effects of gravity.
- how different rod types and brands (even of the same type) behave.
- etc, etc.

I'd also ask on the trailer forum about design - not sure if the 1.6mm material is up to the job of a trailer frame. Certainly not for the drawbar and main rails anyway. There are some pros on that forum, they'll help you out.

As to the welder, no way will you need 200A. My Smootharc happily runs 3.2mm rods, but I rarely use them anyway. Most of my welding is done between 40-80A. It's only the occasional heavy jobs where I go above 100A. Having a 10A plug is handy too.

Duty cycle is important, but less so with lots of small welds (unless everything's fitted up perfectly and you're really quick). The Smootharc has good specs and welds well.