Welding Tips and Tricks

Hello all,

I've been browsing this site for a while now, and you've all convinced me I need a new welder if I'm going to take this seriously!

I'm a hobbyist, so have a need to weld any thickness material without spending any money! My current welder is a cheap Chinese 75A inverter (I think it's probably a lot lower than this). I'm struggling to put a fillet weld on 10mm steel - I end up with a tall thin bead close that doesn't do much to join the metal. I suspect this is because the heat is being dissipated quicker than the welder can heat it up. If I go slow enough to get heat in, I end up with a big mess of slag inclusions. My attempt to TIG the tall bead to make it look prettier barely created a puddle!

New welders seem to state a thickness that they can weld, for instance the "R-TECH 161" welder I'm looking at says "MMA 130A, 35% duty, welds material up to 5mm". Whilst I don't disagree with the 5mm claim, I'm sure it could go infinitely thicker with multi-pass etc.

So, my question: Is there a minimum current that you'd suggest aiming for in a low cost welder? I can spend time doing multi-passes etc, but I need the welder to be powerful enough to create a good root weld in the first place. Is there a rule of thumb for a particular current that'll be high enough to create a decent puddle in any thickness of material (even if the penetration is poor?)

Thank you for putting up with the long winded question!

To stick-weld (MMA) with 1/8 (3,2mm) 7018, I'd look for 60% duty or better at 120A DC. This will allow you to weld 1/4" (7mm) in a single pass stringer, and somewhat heavier with a slight weave. You can also weld to 1/2" (13mm) or more in a multi-pass weld without cold-lap, and even thicker with pre-heating.

For DC TIG, these same numbers will work, but you'll find you'll wish for higher for better control of the puddle, especially at the start of a weld.

This is one man's opinion; I'm sure others will follow.

Keeping these ideas in mind, you should be able to find a new machine with both functions in these ranges for $800-1000, and a step up in features and power around $1200, but these will be imports like Everlast and ATP (both of which offer good warranty and customer service, if the reviews here are any indication).

You can get more power in the used market, with better known names, in the same price range if you watch craigslist.

AKWeldshop and Werkspace can probably coach you on what to look for.

Steve S

Welcome to the forum.

Are you aiming for both mma and tig?
What materials do you want to weld?

I assume you are from the UK since mentioning R-tech, which is good for members to know before talking about machines not available in europe.

30 amps / mm is a good rule of thumb for DC tig.

Thanks for the replies & welcome.

Now you mention it, 35% duty does seem a little low. On the other hand I'm not doing it for a paid job so it's less of a problem for me to sit around (drink tea) for 6.5 minutes whilst it cools down.

Yes, I'm in the UK. From what I can tell here 130A is about the "knee of the curve" for welders, because most power sockets are single phase 13A/240V. Any more than this and the machines are aimed at industrial use, eg 16A/32A or 3 phase. There's therefore a big jump in cost at this point too.

I currently weld mild/stainless steel (TIG 0.5mm sheet up to about ARC on 10mm plate). I'd like to weld aluminium too. I generally only use TIG on the thinner stuff, however that particular welder claims 160A for TIG, 130A for MMA I'm not sure what the difference is (a little in reserve for the "arc force" feature perhaps)? If this is correct, I'd be better placed to TIG the thick steel than ARC, which I didn't expect.

Thank you.

At aproximaely 130 amps you could run 1/8 in 70s2 tig rod all day with no problems. Unless you need alluminum or extreme metal penetration then a machine that maxes out around 200 amps or above is probably a good machine to look into for non production applications. I personally wouldn't consider a machine capable of a 40% or above duty cycle at the amps needed for my average use.

You've convinced me I need to aim higher - I'll be ordering the next model up, 200A TIG and 160A MMA (40% more expensive for 20% more current!).

It'll require installation of 32A sockets in my shed, but I think it'll be worth it.

Thanks for the help.

I think you will find that Rtech 200 amp machine & most other inverter machines around the 200 amp range will run from a 16amp supply without any problem - now if your in the UK that is easy - assuming you have a ring main somewhere near by - that will support 32amps total - or 20 amps at any one location so the simple solution is to make up a short fly lead with 2 * 13amp plugs on & connect them into 1 floating 16amp socket - just put the 2 plugs in a double 13amp socket anywhere on the ring & connect the 16 amp to the welder - just remember if the sockets are not switched then once one is plugged in the other is live that your holding ! sounds kinda redneck but is electrically safe in terms of load - hope this helps - if you do decide on the Rtech maybe you would do a short review as there are very few independent ones around for that brand - mostly only that northern monkey they sponsor on You Tube - not sure if they spec their machines or have them built specifically for them as mostly they appear to be badge engineered Everlast - not sure if that's a good thing or not - warranty seem solid though so still better than Ebay offerings.

Order placed, should be here Tuesday.

I certainly can put together a short review. I admit I've thought the same thing when looking for info on rtech. The youtube guy seems genuine, but it'd be nice to have a few more opinions. Most of the reviews in forums point to the customer service, and how quickly they sort out any problems - that's all very nice, but I would like to know what the problems were! I'm a sophisticated southerner, so I'll probably write about it rather than make a tit of myself on youtube

I like your thinking on the plugs. It'd be especially handy for if/when I need to travel with it.