Hi please can you advise me with alli welding?

[luckinback]

Hello all

Just introducing myself, I trained as a maintenance welder and fabricator for a year back in 81/82 on a couple of YOP schemes, and attended college to study the FJTP 1 course but didn't complete it due to not being able to get time off. The YOP schemes ended, so I ended up training as an electrician and refrigeration/aircon engineer.

I've worked in factory maintenance over the years and occasionally carried out a few weld repairs on various machinery and equipment using mainly stick, and oxy/acet.

Recently I have decided to get back into welding and small fab jobs, and I'm after some advice in choosing a multi function weld set for around 800 quid. I'm currently watching a Stahlwerk 200 multi set on ebay, but I can't find any feed back regarding them. It has an AC and a DC setting, which is what I'm after just in case any alli work comes up.

I do remember from years ago that alli needs to welded preferably using AC for cleaning out the oxides by making use of the polarity shift. However I do remember welding alli using a mig set, but I'm sure it was just a DC set and worked fine uphill on 6 mm alli sheet, but to be honest I'm not sure because it was 34 years ago. After looking around for an AC mig set, there doesn't seem to be any?

Perhaps someone can advise me and correct me about welding alli, and whether or not it needs AC when using mig.

 

[Tom Orrow L]

You're right that aluminium needs welding with AC when it comes to TIG but MIG welding aluminium is done with DC output using either a spool gun or the combination of a very short torch, special contact tips, Teflon liner and 'U' shaped wire feed rollers.

What stuff are you planning on making with your new set and what would you say is max thickness?

Personally I've never had experience with the stahlwerk but I believe there has been a few threads concerning them. My only issue would be the return cost to Germany should it need a repair.
There is a UK version of Stahlwerk called R-Tech.

Take a look at the Parweld XTI 202, Jasic TIG 200P ACDC or even the Stealth Digi TIG 200. They're all around your budget and are all brilliant choices for anyone doing up to around 5/6MM aluminium.

 

[luckinback]

Hi Tom

Thank's for your reply, I'm just allowing myself a larger scope just in case any alli jobs come up, it will be mainly mild steel, SG, and SS that I'm more likely to be welding. Theses days I'm an electro mechanical engineer that works within catering, refrigeration, laundry, and dry clean equipment. The laundry and catering equipment tends to be stainless as you probably know, however they have some degree of mild steel in their construction and the dry clean more mild steel and cast with a small portion of alli.

I am currently rough drafting some designs for a couple of tool trolleys based around the oxy/acet porta pack, then eventually I'll fabricate them out of 20 & 25 mm conduit. Its an absolute P.I.T.A carting gear to and throw from my van in city centres, and as no one does a decent quality trolley, I've decided to make my own, bespoked on my imagination.

Also as some of my work will involve boilers and stills working up to 5-6 bar, and maybe refrigeration equipment up to 35 bar, requiring a strength test of 1.43 x the highest operating pressure, I'm considering either studying a level 3 welding nvq, or maybe a Lloyds/coding for insurance purposes. By the way do you know if there are any exemptions regarding being insurance approved if you are nvq qualified, or do you have to be coded even if you're qualified like you do with gas work?

Anyway thank's for pointing me in the right direction with other brands of sets, and prompting me regarding the Stahlwerk sets, I had wondered if they were a badged up generic make? I had contacted them regarding if they had a UK agent, and they informed that the set would have to be returned to Germany if they developed a fault, not a straight forward carry on. Although regarding their 5 year warranty, sometimes that can be a sign of confidence from the manufacturer, or a sales pitch for them not being on par with manufacturers that have achieved a pedigree that would offer confidence over the years, that in turn would only offer a years guarantee. I had also considered getting their permission for me to diagnose any faults myself and getting them to send me the parts, but that was just another pipe dream.

As you can tell from the work I'm planning to extend into, I'm going to need a multi function set, and if I decide to take on any work that requires speed and more straight forward welding that needs to be competitively priced , I'll have to seperateley purchase an AC mig set. But for now, I'll have to make do with my oxy/acet, and purchase a combined stick, tig, and plasma set.

 

[Tom Orrow L]

No problems at all mate, coding isn't my forte mate so its probably going to be best that I don't comment on any of that.

The Stahlwerk are indeed rebadged generic sets with back up in Germany, you can send it back to Germany but the cost may be high.

An AC MIG doesn't exist they're all DC but they'll weld aluminium (ali MIG is a PITA)

 

[Richard.]

If your doing any welding work for food, hygiene, catering it's nearly always going to be a none ferritic stainless steel (304,316) and it will have to be done with Tig. Spatter and deep grinding marks won't be up to the standard for hygiene reasons that they collect and hold any foreign bodies which soon generates bacteria.
This is a bus mans holiday for our moderator @Paul. as he produces this sort of work day in day out.
Regarding aluminium this can easily be delt with by buying an ACDC TIG set and this covers you to weld all metals to exceptional standards (with practice).
As Tom said an ac mig isn't a thing afaik and for welding Alu mig it's done in dc+ polarity pure argon shield.
Mig Alu is only a pain if the set up isn't bang on. A spool gun or push pull torch system makes like sooooo much easier but it can be done with out if you spend on all the dedicated kit. U shape rollers, butted up roller guides, Teflon liners, and as short a torch cable as possible. 3mtr is often preferred. You need a good plant too with lots of power and I personally love it with a pulse on mig which gets pricey.
Unless your doing long runs or production work Id say an Acdc Tig is the way to go and lots of people around to help you set it up.

 

[luckinback]

Cheers guys, the last time I welded alli was back in 82, I used a miller, I can't remember the model. It was a tipper truck that came in that had an alli tipper with a few splits in it, my old gaffer tried to weld it up several times using tig, but the filler rods weren't compatible with the alloy blend of the alli and the joint just pulled apart when it cooled. But the tig set using smaller wire in spray mode and applying a triple pass made light work of it and the joints held, they were a bit on the runny side but never the less they were strong. I can't remember if a spool gun was used or not.

Once I decide which set to purchase, I'm going to spend about 100 quid on mild steel SS, and alli sheet of various gauges and get them cut into 75 mm x 150 mm strips to practice flat, vertical, and horizontal over head welds.

In the meantime I'll keep the thread updated with my progress.

Thank's again.