GET YOUR WELD ON

AD­VICE TO SET UP YOUR OWN WELD­ING STA­TION AT HOME

NZ Performance Car - - Contents - WORDS: JADEN MARTIN PHO­TOS: NZPC AR­CHIVES

Stack­ing dimes, lay­ing weaves, and drop­ping that sweet, sweet weld porn isn’t the kind of thing you’re go­ing to learn with a five minute Google ses­sion and a cou­ple of YouTube ‘how to’ videos — but hav­ing the right equip­ment be­hind you when learn­ing to do such rad­ness is al­ways go­ing to help. It’s that clas­sic case of be­ing pre­pared for the task you’re tack­ling, and with weld­ing, be it MIG or TIG, there’s a bit more that goes into it than what some peo­ple re­al­ize — what am­per­age ma­chine is best, filler rod se­lec­tion, how tung­sten treat­ments work, why cheaper isn’t al­ways bet­ter with hel­mets, and much more. Hav­ing gear that isn’t de­signed for your in­tended pur­pose and get­ting the setup side of the equa­tion wrong makes for guar­an­teed bird-shit re­sults — the kind of stuff your mates rip you on for life — and will end up cost­ing you more in the long run as you re­place your ill-in­formed pur­chases.

So, to make sure you’re in the know when it comes to buy­ing a new ma­chine, and hav­ing all your con­sum­ables and safety gear in check, we wran­gled to­gether the top sup­pli­ers in the busi­ness to lay down the truth and de­bunk any mis­in­for­ma­tion that may be float­ing about on the in­ter­webs. Here’s your com­pre­hen­sive guide to kit­ting out the shed with the right equip­ment, straight from the horse’s mouth — you can thank us later.

Would you rec­om­mend peo­ple start­ing out with MIG or TIG weld­ing if they have never picked up a torch be­fore?

Chris at Weld­ing Tech­nol­ogy told us: “It de­pends on the job at hand. You’d need to take into ac­count what kind of ma­te­rial you’re work­ing with, the thick­ness of that ma­te­rial, whether or not time is a fac­tor, and what kind of fin­ish you de­sire from it. How­ever, gen­er­ally speaking, you’d opt for a TIG when you want a beau­ti­ful fin­ish, and a MIG for speed. Both types of weld­ing re­quire prac­tise to mas­ter, but MIG would be the eas­ier of the two as it is more of a ‘point and shoot’ op­tion. Set your wire speed and volt­age, and away you go. Whereas with TIG, you’ve got a lot more set­tings to get right, and also feed­ing a rod with one hand and a torch in the other.”

How im­por­tant is it to con­sider duty cy­cle when look­ing to buy a ma­chine?

“Duty cy­cle is fairly im­por­tant when it comes to se­lect­ing a ma­chine — it’s a rat­ing re­gard­ing what the ma­chine can han­dle at its peak use. Mea­sured over 10 min­utes, duty cy­cle in­di­cates the per­cent­age of time for which it can run at peak be­fore re­quir­ing a cool-down pe­riod. For ex­am­ple, if a ma­chine has a 40-per-cent duty cy­cle at 200 amps, you’d get four min­utes of straight weld­ing be­fore the ma­chine re­quired a six minute cool down.

“But most of the time you aren’t go­ing to be run­ning at that peak 200 amps or what­ever your ma­chine may be ca­pa­ble of, and if you’re run­ning a lower am­per­age, you can gen­er­ally weld all day long with it — the per­son at home will prob­a­bly never hit duty cy­cle un­less it’s a re­ally ba­sic ma­chine for what they’re us­ing it for. All our ma­chines are duty-cy­cle rated independently to meet New Zealand and Aus­tralian stan­dards.”

Do I need to pur­chase a foot pedal with a TIG, or will the torch but­ton work in all sit­u­a­tions?

“You can get away with us­ing just the torch but­ton most of the time these days, as newer ma­chines will have a pulse set­ting that fluc­tu­ates the am­per­age, mim­ick­ing the way you would with a foot pedal. How­ever, if you can have one, it is rec­om­mended for to­tal con­trol over your weld, es­pe­cially when it comes to weld­ing al­loy where you’re go­ing to re­quire quite a few amps to break through, and then, as the ma­te­rial gets hot, back off — that foot pedal al­lows you to do it im­me­di­atly, and pump the heat as you go. Nat­u­rally, hav­ing more con­trol over what you’re do­ing, you’re go­ing to end up with a neater fin­ish and make the job a bit eas­ier.”

Should I be us­ing a stan­dard col­lett body or gas lens on my TIG torch?

“Well, a lens sim­ply changes the way the gas is emit­ted. Imag­ine a torch with­out the stan­dard col­let body; the gas comes out, swirling un­con­trolled, whereas a gas lens breathes it out through gauze to con­trol the flow and di­rec­tion to en­sure proper shield­ing.

“A larger lense pro­vides bet­ter gas cov­er­age and you’re able to pull the tung­sten out fur­ther, giv­ing a cleaner weld, as any con­tam­i­na­tion is blocked from en­ter­ing the process. It also makes for that rain­bow fin­ish on the weld that peo­ple like. The rea­son you are able to get smaller cups is down to fit­ting the torch into tighter spaces when weld­ing, as the large cups sim­ply can­not reach some ar­eas, and er­gonom­i­cally, a smaller torch is go­ing to feel bet­ter in the hand.”

If my shed has only sin­gle-phase power, will this limit the size of welder I can run, and there­fore the ma­te­rial I can weld?

Gra­ham from Weld­ing Di­rect says: “Yes, a sin­gle-phase power source is go­ing to limit what ma­chine you can run and there­fore the size of the metal you can weld, de­pend­ing on what ma­te­rial it is. It’s all about power in and out — if you can’t get the power in, then you aren’t go­ing to get it out — mean­ing that you’re lim­ited re­gard­ing what thick­ness you can pen­e­trate. “Sin­gle-phase for steel is go­ing to tap out around the 6–7mm-thick mark un­less you have a ma­chine in the higher am­per­age range, but to fully uti­lize its ca­pac­ity, the power sup­ply will need up­grad­ing — this, like in­stalling three-phase power, can be ex­pen­sive. How­ever, most ve­hi­cle-re­lated ma­te­rial isn’t go­ing to be thicker than that, so sin­gle-phase will be fine. The shed at home doesn’t need to have three-phase power; that’s more for industrial pur­poses where you’re look­ing to weld 10mm and thicker. Al­though, if you have the op­tion there you can al­ways use a three-phase ma­chine to weld thin­ner. “While most panel beat­ers and those re­pair­ing ve­hi­cles will only need a sin­gle-phase op­tion, some­thing you need to con­sider is in­verter ver­sus trans­former ma­chines. There’s a mis­con­cep­tion that you should have an in­verter over a trans­former, but this isn’t true, as there are ben­e­fits to both types. The in­verter style is more mod­ern, more ad­justable, and pre­cise in the set­tings com­pared to a trans­former, which is step-con­trolled with switches, and doesn’t have the same amount of con­trol. How­ever, the ad­van­tage to a trans­former type is that it is much more ro­bust and will last almost a life­time, whereas in­verter types have a shorter life­span.”

When I’m look­ing to pur­chase a weld­ing hel­met, is it a case of the more ex­pen­sive, the bet­ter pro­tec­tion it will give?

“In this in­stance, the gen­eral an­swer is ‘yes’, most of the time the more you pay, the bet­ter qual­ity hel­met you’re go­ing to get. Pricier hel­mets tend to give your eyes more pro­tec­tion. In the old days, if you wanted it to be darker or lighter, you’d need to change the lens it­self — flip­ping the hel­met up for nat­u­ral light, and flip­ping it back down for a sin­gle-shader op­tion — but mod­ern hel­mets are dig­i­tal and au­to­matic. These are able to be set to a pre­de­ter­mined dark­ness that changes from light to dark as soon as the arc strikes. This gives you con­trol over what you’re do­ing with bet­ter vi­sion, while re­main­ing pro­tected. Where the dif­fer­ence in price comes in is the level of ad­justa­bil­ity you have, and the speed at which it can act. “The cheaper op­tions will gen­er­ally have fewer sen­sors and be slower to re­act. In­stead of dark­en­ing at 1/10000th of a sec­ond, it re­acts at 1/30000th of a sec­ond — when it comes to pro­tect­ing your eyes, mul­ti­ple ex­po­sure can add up. “And take TIG weld­ing, for ex­am­ple: you need more vari­a­tion in the shade be­cause the am­per­age is dif­fer­ent to MIG or stick weld­ing. We rec­om­mend a bet­ter qual­ity for TIG, whereas you can get away with a cheaper op­tion for MIG.”

With so many TIG filler rods avail­able, how do I se­lect the type of rod to use, and will I need to have all types on hand to cover my bases?

“For those TIG weld­ing in the shed at a low-vol­ume level, you can def­i­nitely get away with a few key filler rods for dif­fer­ent ma­te­ri­als. A lot of TIG weld­ing is seen in al­loy ap­pli­ca­tions, and you can gen­er­ally man­age with a good grade of ma­rine 5356 al­loy filler rod, which will also weld lower grades of al­loy ma­te­rial, so you don’t need a big range of al­loy rods. “As for steel rods, they’ve very cheap as it is, so you can af­ford to have a few dif­fer­ent types on hand. But again, you re­ally only carry a big range when you’re look­ing to TIG more spe­cial­ist ma­te­ri­als. We gen­er­ally rec­om­mended a ma­rine-grade 316 for stain­less steel. For mod­ern cars, the car man­u­fac­tur­ing in­dus­try is start­ing to use a lot more sil­i­cone bronze ma­te­rial in their con­struc­tion, so a sil­i­cone bronze filler rod is also handy.

And how does the colour-cod­ing sys­tem for tung­stens work?

“Tung­sten is used as the TIG elec­trode to pass the cur­rent (as an arc) as it has the high­est melt­ing tem­per­a­ture among pure met­als, at roughly 3,400-de­grees cel­sius. That means that the elec­trode isn’t con­sumed dur­ing weld­ing, and while in the past, pure tung­sten was the only choice, a num­ber of tung­sten have been stan­dard­ized and form the colour-coded sys­tem for iden­ti­fi­ca­tion. “Pure tung­sten elec­trodes are gen­eral pur­pose and low cost, and are only used for AC weld­ing — they’re coded with green. Ce­ri­ated (CeO2, 1.8 to 2.2 per cent) tung­sten per­form best in DC weld­ing at low-cur­rent set­tings, but can be used pro­fi­ciently in AC to im­prove arc sta­bil­ity, start­ing while de­creas­ing burn-off — they’re coded with grey. Lan­thanated (La2O3, 1.3 to 1.7 per cent) tung­sten has a sim­i­lar ef­fect to ce­ri­ated op­tions and main­tains a sharp­ened point well, which is an ad­van­tage for weld­ing steel and stain­less steel on DC — they are coded gold, black, and blue. Tho­ri­ated (ThO2, 1.7 to 2.2 per cent) tung­sten is eas­ier arc start­ing with higher cur­rent ca­pac­ity and greater arc sta­bil­ity; how­ever, it is ra­di­ated and makes in­hala­tion a health risk — these are be­ing phased out in favour of other op­tions, and are coded with red and yel­low. Lastly, zir­co­ni­ated (ZrO2, 0.15 to 0.40 per­cent) tung­sten is ideal for AC weld­ing as it re­tains a balled tip and has a high re­sis­tance to con­tam­i­na­tion, but should not be used for DC weld­ing — they are coded with brown.” “It’s about se­lect­ing the right tung­sten for the ma­te­rial, size, and thick­ness be­ing used, and some re­search is re­quired for this.”

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