What to buy or just upgrade my SIP

[Montreal]

Hello. This is my 1st proper post. I have a few old cars and need to do some fabrication and body work/chassis repairs. I've had a SIP mig for years and it's always been rubbish! I was just going to sell it and get a TIG. I'm on a budget and I'm also not sure if I really need to go to TIG. I just like the way the welds look mainly.
The 1st project I've got to do is a Mercedes G wagon engine swap and the steel is may 2 mm that needs to be welded to a cast iron manifold. There's also some aluminium intercooler to make up. Next big job is an old Merc that will need some thick chassis underneath and new floors. Do I just upgrade the SIP and try to weld the Aluminium and weld thick 3-4mm chassis plate as well? This will cost me about £30 (not doing the transformer mod) I don't want to spend £500-£600 for an AC/DC TIG right now as I have a big garage(small house) to fix up 1st. I initially thought I'd get an all-rounder AC/DC TIG as they also have Arc MMA for the ticker rings. I've now just seen Parweld XTi 160 Inverter Arc Welder for £280 including a TIG kit but it's still £280 but not AC for Ali. I could go to £280 and get into TIG. What should I do?

 

[daleyd]

I'd prioritise what you need it to do. If you are looking to do mostly bodywork/thinner stuff then to my mind you would be best served with a mig. If you want to do mostly ally then an Ac inverter would be choice.

If it's not needed to look pretty could you not get a decent mig and set it up for ally?

I've got an rtech 3 in 1 and that suits my needs as it's got stick mig and a lift tig function. It's not Ac but I don't need that particular function as I don't do much ally, and what I do can be done with the mig.

 

[Montreal]

I think you hit the nail.... I could just keep the Sip mig for Ally only. I think I need a Teflon liner? If the mig worked well with thin and tick stuff I'd keep it but I don't want to be swapping between liners/rollers.
I'd like all you thoughts on whether to go for TIG/ARC or will a full working SipMig be good enough? It's never been better than old style gas welding since I've had it
D

 

[daleyd]

Modern inverters have some features which make them a bit nicer to use, the older transformer based machines don't have any mod cons but at the end of the day they can produce decent welds, it's more to do with the person on the end of the torch.

Unfortunately I think of you ask 3 different people on here you would get 3 different answers, only you know what you are going to use it for and what you are willing to spend.

You could keep the sip and upgrade it for not much money for thinner bodywork stuff and search out a secondhand Ac/dc set for ally and for stick welding - that would cover all bases surely? What you are asking for is something to do everything from thin bodywork to thicker steel and aluminium as well - you would struggle to do all that with just one machine unless you had a biggish mig and were willing to mig the aluminium.

 

[zzr1200]

Your'll be lucky to find a 240 volt AC/DC Tig Unit for 600 quid, unless its a "For Spares or Repairs",


a working unit may come up now and again, but not very often...

 

[Montreal]

Just thought I'd update y'all on my welding progress. I found a used R-Tech TIG160 DC only machine for a good price. It still has 18 months warranty and saved me a lot of cash. The machine is perfect (my welding is not).
Managed to sunburn my face by being an idiot and trying it out on the 1st day without my new helmet and wearing really dark sunglasses. Anyway the skins grown back now and quite soft (must moisturise more often).....
Seriously good thing. Need to master the dips' and tried out pulse on a real house repair job on some thin picture hanging wires. Worked great. Got it including bug BOC X bottle, 2kg of filler wire, 20 tungsten, shrouds, regulator for .... £260.
I've also put some time into my SIP Handymig. It has never worked so well and I spent about 4 hours practising (with helmet on). Did the wire feed brace mod, New steel liner, New swan neck, shroud and tips. I'm using the small wire rolls for now and desire what it says inside the machine about 'feed wire from bottom' I feed it fem the top and it's better. It won't slip when you hold it back at the torch as I can't decrease the tension on the screw anymore but its fine. Once the speed is fine tuned it burns really well. The thermal overload comes on a bit too quick on full 90Amp (puny) power and takes about 15-20 mins to turn off before I can weld again. Duty cycle is crap @ 15% on full 90A.
I've moored it further by fitting a fan inside the case! I think the larger ones must have a fan already. Mines from a Kingavon fan heater. Very simple. Just had to cut the ali blades down to fit in the case. Its rigged to run when plugged in regardless of if the on/off switch is on. I did this incase the machine needs to be disconnected from the supply to cool during overload lock-down. It allows it cool quickly I think plus it shouldn't get as warm inside. Ideally I want o by-pass the overload circuit but not sure it could/should be done. So all welding may now commence..... Got aluminium Mig set up on the way next ......

 

[Wallace]

Leave the thermal trip it will save the transformer from burning out and the machine will be worthless. If you are regularly exceeding the duty cycle it's time for a bigger machine!

 

[PTvor]

The thermal overload comes on a bit too quick on full 90Amp (puny) power and takes about 15-20 mins to turn off before I can weld again. Duty cycle is crap @ 15% on full 90A.

Almost all hobby migs are really intended for car body work and other light use and have appalling duty cycles at their top end. Very often if it's a 150A MIG, the maximum current they quote at is substantially below the max, say 120A because the duty at the max setting is pitiful. Inverter MIGs usually do a lot better.

Bypassing the thermal cut out is asking to damage the machine. If you want to do a lot of MIG work at 90A and over, sell that and get a more capable MIG welder.

 

[Montreal]

Ok noted. I'll leave alone. I must add that it works for a lot longer on full power with my fan upgrade. Well worth doing and it now works excellently.D