A DIY Plasma-Cutting TIG Welder?

[Cursitor Doom]

Hi all,

I'm seriously considering building a plasma cutter following the thread on same here of a few days ago concerning heavy metal cutting.

However, I like to get as much value out of anything I build as I can, either by making it multi-purpose from the outset, or else designing-in repurposability from scratch to enable straightforward modification at some future time into something else.

So it is with a plasma cutter. If I build one, I may as well construct it in such a way that a few simple mods will enable it to function as a TiG welder as well - two useful gadgets for little over the price of one IOW. After all, the two products do require many very similar constituent parts which could be shared between them.

Are there any possible drawbacks or pitfalls I may have overlooked, though? During hot, humid weather I tend to lose the plot a bit so thought it best to run the idea past the Panel to be on the safe side.

Any observations?

cheers, cd.

[Dave Plowman (News)]

My guess is a plasma cutter man enough to deal with RSJs would need a serious mains supply.

[JimK]

How thick are you aiming to cut? And what will you power it with?

Jim K

[Brian Gaff]

Yes indeed to maintain a plasma some quite serious current is needed as I recall from my school daze. Brian

[F Murtz]

You can buy combination welder plasma now.

[John Rumm]

Significant, yes, but typically less than required for most welding applications. Note also that the current is at a low voltage.

[Cursitor Doom]

Yes, seems to be a *lot* less than MMA at least. Sealey are advertising a handful of such products that run off domestic 230V mains sockets; the meatiest one is only 40A and claims to be able to cut up to 12mm. Can't find any open circuit voltage quoted among the specs, though. Would have been helpful to know.

[Cursitor Doom]

I shall be aiming for 12mm minimum pref. 15mm. The er, "PSU" is already sorted. I'll be using my dual-phase Oxford oil-cooled arc welder (1973 vintage). Running in single phase mode off a 32A trip in the garage CU, it's able to output about 200A at 80V OCV. Should be sufficient. :-)

[Cursitor Doom]

Yes, but where's the fun and challenge in buying one off the shelf?

[The Other Mike]

a) it works b) you won't spend months / years pissing about trying to make your own half assed contraption to work c) you won't spend months / years with heap of semi assembled bit of kit that occupies workshop space, does SFA and that stops you doing something far more interesting d) you can use it to build something else far more interesting with it e) it's way cheaper in the long run f) time to piss about doing things in the workshop is limited g) there is a g but I can't be arsed to write any more

[newshound]

I'm inclined to agree. But this is a DIY newsgroup and I think about far more projects than I will ever undertake.

[Cursitor Doom]

You might be right, but goofing around with electronics is a very long-standing hobby of mine, so I come from a very different perspective.

[The Other Mike]

Unlikely, just you haven't got to the point where you realise what a waste of time, effort and money some DIY / homebrew exercises really are :)

[Dave Plowman (News)]

Yes. With some things, it can be cost effective to build them yourself. Or to get one to your spec which isn't available commercially. And I'd say in this case you'd be lucky to end up with one as good in every way as a bought one - and maybe pay more too.

[meow2222]

Some are some arent. A great many are now, but there's still some room for 1 offs.

NT

[Cursitor Doom]

THis is part of an overarching experiment to see that if I get better over time in evaluating which projects are worth taking on and which aren't, and whether the ones I decide to take on gradually become completed better quality-wise and also more speedily. I would imagine it's like anything else; the more you practice the quicker and better you become.

[Cursitor Doom]

One thing in my favour is there won't be any cheap CHinese components in this, it won't be made to a price and I shall de-rate heavily all the bits that operating at the sharp end with the expectation that the finished item should prove less likely to go "phut!" after a short time working. Ive not nothing esle to do at my time of life than paint the house and I'd sooner be goofing around with my projects. Esp. in this heat!