Questions on choosing a plasma machine

[GrahamGKD]

I'm tentatively thinking of investing in a plasma cutter. I havent used one before and know very little about them. If I buy an older 'industrial quality' machine, e.g. off ebay, do I need to worry about availability of consumables? Is there any standardisation of consumables at all - like the eurotorch offers for MIG torches?

Do I need some kind of drying system on my compressor to use it with a plasma?

If I ditched the plan to buy a second hand industrial machine in favour of a more modern inverter, does the inverter offer any advantages over and above a transformer machine apart from reduced size/weight and increased effiiency?

Anything else I should bear in mind please?

Cheers,
Graham.

 

[wyn]

What sort of material/thickness will you be looking at cutting, Graham.

Will you be running it off 415v or 240v ?

 

[GrahamGKD]

Sorry, should have said, single phase only but I have 16 and 32A sockets. I guess I would want something fairly heavy, e.g. to cut 10mm clean on steel, to give me plenty of options for the future. I don't really want to settle for something small and then find it is not man enough and need to upgrade.
Graham.

 

[astro_al]

Hi Graham.

Most manufacturers use their own torches, although there is some crossover with smaller plasmas, some of which share 'Traffimet' torches (small red plastic ones). Basically, you buy consumables for your machine specifically. You can either go for 'genuine ones' (more expensive, but generally last significantly longer) or cheaper Chinese knockoffs - people swear by each approach, so you need to choose for yourself.

There is no mig-equivalent 'euro-fitting' or anything like that.

Dry air is a real boost to plasma cutting. Its not absolutely necessary if you drain your compressor regularly, but you'll get better cutting with drier air. You can buy air driers, or cobble together your own - copper pipes through old fridges, metal piping with drain valves, google: 'franzinator' etc.

Start out looking at Hypertherm, they are the best.

Al.

 

[GrahamGKD]

Thanks for the advice. Hypertherm certainly seem to be expensive for new machines - I will have to see how much they go for second hand. I haven’t really fixed a budget yet but I was thinking more in hundreds rather than thousands!

One of the things I was wary of was buying an older machine and then having problems getting consumables because of obsolescence.

I guess I'll get hold of a cutter first and then think about fixing up some kind of air dryer. I’m also keeping an eye out thinking to upgrade my compressor to a Hydrovane.

Cheers,
Graham.

 

[shenion]

Most plasma cutters have a reg/water trap already. So, a dryer is not as critical but it will help. It should at least have a water trap.

Mine has a Tramfet-style torch. Consumables are hard to come by. Took me a while to find out my ProArc was the same as a Snap_on, Lincoiln, Maquette and Century.

Note: the Tramfet-style torches are sensitive to water. I got my machine cheap as the previous owner had to replace the torch head and then it died again. The torch has a telescoping head. I found it was stuck. You need to press down/up to start (some do this internally with backpressure.) Faced with a head that did not move and needed replacement anyway, I whacked it hard on the bench. Worked fine ever since. Probably stuck with corrosion due to water.

Now, SnapOn wants $28 each for the electrodes and tips. Found other suppliers at $10-15/ea. I found HTP sells them for about $5. Work better than the ones that came with the machine.

I think for 10mm clean cut you would want at least 50A. Probably not cheap and the consumables will be harder to find. Lots of 30/40A ones out.

If it has HF start and you can't find consumables, you could probably adapt a Chinese torch. If it is like mine and uses a Tramfet-style torch (contact or backpressure start), a replacement will be expensive.

 

[astro_al]

H2O is bad for all plasmas, as I understand it - affects cut quality and decreases torch consumable life.

I think Shenion means 'Trafimet' not 'Tramfet' if you are busy googling it!

Al.

 

[Robotstar5]

If you have concerns about air quality you could use bottled nitrogen

 

[astro_al]

R*5 - does using nitrogen exacerbate nitriding of the material adjacent to the cut?

(I'm only assuming there is a link due to the term nitriding).

Al.

 

[Robotstar5]

Sorry don't know, just posting what's in the manual - dry air or nitrogen

 

[GrahamGKD]

Have been keeping an eye out on ebay - no suitable Hypertherms but there does seem to have been a steady stream of Clarke 50/55 machines coming up and selling in the region of £250 to £300. Are these machines any good??

Graham.