H20 plasma cutter

[billbong]

Hi, yes I looked at the inverters, but the big ones were way up in the dollar bracket.

I didn't fancy having to mess with a heavy battery and getting it in and out of the car would drive me nuts.

The generator is rated at 4Kva, which will give 3,500 Watts peak and 3,000 continuous, so that'll give lots of juice for a portable power house if and when etc.

It'll also be handy for winching my boat out of the water when I decide to go sailing....it's a 12 1/2 foot sailing dinghy, ex club racer....when I get a round tuit.

Fuel consumption is rated at 5 hours for a full tank of about 5 1/2 litres unleaded petrol and the decibel rating is 45 decibels at 7 metres.

I don't anticipate going out and about looking for welding work, and its only for my own use.

The same generator on EBAY currently sells for $579, so with one day to go and the bid at $220, I slapped an opening bid of $400 on it and sat there at the closing stages watching the action as the bidding went up by $10 increments........ and I won the bid at $290, and as is usual all the bidding happened in the last 5 minutes.

I'll have to arrange for a courier to pick it up as it's in New South Wales , over the border.
Ian.

[Flatlander]

I know a little more now

It has been several months since I last posted to this forum on the Multiplaz 3500 and with winter being gone and being able to get back into the shop, I have learned a thing or two about this little wonder machine.

First off I rid myself of their funky rod holder, return clamp, and torch stands. I use a standard stinger to hold the rods but with no wire attached, it serves as an insulated holder only to avoid the heat and the tingle one gets when welding in the "arc" mode II setting. I added alight duty clamp with about 4 foot of very flexible 8ga cable for a return but use mostly with a magnetic attachment since there is less than a 10 amp current draw this works very well. Third but not least is that I also scrapped their torch stand and made a couple of insert stands of my own quick design which works much better for me, "picture attached"

[Flatlander]

A bit more information:

It took me a bit to get used to cutting with the very fine plasma flame and lower pressures but once I learned what I was doing the 3500 does a very nice job. On steel which is all I have really worked with so far, up to 3/16 in I use Mode I step 6 for cutting. This requires 220 VAC as the machine only goes to step 4 on 120 VAC, but it also allows the cutting tip to be run right against the work piece, whereas Mode II "arc" requires an arc gap be maintained. I have been working with 4" square tubing with 1/4 in wall thickness and have been able to make far cleaner cuts with the plasma cutter than I could have using my Oxyacetylene. I also like the ease with which I can clean up the slag along the edges after the cut has been made, it almost like have a very sharp knife of flame to work with.

My welds are not yet as pretty as I would like them to be, but that is more due to my aging eyesight than the limitations of the machine. It took several tries before I finally found a lens that was the proper darkness and still allowed me to wear my glasses but now things are beginning to look up. Filler rod has also been a local availability problem and I had been using mostly 10 gauge clothes line wire which was not the best, but I have found that I can bridge gaps up to 1/4 inch with far greater ease that I ever could with a stick welder. The plasma flame will actually pull the puddle much like working with solder on a well tinned surface, and very little burn through.

The 14,000+ F plasma flame will carbonize the metal turning a welded area to slag if you don't use caution but turning down the heat by moving to a lower step setting seems to correct the problem. The molten puddle forms so much faster with the plasma welder that it is an actual joy to torch weld, and there is also no smoke to contend with as with fluxed rod. Oh yes, and no sunburn on bare arm either.

Bending and forming small flats and rods is far easier with the narrow flame of the plasma welding torch than with a gas torch.

I have not yet done any bend and break tests because until I become more proficient with the machine any test would not be giving the weld being tested a fair chance.

In short, the Multiplaz 3500 has done everything it was claimed to do, and I feel it was well worth the price. I have been rougher on the torches than would be normally recommended and have paid for that with having to replace a quartz tube and one cathode assembly at a total cost of about $26.00, but when they tell you that you need to put the torch in water for cooling after shutting it of, they have a good reason. I would recommend getting an old stainless steel or aluminium pot for water to cut down on the rust that invariably forms in a steel container. I'm still looking for one as the last two I bought were too nice for the shop and so they now reside in the wife's domain.

[billbong]

Hi Flatty......I thought you'd "gone on holiday upstairs" with no posts for a while...LOL.

Have you tried using rebar as a filler material....it doesn't matter if it's a bit rusty as the surface rust just flakes off when it gets to red heat.

It's thicker than a welding rod, but I find a thin rod disappears too quick and you only need to melt a bit off the end now and then as the puddle moves forward, and for that matter you can use just plain swarf from your lathe turnings as it just melts into the pool too, nothing wasted ever.

I would be careful about clothes hanger wire as it might have a zinc coating, probably goes for any wire that gets used outside.

On the subject of the face shield, try a regular full face grinding shield with a #5 dark glass in place of the clear one.......this will allow you to wear your specs all the time without knocking them off with brazing type goggles.

As there is no UV present to protect you from, you could also just fit a piece of darker plastic sheet on the inside of the clear one that they sell at the supermarkets for wrapping present with....green works well....any thing that cuts the glare down from the melted pool brightness.......I prefer a full face shield to protect from the sparks that pop up now and then, but more for the freedom to wear my close up reading glasses to see the work.

BTW, a good project would be a stainless steel pot for tip cooling made from some stainless sheet rolled into a tube or just bent up square and welded or brazed.

You can get loads of thin stainless steel sheet from old microwave cooker casings, probably not 316 stuff as it is magnetic, but it's still stainless.

Copper wire from electrical cables can be used without flux for brazing with steel, maybe stainless too....... I've used copper wire on plain steel to braze without flux.....use mode 1 setting, about 4 heat.

My jam tins have rusted big time, but I find if you empty them out after you finish and let then dry they last a lot longer.

I've just been asked to contribute to a Canadian Multiplaz forum that has been set up specifically for Multiplaz users and to exchange techniques etc.

The person who set up the site is called Rob Taylor, and the site is in Google Groups under multiplaz.
Ian.

[Flatlander]

This, That and Other Stuff

Clothes line wire does have a Zinc coating and for that reason I am looking for another source. Have not tried re-bar but would probably find it too bulky in the long run. I need to check out a couple of local junk and scrap piles I know about.

I tried doing a little hard surfacing using bare tungsten/carbide rod and it was interesting to see that the rod tended to alloy with the work piece rather than just forming a surface coating as is typical with hard rod when used with a stick welder. Haven't found a local source for more rod yet so that I can play further, but have hard surfaced the blades on both of my mowers by removing the flux from stick hard rod and will see how they wear.

I did have to break out the wire welder in order to get into a very tight acute angle on a section of 4 inch tubing I was working with, but I had expected this to be a problem from the get go.

I've been cutting into a couple of old propane tanks during the process of building a wood stove for the shop and find the control I have with the plasma torch far superior to what I would have had with the Oxyacetylene.

I needed to cut out the tops of both tanks and yet conserve the removed portions for future use, so I simply formed a piece of wire around the torch tip and using a 1/2 inch bold which I had drilled out on the lathe for a pivot point cut two nearly perfect circles. I don't try to remove the valves but rather cut them off with a Sawzall and drill out the brass center with a 1/2 inch bit and pneumatic drill after allowing the tanks to sit open for an extended period. I also fill the tanks with water and let stand on their tops to drain and air out over night. No sparks no surprises.

I will also be salvaging some metal from a good heavy 55 gallon drum for some of the other parts and feel I will find the plasma torch much easier and cleaner than using the oxyacetylene system. It isn't quite as clean as using a designated plasma cutter but still not bad and especially since I don't have to worry about empty bottles all the time.

I had been using the grinding shield as you suggested but eventually went back to my adjustable auto darkening welding hood and found that I had better luck under more conditions then with a fixed lens. I still use the grinding shield for cutting however.

Overall I feel that the two grand spend for the Multiplaz machine was a good purchase and that in the long run I will probably do things that I might have other wise put off just due to the aggravation of needing to break out all the other machines. Being able to tote a single small system is so much easier than dragging out all the other stuff and especially if I need to leave the general confines of the shop.

[billbong]

Hi, it's good to see you're having fun.

I have a theory about welding aluminium with the Plaz, as I find that if you hesitate too long on one spot the whole area around the spot gets to melting point and you have a fall in........happened a couple of times to me.

When I get some spare time I want to sit a piece of aluminium in a tank of water to keep it cool and try and weld without getting too much heat into the job all at once, keeping the actual weld zone above the water but the main body in the water, whatever.

What my intention is, is to use the mode 2 to get the heat into a confined pin point spot and melt just that spot as I work along fairly quickly, not dwelling in one spot too long.

The excess heat would be absorbed by the water instead of building up as it flows out laterally and in so doing getting the whole area around the weld pool up to melting point, (which you don't want) as you lose control and the lot melts through....aluminium being a low melting point virtually, but a fast dissipator means the heat you put into that spot will go out of control and melt the whole lot.

Having 8,000 deg C to play with means the ally will heat up rapidly all over with a broader flame, and that it will really quickly is beyond doubt, but not where you really want it due to the heat traveling out so fast.

I learned that from welding thin steel sheet, where you can control the weld pool, without blowing through the thin metal, by using a copper heat sink on the back of the metal.

That means you are absorbing the excess heat as it moves outwards.....this could work for ally too, but I'll have to experiment a bit.

With aluminium, I have a big drum of aluminium Mig wire from an auction sale, and I reel it off and made some "thick" filler rods by stacking six 2 foot lengths together and twisting them into a rod with my cordless drill....slowly slowly...LOL.

I do the same with steel Mig wire as I have a drum of it too....cost me 5 bucks at the time.

I'll have to try the "hard surfacing" with tungsten carbide like you said, as I have a box of old carbide inserts from another auction sale.....I wasn't aware that they would melt onto steel.....I've been using springs, straightened out, as a hard surfacing source, since they are fairly high carbon steel and can be heat treated easily.
Ian.

[Flatlander]

Heat sinks and such

I cabbaged onto a polished copper slug many years ago. It is about 1 inch thick by 3 inches in diameter with a rubber coated back. I had used it as a soft anvil when working with plastic extruder parts to prevent damaging the machined surfaces. I use this when hard coating as it not only pulls the excess heat away but provides a surface the hard rod does not adhere to and I consequently wind up with a very nice cutting edge which requires very little grinding or dressing.

I had planned on checking several junk piles today but the mosquitoes are ferocious and big enough to saddle and ride so that will need to wait for another day. I did however find an aluminium water pot which will now keep my cooling water from getting rusty.

I did learn a rather costly lesson recently when I got sidetracked by a phone call and did not immediately turn the torch off. The torch extinguished itself during the interval and of course I was not right there to plunge it into the cooling water. The end result being that when I reignited the torch it arced internally melting the cathode and the end of the cathode assembly rod. I failed to notice that it also cracked the quartz tube as well. I replaced the cathode assembly and then because the quartz tube was cracked arcing once again occurred between the new cathode assembly and the copper sleeve that holds the quartz tube.

In the process of arcing to the sleeve that holds the quartz rod a small burr formed which promptly broke the end of the new quartz tube when it was installed. A delicate touch with some emery cloth and a bit more care when once again replacing the quarts tube and that part looked good but the new cathode assembly was now pitted as well, and I was reluctant to try using it so another new assembly was used.

A good cleaning with a bottle brush and a soft wire brush and everything was once again back into full operation. Lesson learned; don't be in such a hurry that you don't turn things off and cool the torch. Total cost of the lesson was about 80 dollars plus time. Also don't skimp on cooling water, I like to keep about 3 to 4 inches of water in the pot so that I get a good coverage of the torches tip.

Right after I received the Multiplaz unit I was attempting to weld in a tight 3-way corner and the blow back began to melt the end of the case of the torch so that the metal end was beginning to fall off. a quick dunking while I held the metal part in place and a thin coating of "JB Weld" and the torch body was as good a new, though not quite a pretty. As a result of this lesson I have used the experience as an excuse not to wear a glove on my right hand which holds the torch. This way I can quickly feel when the heat begins to flash back and besides I hate wearing gloves anyway.

I'm also looking for a way to coat the cutting and welding tips so as to prevent arch over when using mode 2. If and when I find a solution I will certainly let everyone else in on the secret.

I guess this about covers things for this go around, and as soon as I finish with the pick-up truck I've been fixing up for my daughter to use on her little farm I will get back to some more serious navigation of the never ending learning curves.

[billbong]

Hi, have a good day mate....on the glove thing, I only wear a glove on my left hand.....don't like to get zapped by the HF...... the right hand is bare as I like to get a better feel on the torch body.
Ian.

[phoenixsteve]

I think I just bought the last few Multiplaz units in the country. and related spares. I figured I'd sell what I don't need and my machine should work out cheap. this thing amazes me every time I pick it up. I jamed it into a concrete paver the other day and glass bubbled out everywhere. Is anyone else having trouble doing fillet welds with it?