grease for tig welder solenoid (gas flow switch)?

[coppercone2]

So I am tying up loose ends and I came to the gas solenoid.

It is simple, spring, metal slug, plastic housing, o-ring. I thought it was a bit rough when I was actuating it so I took it apart and ultrasonic cleaned it. I put a light wipe of oil on the metal slug and spring just so it does not corrode after cleaning during bake out. I did not reassmeble it yet so I can still clean the spring and metal cylinder/slug. I believe there was a tiny amount of grit in there that was making it run with a tiny 'crunch'. It is just a cylinder pushed by a spring that is retracted by the magnetic field of the solenoid.

Should I apply any lubricant on it? I.e. like air tool oil or something. Its for argon. Or a thin coating of grease, like I thought silicone grease maybe. Or are they meant to run clean/dry? IDK if its considered 'contamination' of the weld if there is a tiny bit of grease on that slug.

[TERRA Operative]

We never used to use lubrication. The inevitable workshop dust will stick to it and gum it up.
The actual valve body was usually a sealed, non serviceable part and you don't want any oil inside where the gas goes.

If a good cleaning didn't fix it, it should be replaced. We usully used aftermarket ones that were relatively cheap (price, not quality) as there weren't too many variations in design so a couple part numbers would cover most welders, and customers wanted the welder fixed fast at lowest cost.
We didn't notice any real difference in lifetime between the genuine or aftermarket parts, in fact often the genuine item was the same part we were buying aftermarket, just stuck in a bag with an 'official' welder brand name.

[coppercone2]

Well I figure it should be pretty good if its just hooked up in to the argon tank ? On a 200 it comes apart easy the valve is press fit in a o-ring and the chassis bolt hold it together

I also noticed that its just a metal-plastic seal. I thought there would be rubber or something on the cylinder, but it looks like it just makes contact with the plastic (like a rubber end piece for the metal rod), it just has a lathe cut flat on it that touches a flat plastic to make a seal. Since there is no deformable stuff I figure it can't be that tight.

I wonder if it could be missing parts? How gas tight should they be? But I also don't see how there could be rubber attached to there either, unless it was glued on and someone lost it.

Is metal to hard flat plastic a common 'valve seal" for these things? I figured there would be a cap on it like a syringe plunger. The gas regs all use rubber too.

What I am saying is that the slug is just lathe cut flat on the end (with spiral pattern) and it sits on a smooth plastic ring that is part of the valve body to block gas flow.

Do you think I am missing a piece? I think the term would be 'seatless' or maybe 'hard seat' . I could glue a rubber disk on the bottom, but I am not 100% sure if its supposed to have one.

[TERRA Operative]

We rarely ever took them apart and I have no idea what yours looks like without a picture.

Usually, unless the service manual specified that they were serviceable, if they were playing up we just threw them in the scrap metal bin and installed a new one.

Was no good spending an hour or so poking away at the valve, only to have to do a site visit to replace it for free when it failed again a few days later anyway.

[coppercone2]

oh no this one is dead simple.

Its just 2 plastic parts, held together by 2 screws to the electromagnet part.

A bottom valve body, and a stem body. THe stem has a o-ring on it that press fits into the valve body. The stem has a spring and magnet inside of it.

So you do is remove 2 screws, then yank on the stem with fortune cookie cracking strength and it comes apart, since all you need to do is pull a o ring out of a 4mm deep hole. Then the metal slug and the spring slide right out.

Honestly one of the most simple objects I have seen. I think its very elegant. No snap hinges or nothing, it relies on the sandwich to the coil part to hold it together, otherwise about 1 psi of pressure will cause the top to pop off.

[coppercone2]

wow getting the old conformal coat off these things is a bastard. I got conformal coating remover, a brush and a plastic scraper and it took me 2 hours to get most of the coating off the main board.

I think I will replace the caps before recoating, the little caps, I don;t trust them 2 much.

since replacing the big caps made it boot once, I figure the small caps gotta be hammered also. usually the big caps are fine.

But its not as bad as I thought, it seems to peel it not really dissolve it like flux, I thought it might make a sticky mess. Next time I work on something coated ima strip it first. Bet that yellowing coating was degraded too.

[jpanhalt]

I gather from your multiple TIG threads that you have an older Miller unit.  How about telling us which one?  Mine is circa 1983 and still runs fine.

[coppercone2]

I gather from your multiple TIG threads that you have an older Miller unit.  How about telling us which one?  Mine is circa 1983 and still runs fine.

yeah its a dynasty 200 that revived after 18 months of intermittant work, I replaced the main caps, the igbt rectifier, a tvs diode on the processor, a circuit board (I replaced all the parts on the original PCB, probobly more then once over trying to catch something happening but IDK its just haunted/infested), some zener diodes, and a few char repairs, and some opto (replaced em all) near the IGBT output stage, and I took everything apart and cleaned/baked it, like the transformers etc, and scrubed some rust and varnished stuff.

I am waiting on some caps and resistors (slightly discolored) to solder back into two boards so I can conformal coat it and try it out.

******

Actually there is still 1 unsolved repair, the plastic film that adds extra isolation between the mainboard PCB (stand offs) and the chassis has a pin hole in it. That is, lightning/spark went from a zener diode on the secondary of a flyback power supply (the one that provides 3x 20V rails to the IGBT, isolated, not the hV starter, which is in a different part of the welder, behind a steel wall) though that white plastic sheet you see in like power supplies between the board and the chassis and burned a pin hole through it.

I was going to flatten out the pinhole with heat (it has a crater thing going on) and pressure, then put kapton tape on the bottom, then use a microapplicator to put electronics silicone in there, let it cure, and then put another kapton tape on top.

Its interesting because the board is elevated from the chassis by a 3/4 inch standoff, so that means that some how a spark went from the leg of a zener diode at the corner of the PCB above a plastic nylon standoff and and jumped through the insulation coating to get to earth.  IMO impressive that it managed to shoot through plastic (looks like you poked it with a hot needle) after a 3/4 inch air gap! Because the plastic normally rests on the chassis floor. I assume this is what happens in a dirty/damaged welder when it spark starts (HF spark start) and ends up creating a parasitic krytron some where in the system. Directed energy weapon lol. I thought maybe there was conductive dust on top of the film, like a piece of weld splatter, so the arc start found a shorter path, and maybe did not burn through the plastic, but melted some crap on top of the plastic which sunk down through it (like burning through the mantle of the earth). But IDK, it does kind of look like a gun shot or something (ballistic), so maybe there was a crack in the film, or the voltage was obscene...

[coppercone2]

Think I will also modify the ground strap cables, so I will cut them a little short and solder them to a copper sheet with a hole in it. So long I make sure there is no burr, it should be superior to clamping on the soldered braid, that could effect stability of the contact IMO. Issue of contention but I think its wise. I don't want a stack of like 7 ground lugs to have a solder soaked copper braid in the middle.

IDK if its wise to put a seperate grounding bolt (the frequency is kind of low so I can see the appeal of a true star ground), but what I came up with to improve it is

1) cut yellow ring terminal of correct size in half to split barrel
2) use tools to unfurl it
3) flatten with flat vise, parallel jaw pliers, etc
4) Lay on top of braid and mark where to cut off so that holes are aligned
5) solder
6) add extra heat shrink
7) enjoy properly terminated braid

And I think I will also clean the front panel vents from the weld splatter, sanding sticks. Alot of work but I gotta wait for all the crap I need to come in, might as well. TOok out the front panel circular connector and will clean that too, I forgot about it, its not pretty. 

[TERRA Operative]

Why not roll up the braid at the end and just crimp it into an eye lug in the usual manner?

[coppercone2]

Why not roll up the braid at the end and just crimp it into an eye lug in the usual manner?

It has solder on the end, I suppose I can hot wrap it, its soaked in solder and rolling it would require molten rolling / stuffing because I heard you should not be bending tinned wire or braid because it strains the material. If it was excess long I would do that I guess.

the crimp I took apart (green barrel) kind of looks like the federation symbol from starship troopers movie when I flatten it out too. The big lap joint should be fine.

[coppercone2]

polished up the front panel scars up to 7000 grit with sanding sticks. looks nice and the new finish is smoother then the original. Still some cratering (I am not gonna fix that) but it looks pretty decent now.

Managed to rip the encoder wires (forgot about it and its weak), will replace with some teflon wires of small gauge that I have.

Now to solder the braids.


Also, I cleaned out the front air connector by putting it in a drill, stuffing it with never dull wadding and spinning it while pressing in there with a stick. Looks great and the material removal is zilch, I don't think I ruined the coupling or anything. Followed by ultrasonic clean and very light coating of deoxit on a squeezed wipe. Prior to use I can clean with a IPA wipe. I think you can put a nice quick disconnect of some kind there, it should help with keeping the machine clean. Ultrasonic cleaned the hoses too, and flushed with clean water then baked at 80C.

I put the flattened lug crimps on the braid by lap soldering it with resistance heating. A bit too powerful for the pace heater, you need something with a little more umph, but its convenient to use tweezers.

Now I just need to fix the encoder wiring, wait to attach the resistors and caps I ordered, conformal coat the PCB and reassemble... hopefully it still works! at least it looks better and I am more confident in the grounding scheme then having the damn braid there.

[coppercone2]

put it back together, seems to work. Managed to blow a 10A dmm fuse because of settings (I set it to 1A but the socket were incorrect). Voltage measures with a error of 0.1V (I wonder if there is a trim pot  )

I bought some cheapo front panel lugs and grounding clamps, I want to hook it up to try the stick function using my resistance brazing wires, the front panel lugs can be put in as a denise to lug adapter.

If it makes some sparks I can buy a tig torch thing, but I figure stick is a good proofing test before spending significant amounts of money).

[coppercone2]

the machine works, I scribed a line with a carbon rod I wired directly into the front panel lugs on 0000 cable I use for resistance soldering/brazing @ 70 amps DC set to stick welder mode.

I need to get the proper tig stuff now (I used a rod from a F cell lantern battery embedded in a copper tube fixed into a lug that was all filled with solder).

Just need to silicone the arc igniter coil into place and clean the chassis cover.

Wow... is it finally done?

[TERRA Operative]

Arc test is what we would do for a sanity check, saves connecting a TIG torch and wasting gas.

[coppercone2]

Lol, Yeah I tried AC and DC. I am waiting for the accessories now.

The only thing I don't like is that there is whine from the coil inductor rod on the main PCB board, this powers the isolated 20V rails with a flyback +3x rectifiers on seperate windings.

It measures OK on LCR. I am not sure if its natural, people do complain the machines are loud, and it changes pitch with menu settings.

I thought maybe it could be a cracked core, or maybe a loose winding, but IDK, I know renco chokes, they have a loos wire covered with a heavy heat shrink... this one also had some conformal coat on it.

I replaced all the caps on the main board (9 caps) and all the caps on the h bridge controller (5 caps).I also replaced all the semi conductors on the main board, so I don't know what it could be... but people complain ALOT about noise from dynasty 200's so I assume it might be natural. I think I also remember a large renco choke was making alot of noise in a certain product.

[coppercone2]

tested the gas valve, as expected, the missing seal means there is a slight leak from the front panel when argon is hooked up. It is slight but I ordered a replacement valve.I figured that a plastic hard face solenoid is too good to be true. There must be a rubber piece that is missing, I wonder if I lost it or if it was pulled from the welder, IIRC there was some loose screws on either the relay or the solenoid when I first took the unit apart. I decided to buy a new valve rather then try to glue rubber in there, because the solenoid coil might very well be degraded.

The CK tig torch looks OK, but there was some residue (black rubbery dust shit) inside of the torch, possibly from packaging or something, so I took that all apart and gave it a 30 second ultrasonic bath in alnox followed by IPA spray followed by compressed air blow dry. I reassembled everything with the slightest of deoxit grease film applied with a lint free wipe and left the open face plugged until I get my collets n stuff.

I also took off the o-rings on the CK torch and washed them and put a very light film of silicone oil on them with a oil dampened lint free wipe. I hope that was the right move, but they were rather dirty and did not look well seated...

I found slight damage in the front panel connector, because when I put in the dinse connector adapter, and pulled it out, there was a small bur on the edge of the protrusion. I used a diamond file to very carefully file the bur off, cleaned it well and on reinsertion there does not appear to be new damage. I guess that is to be expected, maybe I should have replaced the front panel connectors prior to assembly but there was no easy way to find it.

When I get my ground cable and tungsten kit I will try it out with the leaky valve, its acceptable just a little wasteful (it builds up enough pressure to bypass a firm finger plug in a few seconds when set to like 20 PSI on the regulator.

[coppercone2]

BTW do those combined gas and electricity connectors weird you out?

It feels like you are going to put 100 amps through a air hose.

Also, the pivot joint on the CK torch makes me a little nervous, you can't get it too tight and it does not stay too tight. I am a little surprised that works, because the reputation seems very good. I only got the 130 amp one though, but still it seems a little anemic on the rotary joint IMO. The knob for the nut is pretty small. I figured it would have more grip and that the mechanism would be more complicated. Guess I will find out.. the whole assembly seems slightly dodgy (rupe goldberg) electrically compared to the ground clamp, which is a solid lug that is screwed into a bolt real tight and has braids etc.

The ground clamp looks like something I would trust in industry, the torch ... not so much

is that gas / electrical connector designed for gas and electric or is it a hack?

[TERRA Operative]

A little grease on the o-rings is fine, used sparingly as you did will prolong their life.

The combined gas/electricity connectors were never much of a problem as long as you kept them clean and firmly seated when in use. Any dirt or loose connection will quickly have them arcing and burning out though, but this is true with any output connection on any welder.
Even the water cooled torches which combined water/gas/electricity were generally pretty reliable, even considering when they were bouncing around a dirty workshop.
They were interesting with the copper conductor, as the conductor was run inside the water hose they could use thinner wire due to the cooling of the water flowing past, so they always seemed on the thin size compared to what I was used to with non-water cooled cables.

I've never used the jointed TIG torches though, I only ever saw the fixed and flexible types when I was working in repair so I can't comment.

[coppercone2]

the idea that it needs gas flow for the conductor not to over heat while in use is reminding me of a NASA rocket engine fuel cooling. I guess slightly warmer gas does not make much of a difference because the arc is so hot.

[coppercone2]

Do you know what the peak voltage is for the HF arc starter, if I wanted to see what kind of probe I would need to try to scope the output?

I assume typically people just use scratch start to see what the wave form looks like.
Hazardous to scopemeter?

I Have a clamp probe with /dc to 400A for amps but I wanted volts too. Not sure how many kV it is

[TERRA Operative]

No idea on the HV voltage. If it worked it worked... We never measured HV voltage/current, only the welding voltage and current.

[coppercone2]

it works! The valve is a little leaky and I managed to destroy a tungsten grind (cerium) because the handle valve was turned off, but after that got sorted it works nicely.

I tried 50, 70 and 100 amps on various AC frequencies and DC on a stainless steel plate that was previously oxy acetylene practice.

I need to add split phase hook up to the welder, its single phase right now, meaning I need to buy some adapters so I can easily convert it between single and split phase like the hypertherm plasma cutter I have.

While difficult working in a bench vise standing up on a roof top shape plate (right angle that I hammered kinda flat to test the previous OA weld a while back), my observations are

1) DC is alot quieter and smoother and easier to maintain an arc then AC and it looks nice
2) AC left a bit more corrosion and stuff. I tried 400Hz and it was pretty wide.

My next things with this are
1) replace gas valve
2) order a few flat bars for the topless welding table I built so I can work while sitting
3) get a flow regulator (using a MIG standard issue cheap regulator now)
4) inspect tungsten grinding angles with magnifier.. I got this loupe that has different inserts including an angle measuring scribe line. I just did a really rough job on a wood mini bench sander with coarse material
5) try to actually use a filler rod
6) torch rest addon to my holder

So fucking amazed I got this thing working. 

Also got the tungsten stuck to the DUT, thankfully it twisted off , i was so scared the glass was going to break but it seems to know if its shorted


I also want to build like a jig that can seat the tungsten to a specific depth (maybe on of those "simple" carpenters micrometers, the one that just are made with brass and have a rule on them, can be used for this.

Also want to make a mounting bracket so I can put a iphone to record the scope meter to have a look at wave forms while welding

[coppercone2]

Nope thought I was on to something, the polarity is correct, I understood the label correctly. On the other polarity (they did not put plus and minus but some pictograms for daniel jackson) it will instantly melt the tungsten at the same power level.

I think I need to sit down while doing this lol, but I need to recharge the finance first because its just goin to fast lol

[TERRA Operative]

Good work!