SIP wire feed modification

  1. dave21478 Member

    Hi, have a sip topmig 170 turbo and its....well, its average.
    Yes, the wire feed is shonky and I notice that it takes a lot of pressure on the adjusting screw to get a decent feed, with the result of the plastic mounting of the idle roller bending.
    Now, I read on a car forum somewhere - cant remember where now dammt! that there was a known "modification" to make to the roller mechanism. From what I remember, it invoved dumping the existing adjustment and makng a little harness from flat steel/alu to hold the idle roller that clamps onto the fixing screws for the grooved roller. 2 lengths of threaded rod or bolts allowed very fine adjustment on the pressure on the rollers.
    As I cant remember what forum I saw this on, I never got round to asking the guy for photos.

    Anyone heard of this being done? I might give it a try myself and see what happens. It certainly cant be much wore I suppose.


    Also, When welding, I find I have to use a much higher power setting than I imagined I would. thin-ish plate for car repairs required the power to be up at 4 or 5 out of the 6 positions, with the lower settings only giving the odd pulse and splat of weld. Im using 0.6 wire with pure co2 gas. I have found that using 0.8mm tips with the 0.6 wire is giving me a slightly smoother result too.
    Possibly faulty windings on the transformer giving not enough juice on the lower settings? or something more mundane?

    Thanks,
    Dave.
  2. shenion

    shenion Tool Pack Rat

    Posts: 7,596
    Stone Mountain, GA USA
    CO2 will lower the current as will using 0.6mm wire. Try 0.8mm wire and I bet you will need to use settings 1-2. It will also run at a much lower wire speed, might work better with the sloppy feed mechanism.

    Using argon/co2 mix would also let you have a wider speed range. CO2 only works well with a feeder that maintains a very constant feed.
  3. RussB

    RussB Member

    Any help on this would also be greatly appreciated by me too, I'm in exactly the same boat. The engineering tutors at work have asked me to bring the mechanism in so that they can have a look at it and then maybe fabricate a working replacement for it. Let's hope they can come up with something

    Cheers
    Russ
  4. malcolm

    malcolm Administrator Staff Member

    Posts: 8,220
    Bedford UK
    In my experience (limited to just one SIP fair enough) they seem better off with a metal wire liner rather than a plastic one.

    See the sip wire liner page and think bags of rice. Mine feeds on much less than max tension after the mod.
  5. sharkey

    sharkey Just this guy, y'know.

    Mine (Weldmate T150P) came with a steel wire liner in the first place, and seems to feed pretty well ... even with a 5kg spool of 0.6mm wire. I don't use much pressure on the idle roller. I marked the speed dial 1 .. 9 and it seems to be pretty consistent between uses too.

    I've only run a kilo or two of wire through it so far though, maybe they've fixed the problem or maybe it'll bite me soon enough.

    cheers,

    -----sharks
  6. dave21478 Member

    Well, I havent done the mod I mentioned, but I have improved it 100001%
    Here is what I did....

    Firstly, it already had a steel liner, yet the feed was still crap.
    I had bought the unit second-hand so knew nothing of its history, so I stripped it all right down.
    Firstly I removed the whole torch and cable. Disconnected the gas pipe (push fit next the drive mechanism)and the 2 spade connectors for the trigger switch. Then a 18mm spanner undid the big nut and allowed me to pull the torch out. I then took the handset apart (4 screws) I blew compressed air through the steel liner which spurted a pile of metal dust out f it. I then usedthe bench grinder to neaten up the ends where the last owner had cut it a bit roughly. I also cleaned through the swan-neck with compressed air, clearing out more filings.
    I then removed the whole drive assembly (just 4 screws from above) it lifted right out and I disconnected the 2 wires to the motor (remember what way round they go)
    The motor - well, its rubbish isnt it? Its a teeny wee puny thing and I have seen better motors in my 3 yeard old nephews toys! anyway, I took the gearbox apart (4 more screws) This revealed the plastic pinions inside. There are 5 of them i think. The whole lot was obviously greased when new, but over the years the grease has dried out and it was all very dry. I pulled all the gears out, cleaned the whole lot and put it all back together using loads of grease (make sure you use one compatile with plastic parts!)
    Now, While I had it all on the bench, I noticed that there is a lot of play in the drive roller. It has a square hole that fits onto the square shaft. The hole is slightly oversized and this meant the roller was free to rattle about on the shaft by a millimenter or so. This would obviously cause irregularities in the smoothness of the feed. The simple solution was to wrap a couple of turns of PTFE thread-sealing tape around the shaft. This took up all the slack. I connected the motor to a 12v supply so I could watch it closely. I then noiced that the hole in the drive roller is actually slightly off-centre, causing it to wobble as it turned. Not much I could do about that though.
    The free-spinning roller that grips the wire is just a roller-bearing. I found mine to be covered in metal filings and a little rough to turn. I cleaned it out and greased it so it spins freely. Make sure you clean all traces of grease off the outside of the bearing so it doesnt slip when in use.
    I then re-assembled everything, cleaning thoroughly as I went. When it came to re-fitting the torch I discovered something else. It is generally thought that you should position the liner so the end is as close as possible to the rollers, reducing the posibility of tangles. Now, my liner was very close, infact almost touching the rollers, so asit was running, the slght oscilation in the roller caused by the off-centre hole meant that the wire would move a couple of mm to the side with each revolution of the roller. This was causing the wire to rub against the inside of the liner. I moved the liner FURTHER AWAY from the rollers by about 6 or 7 mm, allowing enough space for the wire to move side to side without being forced against the side of the liner.
    I ten re-checked the spool holder and foud it to be a little grippy. I greased the bottom of it where it turns against its mounting. I then re-checked the tightness of the nut holding it and adjusted till the reel spun easilly but not too freely so it doesnt unspool when I stop welding.

    In use now, the welder is like another unit altogether. Feed is consistant, smooth and reliable. I can now use the torch in any position where as before I always had to keep the cable as straight as possible so the wire would runfreely. Im very happy with it now.

    As for the modification I mentioned, I looked into it while it was all in bits, and yes, i suppose you could make a better cradle to hold the free-spinning roller withadjustment by threaded rod, but I have found that after this maintenance I dont need to!

    Give it a try, you will find it makes a good improvement!
    Thanks for reading.
  7. dave21478 Member

    Sorry for the spelling in there, i typed it in a hurry, racing to finish before my laptop battery runs out!
  8. steve202

    steve202 ǝlʇıʇ ɹǝsn ɯoʇsnɔ

    Posts: 422
    Wales.UK
    Sounds like a good old fettle there Dave!
  9. marknotgeorge

    marknotgeorge Doing sums for a living since 2009.

    Posts: 475
    Derby, UK
    Have you got any photos? It'd be useful to have an article somewhere about this.
  10. Prytaneion Alan - West Sussex

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