Migmate 130 Banner

Upgrading a SIP Migmate 130 Turbo welder

The story of this upgrade starts with a friend of mine acquiring it about 15 years ago (at which point it was already quite old) and after some use real life got in the way and it was abandoned in a barn for about a decade. At this point I needed a welder for a project and asked to borrow it. Now when I got my hands on it and started trying to use it it became immediately obvious these welders were amazingly basic and poorly constructed and so immediately I started modifying it to make it work a little better.

Factory Wire Feed

First off the standard wire feed is terrible, it’s made of plastic and if you put enough pressure on to push the wire the mounting for the drive (being plastic) actually bends away and just won’t consistently grip. This situation can be improved by changing the plastic torch liner out for a steel one to reduce friction but it’s still dodgy. Bracing the wire feed on the outside helps as well.

Migmate 130 Feed Mod

Here you can see the feed modification. It is simply a bit of scrap metal with a slight bend in it and two holes. The two screws are already in the feed system and hold the parts from the factory so it just picks up on them. This simple mod helps the two feed rollers from deflecting away from each other.

The next issue with the wire feed is the motor is driven off the main transformer output with half wave rectified DC which causes a one main problem, the supply to it isn’t consistent. When the arc is struck the voltage at the motor will drop due to the load change on the transformer which tends to make the motor constantly pulse in operation rather than give a consistent feed so it’ll join metal but not in a particularly convincing way.

To get round this I added a small regulated 24VDC supply for the motor with the help of information I found on the internet such as the wiring diagram for the welder. The was this works is the control board gets its 24V supply from the black wire on the 4 pin connector. If we disconnect this and instead feed it our own 24VDC the supply shouldn’t fluctuate any more. I used the existing supply (the black wire we just intercepted) via a relay (24VAC coil) to turn on the wire feed when the output energises. You should end up with something like this

I’ve not checked the rating on the factory feed motor but I would guess 10W at most. I used a 24VDC 15W PSU module (specifically a Tracopower 15124C that I found on ebay) and it worked well. I managed to fit it behind the main transformer bolted to the outer casing.

Added power supply location

Further to this the motor speed circuit is actually very poorly designed and after a little use can get twitchy and change during use. I didn’t get as far as modifying this but further information can be found here :

Wire speed mod

Or if that should ever go offline also in this PDF :

Earth Lead

Another key usability thing is that these welders have very short leads and the clamp was poor from new and appeared to be a similar thickness to tinfoil and added to that was badly damaged and even rusty and since poor contact causes many issues with consistent welding so I decided to upgrade the cable and clamp to help the situation. For a welder this size you need to be looking at a minimum of 10mm2 cable but this will not allow you to operate at full power consistently (not that this welder is actually capable of that anyway!) 16mm2 would give you plenty of spare capacity.

The clamp itself was just bought off ebay again, they’re about £4 each so difficult to go far wrong. You could go for a different style to the normal clamp if you prefer such as a magnetic one. To connect the cable to the stud on the clamp I used a reusable cable lug which uses two small bolts to tighten to the cable, you could buy crimp lugs but crimping them without the correct tools can be hit and miss. I’ve heard a cold chisel will work but your mileage may vary. I actually used a second reusable cable lug to clamp the new cable onto the transformer outlet inside the welder – not the neatest solution but it worked.

Gas Supply

The standard shielding gas supply on these welders is via a small plastic tube which is intended to be connected to a mini-bottle which sits in two brackets on the back. The brackets aren’t actually fixed to the welder so can be easily knocked off. The standard regulator is rubbish and the one I got with the welder was totally seized shut. I bought a like for like replacement initially and this highlighted the limitation here. The bottle is so small and the regulators so poor that the gas flow actually changes during use and rapidly empties entirely. They have no gauge and so the first you know of having no gas is when your welds go horrible. I looked into it and found a good solution – you can buy regulators that adapt a normal gas bottle to this type of hard line.

I looked into getting gas and found that the time of massive rents on bottles is over. In the UK there are a couple networks of suppliers who will give you weld gas with only a bottle deposit (currently £65 for mine) and no ongoing rental charge. Once the bottle is empty you take the bottle back and get a full one and just pay the gas fill cost (about £30 for the bottle I have) I found a supplier of Hobbyweld gas (Noz-Alls Cheltenham – www.weldingdirect.co.uk) and got their 10L bottle, these are pressurised to 137 Bar giving a total of 1370L of gas. This lasts drastically longer. The shop I went to also sold a standard regulator but with a crimped hose and a push fit to suit this welder off the shelf making this very easy for about £20.

Roll Drag

One other problem I had was the tension spring which is supposed to hold the roll under a little tension to prevent overrunning was actually sharp and biting into the reel. I added a large flat washer under the spring to stop this then added a small washer as a shim to prevent it being over-tightened. This provides friction over a large area to avoid this problem and it seems to work well.

So once I’d done all of this it worked significantly better and we used it for a few projects to good effect right up until we tried to repair and refit the load bed of a pickup truck which involved welding plates onto chassis rails and various other extensive welding work. After burning through multiple contact tips and a couple shrouds we got to the point where the torch died entirely with the wire welding into the inner workings of it and came to the conclusion it was done for. The torch on these being hard wired into the unit finding a replacement wasn’t as simple as a standard euro torch and at this point I wasn’t sure it was worth replacing until we actually needed it again. Some time later I bought a new compact R-Tech MIG which by comparison is a revelation and so the old Migmate got thrown into a cupboard for storage with the expectation it would eventually probably be scrapped.

Though that’s not exactly how the story ends…

8 thoughts on “Upgrading a SIP Migmate 130 Turbo welder”

  1. Interesting story. I have been trying ot repair one of these my borther left me – the wire feed cogs were binding and so feeding unevenly. Having read your post, I don’t think I’m going to bother any more. Hello shiny new one (not SIP!).

    1. Hi,

      Yes it’s technically possible but as you’ve see basically all you’re doing is replacing all the rubbish bits which in the end doesn’t leave much. If you can afford it just get something better – what I did in the end is not really a sensible use of time/effort/money for most people.

      Jon

  2. What a great article. Thanks for taking the time to write up your project. I am trying to do pretty much the same thing on my 130t gassless migmate .
    I have the power supply and have fitted a euro torch and a different reel feed mechanism. I am at the stage of connecting the power supply.
    Do you have the details of the relay you used? Also as I will only ever run the welder in gassless mode the torch and earth are swapped compared to the wiring diagram you shared. Does this have any implications for the power supply mod?

    1. Thanks, I’m always glad to hear of all this info being useful to someone!

      In terms of the torch polarity no, it won’t affect anything because that’s on the output side of the main transformer whereas all the mods are on the supply side. the only thing that defines the polarity is which connection has the two big diodes on it (you can see these bolted to the big aluminium plate in some of the photos) so technically with some longer cables you could make it polarity switchable as well.

      The relays I used were a combination of one I had lying about from another project and one I bought off eBay. The relay that switches the supply to the main transformer (R2) is the important one as it’ll be under most stress. On mine I bought a Finder 46.61 (24Vdc coil, 16A) which has Faston (spade) connectors which makes wiring decently thick wire easy. You can buy a clip mount to mount these with the terminals facing outwards as part numbers 046.05 for screw down and 046.07 for rail mount. Alternatively you can get base 97.01 which costs more but mounts to din rail and has screw terminals for the wiring so if you need to change the relay you can just unplug it from the base and plug a new one in. The other relay (R1) hasn’t got much load but I had a Finder model 40.52 I think it was (24 VDC coil, 8A, double pole) left over from another project so I used that. Similarly you can get different bases (part 95.xx) for these but the model 40 relay has round pins not Faston connectors so they’re all plug in type with screw terminals for wires.

      You could just use two of the same type such as the 46.61 or any other similar relay but what you really need is 24 VDC coils, one relay with a switching capacity of at least of 16A or more if you can find it for the main supply, rating for 230 VAC switching and some sensible way to mount them securely to the enclosure. I like the Finder ones because they’re really easy to get replacements and mounts and things for.

      I should probably point out I have no idea how long these relays will last in this usage, the RL2 particularly is experiencing very high inrush each time the main transformer is energised but I would expect it to be well into the thousands of switching cycles regardless and a replacement relay is only about £5.

      Good luck with it!

      Jon

      1. Hi Jon

        Your reply was appreciated thanks. Had a first attempt at the mod today and although I have not blown up my house I failed at getting the wire feed to work. I have two issues.

        Firstly I do not have the correct relay. Stupidly I just bought a 24v dc relay before your reply came back. So connecting the coil to 250vac clearly will not work. My bad. Will source a ‘correct’ relay then I can try again.

        Secondly where I have converted to a euro torch the trigger switch has a pair of cables ie there and back. I connected one as per your diagram to the blue cable on the circuit board but where do I need to connect the other end?

        I think with the correct relay and the second wire from the gun connected I should be in business. Maybe.

        Thanks again

        Michael

        1. Hi,

          Sorry I’ve just realised you’re doing the version 1 welder mods, I was talking about the later version 2 where I remove the original control board entirely! Apologies for the confusion!

          For V1 both the coil and contacts of the relay RL1 are at 24 VDC (approximately), if you have 250 VAC on the coil you have something wrong!

          The other end of the blue wire is fed from the torch tip on V1 which is live at about 24V DC when in operation but I think there’s a separate supply from a common pin on the PCB (marked CN5). For the V2 version this was fed directly from the positive on the extra PSU – if you’re going to so much effort you may want to have a look at part 2 of these upgrades. There will probably actually be a part 3 at some point but I’ve not got round to writing it up. If you go into the comments on part 2 I’ve included most of the parts I used. I did later upgrade to a higher 10A rated ebay motor controller. The original didn’t fail but it seemed a more robust solution.

          Good luck!

          Jon

          1. Hi Jon. Thanks again. I do have a pwm and did plan to do the stage two once I had proved I have not made a complete balls up of part one 😉

            The drawing I was working from showed one relay, the coil was getting its power from the fan side of the mains supply. Think I need to take a deep breath and park this until I have a few less other things happening. Thanks for your help so far and rest assured I will be picking your brains again soon.

            Michael

          2. Feeling like a plonker! I have been working from a diagram found elsewhere on the internets rather than the ones you posted. I think I can now see where I messed up. With luck in a couple of weeks time I will have another try. Fingers crossed.

Leave a Reply

Your email address will not be published. Required fields are marked *