wacky7791
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I replaced the single turn pot with a 10 turn one to get the finer adjustment, did make WFS adjustment loads easier.
- Thread starter BChild
- Start date
I replaced the single turn pot with a 10 turn one to get the finer adjustment, did make WFS adjustment loads easier.
BChild
SIP - enough with the mods!!!!
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I did too - made a massive difference to stability - if you breathed on the one turn pot it changed the wire speed - I was just interested in if Tray is still running the original
Tray
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Thanks wacky.
Like you I had pretty much given up on trying to weld.
The quote I got of over £7k to do the sills and some bulkhead repairs on an old merc I’ve had garaged for over 10 years made me look into welding again.
Maybe in another 10 years I’ll be good enough to do the welding myself.
Like you I had pretty much given up on trying to weld.
The quote I got of over £7k to do the sills and some bulkhead repairs on an old merc I’ve had garaged for over 10 years made me look into welding again.
Maybe in another 10 years I’ll be good enough to do the welding myself.
wacky7791
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same mate, sills,inner sills, bulkhead, spare wheel well, patches here and there. learning as I go really BUT it was a cheap old car lol
nice Mercedes love the older ones, when they were built well
BChild
SIP - enough with the mods!!!!
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nice Mercedes love the older ones, when they were built well
OT but I bought Mrs BC a 2001 Mercedes SLK 230 Kompressor with a 6 speed manual box 6 years ago - it has to live outside and we don't live in the best area so a soft top was a no no (a magnet for ***** to run a knife thro). The running gear is still perfect the body is utterly shagged - rust appearing everywhere even from the middle of panels without any signs of stone chips or damage
Mercedes stopped building cars and pricing them and started setting a price and building cars to that price and cutting corners to achieve it
Tray
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I have only tried it on 4mm box section but will definitely need to be able to weld bacofoil at some point.
The PWM is adjustable in 1% increments but it is a very small movement on the Knob.
The pot came with the PWM and is 100K single turn. Luckily the original knob fitted on it with a little packing as the knob that came with the PWM was rather small.
I added the original 2K pot to feed the 100K pot as a temporary fine adjuster (2%) and after a bit of testing the PWM doesn’t seem to vary the speed if the adjustment equates to less than a whole % rather it switches between say 47% and 48%. I’m only basing this on hearing the motor tone change as it’s difficult to measure just a 1% speed change. I don’t see this as a problem though.
I may add a 10K pot permanently to allow fine adjustment of 10% or just a geared precision knob that I have just noticed on eBay if the setting becomes annoying or seems unstable.
I think a 10 turn pot might be annoyingly fine.
BChild
SIP - enough with the mods!!!!
- Messages
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I don't regret it when I was using mine - the only time you need big adjustment changes is when you go from thin to really 4mm plus but it's not like it takes ages to change
What I do like is the coarse and fine approach you've tried - that is clever
My issue which I will get back to one day is have a strong feeling that my original PCB was flawed and that's why my Cosmo really struggled to maintain a consistent wire feed speed
Tray
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Was it you who mentioned earlier in the thread that you had to keep adjusting the pot down over time?
When I looked into the components on the original PCB there seems to be a voltage dependant resistor in the circuit to avoid voltage spikes, looking into this a little more it seemed that if this had started breaking down it could cause this.
I have removed the entire original PCB from my machine.
wacky7791
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i put a voltmeter on mine and the feed speed seemed to creep up very very slowly on both original and PWM board.
I just got rid of it and bought a workshop mig for $50 that didnt work either
Tray
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I would guess it was your power supply, it’s the common item to the problem.
Bit late now but some laptop supplies have some circuitry in them to adjust the output depending on the charge state of the battery.
My one for example has a tiny third core right down the centre of the cable.
I have left it isolated at the mo and it seems to be giving a stable output.
I will know better this weekend, I’ve acquired some scrap from work to do some practicing on.
Bit late now but some laptop supplies have some circuitry in them to adjust the output depending on the charge state of the battery.
My one for example has a tiny third core right down the centre of the cable.
I have left it isolated at the mo and it seems to be giving a stable output.
I will know better this weekend, I’ve acquired some scrap from work to do some practicing on.
TimW4302
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Hi All, been following this thread for a while, , finally got my project car ready to start working on again a few weeks back, and my SIP 170 decides to crap itself.
First thing i did was to give it a separate 24VDC power supply, one of these (AC 110-240V TO DC 12V/24V 5A/10A/15A/20A/30A Transformer Regulated Power Supply) off ebay, mount that in the case, rigged through a relay and the original speed control board. got this all tidied up and looking sweet, put everything back together and did some test welds.
All good, speed nice and controlled, test pieces welded up nice. so over to the car.
Made up the first patch, clamp in place, fire up the psycho SIP, first couple of welds all good, stop for a moment to inspect, machine left running, then start welding again.
Blows holes in everything, try to turn speed down, has no effect, i realise the the wire speed is no flat out.
Stop everything, shut off gas, open Wire Hold Down roller and try it, Motor running max speed, control pot having no effect.
Bugger, the TIP035 has blown up, full 24V to motor.
So i decide to go the PWM route, order this (AU Pro 40A DC Motor Speed Switch Control PWM HHO RC Controller 12V 24V 48V 2000W) from ebay, wait all week, it finally arrived friday.
late friday night, quickly jury rig it in place to test, runs good, controls speed beautifully.
Yesterday, wire and fit the new speed controller, looking really sweet, all fitted and tidied set for Sunday welding day.
get down there this morning, start off with test welds, looking perfect, good penetration, easy control.
Move everything over to the car and connect up. start by refilling the holes i blew through last week, perfect, easy going, seam up a couple of spots, still good.
Hang the torch up for a moment, unit still running, tap a repair patch closer to the skin, pick up torch and start welding again.
BANG, starts blowing holes and motor running max speed.
Shut down, open up the new PWM, one of the transistors has melted the plastic case and fried itself.
Stupid SIP!.
After walking outside and cooling myself down i decided to test the current draw on the motor. at straight 24VDC it seems to have about 400mA, not that much for a supposed 40A controller.
So now i have no idea if im just really unlucky to have the same fault twice in a row, or if there is something else i have missed?
works fine at initial test, works fine for the first couple of welds, then self destructs???
First thing i did was to give it a separate 24VDC power supply, one of these (AC 110-240V TO DC 12V/24V 5A/10A/15A/20A/30A Transformer Regulated Power Supply) off ebay, mount that in the case, rigged through a relay and the original speed control board. got this all tidied up and looking sweet, put everything back together and did some test welds.
All good, speed nice and controlled, test pieces welded up nice. so over to the car.
Made up the first patch, clamp in place, fire up the psycho SIP, first couple of welds all good, stop for a moment to inspect, machine left running, then start welding again.
Blows holes in everything, try to turn speed down, has no effect, i realise the the wire speed is no flat out.
Stop everything, shut off gas, open Wire Hold Down roller and try it, Motor running max speed, control pot having no effect.
Bugger, the TIP035 has blown up, full 24V to motor.
So i decide to go the PWM route, order this (AU Pro 40A DC Motor Speed Switch Control PWM HHO RC Controller 12V 24V 48V 2000W) from ebay, wait all week, it finally arrived friday.
late friday night, quickly jury rig it in place to test, runs good, controls speed beautifully.
Yesterday, wire and fit the new speed controller, looking really sweet, all fitted and tidied set for Sunday welding day.
get down there this morning, start off with test welds, looking perfect, good penetration, easy control.
Move everything over to the car and connect up. start by refilling the holes i blew through last week, perfect, easy going, seam up a couple of spots, still good.
Hang the torch up for a moment, unit still running, tap a repair patch closer to the skin, pick up torch and start welding again.
BANG, starts blowing holes and motor running max speed.
Shut down, open up the new PWM, one of the transistors has melted the plastic case and fried itself.
Stupid SIP!.
After walking outside and cooling myself down i decided to test the current draw on the motor. at straight 24VDC it seems to have about 400mA, not that much for a supposed 40A controller.
So now i have no idea if im just really unlucky to have the same fault twice in a row, or if there is something else i have missed?
works fine at initial test, works fine for the first couple of welds, then self destructs???
Tray
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Sounds like if you didn’t have bad luck you wouldn’t have any.
Haven’t had a chance to play with mine other than the couple of beads when I finished modding it due to this.....
https://www.mig-welding.co.uk/forum/threads/the-mrs-and-mechanical-sympathy.103213/
and I’ve got a brand new XR938 to test out too
It could be a short in the motor windings that’s only showing up once it’s warmed up a bit, something shorting somewhere on the wiring to the motor or you may just have been really unlucky.
I’m guessing the 400mA was with no load i.e. wire being fed, maybe try getting a reading with a load on the motor.
Did you check the voltage at the motor?
Try locking the wire drum up and put a light pressure on the roller wheels rather than dumping loads of wire out of the gun.
TimW4302
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may have been just dud components.
the PWM i fitted has 6 transistors in parallel sharing the load. i cut out the 2 dead short ones and tested it with them out of the cct and it was operational again with fully controllable motor speed.
But im obviously not going to weld with it like that. just waiting on the replacement unit to arrive
the PWM i fitted has 6 transistors in parallel sharing the load. i cut out the 2 dead short ones and tested it with them out of the cct and it was operational again with fully controllable motor speed.
But im obviously not going to weld with it like that. just waiting on the replacement unit to arrive
Tray
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Just thought I’d post a quick vid of me welder in action after the mods.
I’m still learning and haven’t used it for any real length of time but it seems good now.
0.8 flux core Lowest power setting, 30% motor speed, spare car door (thanks to the Mrs poor spacial awareness)
Run practice
Small stitches practice
More pics and videos going up here as I learn.
https://www.mig-welding.co.uk/forum/threads/finally-got-round-to-having-a-go-at-welding.104056/
Thanks to all who have contributed to this thread and helped me on my way.
I’m still learning and haven’t used it for any real length of time but it seems good now.
0.8 flux core Lowest power setting, 30% motor speed, spare car door (thanks to the Mrs poor spacial awareness)
Run practice
More pics and videos going up here as I learn.
https://www.mig-welding.co.uk/forum/threads/finally-got-round-to-having-a-go-at-welding.104056/
Thanks to all who have contributed to this thread and helped me on my way.
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