Munkul
Jack of some trades, Master of none
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I've seen those before but can't think where or when... something to do with a gullco carriage perhaps?
- Thread starter qwakers
- Start date
Shox Dr
Chief Engineer to Carlos Fandango
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No. its a foot?
dan.taylor.1
General Tinkererer
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First aluminium welding after having the jasic ac tig for well over 18 months... 
Fixed this cast bit that I believe is from a potters wheel, it was certainly caked in clay when I got it!
No pre cleanup shots, but it took a long time to get the settings right to boil all the carp out of it, that's after a thorough wire wheel, acetone wash several times, and between weld cleans with a new stainless wore brush and more acetone!
Quite happy with how it turned out to be honest, I've only ever run a few beads when testing machines out before ei bought the jasic.
Fixed this cast bit that I believe is from a potters wheel, it was certainly caked in clay when I got it!
No pre cleanup shots, but it took a long time to get the settings right to boil all the carp out of it, that's after a thorough wire wheel, acetone wash several times, and between weld cleans with a new stainless wore brush and more acetone!
Quite happy with how it turned out to be honest, I've only ever run a few beads when testing machines out before ei bought the jasic.
Take a foot pump - just in case...A while ago, I rescued one of those battery-operated pistol-grip air compressors from a skip at work - as soon as you plugged the battery in, the pump would run.
It has a built-in controller that allows you to preset the pressure in whatever units you fancy - psi, Bar, kpa etc. - and then shuts off when it reaches the figure.
It would still pump air, you just had to whip the battery out when you'd finished. Given some of the locations it got used on jobs though, it was less than ideal so it was skipped.
I stripped it down and found a MOSFET on the controller board that had gone short-circuit. That would be a surface-mount MOSFET, about 8mm square. That I could barely see, never mind read.
I used the Hubble telescope to get the part number off it (MDD1501, rated for about 30A!) and then found that nobody in the UK, or Europe or indeed this solar system has any. Luckily someone in China had them on Ebay, five for a couple of quid, so I punted my wad into the ether and expected to be disappointed.
Unbelievably, in a matter of a couple of weeks, a small envelope arrived bearing the requisite components. I duly scrounged the SMD rework station from the office and set myself up in the kitchen at Wedg1e Villas. First I used some isopropyl alcohol to clear away some oxidation that was present around the board, then it was the work of mere moments, once I'd armed myself with one of those 'mongnifiers' - you know, a headband with clip-in high-power lenses that makes you look like some kind of stamp-collecting pervert - and got the hot air gun at 480C, way beyond what my 50W Antex could do, to desolder the MOSFET.
Then I used my Hands Like A Paedophile (tm) to carefully position the replacement trannie and melted some soldery goodness.
Leaving all the guts hanging out like a freshly-Scania'd hedgehog I clipped the battery on and - nothing. Which was a good start. The display lit up, I pressed some buttons and then the trigger. Sod-all happened
Right then.
Out with the sort of magnifier a chap needs after a long walk in the coldand I realised that the corrosion I'd cleaned off had actually been worse than I thought, and a transistor near the MOSFET only had two of its three leads! As I didn't have any spare SMD transistors to hand I thought I'd see if I could clean up the raggy stump of lead and get some solder on to reconnect it to the track. Pressed the trigger: still nothing. Bums, I said.
Testing with a multimeter (and when working around SMD stuff with a magnifier on, meter probes look like scaffold pipes) revealed that there was no connecton between the corroded transistor and the new MOSFET, despite them being coupled by a 1200 Ohm resistor. That bloody corrosion had eaten the metallic pad off one end of the ceramic resistor, which must measure all of 2 x 1mm! I desoldered it and rummaged in my spares racks that have followed me around since I got into electronics in '82 and found a resistor of the right value - but of course it was a full-size, wire-ended thing, a monster in comparison! Luckily, although my eyes are shot, my joints creak and I have tinnitus that sounds like a dentist's drill in the next room I still have a steady hand so with a bit of fiddling I got the new resistor in...
And it only bloody works! Choose your units, preset your pressure, press the trigger and watch the digits count up until the pump cuts out.
Whoever chucked it also saw fit to include the carry case, charger, fag lighter adapter etc. - so I can throw it in one of the bike panniers for the next time one of our squad gets a puncture in the middle of nowhere. Soon be spring
Good job though, I just can’t get into SM electronics...
The_Yellow_Ardvark
https://www.death-clock.org/
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This arrived yesterday. I was told it is only suitable for spares only.
After a good look I found the following faults.
Cup washer in pump was wrong size. So it did not pump any pressure.
Mantle was torn and wrong type.
The fuel residue was not paraffin.
The top image is a pre-warm
Correct mantle fitted, fuel tank and internals cleaned and a suitable pump washer fitted.
The_Yellow_Ardvark
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I have ben known to enjoy a coffee.
My local does a very good brew. But their best coffee machine is old and spares are hard to come by.
Alas, in the past poor repairs have been carried out.
This is a good example of a poor fix.
None food grade PTFE tape.
Spout facing the wrong way.
Handle rattles.
A new filter cup is about £30, if you can get one.
Handle fitted. I needed to make a M6 long bolt.
Remove the PTFE tape and repair the thread.
A copper washer fitted. Allowed the spout to be fitted and tightened to allow it to face the correct way.
My local does a very good brew. But their best coffee machine is old and spares are hard to come by.
Alas, in the past poor repairs have been carried out.
This is a good example of a poor fix.
None food grade PTFE tape.
Spout facing the wrong way.
Handle rattles.
A new filter cup is about £30, if you can get one.
Handle fitted. I needed to make a M6 long bolt.
Remove the PTFE tape and repair the thread.
A copper washer fitted. Allowed the spout to be fitted and tightened to allow it to face the correct way.
Last edited:
slim_boy_fat
Forum Supporter
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^^ That repair must have scored you a few pints free gratis?
The_Yellow_Ardvark
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I was rewarded, yes.
I'm going to need some education on this . . . unless is lubricated, or got additives for antiseize etc, I was under the impression as PTFE is chemically inert, odourless and tasteless, it was suitable for food grade use?
Only time I've been told to be careful of its use, was in cigarette making and packaging machinery, where the worry was it would be in a burning item, being breathed in.
Maker
Most folk just call me; Orange Joe
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You wouldn't want to accidently give a load of smokers respiratory diseases.
The_Yellow_Ardvark
https://www.death-clock.org/
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It was on thge list of items not allowed to be used. So i followed the instructions.
James1979
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- Orkney
I was always told you shouldn’t use plumbers PTFE on oxygen connections.
I’ve got a roll of gas safe that I was given in BOC years back. Never used it because I put torches together dry anyhow.
Not sure what is in the plumbers one. Lube of some sort I imagine?
Maker
Most folk just call me; Orange Joe
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Is your gas safe PTFE the yellow stuff? If so, it's just thicker as far as I know, it's absolutely not safe for oxygen. Neither would some sort of lubed tape, for the same reason.
James1979
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Shows how much BOC know!
It is much thicker from memory. I’m not sure what else is different about it. Never used it. It feels different. Drier. Maybe that’s just the maker?
I did point this out at the time (1992 ish) . . . something like they knew what some of the constituent parts would do to them, and accepted the risk.You wouldn't want to accidently give a load of smokers respiratory diseases.
I suppose if they had added it to the warning label, it would have been okay
Pure PTFE, and unlubed as you mention is okay for oxygen use - but beware of loose bits getting into the flow.
I guess cheapo plumber stuff is lubed and isn't necessarily pure PTFE. So having your coffee lubed with funny white bits floating in it might not be good for business
Working in the USA 20 yrs ago, different colours simply seemed to indicate different thicknesses - and the thicker it was, the more you seemed to have to stretch it (making it thinner) to make it stay put as you assembled the joint - so you might as well use the thinner stuff to begin with
I think the Americans do have some rules (of thumb maybe,rather than law?) as to different thicknesses on different diameters.
James1979
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This is the stuff I got given in BOCPure PTFE, and unlubed as you mention is okay for oxygen use - but beware of loose bits getting into the flow.
I guess cheapo plumber stuff is lubed and isn't necessarily pure PTFE. So having your coffee lubed with funny white bits floating in it might not be good for business
Working in the USA 20 yrs ago, different colours simply seemed to indicate different thicknesses - and the thicker it was, the more you seemed to have to stretch it (making it thinner) to make it stay put as you assembled the joint - so you might as well use the thinner stuff to begin with
The standard quoted says it’s unsintered. No idea if that’s good or bad for oxygen as I’ve never used it!
Even a diagram on which way to wrap it - I tried explaining to an apprentice a long time ago which direction to wrap as he was having issues . . . maybe I spoke Yorkshire or summat as he just looked befuddled . . . I can't remember anyone ever explaining it - it just seemed obvious after the first attempt at the wrong way.
