Stubourn Philips Screws

[Kim]

Re MIG ownership practicalities; I do have quite a lot of welding kit these days but my first (and still to this day most-used/favourite) MIG set cost £35 used and I think I was up and welding for a net outlay of less than £60.  A hobby MIG takes up about two cubic feet of storage space and you don't need a workshop per se

Yeah, but it's not about those two cubic feet, so much as all the other cubic feet of all the other workshop equipment that comes higher up the priority/dependency list.  Sure, welding's nice to have, but probably only after you've got a decent assortment of hand tools, bench vice (and associated bench), drill press, grinder, etc, etc.  Not to mention a stash of useful bits of material to work with.

There's no point in putting effort into a setup like this when there's an ongoing risk that you're going to have to move into a poxy flat in six month's time.

(And quixoticgeek's point about the electrickery, which I hadn't considered.)

[Brucey]

re electricity supply; my favourite machine is rated at 90A output and the average voltage at the contact tip (under load) is not more than around 20V, making the machine's peak output about 1800W. You can do a lot of useful welding at lower currents than this.   It uses a 13A plug top fuse but I would expect it to run quite happily on a 10A fuse (2300W on a 230V supply) if necessary, perhaps provided the peak power settings are not employed. I have often used it on the end of a 50m extension reel and things have been fine.

Many years ago (before hobby MIG welders were popular) you could buy a very simple, compact electric welding apparatus that comprised little more than a transformer in a box, a little smaller than a shoebox. This was just enough to run small (~1.6mm IIRC) MMA electrodes. The power setting was adjusted using an incredibly crude inline resistor made from a spiral of thick wire that had a higher resistance than normal; a crocodile clip was placed on it so that more or less resistance could be in the circuit, affecting both the voltage and the current in the arc. There was no voltage adjustment otherwise. The kit also came with carbon arc electrodes so that you could do certain types of brazing and heating too.  The set drew a lot less than 10A under load.  Now just for fun I bought one of these units (used) a few years ago and even though I would describe myself as 'reasonably competent' these days I did find it extremely difficult to do any good quality work with it. 

I guess this is a modern equivalent more or less

for MMA welding.

So it is easy enough to assume that you can't have or run welding equipment, when in fact it isn't necessarily the case.  I also think that it is easy to get sucked into thinking you need a fully equipped workshop as well; not so. A hand held electric drill, an angle grinder and a welding set will get you very far indeed.  The main thing is if you really want to do it, not to let things get in your way.  If you have enough drive to do something, there are always ways and means.  For example in many towns and cities you can take a night class in welding which will allow you access to all kinds of equipment and you will meet folk who have their own kit at home and so forth.

Some notable examples of 'domestic welding' include that Graham Obree largely built his 'beastie' machine in his kitchen, and there have been several instances of folk building a car chassis indoors too. In the latter instance things have got out of control a bit in some cases and the machine has only come out of the house by virtue of some, er, demolition and remodelling work...    Obviously this isn't for everyone, but where there is a will there is usually a way!

cheers

[bobb]

All this talk of buying tools and welding kit, have you considered just buying a new pair of pedals?! 

[quixoticgeek]

All this talk of buying tools and welding kit, have you considered just buying a new pair of pedals?! 

Well there is that option... but... tools are shiny...

J

[mzjo]

re electricity supply; my favourite machine is rated at 90A output and the average voltage at the contact tip (under load) is not more than around 20V, making the machine's peak output about 1800W. You can do a lot of useful welding at lower currents than this.   It uses a 13A plug top fuse but I would expect it to run quite happily on a 10A fuse (2300W on a 230V supply) if necessary, perhaps provided the peak power settings are not employed. I have often used it on the end of a 50m extension reel and things have been fine.

Many years ago (before hobby MIG welders were popular) you could buy a very simple, compact electric welding apparatus that comprised little more than a transformer in a box, a little smaller than a shoebox. This was just enough to run small (~1.6mm IIRC) MMA electrodes. The power setting was adjusted using an incredibly crude inline resistor made from a spiral of thick wire that had a higher resistance than normal; a crocodile clip was placed on it so that more or less resistance could be in the circuit, affecting both the voltage and the current in the arc. There was no voltage adjustment otherwise. The kit also came with carbon arc electrodes so that you could do certain types of brazing and heating too.  The set drew a lot less than 10A under load.  Now just for fun I bought one of these units (used) a few years ago and even though I would describe myself as 'reasonably competent' these days I did find it extremely difficult to do any good quality work with it. 

I guess this is a modern equivalent more or less

for MMA welding.

So it is easy enough to assume that you can't have or run welding equipment, when in fact it isn't necessarily the case.  I also think that it is easy to get sucked into thinking you need a fully equipped workshop as well; not so. A hand held electric drill, an angle grinder and a welding set will get you very far indeed.  The main thing is if you really want to do it, not to let things get in your way.  If you have enough drive to do something, there are always ways and means.  For example in many towns and cities you can take a night class in welding which will allow you access to all kinds of equipment and you will meet folk who have their own kit at home and so forth.

Some notable examples of 'domestic welding' include that Graham Obree largely built his 'beastie' machine in his kitchen, and there have been several instances of folk building a car chassis indoors too. In the latter instance things have got out of control a bit in some cases and the machine has only come out of the house by virtue of some, er, demolition and remodelling work...    Obviously this isn't for everyone, but where there is a will there is usually a way!

cheers

The usual power problem with an arc welder, including MIG and TIG, is the voltage surge when starting the arc. I don't know what is required for MIG but "stick" welders need about 45v and I imagine scratch-start TIG to be much the same. I could go away and look up MIG requirements if I had to but someone will surely be along to give chapter and verse. This is the stage that blows your fuses. (when you are used to a 450A Miller in a big workshop with loads of amps available on the circuit it is not something that you think about). I also have one of those old cheap welding transformers (now 30yrs old) which is due to have its secondary rewound using copper instead of aluminium although it might be cheaper to simply replace it. It cost £50 30 years ago and they haven't gone up in price much since but I would advice anyone a bit serious to invest in a small portable dc unit (but buy a decent one, which is not cheap) because they are so much nicer to use  and decent results are so much easier to make. I have been told by friends who have studied this that £60 would not cover your annual argon rental for a MIG welder (and 1cubic meter costs the same as 3 so you can't save there). Piching a CO2 bottle off a brewery is the only cheap option. Welding outdoors greatly increases your gas consumption. Flux-cored wire is a possibility but has other disadvantages.

I don't have access any longer to the big MIG welder but yes I do know someone with a little one and no when I have needed such a thing I have had to fall back on throw-away oxy-propane or my old ac arc machine. I wouldn't be welding pedals with either if I could avoid it but I could heat the screw to try to help it on its way. I do have an impact driver though 

[jsabine]

The usual power problem with an arc welder, including MIG and TIG, is the voltage surge when starting the arc.

That's one advantage of old-school fusewire - higher tolerance to overload for a time. Even MCBs won't trip instantly unless they're subjected to a 5 or 10x overcurrent - they'll pass a smaller overload for anything from a few seconds to a few hours before cutting out.

[Kim]

The usual power problem with an arc welder, including MIG and TIG, is the voltage surge when starting the arc.

That's one advantage of old-school fusewire - higher tolerance to overload for a time. Even MCBs won't trip instantly unless they're subjected to a 5 or 10x overcurrent - they'll pass a smaller overload for anything from a few seconds to a few hours before cutting out.

There are different flavours of MCB to allow for loads with high inrush currents.  You probably need a type C or D for a welder if you're doing things properly.

[Brucey]

The usual power problem with an arc welder, including MIG and TIG, is the voltage surge when starting the arc. I don't know what is required for MIG but "stick" welders need about 45v and I imagine scratch-start TIG to be much the same. I could go away and look up MIG requirements if I had to but someone will surely be along to give chapter and verse....

 The open circuit voltage of a typical (<100A) hobby MIG is ~25V or less; this droops under load in a controlled way, thus you can adjust the open circuit voltage (using switched wire tappings on the transformer usually) and the wire feed speed to hit 'the sweet spot' for any job, provided the bloke that designed the thing knew what he was doing, which doesn't have to cost a fortune. IME the Clarke range of machines are pretty good in this respect. There is an inrush current but it can't be so very much with a well-designed set; the inline choke slows it down too.

... I have been told by friends who have studied this that £60 would not cover your annual argon rental for a MIG welder (and 1cubic meter costs the same as 3 so you can't save there). Piching a CO2 bottle off a brewery is the only cheap option. Welding outdoors greatly increases your gas consumption.

Renting gas bottles from the major players is a mug's game. There are many other options which your friends presumably have not thought of ;

1) £10-£15 a go throwaway bottles containing ~500-800g of CO2 are OK for occasional use (but will usually leak down to nothing if left for a few months)

2) my local car spares emporium will sell you a (~5-7kg) bottle of CO2 gas for less than £30 (plus bottle deposit first time round).

3)   Out of date (but full) CO2 extinguishers are worth pennies and contain a lot of useful gas.  Once the horn is unscrewed, lo and behold, the standard CO2 regulator thread is exposed.  Once you have a regulator (I bought an old O2 rated one for £3 and modified it to fit CO2) gas costs can be very low this way. Some outfits (that do fire extinguisher refurbs) will do a replacement 2kg extinguisher for ~£15 on an exchange basis, a bit more for a large one (~5kg of gas) .  I have occasionally bought CO2 extinguishers at boot sales; typical cost is £3-5 a go.

Obviously a small gas shroud and an M5 contact tip will reduce the gas consumption (to about half) vs a larger one. Outdoors, a local shield will keep the breeze at bay; I often use my (heavily gloved) left hand to shield the work from the breeze.

 BTW simply turning up the gas flow when welding out of doors is almost invariably  100% counterproductive; the gas must leave the shroud under laminar flow conditions, else air is entrained in the (now turbulent) shielding gas flow and the benefit of the shielding gas is lost, with or without a breeze of any kind.... .  If you don't have a gas flow meter, you can put the torch up to your ear (wire feed off obviously) and listen carefully. You can usually hear when the flow in the shroud transitions to turbulent, because the sound is quite different. Whatever setting that is, the optimum flow rate is usually a bit less than that.   IME, very much shielding gas is simply wasted by people who ought to know better....

hth

cheers

[mzjo]

Arcox is so much nicer to use thobut  I think if I were welding MIG outdoors I would be very tempted to try flux-cored wire and no gas, if the pulleys were available for the welder.

I think UK gas prices are much lower than I could find where I am. Throw-away argon is 60€ a pop; throw-away oxygen is 18-26€ depending on which shop you use (all the same make of bottle though). I have considered recharging my bottles but you don't want to make mistakes with 200bar of oxygen. I don't think I have ever seen throw-away CO2.

For the price of my brother-in-law's small MIG I could have a dc arc set which would also handle scratch-start TIG which would be more useful to me - "mais bonjour le prix de gaz!"

[Brucey]

ArCO2 gas is OK; I keep a bottle of it for welding stainless steel. I use CO2 on other steels.  People make a lot of fuss about how one is better than the other but

- the right settings are different for each gas; you can't just switch from one to the other
- if you are doing repairs or welding anything that isn't quite clean, CO2 is probably better because it has a reducing action (it is an active gas rather than inert, so strictly speaking MAG rather than MIG)
- CO2 makes for a slightly hotter arc; this makes the most of low-powered hobby MIG welders where an ArCO2 weld would perhaps run a bit cold
- If you are going to run over the weld beads with a cup brush anyway, by the time you have done that you won't easily tell the difference between an ArCO2 weld and a CO2 weld
- if you are going to dress the weld beads by grinding, it doesn't matter what gas you use; in fact CO2 is arguably  better because there can be less porosity if the welded parts are not perfectly clean
- CO2 comes in liquid form, but ArCO2 mix doesn't, so the weight you get in a similar sized bottle is usually far greater with CO2 (although this does vary with the fill pressure of ArCO2 obviously). The volume of gas (weight  for weight) is about the same both ways BTW.

FWIW whilst it does have a place (and I do keep a reel or two of the wire kicking around) I would rather bang nails through soft parts of my anatomy than use flux-cored wire when I could use gas MIG instead, because;

- the fumes are very poisonous
- there is much more UV from the arc
- the consumable is ludicrously pricey (~x5 vs standard wire)
- the consumable doesn't feed as well as solid wire
- the welds themselves are pretty shite (often full of porosity)
- the welds are horrible to look at with lots of spatter in most cases, and require a lot of clean-up
- the yield of weld metal (per weight on the reel) is pathetic; between the flux and the spatter losses, a yield of 30-50% is about as good as you can get, making the weld metal ~x10 to x15 more expensive net (before gas costs).

I don't see why you can't use a CO2 fire extinguisher as a CO2 gas source...?

FWIW a MIG set is arguably more versatile than any other single welder type; particularly if you can use inexpensively sourced CO2 gas, it is also the least expensive to run, by far.   By contrast TIG is no good for repair welding (the cleanliness standards required are too high in most cases, unless you like using your tungsten as a consumable... ) and MMA is next-to-useless on thin materials by comparison (it also creates much more distortion because the heat input per unit weld metal is usually far higher).

 MIG is also far easier to do well, and you can do it one-handed, which leaves a hand free to hold the work. The latter point might not sound that important, but setting up, jigging and tacking are so much easier and quicker, often a one-off job can be MIG welded completely before welding even starts with a  TIG welded version.

cheers

[Gattopardo]

Doesn't co2 freeze the tip?

[Brucey]

Doesn't co2 freeze the tip?

The torch does not get chilled appreciably, but the contact tip does see some cooling benefit from the gas flow; gasless MIGs do tend to overheat the contact tip by comparison.  The shielding gas cools at the point where the phase changes and/or pressure changes and it expands (i.e. in the bottle and regulator).  Unless the flowrate is very high, the gas is back near ambient temperature by the time it reaches the torch, but does help cool the contact tip nonetheless.

There is a phase change in the bottle (the liquid CO2 is in equilibrium with gaseous CO2 which is extracted at the top of the bottle) so the bottle itself  gets cold if you do a lot of welding and the pressure in the bottle can even  drop somewhat; in warm weather the bottle can be at ~50bar and in cold weather after a lot of use I have seen the bottle gauge go down to about 10 bar.

 The pressure change in the gaseous phase is in the regulator, not the torch. The flow regulation is done by altering the output pressure of the regulator and then passing the gas through a flow restrictor (fixed or adjustable) near the regulator which only has a small pressure drop. [There is almost no pressure drop at the torch itself; in fact if you have  a Euro torch fitting and the gas O ring is bad, the usual thing is that air leaks into the gas line rather than that gas leaks out at the bad joint...]

So in hard use (lets say you use 1/2kg of gas by doing lots of welding in a short space of time and the ambient temperature is low to start with) the bottle may get cold enough to get a frost ring on it (at the liquid level inside the bottle) and the regulator may also get covered in frost too.  A decent two-stage regulator will carry on working even with frost on the outside of it, but a cheap single stage regulator might not carry on working as well as it should. I have occasionally had to make an adjustment to the flowrate when using the latter type when it has got cold. 

 BTW the cooling effect in the regulator may well be less severe with CO2 than with ArCO2 because the pressure change inside the regulator is less. A full-ish ArCO2 bottle is usually around 200bar or so, i.e. about x5 or x10 more than a CO2 bottle.

cheers

[Moleman76]

Several applications of a penetrating oil made to assist in the loosening of threaded fasteners may help. 

I'd mention product names, but they probably wouldn't translate from USAnian to The Queen's English.

well, actually, Google tells me that "PB Blaster" and "Kroil" may be stocked by a few sources. 

Warning - they have a smell that penetrates as well as the oil does.  Best to not use in one's living space if possible, and might require a fume-tight receptacle while you're awaiting their magic action.

[Gattopardo]

Re MIG ownership practicalities; I do have quite a lot of welding kit these days but my first (and still to this day most-used/favourite) MIG set cost £35 used and I think I was up and welding for a net outlay of less than £60.  A hobby MIG takes up about two cubic feet of storage space and you don't need a workshop per se

Yeah, but it's not about those two cubic feet, so much as all the other cubic feet of all the other workshop equipment that comes higher up the priority/dependency list.  Sure, welding's nice to have, but probably only after you've got a decent assortment of hand tools, bench vice (and associated bench), drill press, grinder, etc, etc.  Not to mention a stash of useful bits of material to work with.

There's no point in putting effort into a setup like this when there's an ongoing risk that you're going to have to move into a poxy flat in six month's time.

(And quixoticgeek's point about the electrickery, which I hadn't considered.)

Tool porn?

[quixoticgeek]

Several applications of a penetrating oil made to assist in the loosening of threaded fasteners may help. 

I'd mention product names, but they probably wouldn't translate from USAnian to The Queen's English.

And even less chance of translating to the King's Dutch...

well, actually, Google tells me that "PB Blaster" and "Kroil" may be stocked by a few sources. 

Warning - they have a smell that penetrates as well as the oil does.  Best to not use in one's living space if possible, and might require a fume-tight receptacle while you're awaiting their magic action.

I received an impact driver with a jis head from Japan on Friday, will give it a go when I'm next at the place with a vice.

J

[Gattopardo]

Doesn't co2 freeze the tip?

The torch does not get chilled appreciably, but the contact tip does see some cooling benefit from the gas flow; gasless MIGs do tend to overheat the contact tip by comparison.  The shielding gas cools at the point where the phase changes and/or pressure changes and it expands (i.e. in the bottle and regulator).  Unless the flowrate is very high, the gas is back near ambient temperature by the time it reaches the torch, but does help cool the contact tip nonetheless.

There is a phase change in the bottle (the liquid CO2 is in equilibrium with gaseous CO2 which is extracted at the top of the bottle) so the bottle itself  gets cold if you do a lot of welding and the pressure in the bottle can even  drop somewhat; in warm weather the bottle can be at ~50bar and in cold weather after a lot of use I have seen the bottle gauge go down to about 10 bar.

 The pressure change in the gaseous phase is in the regulator, not the torch. The flow regulation is done by altering the output pressure of the regulator and then passing the gas through a flow restrictor (fixed or adjustable) near the regulator which only has a small pressure drop. [There is almost no pressure drop at the torch itself; in fact if you have  a Euro torch fitting and the gas O ring is bad, the usual thing is that air leaks into the gas line rather than that gas leaks out at the bad joint...]

So in hard use (lets say you use 1/2kg of gas by doing lots of welding in a short space of time and the ambient temperature is low to start with) the bottle may get cold enough to get a frost ring on it (at the liquid level inside the bottle) and the regulator may also get covered in frost too.  A decent two-stage regulator will carry on working even with frost on the outside of it, but a cheap single stage regulator might not carry on working as well as it should. I have occasionally had to make an adjustment to the flowrate when using the latter type when it has got cold. 

 BTW the cooling effect in the regulator may well be less severe with CO2 than with ArCO2 because the pressure change inside the regulator is less. A full-ish ArCO2 bottle is usually around 200bar or so, i.e. about x5 or x10 more than a CO2 bottle.

cheers

Last time I welded with pub gas I found that the tip would get a bit of frost on it, and the tips needed cleaning more often than when using argo shield.  That was welding outdoors.

[Brucey]

FWIW if the tip gets frost on it, that strongly suggests that something was wrong with the setup, e.g. too much gas flow, choked flow at the torch, gas delay set far too long, that kind of thing.

If the gas flow is set wrongly, this may have caused the contact tip to need more frequent cleaning too.

cheers

[mzjo]

FWIW if the tip gets frost on it, that strongly suggests that something was wrong with the setup, e.g. too much gas flow, choked flow at the torch, gas delay set far too long, that kind of thing.

If the gas flow is set wrongly, this may have caused the contact tip to need more frequent cleaning too.

cheers

I never saw or experienced any cooling of the tip by gas freezing with Arcox nor freezing on the bottle or regulator. My workmates frequently welded at 30l/m although I felt that was a bit high and used to turn it down a bit. Our Blupak 450 only had aircooling for the torch although the models in the showroom afterwards had liquid cooling. We could have done with it! Recharging concrete shears we could go through a spool of wire in a day. I welded with liquid-cooled torches under training, they were OK but a bit heavy at the end of the day.
Spatter shouldn't be a problem if you are adjusted correctly and you use a suitable anti-spatter spray or paste.

[Brucey]

ArCO2 doesn't undergo a phase change so there is less cooling effect in the bottle. The regulators still get cold though; I guess it is pot luck if is cold enough/humid enough to get frost showing; I've regularly seen condensation on the bottles and regulator of three-phase machines that are seeing hard use. 30l/min seems a very high flowrate; a (much smaller) hobby MIG torch will usually work happily at a small fraction of that flowrate.

[BTW I have seen folk 'need to use that flowrate' because (unbeknownst to them) their gas line is leaking -usually at the euro connector- and unless the flowrate is turned up so high that the torch starts to choke the flow, air is dragged into the gas line (via Bernoulli effect) and the shield 'obviously isn't good enough'.  I've even seen blokes trying to weld with no 'O' ring at all in the Euro connecter, leave alone a worn or damaged one.... ..]

BTW I have often wondered if  torches were designed differently (i.e. so that there is a significant pressure drop at the torch, and therefore more cooling effect) if this might allow harder use before overheating ensues.  However whilst we are still on eurotorch fittings, it seems unlikely to me that the arrangement will be reliable enough...

cheers

[Asterix, the former Gaul.]

A while ago someone on here recommended this stuff:

https://www.amazon.co.uk/d/Automotive/Bearing-Station-8040x400ml-Loctite-Freeze-Release-400ml/B0030MJQDW/ref=sr_1_7?ie=UTF8&qid=1501669200&sr=8-7&keywords=plus+gas

It was extremely effective if left for a bit after application.   Impatience will get you nowhere!

[KM]

I received an impact driver with a jis head from Japan on Friday, will give it a go when I'm next at the place with a vice.

J

The tension is unbearable!

[Jacomus]

If the screw isn't too badly stuck in place, laying a rubber band (just the one strip, not folded over!) over it, then applying the srewdriver with as much downward force as you can manage can help.