Welding

[Catweazle]

For welding razor blades to a boat anchors. Every home should have one.

With some welding methods it is difficult to join pieces of different thickness, the thin piece melts away whilst the thick piece doesn't get hot enough. The TIG is particularly good for repairing broken metal parts, the heat affected area is quite small and as I mentioned earlier it's very controllable. It's a bit too slow to use for large volume fabrication, but as a versatile repair tool is unbeatable.

[careful_eugene]

Do you have an idea of what you want to weld and where? I ask because if you are welding outside it is difficult to weld using a gas shield (MAG and TIG), most of the site welding we do is either done with MMA (stick welding) or MAG using a flux core wire which is expensive.
MAG welders are great for volume but can use a lot of consumables (tips, shrouds, liners, torches). MMA welding is simple, there are lots of cheap plants about and is probably the best choice if you're only welding occasionally, although this does depend on the thickness of material you want to join (don't expect to be welding car bodies with MMA). For thin mild steel, stainless and aluminium, Tig is the best. Hope this helps.

[clv101]

The TIG is particularly good for repairing broken metal parts, the heat affected area is quite small and as I mentioned earlier it's very controllable. It's a bit too slow to use for large volume fabrication, but as a versatile repair tool is unbeatable.

Yeah, this is why I'm interesting in TIG - a versatile repair (and fabrication) tool. My primary interest is bicycle frames, for that I'm planning on an oxyacetylene set up. TIG welding is a secondary interest but seems like a useful skill/tool to have.

[Little John]

Do you have an idea of what you want to weld and where? I ask because if you are welding outside it is difficult to weld using a gas shield (MAG and TIG), most of the site welding we do is either done with MMA (stick welding) or MAG using a flux core wire which is expensive.
MAG welders are great for volume but can use a lot of consumables (tips, shrouds, liners, torches). MMA welding is simple, there are lots of cheap plants about and is probably the best choice if you're only welding occasionally, although this does depend on the thickness of material you want to join (don't expect to be welding car bodies with MMA). For thin mild steel, stainless and aluminium, Tig is the best. Hope this helps.

If it was car body work you could just use oxy-propane brazing. So. between brazing and stick, most stuff that most people are going to need to do is covered.

[careful_eugene]

The TIG is particularly good for repairing broken metal parts, the heat affected area is quite small and as I mentioned earlier it's very controllable. It's a bit too slow to use for large volume fabrication, but as a versatile repair tool is unbeatable.

Yeah, this is why I'm interesting in TIG - a versatile repair (and fabrication) tool. My primary interest is bicycle frames, for that I'm planning on an oxyacetylene set up. TIG welding is a secondary interest but seems like a useful skill/tool to have.

Good choice, you can also cut steel with oxyacetylene, I'm sure you'll be careful with the gas cylinders and will read up on correct storage and use.

[Catweazle]

Reading about this makes me wonder about the post-huge-crash usefullness of my TIG set, eventually I'll run out of shielding gas and have no idea how to make more.

On the other hand, if I can generate electricity I can make Hydrogen and Oxygen. I only have a small gas setup, one of those DIY jobs that run off oxygen and MAPP gas, but I guess it would work well enough with O and H to at least braze or silver solder.

Does anyone know how to make a DIY shielding gas ?

[JavaScriptDonkey]

Any idiot with 30minutes instruction can puddle some slag on the surface of a bit of dirty steel and think he's mastered welding.

I've seen some shocking repairs over the years that looked okayish until the vehicle was in an accident and then it parted like it was held on by sticky oxides.

Grab the chance for some professional guidance while it's available as a lot of colleges have already converted their engineering workshops in to classrooms for Business Studies.

[Little John]

Reading about this makes me wonder about the post-huge-crash usefullness of my TIG set, eventually I'll run out of shielding gas and have no idea how to make more.

On the other hand, if I can generate electricity I can make Hydrogen and Oxygen. I only have a small gas setup, one of those DIY jobs that run off oxygen and MAPP gas, but I guess it would work well enough with O and H to at least braze or silver solder.

Does anyone know how to make a DIY shielding gas ?

I can tell you how to make diy shielding flux for a diy arc electrode; Borax soap and a steel coat hanger (or any other thick piece of steel wire. Fencing wire, for example).

You can also make a diy arc welder in 5 minutes with three car batteries and 2 sets of jump leads. You wire them up in series and so end up with 36 volts. The positive from the battery at one end of the series and the negative from the battery at the other end of the series provide you with your positive and negative for the welding job. You attach the negative to earth and you put the electrode on the positive clamp for the weld itself. Cos there is no limit on the amps, you can weld really quite thick steel with them. Though they will discharge sooner, obviously. If you want to limit the amperage to weld some finer stuff (or to protect your batteries), you simply put some thick gauge wire between the positive and negative battery terminals in the middle of the series. This will increase resistance and so decrease the amperage coming out of the end.

You can't get more DIY and low tech than that lot.

Edit to add:

It goes without saying (but I'm going to say it anyway), that you should use batteries that are not sealed and so allow for venting of hydrogen in the event of the batteries being discharged quickly and so getting warm. That being the case, it is a good idea to do this somewhere very well ventilated and also, as a final precaution, place a blanket or other non-flammable covering over the batteries to avoid sparks landing on them.

[Tarrel]

Reading about this makes me wonder about the post-huge-crash usefullness of my TIG set, eventually I'll run out of shielding gas and have no idea how to make more.

On the other hand, if I can generate electricity I can make Hydrogen and Oxygen. I only have a small gas setup, one of those DIY jobs that run off oxygen and MAPP gas, but I guess it would work well enough with O and H to at least braze or silver solder.

Does anyone know how to make a DIY shielding gas ?

I can tell you how to make diy shielding flux for a diy arc electrode; Borax soap and a steel coat hanger (or any other thick piece of steel wire. Fencing wire, for example).

You can also make a diy arc welder in 5 minutes with three car batteries and 2 sets of jump leads. You wire them up in series and so end up with 36 volts. The positive from the battery at one end of the series and the negative from the battery at the other end of the series provide you with your positive and negative for the welding job. You attach the negative to earth and you put the electrode on the positive clamp for the weld itself. Cos there is no limit on the amps, you can weld really quite thick steel with them. Though they will discharge sooner, obviously. If you want to limit the amperage to weld some finer stuff (or to protect your batteries), you simply put some thick gauge wire between the positive and negative battery terminals in the middle of the series. This will increase resistance and so decrease the amperage coming out of the end.

You can't get more DIY and low tech than that lot.

Edit to add:

It goes without saying (but I'm going to say it anyway), that you should use batteries that are not sealed and so allow for venting of hydrogen in the event of the batteries being discharged quickly and so getting warm. That being the case, it is a good idea to do this somewhere very well ventilated and also, as a final precaution, place a blanket or other non-flammable covering over the batteries to avoid sparks landing on them.

Probably the most useful tip I have read in a long while!

[Little John]

Any idiot with 30minutes instruction can puddle some slag on the surface of a bit of dirty steel and think he's mastered welding.

I've seen some shocking repairs over the years that looked okayish until the vehicle was in an accident and then it parted like it was held on by sticky oxides.

Grab the chance for some professional guidance while it's available as a lot of colleges have already converted their engineering workshops in to classrooms for Business Studies.

That's not right. I have shown 4 people how to stick weld and they all got it in under an hour. Their welds looked as ugly as sin, but they were strong enough. It's not hard to learn to make a strong arc weld at all. It's just hard to make one look pretty. But that comes with time.

[woodburner]

It goes without saying (but I'm going to say it anyway), that you should use batteries that are not sealed and so allow for venting of hydrogen in the event of the batteries being discharged quickly and so getting warm.

If SHHTF, this is not a good thing to do to batteries unless they are traction batteries. Ordinary starter batteries (including "leisure" batteries) will have a very short life.

For sticking aluminum, look at http://durafix.co.uk/ and http://www.techno-weld.co.uk/home.html. Much easier.

[Catweazle]

It goes without saying (but I'm going to say it anyway), that you should use batteries that are not sealed and so allow for venting of hydrogen in the event of the batteries being discharged quickly and so getting warm.

If SHHTF, this is not a good thing to do to batteries unless they are traction batteries. Ordinary starter batteries (including "leisure" batteries) will have a very short life.

For sticking aluminum, look at http://durafix.co.uk/ and http://www.techno-weld.co.uk/home.html. Much easier.

There will be a lot of spare car batteries when the petrol runs out.

[woodburner]

But wasting such a resource by inflicting abuse is not a wise move. It is currently what most "civilised" people are doing now, and look where it's got us

[adam2]

If TSHTF suddenly, I would not worry about "wasting" car batteries by using them for arc welding.
There will be a large surplus of used car batteries, most of which would rapidly become useless.
Unlike grain, tinned food, clothing, blankets etc, car batteries dont keep and may as well be "used up" for improvised welding rather than going to waste unused.

It is also possible to arc weld from a bank of good batteries as would be used in an off grid home.
To avoid damage to the battery bank, it must be very large, such that the current used for welding is comparable to normal load currents.

100 to 200 amps is a reasonable welding current, suggesting that a battery capacity of at least 1000 amp hours is required.
A series resistance would be needed to limit the current to a reasonable figure.
With a 48 volt battery bank, a series resistance of about 0.2 ohm would be about right, that would give a short circuit current of about 240 amps, and a welding current of less than that, due to the voltage accross the arc.

This resistance should consist of a length of suitable heavy cable, if long enough the welding leads may have enough resistance.

Another possible emergency source of welding current in sunlight, would be a large PV array.
After TSHTF, a re-purposed large formerly grid tied array could provide enough power for welding.
A 5KWp array, if re-configured for about 30 volts on load/50 volts open circuit, would provide a reasonable welding current.
PV modules are inherently current limited and can not be overloaded.

Such an array could power a large DC motor when not needed for welding, that could be used for grinding grain, pumping water, weaving cloth, sawing wood etc.

A large PV array has many post disaster uses that dont all need a battery.

[Little John]

It's also relatively easy to make a DIY arc welder out of step down transformers from a couple of old microwaves.

It goes without saying, of course, that electricity is dangerous and anyone attempting this does so at their own risk.

Here's a web site with photos and instructions

http://aaawelder.com/

Here's 3 vids below take you through the steps to make one.

http://www.youtube.com/watch?v=wUHnLfgg ... re=related

http://www.youtube.com/watch?v=k8tIT7ysAh0&feature=plcp

http://www.youtube.com/watch?v=K0LjBP-OrYc&feature=plcp

And here's a vid of one of them in action

http://www.youtube.com/watch?v=TcUIDE3D ... re=related