Arc welding

[firebird]

Hi

I'm going to buy an (cheap) arc welder. The ability to "stick" two bits of steel together for jig and tool making amongst other etc appeals to me. Anybody have any tips as what sort I should look at.

Cheers

Rich

 

[Troutsqueezer]

You're going to get all sorts of different advice on this topic Rich. Ask 10 welders and you'll get 11 different answers.

Cheap arc welders will weld but when you see what more expensive welders can do, you'll wish you had one of those before long.

My advice: Welders pop up frequently on Craigslist. I'd keep an eye out for a used Miller, Lincoln or similar brand (assuming those are sold where you are) MIG welder with gas. Welders work for years but the prices become very reasonable as they get a little older.

The most accurate welding is done with TIG and those welders are a little more expensive but again, thru Craigslist they can be had for a lot less than new prices. It takes a lot of practice to weld with TIG. MIG takes a little practice and does a decent job.

This will be first of many different opinions coming your way.

-Trout

 

[Jasonb]

This UK forum is quite good, have a read of the section on how to arc weld as it goes into the various types, the very cheap AC ones are not as easy to use as the DC inverters for stick welding.

http://www.mig-welding.co.uk/

For tig you would be best with HF start but that puts you towards £1000 price bracket.

Jason

 

[robwilk]

I don't know much about power and amps and that sort of stuff but be care full as i got a cheap arc welder and if i have it turned up to much when i get welding it trips my electrics which is very annoying when you are half way through a weld.
Rob....

 

[Lakc]

Jig and tool making for a machinist, generally will exclude welding, as there is too much distortion to hold tolerances. They are handy to have, but any bits you stick together will likely be +- 5 degrees when they cool. They are extremely handy as a "putting on" tool, however.

 

[Brian Rupnow]

As a general rule, machining and welding are somewhat incompatible. I have a stick welder, a mig welder, and an oxy-acetylene welding set up, and while they are all great for fabrication, they all cause distortion in the metals they weld. Ask any senior machinist, and they will all tell you how nasty it is working on components that have been welded. If they had their way, everything would be drilled and dowelled and bolted together. If you can do it, buy a tig set up. If you can't, then consider that most stick welders capable of 180 to 225 amp output will give a far greater strength weld than any 110 volt mig, but you have to deal with the slag. A 110 Volt mig with a gas bottle won't give you much strength (as in weld penetration) but are clean, easy to use, and do great for "temporarily" sticking things together.

 

[Troutsqueezer]

It seems to me that once welded, some distortion can be machined out, depending on the tool or project of course. Bob did a nice job on his engine block in his "Hit me Miss Me" thread.

Keeping in mind, I'm looking at it from a novice machinist's point of view.

-T

 

[Jasonb]

Does rather depend on the type of engines you are building, if you like the bolted together bar stock look thats fine but if you want to fabricate something that looks like it was cast then a welder will be a big asset for fabricating parts, the base and main frame for this engine were stick welded, the only castings were the flywheels. And the next traction engine I want to do needs a fair bit of welding.

As trout says you can weld up a part and then treat it as a "casting" you just build in machining allowances

Jason

 

[Blogwitch]

Rich,

As I know you are in the UK, if stick welding takes your fancy, keep away from cheapo air cooled units. If you do a search about, you should be able to find a used single phase oil filled for somewhere between 50 and 100 squid. Have a search for 'oil arc welder' on fleabay

Air cooled give a very harsh arc, whereas an oil cooled unit is usually silky smooth and much more controllable.

I have very successfully stick welded 1/16" plate using an oil cooled unit, with very little distortion, whereas with an air cooled on the same amperage you would easily blow holes thru 1/8" plate.

I wish I still had my gas and arc welding gear, for the same reason as yourself, but I just don't have the room to store it.


John

 

[Kermit]

Hi Rich.

I'm one of those people, that like you, wanted to get a cheap stick welder. It will do fine, if you don't expect much from it.

Most of my boo'boo's have been from operator error, and persistence has learned me pretty good. It will make things stick together. It won't be pretty. If that's all you need then go ahead and get one.

I've wished for a better one before, but have yet to have a situation arise where I HAD to have something better. I'm not a welder by trade and because that isn't my preferred tool I find other solutions than welding most times. Sometimes though, only welding will do.

A broken bracket for a post that holds the swing gate in the backyard...could be done with lots of drilling and bolts and time, but two small one inch beads and 15 minutes later the bracket is good for another 5 or 10 years. ;D Then I put the welder back in the garage for next time I need it...... ;D

Kermit

 

[Maryak]

Trout - Thanks for the kind words. :bow:

Distortion is the bane of electric/gas glue. I try to follow this:-

1. Think about the sequence of operations which will allow each subsequent weld to minimise the distortion caused by the one before it.

2. Where possible use substantial clamps to locate the parts so that they can't move around.

3. Tack weld an assembly and adjust for true after each tack. Then when the assembly is true and stable fill in the gaps following 1. above.

4. Treat the assembly like a casting, provide a machining allowance where necessary and don't do any machining until the welding is complete.

As for the welder - don't buy one which has a poor duty cycle - usually means no cooling system. You are better off keeping your money in your pocket as there are cheaper ways to become angry and frustrated, (ask me how I know ).

Hope this makes sense and helps

Best Regards
Bob

 

[Tin Falcon]

I have a little Campbell Hasfeld flux core wire feed welder. It is very handy for welding 1/16 to 1/8 steel. I have used it to build a stock rack a bench and a couple of selves. I would love to have a A/C DC inverter rig that would do stick and TIG. But as soon as you go A/ C tig the price goes up especially the ones you can program the wave patterns . I need to get the cheater lenses in my welding shield so I see the puddle. the last project I did the welds were not exactly where I wanted.
Tin

 

[Maryak]

You cannot weld one-handed.

Pat J

Sorry Pat but a good professional welder rarely welds any other way and equally with either hand. There are many jobs where it is not possible to get more than one hand and the rod into the correct position to carry out the weld.

And no I'm not a professional welder, but I've been around them most of my working life building ships and repairing boilers etc.

I don't want to start a bun fight but IMHO the above gives a newbie to welding a most undesirable handicap.

Best Regards
Bob

 

[tel]

And no I'm not a professional welder, but I've been around them most of my working life building ships and repairing boilers etc.

Well I was, and I agree - one handed welding is the only way to do it, and as Bob says, become proficient with both hands. Mind you, Australian welding practice is somewhat different to the US, with our use of stringer beads rather than heavy runs. There are a lot of reasons for this, but the bottom line is better welds and better metal in 'em.

 

[Blogwitch]

When doing my two year college course on gas and arc welding (courtesy of HM government, and no I wasn't locked up), the instructor allowed us for the first couple of lessons to cut our rods in half.
Striking the arc is one of the difficult bits to master, especially at a distance, and having a shorter rod allows you to practice striking and the first tentative runs much easier, because of less trembling at the strike and run point. Once you got that under your belt, you then went onto full length rods.
One of the final exam tests was to strike and weld a deep filletted joint, both horizontal and vertical at full arms length.

You shouldn't be needing to weld anything like that, but in the beginning, the short stick method might come in very handy, and allow you to get things made.

Bogs

 

[firebird]

Hi

Thank you one and all for the very in depth reply.

Allow me to explain my reasons a little better. I have the propane bottle of course and I also have at the moment a small portapack oxy/acet welding set. I think that shortly I will lose my way of getting the bottles exchanged. The cost of registering and paying the rent is going to make them not cost effective. My mate Julian has an arc welder and a gasless mig welder and of the 2 the arc welder seems to be the better. I have been looking at the Machine Mart welders that are in the £100.00 bracket. Would John Bogstandards second hand idea be a better choice????

Cheers

Rich

 

[Noitoen]

In relation to gas bottle renting here in Portugal, they have 1 cubic meter cylinders that are "rent free". The gas is a little more expensive but all you have to do is buy a set and the extra charge takes care of the rest of the "bureaucracy". In relation to the MIG welding, some guys "make friends" with the local bar and get the CO2 gas for the beer machine for the welding machine. They come in little aluminium cylinders an although nowadays the gas mixture for MIG is a little different, the result is much better than the "gas less" welding.

You can also check this out http://www.premierpowerwelder.com/readyweld/readyweld.html

 

[tel]

Pat, I still disagree with using two hands, if you are going to weld you might just as well learn to do it properly from the get-go. As a fabricator, rather than a ship builder , I lot of my work involved/involves steel of light section, often RHS or small section angle, but the same rules still apply. Here's one of mine from a couple of years back, a job like this you just don't have a spare hand to put on the stick holder, and wouldn't if you had 6 of the things.

 

[tel]

And here's a job from a week or so back - some brackets for a local builder.

 

[tel]

Something a little larger