Harbor Freight 90amp Flux-core Welder- Teardown!

[FenderBender]

Well darn I was just going to buy that autodarkening helmet...I guess I'll go splurge at Home Depot for a Lincoln. What's wrong with it? (by the way)

I have the HF auto-darkening helmet too.  It works well.  It's usually on sale, too.

Yep. I picked it up for $37 today.

[FenderBender]

... nothing pulls your attention away from the work like a hot gob of metal burning through your shirt.

This. Even worse is it burning through your plastic sneakers and sock. Wear high sided full-leather boots, full trousers, and leather jacket and gloves. No exceptions. Oh and btw, the arc UV doesn't just burn exposed skin. It also slowly disintegrates some types of cloth.

I second the 'leave it alone, use it to learn, and then someday buy a better one if you need it' comments.
Professional MIG machines are very nice, with the downside of having to pay rental on a gas cylinder. Here in Australia it's not possible to purchase the cylinders to achieve zero 'idle' cost. You can only rent them, and that's expensive. With a MIG, a TIG (different gas needed), and an oxy set, the yearly cost for those four gas cylinders dwarfs all my other yearly running costs together.

If you keep a lookout, you can likely get a very good second hand industrial welder of whatever type you decide you need, for relatively little cash. Maybe even free if you are lucky. For instance my MIG (Esab Smashweld 250) was a gift, as 'broken', but was easy to fix.
Also, watch some youtube howto videos on welding, and buy some secondhand welding theory books (abebooks, amazon etc) asap. Bad welding habits acquired in self-taught mucking around will be very hard to unlearn later on.

Another thing - get yourself an angle grinder or two. A welder without an angle grinder is like a rowboat without oars. With them together, steel is your malleable friend. Partly cos you can entirely undo your mistakes, and do it over. Side grinding wheels for beveling edges for welding, removing scale, spatter and smoothing welds; thin cutting disks for getting pieces in the right shape. Actually I keep two angle grinders, so I don't have to keep changing disk type all the time.

Understood. I'll go see if I can find some sort of apron of some sort.

[SeanB]

Don't forget a hat as well if working in the sun. Nothing worse than a burnt back of neck, along with some of those little splashes can fly up a considerable distance and land in your hair.

[chickenHeadKnob]

 Don't weld anything galvanized, the zinc will vaporize and give you a kind of of brain rotting "happy". Actually the least healthy thing about welding is all the metal vapours. James Huberty the San Ysidro Mcdonalds massacre (1984) shooter was a welder who quit/was fired from his job because he said it was making him crazy. While he had a previous record of mental illness and violence his post mortem blood levels for cadmium were off the charts and should have been fatal. I hobby weld and don't worry about it too much but I keep a fan at my back.

[TerraHertz]

Huh. You learn something every... something. I didn't know about zinc being harmful. Though I avoid welding zinc plated stuff just because it's so messy.
Did know about the 'smooth machining' mild steel alloys that include an amount of lead to make it cut better on a lathe. Don't weld them either.

The one that really freaks me out, is brazing fluxes consisting of fluorine and/or boron compounds. Just great.

[akcoder]

I have never welded in my life. Nor has anyone in my family or anyone that I know. A name brand machine, say a Millermatic, starts at around $700. Yes, I am sure it is easier to work with, but for the amount of use I expect this welder to get, I do not think it's worth it. $90 is a hell of a difference from $700. I'm sure you get some great benefits with a "real" welder, but for the time being, I want to see what I can do with this.

My buddy gave me his old Daytona (a cheap Italian made welder - what china is to electronics, Italy was to welders) 220v welder a couple years ago because it would go into thermal shutdown. I let it sit for a year plus before discovering that the bearings on the fan dried out and causing the fan to spin at minutes per revolution.

After fixing the fan and putting in a distribution bus so I could reverse the polarity to do flux-core, its turned into a very handy tool. I end up using it a lot more than I thought I would. So much in fact that the reverse polarity mod was short lived and I ended up getting a bottle of 75/25.

I've made a light bracket for my snow blower, fixed a stripped out stamped "nut" that held the handle on said snow blower by grinding off the stamped piece and welding a 3/8's nut in its place. Plus countless other things for myself. And once people find out you have a welder... :-)

weldingtipsandtricks.com is a good site to learn welding techniques, he covers mig, tig, stick.

-dan

[akcoder]

Professional MIG machines are very nice, with the downside of having to pay rental on a gas cylinder. Here in Australia it's not possible to purchase the cylinders to achieve zero 'idle' cost. You can only rent them, and that's expensive. With a MIG, a TIG (different gas needed), and an oxy set, the yearly cost for those four gas cylinders dwarfs all my other yearly running costs together.

Thats really lame. Here, you can buy a 4 ft cylinder for $160. When I got mine a year ago, it came with a free filling of 75/25. I learned that maneuvering a 4ft bottle by yourself is a complete pain. It fit perfectly on the back seat floor of my mid-sized car. And took me almost 5 minutes of wrestling by myself to get it out!

Another thing - get yourself an angle grinder or two. A welder without an angle grinder is like a rowboat without oars. With them together, steel is your malleable friend. Partly cos you can entirely undo your mistakes, and do it over. Side grinding wheels for beveling edges for welding, removing scale, spatter and smoothing welds; thin cutting disks for getting pieces in the right shape. Actually I keep two angle grinders, so I don't have to keep changing disk type all the time.

A bench grinder with a wire wheel on it is also handy to have. The wire wheel works great to smooth out any rough spots from grinding.

-dan

[SeanB]

2 grinders very useful. Actually getting the wire brush cup for the grinder works better then the bench grinder. Wear eye protection when using the grinder cup brush, those wires fly everywhere when they break off, and are merely annoying dug into your arm but very bad in your eye. Having an Opthalmic surgeon saying don't blink while he is bringing a needle into focus on your eye is not fun.

[G7PSK]

The reason you 'weld zinc is that the fumes give you metal fever this is the same thing that the tank gunners got in the 2nd WW, brown trouser time for a day or two after breathing too much zinc fumes. The main problem with those little MIG/MAG welders is the live torch and some don't even have a gas solenoid let alone pre and post flow burn back etc. Got to a welding school and have a go there or even a proper welding distributor who will usually have a demonstration machine or two, in my experience those cheapie machines are so awful that it makes it very hard to learn to weld with them. I once bought a SIP machine (made in Italy) as it was offerd cheap to me and I was looking for a machine for site work at the time, big mistake I ended up getting so pissed of with the poor duty cycle and the wire feed perpetually producing birds nests that I borrowed a JCB with a 4in 1 front bucket picked the thing up and gave it a squeeze then dropped it into a skip and that is where all such crap belongs.

[TerraHertz]

Thats really lame. Here, you can buy a 4 ft cylinder for $160. When I got mine a year ago, it came with a free filling of 75/25.

Sigh. Remind me again how Australia is the land of excessive regulation and corruption.
The gas companies claim 'rental only' is necessary to ensure regular cylinder safety testing. They'll trot out horror stories of old gas cylinders that were used for 20 years on boats in salt spray, exploding during filling, etc. Therefore a guy like me who'll have the cylinders sitting in a clean hobby workshop for years and sometimes might not even use them all year, and will go several years between refills, can't own them and must pay rental. Because when you do need them, you really need them.
It's entirely coincidental that the gas companies make most of their income from cylinder rental, and the eagerness of the government to legislate private cylinder ownership out of existence has nothing to do with cash incentives to those responsible.
This situation totally sucks.

Even garden variety propane cylinders have a rort here - they are stamped with their manufacturing date, and illegal to refill from 5 years after that date, unless inspected, retested, and restamped. But try to get a cylinder actually retested... ha ha ha. Nope, buy a new one. Never mind that the old one is fine.
Well, at least there's a workaround for that, which involves having one large 'in date' cylinder, and as many other random aged cylinders as you like to use.

I learned that maneuvering a 4ft bottle by yourself is a complete pain. It fit perfectly on the back seat floor of my mid-sized car. And took me almost 5 minutes of wrestling by myself to get it out!

Hmm... well at least I'm only old, not old and feeble yet.
Why didn't you buy a smaller one? You can get cylinders you own refilled, right?

A bench grinder with a wire wheel on it is also handy to have. The wire wheel works great to smooth out any rough spots from grinding.

Come to think of it, just realized I have three angle grinders. The third one I bought to build into a tool I made to precisely grind down weld beads on MIG welded stainless steel tubing. This thing:

[G7PSK]

Gas cylinders are rental only in the UK other than the small DIY cans that you buy and then throw away, I have known people get an old CO2 cylinder from a pub and then transfer Argon mix into it from a rental one then take the rental back and put it off hire until next time. All you need is two cylinder connectors on a piece of high pressure pipe but you have to be very careful not to let the pie or cylinder get too hot as that would be a very embarrassing bang. 

[PaulAm]

Years ago the only way to get cylinders was to lease them, but that changed.  I have a number of half size cylinders now.  They're all filled on an exchange basis so I never have to worry about recertifying them either.  The half size is a little easier to move around and, given the amount of welding I do, lasts for a long time.

The last time I swapped out my acetylene cylinder they changed from the flat top tank that's been used forever to the normal style gas cylinder.

[TerraHertz]

Gas cylinders are rental only in the UK other than the small DIY cans that you buy and then throw away, I have known people get an old CO2 cylinder from a pub and then transfer Argon mix into it from a rental one then take the rental back and put it off hire until next time. All you need is two cylinder connectors on a piece of high pressure pipe but you have to be very careful not to let the pie or cylinder get too hot as that would be a very embarrassing bang.

Transferring works great for propane, since you're pouring a liquid from one cylinder to the other under gas pressure (using the vents to create the 'push') and so you waste only a tiny fraction of the stuff you paid for.
But transferring shield gas results in losing 50% of the gas - it's still in the rental cylinder when you return it. Unless you have multiple storage cylinders, but you're still leaving 50% of the initial source amount on each transfer.  Only way around this is to have a high pressure transfer pump, and I've never found a source for such a thing. Plus there are potential problems of contamination, explosion risks for oxygen, and complete impracticality for acetylene due to the necessary solvent in the tank.

PaulAm, which country are you in? America?

[Stonent]

In the US, propane for gas barbecue grills is usually exchanged. Most grocery stores have an exchange area where you turn in the old tank for a new one.  However you can also usually take the tank to a camping supply store or RV park and get it refilled for cheaper.

The place I used to work had a company called Matheson Tri-Gas across the highway that sold CO2, Argon and other gasses used in industrial environments. They could refill cylinders or come on site and refill cylinders and tanks.

Cylinder exchanges are fairly normal as far as I know in the US. That helps keep old dangerous cylinders out of production.

[G7PSK]

Gas cylinders are rental only in the UK other than the small DIY cans that you buy and then throw away, I have known people get an old CO2 cylinder from a pub and then transfer Argon mix into it from a rental one then take the rental back and put it off hire until next time. All you need is two cylinder connectors on a piece of high pressure pipe but you have to be very careful not to let the pie or cylinder get too hot as that would be a very embarrassing bang.

Transferring works great for propane, since you're pouring a liquid from one cylinder to the other under gas pressure (using the vents to create the 'push') and so you waste only a tiny fraction of the stuff you paid for.
But transferring shield gas results in losing 50% of the gas - it's still in the rental cylinder when you return it. Unless you have multiple storage cylinders, but you're still leaving 50% of the initial source amount on each transfer.  Only way around this is to have a high pressure transfer pump, and I've never found a source for such a thing. Plus there are potential problems of contamination, explosion risks for oxygen, and complete impracticality for acetylene due to the necessary solvent in the tank.

PaulAm, which country are you in? America?

It works due to the high cost of rental (BOC charge £135 plus per year for ) so wasting gas is far cheaper if half a cylinder costs less than a full years rent A PD size costs almost the same as a W size and the gas fill costs twice as much per CU M. so decanting can work very well for a small user.

[SeanB]

I have had 2 cylinders that the gas place refused to fill this year. I just went and got a new one, then vented the old one when it was empty and filled it with water, then cut it and scrapped it. Been doing it with disposable cylinders, though those normally get recovered to a good vacuum then have a big cut made in them, as otherwise the scrapyards do not want them. Looking for a cylinder of either argon or dry nitrogen and a regulator. Helium will do as well. Those unfortunately need a rental, portapack cylinders do not, they are done on an exchange basis.