DIY Spot Welder: Good idea or death?

I have a project idea in my head that would involve a lot of sheet metal welding. One option is to get a spot weld kit from Eastwood (or make one) :

Kit from Eastwood

Another would be, as the title implies, to make a spot welder out of a microwave. YouTube is full of how to videos. (arranged best to worst)

Wooden spot welder frame

Stand spot welder

Is this legit or a waste of time and energy?

Is this safe and sound?

I am welding 16g metal to 16g. Steel. I dont think any thicker than that. I could just drill a lot of hole and do a lot of rosette welds and grind them smooth or just buy the Eastwood kit. But with this it might leave a nicer and more consistent finish and less warp?

Thoughts?

No need to berkeley around winding transformers when old AC stick welders that will make a fine and safe power supply are a dime a dozen on CL.

Harbor Freight has a cheap spot welder.

Shameless plug: I have one of those hf 110v spot welders I don't use... would part with it for cheap.

Is the DIY method sound though?

In reply to CarKid1989:

A spot welder is just a device that clamps some sheetmetal between two electrodes and applies power to melt the metal together, so yes. If you have at least some understanding of electromagnetism, want to screw around with old microwave transformers to save $50 and are comfortable (but not too comfortable!) working with mains power then what they're doing is perfectly valid.

oldtin wrote: Shameless plug: I have one of those hf 110v spot welders I don't use... would part with it for cheap.

This sounds like the easy button.

I've been around exactly two diy spot welders. I wouldn't operate one with a pair of stolen hands.

I've made one.  It can be very dangerous if you are not careful.  Just like a lot of things. 

Using a 4 inch cutoff wheel is  the most dangerous thing I do, and I do it often.

I have the scars to show for it.  Same goes for high voltage ev batteries.  I once grabbed both ends of one and get 120 volt dc through my body how come I am not dead...oh that explains why I can't remember I owned a 1970 Mach 1 anymore.  lol

I can recall most every time I've been shocked by electricity. I used to work for a builder that told us to pull off the spark plug wire when needing to kill the lawn mower engine - ooowww.   I also stepped on a few nails that went through my boot.   
 

Can't erase those memories 

Making a mistake while dinking around with a microwave transformer won't just give you a nasty shock, it will kill you right dead before you realize you made a mistake. 

A search for "microwave transformer death" brings up scores of incidents where people cooked themselves while trying a craft project/diy/experiment they saw online. Unless you are an actual trained expert who works with high voltage, I would pass on a project like that.