I'm starting this thread to prompt others to chime in -- I've done OK with evap, but I'm betting some others here know a heck of a lot more than I do, so this should get things going.
I have done evap in two different systems -- one fairly crummy vacuum (my mini bell jar with big rubber seals and just a two stage mech pump) and my really good big system. To say the least, with Al, the results were far better in the big tank in terms of the deposit quality. Al seems to act like a pretty good getter while evaporating, but this means that a lot of what hits the target is oxidized on the way there....and of course I've found that pure Al canes from Lesker work a lot better than say, Al alloy MIG wire as a material source.
So far I've been using the coil type heat source from Lesker for Al as it wets the tungsten and becomes a nice uniform source when you premelt it as I do. And a little goes a long way when making mirrors or beam splitters this way -- you get a lot of runs before having to add more Al to the source. The Lesker part number for this is EVF53025W, and is one of the lower power ones they sell, but still needs plenty to run. One thing to realize is that in their catalog, they are listing the max power you can use and not melt it, but for things like aluminum, you need no where near that much.
As I'm just staring out with this, I made a fairly kludgy power supply for it, which is nevertheless complete overkill for this job. What I did was to re-wind the secondary of a spot welder from Harbor freight with about 7 turns of # 6 wire, and have enough taps so that I can have from .5 turn to 7 turns in 1/2 turn increments. I am using about 3 turns for the Al job, which is a bit over 3 volts on the heater, and have just a very simple control - solid state relay and pushbutton (and a lot of MOV type kickback protection on that). In use, it takes a few seconds to melt the Al, and another couple to reach fast evaporation temperature. I do pre-melt the Al before doing the deposition run. letting it flow into the spaces between the 3 wires that make up the heater. This seems to give the best results, and since I make more than one run per loading, it's what all the subsequent runs are anyway, so this is a little more uniform way to go about things. I would bet that a smaller transformer (like a rewound MOT) and some better control than bang-bang on/off would do better for this and be smaller too.
One thing for a beginner to be warned about -- this isn't a particularly well controlled thing with the way I am doing it -- and of course (in hindsight) the Al comes flying off there in every direction -- about like hitting a can of spray paint with a rifle bullet in effect. This means my first couple runs coated my tank nicely, ruined a few insulators in there, and so on.
Not good.
My source is kind of floating up in the middle of the tank, on a couple of 1/4" Cu feedthrough rods I can bend around some to position it where I want. I took an old chemistry set ring stand and added a low shelf to it, ground off the edges of the circle so a 6" thing would fit through my 5.9" door, and assemble it all inside the tank. The lower shelf holds a cut off coffee can to keep the Al from dropping into the tank on melting, and to catch any Al vapor going that way, with slots cut in it for the FT rods to come in. This fits up against the bottom of the ringstand fairly well as I made the shelf that sits on adjustable. I made a couple of target holders that sit on the top of the stand, basically pieces of sheet metal with holes in them for the Al vapor to come through that I can set substrates over for coating. This works pretty well and keeps the Al vapor off things in the tank. I can see how hot it is getting through the sloppy holes for the FT inputs. Which also means. some Al vapor comes out that way. One trick I've used is to cut some mica washers to slip over the rods and block that path to keep my main window clean, and with a little experience, you can tell by how quick they get opaque when your real deposition target has the right amount of Al on it. Of course, you have to get off the button a little early, as it doesn't stop right when you drop input power.
I am thinking of trying gold off this same setup, but haven't risked it yet -- that stuff isn't cheap, even if one loading of pure wire will probably do all I'll ever need -- if it stays on the wire and doesn't just drop off when I go to melt it, that is.
Let 'er rip fellas -- I've just barely scratched the surface here and am a real beginner at it, though I was surprised it works as well as it does with the cheezy setup I'm using.
I built a thing that holds three boats and has a shutter in a Cu flashing box to keep most of the heat and excess vapor, but it hasn't made it into the tank yet, as I'm doing mostly fusion in there at the moment....Picture later when I have a clue if it even works -- "looks good on paper" but who knows. The idea behind that one was to use the shutter to control preheat and so on, and get more accurate deposition, as the shutter can be closed fast with a small solenoid (I have some very small ones that seem not to mind intermittent use in vacuum and don't outgass much, as long as you don't get them hot).