Quality Control Inspector, Alumalite Panel Production Unit (Gesso Division, Desert Sector) of Linda Tracey Brandon, PC, LLC, PLC.
I just completed my second large painting on an Alumalite panel and since I'm starting my third one, I thought I'd share my process of making them, using gesso and acrylic paint. You can always mount linen to Alumalite instead; I'll post later on about how to affix linen.
Alumalite is a product (like Dibond) in which two thin sheets of aluminum are bonded to a plastic core. Both are proprietary names and there are other brands and variations of this (such as Econolite, etc.) Dibond is sturdier, somewhat heavier and somewhat more expensive. Alumalite has a corregated plastic core and comes in various thickness. The sheets I order come in 4' x 8' sizes which I don't cut myself. Alumalite is just like its name, liteweight and can be dented, so watch out. It's not as fragile as something like foamcore but you can still damage it if you kneel on it or bash something against it. It's also hard to cut (so I'm told) so either find yourself somebody who can handle this for you (for all I know, that could be you, showoff) or ask the company that supplies it for you to make the cuts while you are also asking them to deliver it to you. Also, ask them to have their resident finicky neurosurgeon make the cuts so nobody will scratch it or make gouges in it. Don't make a huge order with anybody until you determine they are fussy enough for your taste.
Alumalite is very firm and will not flex, at least in the thickness I've been using, 1/4" (you can get other thicknesses). You won't need to brace it when you frame it. I haven't gone whole-hog and made the 4' x 8' size for a painting, though, so if you do that let me know if it will need bracing.
Alumalite comes with both sides coated with vinyl for delivery purposes. Remove the vinyl by stripping it off, that's pretty obvious.
Apply the gesso. I use Daniel Smith's stone gray acrylic gesso.
It's nice gesso, but I hate gesso. It's awful stuff, a hostile alien life form which wants to invade every orifice. If you drip it anywhere it will dry almost instantly, especially if you live in a desert environment, ruining everything since it will never wash out....! Wear plastic gloves, headgear, eye, mouth and ear protection too, if you have it!
Don't answer phone texts while working with gesso!
If possible, have one of your many lower-tier employees apply the gesso.
These big sponge brushes are fine for this part of it but they are badly made and always fall apart in the middle of a big job. Let this dry overnight, sand lightly the next day, wipe down with another old towel and repeat.
Man up, artist, because you are going to do the whole thing again but this time, you're going to apply coats of Golden's white acrylic paint. I decided to thin this a little with water and apply with a foam roller. I guess I could have used the foam roller with the gesso coats also, I just don't like to thin down the gesso very much, but you could do it. I'll probably skip the sponge with the gesso and just roll with the roller next time, it's just that my gesso dries so fast I wasn't sure I could do the whole panel, and I thought I might get a soft light spraying of gesso spatter on every possible surface, including me. I bought a super-soft roller so the coat was even with few ridges. After the coat with the foam roller, I sanded again very lightly by hand.
I wrapped up the foam roller in case I wanted to use it again for the next coat... but...
...I ended up using little makeup sponges for the last, final coat. I wet the sponge with a little bit of water and it goes on nicely, but the sponges end up feeling like wet marshmallows, disintegrate with use and need to be replaced often, so you'll go through several of them.
By this time your hourly employees have gone on strike and you're having to cross picket lines of angry masked protesters screaming and wielding broken beer bottles, nervously held back by riot police. So, by now you are doing it all by yourself. You should send this whole operation offshore! All this, for one lousy panel! You'll feel like drowning your sorrows with this sponge water by the time it's over, but don't do it.
The final thing to do is a light wet sanding. I used a block wrapped in wet/dry sandpaper for this.
My gesso/acrylic preparation process is basically what David Kassan does with his aluminum panels, unless he's changed his process. The Stone/Gluck team over on Painting Stuff to Look Like Stuff are also painting on aluminum substrates and have recently described their process as well - both links are on the right side of this page, be sure to click over there on both sites for more info.