This past year I made the leap from my old standby surfaces - wood panel or masonite for oil paintings and illustration board for pastels - to ACM (Aluminum Composite Material). ACM is used for commercial signs and is easy to use, easy to frame (it's 3mm thick!), won't bend or warp, takes any surface you want to put on it, is more archival than anything on the market today, and most importantly cheaper by the foot than stretched canvas or commercial pastel papers if you prepare it yourself. A common brand name of ACM is Dibond and you can usually get it from your local sign maker or plastics manufacturer (Pro tip - when shopping ask for ACM instead of Dibond and save yourself $30+ per sheet). I get mine from Piedmont Plastics in Albany, NY. Prices can fluctuate but the last time I picked up a couple sheets it was $65 per 4x8' sheet. Most places will cut it down for a small fee you so it'll fit in your car.
So what do you do with this giant sheet? First remove the protective sticker on both sides (shown above). ACM cuts easily with a carbide-tipped saw blade - if you have a table saw or circular saw you probably have a carbide-tipped blade already. I like to use an 80 tooth blade for a smoother cut but I've read that you can even cut ACM using a utility knife - just score it a several times on both sides and snap it off.
Once it is cut to size you need to sand the side that you're going to paint on. There's a primer on the panel that you want to scuff up so your gesso will adhere - but do not sand so much that you remove the primer or your gesso won't stick. It sounds scarier than it is: I use a palm sander with 300+ grit paper and very little pressure in a circular motion. The semi-gloss panel that you had before should look matte when you're done. Wear a dust mask.
Now you need to degrease the panel and remove the primer dust. Rubbing alcohol and a paper towel will do the trick. You're done when all the dust has been removed. If you're not going to immediately gesso your panel then make sure to degrease again beforehand. You want a clean surface.
Use your gesso of choice (actually acrylic dispersion, traditional gesso is something else but most manufacturers call it gesso). I'm partial to Golden's. Paint on a coat of gesso making sure your brush strokes are all going in the same direction and then allow the paint to cure. Notice I didn't say dry. The gesso will be dry to the touch in an hour or two but it won't be cured for about 8-12 hours. You know it has cured when it is room temperature - uncured gesso will be cool to the touch. Ain't science awesome?
Paint on 4 coats of gesso (curing between coats), with each coat's brush strokes at a right angle to the previous. This will create a slight weave-like texture that will help subsequent layers adhere.
If you're an preparing the panel for oil paint then you're good to go! You can sand the texture down if you like, you can paint directly on the gessoed surface, or if you have a preferred oil painting ground now is the time to add it.
But what if you want to work in pastels...
Here's the recipe for my patented hand-dandy homemade pastel surface:
- 1 part gesso
- 1 part powdered pumice
- 1 part Golden Fine Pumice Gel
- Acrylic paint if you want a toned surface
- A little bit of water to help it all mix together
Store the unused portion it in a tight sealed jar and it'll stay viable for years.
Paint on 2-3 coats. It'll hold your brush strokes if you want them for added texture, otherwise you can go over each coat lightly with a soft brush to remove them.
If the surface is too gritty when you're done a single pass with 300+ grit sandpaper will even it out nicely.
Credit where credit is due: I learned much of this process from Kate Stone's blog http://paintingstufftolooklikestuff.blogspot.com/2013/10/more-apocalypse-surviving-panels.html and Underpaintings magazine https://underpaintings.com/prepping-an-aluminum-panel/. The pastel part is all me though. :)