One of our collaborators wrote an awesome post a few weeks ago, called Controlled Rust. It explained a bit of the science behind anodizing, suggesting that it’s a great way to protect and beautify laser-cut aluminum parts. Something he neglected to mention, however, is that while SendCutSend can take care of this and other outside processing steps for our customers, there’s a 50-piece minimum for this service. Sorry about that, it’s one of those economies of scale things.
More is better
Considering the discounted pricing model that company owner Jim Belosic announced recently, this probably isn’t as big a deal as it once was. Still, the fact remains that many of SendCutSend’s customers are engineers, inventors, and hobbyists, and are only looking for quick turnaround on one or two laser-cut parts. And not surprisingly, they often want them to look pretty.
Don’t despair. Since you’re reading this, we can safely assume that you’re a maker or tinkerer, and aren’t afraid to get your hands dirty. Enter DIY anodizing.
Do a little Googling on that exact search term and you’ll soon realize that what appears to be a deeply technical process is actually not all that difficult. If you can dye Easter eggs and are comfortable charging a car battery, you’re mostly there. Better yet, you probably already have much of what’s needed, and the rest you can pick up at the local hardware store for about the price of a good shovel.
Do your homework
We’re not going to take a deep dive into anodizing here. As I said, there are plenty of websites and YouTube videos available on the Internet, and if you’re serious about aluminum anodizing, check out www.caswellplating.com, where you can buy a complete kit for around $500 or so.
Too steep? I thought so too, but they also offer a detailed manual on the subject for thirty bucks, as well as all the chemicals, dyes, degreasers, strippers, and other stuff found in the kit. Otherwise, anodizing on the cheap is far from rocket science.
Here it is in a nutshell:
Step 1: Buff it Out
Anodizing tends to highlight any surface imperfections, so if your laser-cut parts don’t already have a nice finish, it’s time to get sanding, buffing, and polishing.
Step 2: Get it Squeaky Clean
You’ll also need to get your laser-cut aluminum parts clean. I mean really clean. Start with some soap and water, then degrease them (Simple Green is one good option) and possibly “desmut” your parts in some diluted lye (i.e. drain cleaner).
Step 3: Suit Up
Did I mention safety glasses, rubber gloves, and an apron to protect your favorite t-shirt? All are swell ideas.
Step 4: Mix It
Fill a plastic bucket with a 1:1 mixture of battery acid and distilled water, making sure to add the acid to the water, not the other way around. You should probably turn on the ceiling fan or open the garage door.
Step 5: Prep It
Securely attach your soon-to-be-beautiful workpiece to a length of aluminum wire and suspend it in the bucket (note: titanium wire is even better, but let’s keep things simple for now).
Step 6: Charge It
Now attach the other end of said wire to the positive (red) terminal of a 12-volt power supply—a car charger works, although larger parts might require a more powerful DC power supply (there are loads of them on Amazon). This is known as the “anode.”
Step 7: Get It Grounded
Peel off another chunk of wire or, better yet, pick up some lead sheet (Amazon again), cut off a strip, and attach it to the power supply’s negative side. Clamp this “cathode” to one side of the bucket, with one end in the drink.
Step 8: Power Soak It
Fire up the power supply and let it run. Don’t be alarmed by the little bubbles that form around the anode. After 45 minutes or so, pull out your freshly anodized part and give it a good rinse in distilled water.
Step 9: Dunk It
Here comes the fun part. While all that bubbling was going on, you should have been heating some clothing dye—Rit Faded Strawberry is my favorite—in an old pan on the stove. Now dunk your anodized part in the dye for around 15 minutes, give or take.
Step 10: Boil It
The last step is to boil your masterpiece in distilled water for half an hour, sealing in the color for all eternity. Congratulations, you’re on the way to becoming an anodizing professional!
The devil’s in the details
As you might have guessed, I’ve skipped a bunch of important stuff. There’s the amount of electrical current to consider (based on the size of the workpiece), as well as chemical to water ratios, acid bath and dye temperatures, etc., but you get the idea. You should also have plenty of baking soda on hand to neutralize any wayward acid, just as you might want to experiment with some scrap metal before starting on your actual workpiece (or purchase a few sacrificial spares when you place your online order). Either way, you’ll be DIY anodizing in no time. Good luck!