Introduction: How to Restore Rusty Metal Parts With the Help of a Dremel Rotary Tool and Wire Brushes
For this Instructable, I have enlisted the help of my recycled sculpture friend, Emma. Emma was initially created during the late fall of 2010. She was part of my first (and only, so far) solo art exhibition, where she watched over the 4th and Jackson garden in Hoboken, NJ all winter. As you may be able to see, she is made of many different parts, all of which were found or recycled, and many of which are steel, something not particularly suited to outdoor exposure without proper treatment, especially after grinding or welding – so, about that proper treatment; since my sculptures are all one-of-a-kind, they go through many phases and are all initially prototypes. By the time my show rolled around, I didn’t have any time left to disassemble, weatherproof, and reassemble her. As you can imagine, a New Jersey winter outside was not kind to her exposed ferrous parts.
For the removal of rust and corrosion on detailed and intricate parts, you will need:
* Safety goggles
* Latex or nitrile gloves
* Clean shop rags (washed old socks and underwear work just fine)
* Clean worktable in a ventilated area
* Dremel Rotary Tool (we have the Dremel 4000)
* Hand-held steel-bristle wire brush
* Air compressor with air nozzle attachment
* Wax & grease remover (isopropyl will suffice for most projects)
* Masking tape (preferrably painter's tape)
For rust prevention and sealing:
* Rust converting spray or rusty metal primer
* Rust-preventing paint/spray paint of choice (I used this stuff)
* Clear acrylic spray paint/sealer
Possible items to help could include:
* Bench grinder with wire brush wheel
* Dremel cut-off wheels
* Full-face clear protective shield
* Naval jelly
Step 1: Initial Inspection and Dis-Assembly
Getting acquainted (or reacquainted) with your project is essential. The more familiar you are with a project in your head, the easier it will be to run through assembly/dis-assembly, especially if you have more complicated projects requiring many parts and multiple cycles of this process. This is where owner's manuals and assembly drawings come in very handy if they are available. If there are no assembly instructions for your project, have a camera handy and take detailed pictures (with notes, if necessary) of all your parts both before and after separation.
My Grandpa on my mother’s side, an engineer his whole life, has shared many years of wisdom with me. One of the simple gems was, “If something doesn’t work, take it apart and clean everything.” Solid... Well, you heard the man, ladies and gentlemen. Start unscrewing!
Now, if your parts are thoroughly corroded either from oxidation or galvanic action between dissimilar metals, you will likely have a hard time loosening them. Put on your latex or nitrile gloves and safety goggles and spray the affected parts liberally with penetrating oil. Let them sit for at least 15 minutes. Spray them again and try to loosen, using repeated short bursts of force, as opposed to one long, continuous push, which can bend or shear parts. If they still aren’t going anywhere, you have a few more options: if the parts are oxidized (rusted), soak them in a dish of penetrating oil or a heavy coat of naval jelly. If they appear to have galvanic corrosion, your best bet is probably to throw one of the metal cut-off wheels on the Dremel and remove your stubborn hardware with a vengeance (EZ Lock-compatible cutting wheels highly recommended). Blowtorching your frozen parts is NOT RECOMMENDED, as some metals give off irritating or poisonous and potentially deadly fumes when heated hot enough.
Step 2: Detailed Inspection and Documentation
Pretty straight forward here. Inventory all your parts and figure out what needs attention. Pictures are your friend.
As you can see in the images, Emma's vintage aviator goggles are heavily rusted, as are many of the fasteners, and some of the parts that I welded or ground.
Okay, let's get you cleaned up there, little lady!
Step 3: Get Your Grind On
So, you'll first want to put on your dust mask, and then remove any large chunks or loose bits of rust/corrosion with the steel wire hand brush or bench grinder wire wheel, if possible. These are often pretty large, so if it just isn't feasible, move on to the Dremel brushes, but note that there will be quite a bit of dust and debris flying around. I would recommend a face shield if this is the case for you.
Now, begin with the 531 Stainless Cup Brush. You'll need to hold down the shaft-lock button (located between the power switch and the rotating tip of the Dremel, seen under my left thumb in the 3rd picture) so that the chuck doesn't rotate freely as you try to tighten it. As a side note, I have shown in the pictures that i find it easier to tighten the chuck with my multi-tool pliers than the little wrench that comes in the Dremel kits.
I've found this brush works best around 15,000 RPMs. Any less and the Dremel motor will bog down when you put a load on it, too much more and you risk burning, marring, or wearing away your piece. At the very least, you will destroy the brush much more quickly, so it is in your best interest to keep the RPMs as low as possible.
Hold the Dremel at about 30 degrees from your grinding surface. This should allow you to use the edge of the front of the cup part of the brush. Put just enough pressure on the brush so that you hear the motor start to slow down, and then back off a little bit so your RPMs stay constant, but try not to have so many prepositional phrases in one sentence when describing something.
When you have removed as much corrosion as you could reach with the Cup Brush, switch to the 428 Brush Wheel for the details and hard to reach places. Loosen the chuck on the Dremel and put the new brush in, making sure you have enough of the shaft sticking out to reach your surface, but ensure you have at least 3/8" (~10mm) in the chuck so your brush doesn't decide to separate itself from the Dremel while spinning. I found that this brush did well at around 20,000 RPMs, and that rotational energy is nothing to take lightly. I also used this brush to polish her feet, which are brass-plated hinges. I was careful, and it went pretty well, but generally for delicately-plated or soft-metal cleaning, this is where you would use the 403 Nylon Brush Wheel.
Step 4: Coating/Recoating
At this point, you should have all your parts free of loose rust. Get your gloves back on, and give everything a thorough wipe-down with the wax & grease remover or isopropyl alcohol. MAKE SURE YOU ARE USING A CLEAN RAG to wipe down your parts. The whole point of this step is to remove any small bits of solid or liquid that can and will hurt the integrity of your sealing coat.
You can see at the end of the wire brush grinding on the goggles, the corrosion was so heavy that parts of the surface were permanently discolored. I didn't mind this and went with a nice coat of clear acrylic sealant on Emma's aviator goggles after taping off the glass, and coated her tail (the metal steamer basket), as well. I used the appliance epoxy spray on her base/legs, the bolts that hold her eyes in place, and a small L-bracket and washer. The inside of her eyes got a fresh coat of gold. Her neck is aluminum and the head is galvanized steel, so I wasn't particularly concerned with those parts
Let everything dry to full cure, usually 24-48 hours for most paints, and make sure all your mating parts are not covered excessively with paint, as it may be hard to reassembly them as intended. If there are any large drops of amassed paint, you may have to get your Dremel brushes back out and do some minor touch-up work.
Step 5: Final Reassembly
Before putting her back together, I decided Emma needed a little more style though, so I decided to curve her wings to make it look like she was in the process of landing. Her wings are a piece of scrap aluminum from my old job, so it bent nicely around some large pvc pipe with a little elbow grease.
Alright, so here we are! Everything is dried, cleaned, and ready to put back together. At this point, you ideally would do a "dry fit" to make sure everything goes back together properly, then take it back apart and put threadlock on all your fasteners. I had drilled and tapped some of the holes for which i was previously using self-tapping screws, so i knew everything went together already. Threadlock's away!
And now she's ready for her new home with a very special friend in Colorado. Good thing she's already used to the snow :)
Big thanks to Dremel and Instructables for hooking us up with the right tools for the right job to host a Dremel Build Night. Come on down to the MakerBar and check 'em out for yourself any Wednesday or Friday night, and link up with our Meetup for special events and classes.
MakerBar Shop Manager