Ultrasonic cleaner for bike components
Practical guide: what to clean, what solution to use, how to run a cycle, and how to reuse/filter the solution.
TL;DR
- Default mix: 1 part Simple Green Pro HD : 10 parts hot water, 55 °C, 8 min.
- Rust: 5–10% citric acid, 50 °C, 10 min → baking-soda rinse → oil.
- Never use solvent-based degreasers (mineral spirits, brake cleaner, acetone, gasoline) — fire risk.
- Never ultrasonic sealed bearings, hydraulics, electronics, carbon, or painted/decal parts.
- Filter solution after each session with a $2 paint-strainer bag; reuse 3–10× before dumping.
- Re-lube everything immediately — ultrasonic strips all oil.
- Chains flash-rust in minutes after a water-based wash. Hot rinse → forced-air dry → IPA water-displacement dip → low oven → lube while still warm. See §3a.
1. What to clean (and what NOT to clean)
✅ Good candidates
- Chains (pre-soak in degreaser first to keep the tank clean)
- Cassettes, chainrings, jockey wheels
- Derailleurs (remove pulley seals / b-tension spring if possible)
- Brake rotors (no pads — they’ll absorb solution and be ruined)
- Pedal bodies (after removing internal bearings)
- Small steel hardware: bolts, axle nuts, quick-releases
- Rusty steel parts (use the citric-acid recipe)
🚫 Do NOT ultrasonic
- Sealed cartridge bearings — solution gets past seals → ruined grease
- Suspension parts (forks, shocks, dropper posts)
- Electronics: Di2, AXS, eTap, smart sensors, head units
- Hydraulic brake calipers with seals/pistons assembled
- Carbon parts with bonded metal inserts
- Painted frames, decals, anything with adhesive graphics
2. Solutions
Recommended
| Solution | Best for | Dilution / temp | Notes |
|---|---|---|---|
| Hot water + dish soap (Dawn) | Light grime, default starter | 5–10 ml/L, 50–60 °C | Cheap, safe, low foam |
| Dedicated US degreaser (Elma Tec Clean A4, Branson EC, Crest Citrus) | Cassettes, chainrings, jockey wheels, derailleurs | 5–10% in water, 50–60 °C | Formulated for ultrasonic tanks — low foam, longest service life |
| Simple Green Pro HD / Crystal | Heavy grease | 1:10 to 1:20, 50–60 °C | Only “Pro HD” or “Crystal” on aluminum — regular Simple Green etches alu. Rinse thoroughly. |
| Sodium carbonate (washing soda) 1–3% | Cheap general degreasing, steel | 50–60 °C | Will dull/etch aluminum — keep cycles short or avoid on alu |
| Citric acid 5–10% | Rust removal, steel parts only | 50 °C | Never on aluminum or anodized. Neutralize with baking-soda rinse and oil immediately after |
| Isopropyl alcohol (≥90%) | Final degrease / chain prep before wax | Room temp, sealed jar | Flammable — sealed lid only, no heat. Use in a secondary glass jar inside a water-filled tank |
Can I use degreaser? — Yes, with caveats
- ✅ Water-based / citrus degreasers (Simple Green Pro HD, Finish Line Super Bike Wash, Muc-Off Drivetrain Cleaner, Pedro’s Pig Juice) — safe; work better in ultrasonic than by hand. Dilute per label (typically 1:5 to 1:20).
- 🚫 Solvent-based degreasers (mineral spirits, kerosene, Varsol, brake cleaner, acetone, gasoline, diesel) — DO NOT USE. Flash point too low; cavitation heats and aerosolizes them → fire / explosion risk. Chlorinated solvents can also attack the stainless tank.
- 🚫 Heavy-duty alkaline degreasers (Purple Power, engine degreaser, oven cleaner, pH ≥ 13) — etches aluminum and strips anodizing within minutes.
3. Running a cycle
Settings
- Temperature: 50–60 °C (sweet spot for cavitation; >70 °C reduces cavitation and accelerates alu etching).
- Time: 5–10 min for most parts; cassettes up to 15–20 min if heavily greased. Longer = more etching risk on aluminum.
- Degas fresh solution 5–10 min before loading parts (most tanks have a degas mode; otherwise just run empty).
Setup
- Fill tank with plain water + a drop of dish soap as the coupling fluid (protects the stainless tank).
- Put your actual cleaning solution in a secondary container (glass beaker, HDPE jar, or even a Ziploc bag) and suspend it in the tank. Lets you swap solutions without draining the tank.
- Pre-wipe heavy grease off parts with a rag — biggest single thing that extends solution life.
Recipes
Default drivetrain mix
- 1 part Simple Green Pro HD : 10 parts hot water
- 55 °C, 8 min
- Rinse → dry → re-lube
Rusty steel parts
- 5–10% citric acid in hot water
- 50 °C, 10 min
- Rinse → baking-soda water dip (neutralize) → rinse → blow dry → oil
Final chain degrease before waxing
- 90%+ IPA in a sealed glass jar, set inside a water-filled tank
- 3 min, no heat, lid on
- Air dry on a clean rag
After the cycle
- Rinse in clean hot water immediately → blow dry with compressed air or low-heat oven.
- Re-lube right away — ultrasonic strips ALL oil, including factory grease in bearings.
3a. Chains — flash-rust prevention
Bike chains are the part most likely to come out of an ultrasonic looking great and then bloom orange rust within an hour. Water gets trapped inside the rollers and bushings, bare steel sees oxygen, and you get flash rust before lube goes on. The cleaning step is fine — the drying step is what fails.
Why it happens
- Water-based degreaser strips every molecule of oil from inside the rollers.
- A pin/bushing/roller stack holds water by capillary action — surface looks dry, inside is wet.
- Bare steel + water + air = visible rust in 10–60 min, faster if warm.
- Air-drying on a rag, or leaving overnight before lubing, almost guarantees it.
Fix — full anti-flash-rust workflow (do all of these)
- Final rinse in BOILING water (not just hot). Drop the chain into a small pot of boiling water for ~30 s. When you lift it out, the residual heat flashes the surface water off in seconds. Optional: add 1 tsp washing soda or borax per litre as a mild rust inhibitor and pH buffer (alkaline rinse passivates steel briefly).
- Compressed air through every roller. Hold the chain vertically, blast each link — you’ll see water spray out. A small inflator or air compressor with a blow-gun works; a hair dryer on cool is a weaker substitute.
- IPA (≥90%) water-displacement dip. Swirl the chain in a jar of isopropyl for 30–60 s. IPA mixes with the trapped water and carries it out, then evaporates cleanly. Replace the IPA when it gets visibly cloudy with water. (WD-40 also works as a water-displacer — that’s literally what the “WD” stands for — but it leaves a film that fights wax adhesion. Use IPA if you’re waxing; WD-40 is fine before oil lube.)
- Low oven, 90–100 °C (200 °F) for 10–15 min, chain hung on a wire or laid on foil. Drives out the last of the moisture from inside the pins. Skip only if you’re going straight to hot wax (the wax pot does this for you).
- Lube while the chain is still warm — warm steel pulls oil/wax into the rollers by capillary action; cold chain just coats the outside.
- Hot wax: drop straight from oven into the molten wax pot.
- Drip wax / oil: apply within 5 min of pulling from oven, work it through every link, wipe off excess.
Shortcuts (ranked, best → acceptable)
| Workflow | Rust risk | Notes |
|---|---|---|
| Boiling rinse + air blast + IPA + oven + warm lube | Near zero | Do this for waxed chains every time |
| Boiling rinse + air blast + immediate oil lube | Low | Acceptable for daily-driver chain with oil lube |
| Hot rinse + hair dryer + immediate lube | Medium | What most people do; works if you’re fast |
| Air-dry on a rag, lube later | High — this is what rusted yours | Don’t |
Other things that cause flash rust
- Citric acid rinse not neutralized — always follow with a baking-soda dip, then plain rinse, then dry + oil. Residual citric acid keeps eating steel.
- Tap water with high chloride / hard water — minerals stay behind and accelerate corrosion. Use a final rinse of distilled water if your tap is bad.
- Storing a “clean” chain in a humid garage without lube — even with lube, a cold chain in summer humidity sweats. Hang it indoors or in a sealed bag with a silica packet until install.
- Mixing chain cleaning with the same solution as cassettes — cassette grease emulsifies and re-deposits on the chain as a thin film that traps water under it. Clean chains in their own dedicated solution or in IPA.
Recovery — if a chain already flash-rusted
- Light surface bloom: 5 min in 5–10% citric acid, 50 °C → baking-soda neutralize → rinse → full anti-flash workflow above → lube.
- Heavy rust inside the rollers (chain feels stiff, links don’t articulate freely): chain is done. Pins and bushings are pitted; replace it. Don’t try to save a drivetrain chain that’s lost articulation — it’ll skip and wear the cassette.
4. Reusing & filtering the solution
You can reuse a solution 3–20 cycles depending on type, and basic filtering extends life 2–5×. Bike drivetrain grime kills solutions fast (lots of grease + steel particles).
Solution lifespan (bike drivetrain use)
| Solution | Typical reuses | When to dump |
|---|---|---|
| Dish soap + water | 2–4 | Looks like coffee, foam collapses |
| Simple Green Pro HD (diluted) | 3–6 | Grease floats instead of emulsifying |
| Dedicated US degreaser (Elma/Branson/Crest) | 8–20 | Per spec — usually until heavily loaded |
| Citric acid 5–10% | 1–3 (steel only) | Fizzing stops, turns yellow/orange |
| Washing soda 1–3% | 3–5 | Greasy film, soap scum |
| Isopropyl alcohol (final rinse) | 2–4 | Visibly dirty or water-contaminated |
Dump it when: cavitation sounds duller, foam won’t break, or parts come out streaky.
Filtering — three tiers
Tier 1 — Settle + skim (free, ~30 min, ~70% of solids)
- Let solution sit 30 min to overnight in a tall narrow container (taller = faster separation).
- Three layers form: top = oil film, middle = clean solution, bottom = sludge + swarf.
- Skim the top with a paper towel laid flat (wicks oil up) or an oil-only spill pad.
- Decant the middle into a clean jug; stop 1–2 cm above the sludge.
Tier 2 — Paper or bag filter (~$2, 5 min, ~95% of solids)
- Paint strainer bag (best): 5 µm or 1 µm bags at Canadian Tire / Home Depot / auto parts (Trimaco, 3M, generic; ~$2 for 2-pack). Stretch over jug mouth with elastic, pour through.
- Coffee filter + funnel: #4 cone in a kitchen funnel. Pre-warm solution to ~40 °C or it clogs immediately. ~500 ml per filter.
- Improvised: 200+ mesh stainless kitchen strainer lined with paper towel.
Tier 3 — Magnetic + two-jug settling (shop setup, best long-term)
- Stick a strong neodymium magnet (~1”) on the outside of your storage jug — pulls ferrous swarf (chain/cassette particles) to the wall. Wipe magnet area clean periodically.
- Use a two-jug system: “dirty” jug for spent solution, “clean” jug for filtered. Pour into “dirty” after each session, settle overnight, filter top 80% into “clean” next day.
What filtering will NOT fix
- Emulsified grease bound to surfactant (cloudy solution that won’t separate) → chemically spent; dump.
- pH drift (citric acid neutralized by rust, alkaline cleaners losing strength) → dump and remix.
- Sub-micron abrasive grit.
Filter kit (~$10, lasts months)
| Item | Where | ~Cost |
|---|---|---|
| Paint strainer bags 5 µm (2-pack) | Auto parts / paint section | $2 |
| Kitchen funnel 5”+ | Dollar store | $2 |
| Two HDPE jugs (clean + dirty) | Reuse laundry detergent jugs | $0 |
| Oil-absorbent pad / bilge sock | Auto parts | $3–5 |
| Neodymium magnet ~1” | Hardware, Lee Valley, Amazon | $3–8 |
| Coffee filters (backup) | Grocery | $2 |
End-of-session workflow
- Remove parts, rinse, set aside.
- Pour tank contents into the “dirty” jug.
- Wipe the tank dry; refill with plain water + drop of soap for next session’s coupling fluid.
- Once the dirty jug has settled (≥30 min, ideally overnight):
- Skim top oil layer with paper towel.
- Pour through paint-strainer bag + funnel into the “clean” jug.
- Stop 1–2 cm before the sludge; rinse the sludge into trash or the HHW container.
- Solution is ready to reuse next session.
Two-stage wash strategy (extends premium-degreaser life)
- Stage 1: cheap dish-soap mix for bulk grime (dump frequently).
- Stage 2: dedicated degreaser for the final clean (lasts much longer because parts are already mostly clean).
5. Storage & disposal
Storage between sessions
- Opaque HDPE jugs with tight lids (laundry detergent jugs work great). Label with solution type + date.
- Away from heat, freezing, sunlight.
- Citric acid can grow mold after a few weeks — refrigerate, refresh with more citric acid powder, or just mix fresh (it’s cheap).
- IPA only in sealed glass — evaporates fast.
Disposal (when finally spent)
- Soapy water / water-based degreaser: small amounts down a utility sink with lots of running water (most CA municipalities accept this). Larger or heavily contaminated → household hazardous waste depot.
- Citric acid: neutralize with baking soda until fizzing stops (~pH 7), then down the drain.
- IPA: small amounts evaporate outdoors safely; larger → HHW depot.
- Never pour drivetrain wash water into storm drains or onto soil — contains heavy metals (zinc, lead from chain wear) and emulsified petroleum grease.
Waterloo region: see HHW disposal - Waterloo — free drop-off at 925 Erb St W (Gate 2, Waterloo) or 201 Savage Dr (Cambridge), Mon–Sat 7 am–6 pm. Max 25 L per container, must be labeled, no glass.
Tank maintenance
- Drain and refill the coupling fluid every few sessions or when visibly dirty.
- Wipe the tank dry between sessions — standing water + minerals will pit stainless over time.
- Use distilled water for the tank if your tap water is hard.
- Never run the unit dry — kills the transducers.
6. Safety quick-list
- No flammable solvents in the tank — ever
- Lid on whenever heat or volatile chemicals are involved
- Gloves + eye pro for citric acid, alkaline degreasers, IPA
- Ventilate the room — even “safe” degreasers off-gas when heated
- Never run the unit dry