Contents
- How to use this guide
- Where it fits
- Quick decision map
- Key decision factors
- Common methods (spray/immersion/recirculation/wipe)
- Chemistry options (high-level)
- Monitoring signals
- Troubleshooting: symptom → first checks
- Specification & acceptance checks (COA/SDS)
- Handling & storage
- RFQ notes (what to include)
How to use this guide
This is a practical decision aid for B2B teams. Use it to align procurement, EHS, and operations on selection criteria, acceptance checks, and monitoring signals. If you share your paint system and constraints, we can shortlist compliant, supply-ready options.
Safety note: Paint strippers and strong cleaners can be corrosive, irritant, flammable, or reactive with certain metals/plastics. Always follow site EHS rules, SDS/labels, ventilation requirements, and lockout/tagout procedures for line equipment.
Where it fits
- Process goal: define the KPI you are optimizing (uptime, finish quality, defect rate, maintenance time, safety, or cost).
- Operating window: temperature, dwell time, agitation/impingement, and rinse quality.
- Interfaces: what the chemistry touches (metals, plastics, elastomers, seals, pumps, hose liners, booth materials).
- Constraints: VOC limits, wastewater treatment limits, restricted substances, and site policies (e.g., solvent-free, NMP-free).
Quick decision map
| Situation | Usually best starting point | Why |
|---|---|---|
| Uncured paint / wet overspray | Routine cleaner (often aqueous or low-VOC solvent blend) | Focus on wetting + solvency + rinseability; lower risk to equipment |
| Cured/baked paint build-up | Stripper (alkaline, neutral pH, or solvent-based depending on constraints) | Needs stronger chemistry and time/temperature to break the film |
| Powder coating hooks/hangers | High-performance stripper matched to metal + cycle time | Powder films can be highly crosslinked; substrate protection matters |
| Mixed soils (oil + paint + dirt) | Two-step: degrease/clean → strip (if needed) | Removing oils first improves stripper contact and reduces consumption |
Practical rule: Don’t “upgrade to a stronger stripper” before confirming three basics:
(1) paint type + cure state, (2) substrate/elastomer compatibility, (3) your real operating window (temperature + dwell time + rinsing).
Key decision factors
| Factor | Examples | Why it changes selection |
|---|---|---|
| Paint chemistry | Epoxy, polyurethane (2K), acrylic, alkyd, e-coat, powder | Crosslink density and resin type drive required chemistry and dwell time |
| Cure state / thickness | Wet vs skinned vs baked; thin film vs heavy build-up | Heavier and more cured films need stronger chemistry or heat/time |
| Substrate + elastomers | Carbon steel, stainless, aluminum, galvanized; EPDM, NBR, FKM, PU hoses | Some strippers attack aluminum/zinc and swell certain elastomers |
| Application method | Immersion tank, spray-in-place, recirculation, wipe | Impingement + temperature can reduce chemical intensity needed |
| Compliance constraints | VOC caps, restricted substances, wastewater limits, odor constraints | May rule out certain solvent systems or high-COD approaches |
Common methods (spray/immersion/recirculation/wipe)
| Method | Best for | Control points | Common failure mode |
|---|---|---|---|
| Immersion | Hooks/hangers, small parts, removable fixtures | Temperature, dwell time, agitation, tank loading, filtration/skimming | Overloading tank → slow stripping; residue redeposition |
| Spray wash / impingement | Routine line cleaning, conveyors, accessible surfaces | Nozzle pressure/pattern, concentration, dwell, rinse quality | Insufficient dwell; poor coverage in shadowed zones |
| Recirculation / CIP | Pipes, manifolds, booths (system-dependent) | Flow rate, temperature, compatibility with pumps/hoses/seals | Seal swelling or corrosion; foam that reduces pump performance |
| Wipe / localized gel | Spot removal, sensitive areas, controlled exposure | Contact time, containment, residue removal and neutralization | Inconsistent coverage; residue left behind |
Chemistry options (high-level)
This is a selection framework, not a recipe. Always validate on your materials, at your conditions.
| Chemistry family | Typical use | Strengths | Watch-outs |
|---|---|---|---|
| Alkaline aqueous cleaners | Uncured paint + oils; routine maintenance | Good rinsing; lower VOC; scalable in spray systems | Can cause flash rust on steel if rinse/dry is poor |
| Alkaline strippers (caustic-based) | Cured films on compatible metals; some powder/hanger systems | Strong stripping power; often economical | Corrosion risk (esp. aluminum/zinc); high pH handling controls needed |
| Neutral/near-neutral strippers | Where substrate sensitivity or safety constraints are high | Often gentler on some substrates; reduced caustic risk | May need more dwell/heat; verify performance on crosslinked coatings |
| Solvent / low-water strippers | Hard-to-remove coatings; spot stripping; specific compliance windows | High solvency on many resins; fast action in some cases | Flammability/VOC/odor; compatibility with plastics; ventilation critical |
If you’re unsure: share paint type (and whether it’s baked), substrate list (including elastomers), and your max temperature/dwell.
That’s usually enough to narrow down the correct family quickly.
Monitoring signals
| Signal | What it suggests | First thing to check |
|---|---|---|
| High foaming / poor rinsing | Surfactant mismatch or too much agitation; contamination load high | Concentration, temperature, water hardness, mechanical action |
| Flash rust after cleaning | Steel exposed + residue + slow dry or high conductivity rinse | Rinse quality, time-to-dry, inhibitor/passivation step feasibility |
| Residue / spotting | Incomplete rinsing or redeposition from dirty bath | Bath loading/filtration, final rinse quality, concentration |
| Stripping slows over time | Bath exhausted or overloaded; temperature drift | Active concentration, bath contamination, temperature control |
| Seal swelling / leaks | Compatibility issue with elastomers or solvent exposure | Seal material (EPDM/NBR/FKM), exposure time, product family |
Troubleshooting: symptom → first checks
| Symptom | First checks | Likely direction |
|---|---|---|
| Paint not lifting (cured film) | Confirm paint type + cure; verify temperature and dwell; check bath loading/exhaustion | Need different chemistry family or more heat/time |
| White haze / residue after rinse | Rinse water hardness/conductivity; bath contamination; concentration too high | Improve rinse; adjust concentration; add filtration/skimming |
| Flash rust on steel parts | Time-to-dry; final rinse quality; alkaline residue; inhibitor option | Rinse/dry control + inhibitor/passivation consideration |
| Aluminum darkening / etch | Verify aluminum exposure; check pH and chemistry family | Switch to aluminum-compatible chemistry or reduce exposure |
| Persistent foam / pump cavitation | Agitation/nozzle setup; surfactant level; contamination (oils/paint) | Lower foam formulation or adjust mechanics; consider defoamer compatibility |
Specification & acceptance checks (COA/SDS)
When comparing products, ask for data you can verify on receipt:
| What procurement should lock down | Why it matters | What to verify on receipt |
|---|---|---|
| Identity & traceability | Consistency in stripping rate and compatibility | Product name/grade, manufacturer, batch/lot on labels + COA |
| Quality (COA items) | Active concentration affects dwell time and outcomes | Appearance, density, pH (as supplied), assay/active (as applicable), viscosity (if relevant) |
| Compatibility statements | Prevents damage to aluminum/zinc/plastics/elastomers | Recommended materials-of-construction guidance (or exclusions) |
| Safety documentation | EHS approval and correct PPE/ventilation controls | Up-to-date SDS revision date; hazard class, PPE, storage segregation |
| Logistics | Downtime risk if supply slips; handling constraints | Lead time, Incoterms, shelf life, storage temperature range |
| Packaging | Prevents leaks and ensures safe transfers | Drum/IBC/bulk; liner type; closures; labeling; integrity on arrival |
Handling & storage
- Store in original, sealed packaging, away from incompatible materials (follow SDS guidance).
- Use secondary containment and clear labeling in the operating area.
- For transfers: verify hose/seal compatibility; implement spill-control basics; ensure ventilation where needed.
- Keep an emergency rinse/eyewash available as required by site EHS.
RFQ notes (what to include)
- Paint system: type (powder/e-coat/epoxy/PU/acrylic/alkyd), and whether it is baked/cured; typical film thickness/build-up.
- Soils: paint only vs mixed oils/grease/dirt; frequency of cleaning and downtime window.
- Substrates & elastomers: carbon steel/stainless/aluminum/galvanized; seal and hose materials; any “must not attack” components.
- Method: immersion/spray/recirculation/wipe; available heat; max dwell time; agitation/pressure.
- Acceptance KPI: stripping time, residue-free surface, no substrate attack, rinseability, corrosion/flash rust limits.
- Compliance: VOC limits, restricted substances policy, wastewater constraints, odor/ventilation constraints.
- Supply: monthly volume, packaging preference (drum/IBC/bulk), delivery country, required docs (SDS/COA).
Need a compliant alternative?
Send your constraints and target performance. We’ll propose options with SDS/COA expectations and procurement-ready specs.
Educational content only. Always follow site EHS rules and the supplier SDS for safe use.