Castair CAST-CLEAN Industrial Parts Cleaning Solvent
CAST-CLEAN is Castair's industrial parts cleaning solvent, designed for use with air compressor service and maintenance. Castair carries a rotary varnish cleaner (Varnasolv) listed on their website for rotary screw compressor maintenance, used to clean varnish deposits from the oil system — mixed at 10%, run for 50 hours, then drained with a full oil and separator filter change. Whether CAST-CLEAN is Varnasolv or a separate general-purpose parts cleaning solvent, it's Castair's factory-recommended cleaning product for their compressor service applications.
Research note: Castair lists a rotary varnish cleaner (Varnasolv) on their oil/chemical page but does not publish a dedicated spec sheet for CAST-CLEAN under this exact name on their public website. Contact us or Castair to confirm the exact formulation and application before ordering.
What Compressor Cleaning Solvents Are For
Air compressors accumulate internal deposits over time — particularly rotary screw compressors where oil circulates continuously through the compression element, oil separator, and heat exchanger. Varnish and carbon deposits build up on internal surfaces, restricting oil flow, reducing separator efficiency, and contributing to elevated operating temperatures. A cleaning solvent flush removes these deposits before they cause damage or require expensive disassembly.
Typical Applications
- Rotary screw compressor varnish removal: Mix at 10% with compressor oil, run for 50 hours to loosen and suspend varnish deposits, drain warm, then change oil and oil separator filter — this is the Varnasolv/rotary cleaner application per Castair's published protocol
- Pump component cleaning: General parts washing for compressor pump heads, valves, and internal components during service and overhaul
- Preventive maintenance: Used as part of scheduled overhaul intervals on compressors with high operating hours or those switching from mineral oil to synthetic
Castair Rotary Cleaner Protocol (from Castair's published data)
For rotary screw compressor applications, Castair's published recommendation:
- Mix cleaning solvent at 10% ratio with existing compressor oil
- Run compressor for 50 hours at normal operating conditions
- Drain oil while warm (better suspension of deposits)
- Change both oil and separator filter simultaneously
- Fill with fresh Castair-approved compressor oil (GA4000 or FG4000 for rotary screw)
Castair Oil and Chemical Product Line
| Product | Type | Size | Application |
|---|---|---|---|
| QT5W30 / GA5W30 | Semi-synthetic piston oil | Qt / Gal | Piston compressors — 4 months/400 hours |
| QT10W30 / GA10W30 | Full synthetic piston oil | Qt / Gal | Piston compressors — 8 months/800 hours |
| GA4000 / FG4000 | Full synthetic rotary oil | 1 Gal / 5 Gal | Castair rotary screw — 1 year/4000 hours |
| CAST-CLEAN | Industrial cleaning solvent | TBD | Internal cleaning / varnish removal |
When to Use a Compressor Cleaning Solvent
- When switching oil types (mineral to synthetic) — incompatibility can cause sludge; flush first
- When a compressor has been running with degraded oil past its service interval
- When operating temperature is elevated — often indicates varnish deposits restricting oil flow
- As part of a major service interval on high-hour compressors (typically every 2,000-4,000 hours on rotary screw)
- When an oil analysis shows high varnish potential number (VPN) — common in synthetic oil systems running near their service limit
Why Buy From Air Compressor Factory Direct?
We carry Castair oils, chemicals, and service products and can help you select the right cleaning and maintenance products for your compressor type. Free shipping on qualifying orders. Free tech support at 866-217-0063. Call us to confirm the correct application and mixing ratios for CAST-CLEAN before use — cleaning solvents used incorrectly can damage seals or accelerate oil degradation if the flush isn't completed properly.
Call 866-217-0063 for quick answers and help!
