Visible Penetrant Aerosols

		SKC-S	SKD-S2	SKL-SP2	SKL-WP2
Part Number		01-5750-78 Buy Now	01-5352-78 Buy Now	01-5155-78 Buy Now	01-5190-78 Buy Now
Description		Non-halogenated Solvent Cleaner	Solvent based Developer	Post-emulsifiable Visible Dye Penetrant	Water Washable Visible Dye Penetrant
Type		Class II	I & II	II	II
Method				B, C, & D	A & C
Level				II	II
Temperature Range				40 – 125°F (4 – 52°C)	40 – 125°F (4 – 52°C)
Net Weight per Can (g)		300	330	300	330
Industry	Aerospace	✔	✔	✔	✔
	Automotive	✔	✔	✔	✔
	Field Inspection	✔	✔	✔	✔
	General Use	✔	✔	✔	✔
Specifications Compliance	AECL	✔	✔	✔	✔
	AMS 2644	✔	✔	✔	✔
	ASME BPVC	✔	✔	✔	✔
	ASTM E1417	✔	✔	✔	✔
	ASTM E165	✔	✔	✔	✔
	Boeing BAC 5423 PSD6-46 or 8-4	✔	✔		✔
	Boeing PS-21202	✔	✔		✔
	GE P3TF2		✔
	GE P50YP107	✔	✔		✔
	Honeywell EMS 52309		✔
	ISO 3452-2	✔	✔	✔	✔
	MIL-STD-2132	✔	✔	✔	✔
	MIL-STD-271	✔	✔	✔	✔
	NAVSEA T9074-AS-GIB-010/271-REV-1	✔	✔	✔	✔
	NAVSEA 250-1500-1	✔	✔	✔
	QPL SAE AMS 2644		✔	✔	✔

 

Each penetrant is a Type 2 (visible red dye) formula with ISO sensitivity Level 2.  SKL‑SP2 is solvent-removable (petroleum-based), SKL‑WP2 is water-washable (petroleum/surfactant blend), and SKL‑4C is a special water-based dye for chemically sensitive plastics and leak testing.

Typical Applications

• SKL‑SP2: Suited to metal welds, forgings, castings, pressure vessels, tubes, etc. – a general-purpose penetrant for ferrous and non-ferrous parts in aerospace, automotive, maintenance, and fabrication settings. It finds cracks, porosity, incomplete fusion, leaks and similar defects in hard materials (metals and non-porous ceramics).
• SKL‑WP2: Ideal for large surfaces, rough parts, and field inspections where ease of cleanup is important. Typical uses include weld inspections, castings, forgings, pressure vessels and other heavy equipment. It locates weld cracks, shrink cracks, porosity, undercuts, leaks, incomplete fusion, etc. Because it’s low-odor and water washable, SKL‑WP2 is popular for assembly-line or outdoor use where running water rinse is convenient.
• SKL‑4C: A dual-purpose visible/fluorescent penetrant used on plastics, ceramics, and leak detection tasks. It is formulated for chemically sensitive parts. Fluorescent capabilities allow inspection under UV as well as visible light. Typical applications include ceramic components, sensitive plastic parts (e.g. polymer housings), and leak testing (it can be used as a leak detection dye). SKL‑4C is water-based and should be tested on any plastic before use.

Usage Instructions

General Penetrant Procedure (all products): First pre-clean the part thoroughly to remove oil, dirt and coatings. A solvent cleaner (e.g. Magnaflux SKC‑S) is typically used. Spray SKC-S (or equivalent) and wipe or rinse the surface dry. Good cleaning is critical for reliable inspection.

Next, apply the penetrant. Shake the aerosol can and spray a uniform mist over the test area so that the penetrant fills any surface flaws. Allow sufficient dwell time (penetration time) for the liquid to seep into defects. A minimum of about 10 minutes is generally recommended (Magnaflux guides suggest 10–30 min dwell for most visible inspections). Keep the part at normal ambient temperature (roughly 40–125 °F) during dwell.

After dwell, remove excess penetrant from the surface:

• SKL‑SP2: Wipe off surface penetrant with a clean cloth dampened with SKC‑S or similar solvent (Method C). (Alternatively, a light water-wash + wipe with solvent is Method B, or use an emulsifier spray like ZE‑4E for Method D.) The goal is to remove all visible red fluid from the surface while leaving any fluid trapped in defects.
• SKL‑WP2: Since it is water-washable, remove excess by rinsing with a moderate stream of clean water at ambient temperature. (If using Method C, you may wipe with SKC‑S solvent to assist removal, but usually a water spray alone suffices.) Then dry or wipe the part thoroughly.
• SKL‑4C: Remove excess similarly by rinsing with water. SKL‑4C is water-washable by design. A dilution (1:1 with water) can be used to conserve material, then rinse with water and dry. Because it’s water-based, ensure the surface is dry before applying any nonaqueous developer.

With the excess penetrant removed and the surface dry, apply developer to draw out any trapped dye for visibility. For visible dye penetrants, a white background developer makes red indications stand out. Common developers for these penetrants include:

• SKD‑S2 (Solvent-based spray developer): Quick-drying spray, applied evenly, part must be dry before application.
• ZP‑9F (Solvent spray developer, SKL‑SP2 only): Similar to SKD‑S2, quick-dry solvent developer.
• ZP‑5B (Water-suspendible dip developer): Apply by dip or spray; after application, dry the part before inspection.
  Magnaflux data sheets confirm these choices (e.g. SKL‑WP2 recommends SKD‑S2 or ZP‑5B, while SKL‑SP2 can use SKD‑S2, ZP‑9F, or ZP‑5B). Allow the developer to dwell (10–60 minutes), then inspect under visible light. Indications (red fluorescing threads) will appear on the white background.

Key Differences & Recommendations

• Removal & Cleanup: SKL‑SP2 (solvent-removable) requires solvent wiping (no water) which is excellent for oily or hard-to-rinse parts; it also supports post-emulsification for even tighter defects. SKL‑WP2 (water-washable) can simply be rinsed off, eliminating solvents altogether.
• Surface Compatibility: SKL‑WP2 and SKL‑SP2 are both formulated for metals and ceramics. However, SKL‑SP2 (petroleum-based) can attack some plastics or rubbers, so it should be tested or avoided on plastic components. In contrast, SKL‑4C is fully water-based and designed for plastic/ceramic parts; it will not attack sensitive plastics. Use SKL‑4C for polymer housings, seals, or any chemical-sensitive materials.
• Ease of Use: Both SP2 and WP2 are low-odor and compliant with key NDT standards (AMS 2644, ASTM E165/E1417, etc.). WP2’s water rinsability often makes it more convenient in the field or on large parts (no solvent disposal issue). SP2’s solvent base may penetrate deeper and resist drying, which can improve sensitivity on very fine defects, but requires ventilation.
• Fluid Behavior: SKL‑SP2 is a mineral oil carrier (about 70% white oil), providing excellent wetting and slow flash-off (so it stays longer in defects). SKL‑WP2, although water-washable, still contains hydrocarbon solvents and surfactants – it flows well and can “flow out” easily under water rinse. SKL‑4C’s carrier is water (with added wetting agents), so it dries by air.

Recommendations: Use SKL‑SP2 for tight cracks on hard metal parts where solvent removal is acceptable. Use SKL‑WP2 for quick, easy cleanup on metal surfaces (e.g. maintenance, castings, large welds) where rinsing is practical. Use SKL‑4C when inspecting plastics, ceramics, or when working with components that cannot tolerate petroleum solvents. All have roughly the same sensitivity (ISO Level 2), but choice depends on substrate, cleanup method, and required penetrant base.