Is Amerlock 2 or Amerlock 400 NSF certified for potable water?

Amerlock 2 is ANSI/NSF Standard 61 certified for tanks, pipes, valves, and fittings — the full scope of potable water immersion service. Amerlock 400 holds NSF Standard 61 certification for valves only. If your project requires NSF 61 for potable water tank lining or pipe lining, you must use Amerlock 2, manufactured at a US facility. Amerlock 2 also meets FDA requirements for direct food contact.

What is the minimum application temperature for Amerlock 2 vs Amerlock 400?

Amerlock 2 can be applied and cured with substrate temperatures down to 32°F, with a dry-to-handle time of 38 hours at that temperature. The Amerlock series brochure notes application down to 0°F with surface free of ice. Amerlock 400 requires a minimum substrate temperature of 41°F. For cold-weather jobs, Amerlock 2 is the correct product.

How long can you wait before recoating Amerlock 2 or Amerlock 400?

Amerlock 2 has a maximum recoat window of 1 month at all temperatures when overcoating with epoxy or itself. Amerlock 400 has a longer maximum recoat window of up to 3 months at 50–68°F when overcoating with epoxy. If the maximum window is exceeded for either product, roughen the surface before recoating. Amerlock 400's longer window provides more scheduling flexibility on large projects.

What is the mix ratio and induction time for Amerlock 2 and Amerlock 400?

Both Amerlock 2 and Amerlock 400 mix 1:1 by volume (base to hardener). Amerlock 2 requires an induction time at lower temperatures: 45 minutes at 32°F, 30 minutes at 50°F, 20 minutes at 59°F, 10 minutes at 68°F, and no induction time above 73°F. Amerlock 400's PDS does not specify a required induction time in the same format — consult your PPG representative for low-temperature guidance.

Can Amerlock 2 or 400 be applied over rust and existing coatings?

Yes — both Amerlock 2 and Amerlock 400 are surface-tolerant epoxies designed for application over tightly adhering rust and intact old paint, making them suitable for maintenance projects where blast cleaning is impractical. For immersion service, both require blast cleaning to ISO Sa2½ (SSPC SP10) on carbon steel. For atmospheric service, minimum SSPC SP6 or power/hand tool cleaning to ISO St3/St2 is acceptable. Good adhesion on damp surfaces is also a feature of both products.

Amerlock 2/400 Epoxy Coating 2 Gallon Kit

Q: What is the difference between Amerlock 2 and Amerlock 400?

Amerlock 2 and Amerlock 400 are both two-component, 85% volume-solids, 1:1 mix-ratio surface-tolerant epoxies with the same coverage rate and DFT range. The key differences: Amerlock 2 cures at lower temperatures (down to 32°F vs. 41°F for Amerlock 400), holds NSF/ANSI 61 certification for full immersion service including tanks and pipes (Amerlock 400 is NSF 61 for valves only), meets FDA requirements for direct food contact, dries to recoat faster at higher temperatures, and has the least odor in the series. Amerlock 400 offers a longer maximum overcoat window (up to 3 months vs. 1 month for Amerlock 2) and is compatible with PPG 861 accelerator to cut all cure times in half.

Q: What is the coverage rate for Amerlock 2 and Amerlock 400?

Both Amerlock 2 and Amerlock 400 have identical theoretical coverage rates based on 85% volume solids: 341 ft²/gal at 4.0 mils DFT, 273 ft²/gal at 5.0 mils, and 170 ft²/gal at 8.0 mils. Practical coverage is typically estimated at 70% of theoretical. Allow for loss in mixing and application.

Q: What topcoats are compatible with Amerlock 2 and 400?

Both Amerlock 2 and Amerlock 400 are compatible with the same family of topcoats: AMERCOAT 450 Series, SIGMADUR Series, SIGMACOVER Epoxies, AMERCOAT Epoxies, AMERSHIELD aliphatic polyurethane, and PSX topcoat series. Amerlock 2 is also compatible with PITTHANE ULTRA Series and DURETHANE DTM. For best results apply topcoats within the maximum overcoat window; if exceeded, roughen the surface and consider a PREP 88 wash.

Thinner	Use Case	Max Rate
Amercoat 65 (Thinner 21-06)	NSF/ANSI 61 potable water applications · All spray methods · General global use	Air: 10% · Airless: 5%
Amercoat T10 (Thinner 91-82)	Non-NSF applications · Temps below 90°F · Amerlock 2	Air: 10% · Airless: 5%
Thinner 91-92	Non-NSF applications · Amerlock 400 · Global	Air: 10% · Airless: 5%
Amercoat 101 (Thinner 21-25)	Non-NSF applications · Hot conditions above 90°F · Slows cure in heat	Air: 10% · Airless: 5%

Protective & Marine Coatings — Amerlock Series

Product Specs — PPG Amerlock 2 / Amerlock 400

Amerlock 2 and Amerlock 400 are two-component, high-solids, surface-tolerant epoxy coatings from PPG Protective & Marine Coatings. Both products share the same 85% volume solids, 1:1 mix ratio, and 4–8 mil DFT range. The key difference is where and when each is certified to be used — especially for potable water and low-temperature applications.

Both coatings apply directly to tightly adhering rust and intact existing paint, resist damp surfaces, and perform as a combined primer/topcoat or primer under PPG polyurethane topcoats such as Amershield or Amercoat 450.

✓ Self-Priming ✓ Surface Tolerant ✓ Damp Surface Compatible ✓ 85% Volume Solids ✓ 1:1 Mix Ratio ✓ USDA Incidental Food Contact

✓ ANSI/NSF 61 (Amerlock 2 full scope; Amerlock 400 valves only) • ✓ AWWA D102-06 ICS #1, #2, #3, #5 • ✓ USDA Incidental Food Contact • ✓ FDA Direct Food Contact (Amerlock 2) • ✓ NFPA Class A Flame & Smoke • ✓ Nuclear Service Level 2 • ✓ LEED Anti-Corrosive Paint

✏️ Need a project quote? Request Online

📞 Questions? Call (800) 567-5358 — Mon–Fri 8AM–5PM EST

PPG Amerlock Series

PPG Amerlock 400 high-solids surface-tolerant epoxy coating — two-component kit — PPG Amerlock Series — Amerlock 2 and Amerlock 400
Two-component, 85% volume solids, 1:1 mix ratio

Which Product Do I Need? — Amerlock 2 vs. Amerlock 400

Both products are 85% solids, 1:1 mix-ratio, surface-tolerant epoxies with identical coverage rates. The right choice comes down to three things: your certification requirements, your minimum application temperature, and how much scheduling flexibility you need.

Choose Amerlock 2 When…

Amerlock 2

Potable water immersion — NSF/ANSI 61 certified for tanks, pipes, valves, and fittings.
FDA food contact — meets FDA requirements for direct food contact service.
Cold weather — cures down to 32°F; the PPG brochure notes application to 0°F on ice-free surfaces.
Fast turnaround — dry to touch in ~2 hours and recoatable in 3 hours at 70°F.
Confined spaces — lowest odor of the Amerlock series.
AWWA D102-06 — ICS #1, #2, #3, and #5 all required.

Choose Amerlock 400 When…

Amerlock 400

Scheduling flexibility — overcoat window up to 3 months (vs. 1 month for Amerlock 2), ideal for large phased projects.
Valve-only NSF 61 — when potable water certification is needed for valves but not tank or pipe lining.
PPG 861 accelerator — compatible with Amercoat 861 to cut all cure and recoat times in half (US supply only).
Moderate temperatures — minimum substrate temp of 41°F; no cold-weather cure needed.
Maintenance & infrastructure — bridges, tank exteriors, and large structures coated in phases.
Nuclear Service Level II — qualified per ANSI N 5.12 and ANSI N 101.2.

⚠️ NSF/ANSI 61 scope differs between products. Amerlock 2 is certified for full potable water immersion — tanks, pipes, valves, and fittings — but only when manufactured at a US PPG facility. Amerlock 400 is certified for valves only. If your project requires potable water tank or pipe lining, you must use Amerlock 2. Confirm the current listing at nsf.org before ordering.

Side-by-Side Comparison

Property	Amerlock 2	Amerlock 400
Generic Type	Two-component, high-solids epoxy
Volume Solids	85% ± 2%
Mix Ratio (base:hardener)	1:1 by volume
Recommended DFT	4.0–8.0 mils per coat
Coverage @ 4 mils	341 ft²/gal — theoretical
Coverage @ 5 mils	273 ft²/gal
Coverage @ 8 mils	170 ft²/gal
VOC (as supplied)	1.5 lb/gal — EPA Method 24
Gloss	Semi-gloss
Min. Substrate Temp.	32°F — down to 0°F per brochure	41°F
Max. Substrate Temp.	122°F
Dry to Touch @ 70°F	~2 hours (per brochure)	6 hours
Dry to Handle @ 68°F	5 hours	20 hours
Min. Overcoat @ 68°F	6 hours	16 hours
Max. Overcoat (epoxy) @ 68°F	1 month	3 months
Max. Overcoat (urethane/PSX) @ 68°F	7 days	1 month
Pot Life @ 68°F	1 hour	2 hours @ 70°F
Full Cure @ 68°F	4 days
Induction Time @ 59°F	20 minutes	Not required
NSF/ANSI 61	Tanks, pipes, valves & fittings (full immersion)	Valves only
AWWA D102-06	ICS #1, #2, #3, #5	ICS #1, #2, #3, #5
FDA Direct Food Contact	Yes	No (USDA incidental only)
USDA Incidental Food Contact	Yes — both
Nuclear Service Level 2	ANSI N 5.12, ASTM D5144	ANSI N 5.12, ANSI N 101.2
PPG 861 Accelerator Compatible	Not listed	Yes — halves cure, recoat, and pot life (US only)
Odor	Least odor in series	Standard
Temp. Resistance (Continuous)	To 250°F
Temp. Resistance (Intermittent)	To 350°F
Shelf Life — Base	Min. 36 months (cool, dry, sealed)
Shelf Life — Hardener	Min. 24 months	Min. 36 months

Source: PPG Amerlock 2 PDS (Ref. 7989, Aug 2025) · PPG Amerlock 400 PDS (Ref. 7988, Jan 2025) · PPG Amerlock Series Brochure (PM17703/69)

Shipping & Packaging

Call (800) 567-5358 for pricing and logistics questions.

PPG Amerlock orders ship from regional warehouses nearest to your location.

Most orders ship within 2–3 business days of order placement.

Both Amerlock 2 and Amerlock 400 are supplied as two-component kits (base + hardener, mixed 1:1 by volume). Do not mix partial kits.

Shipping Map — Delivery Timing

US regional warehouse map showing estimated shipping transit times for PPG Amerlock orders from Material Warehouse — Typical transit times vary by destination zone.

Coverage Rates

DFT Range: 4–8 mils (100–200 µm) per coat. The same coverage rates apply to both Amerlock 2 and Amerlock 400. Coverage is based on 85% volume solids. Practical coverage is typically ~70% of theoretical; allow for loss in mixing and application.

DFT per Coat	Theoretical Coverage
4.0 mils	341 ft²/gal
5.0 mils	273 ft²/gal
8.0 mils	170 ft²/gal

Theoretical coverage based on 85% volume solids. Practical coverage ~70% of theoretical; allow for loss in mixing and application.
Source: PPG Amerlock 2 PDS (Ref. 7989) · PPG Amerlock 400 PDS (Ref. 7988)

Curing Schedules & Overcoating Intervals

Amerlock 2 — Curing (DFT up to 8 mils)

Substrate Temp.	Dry to Handle	Full Cure
32°F (0°C)	38 hours	21 days
50°F (10°C)	14 hours	7 days
68°F (20°C)	5 hours	4 days
86°F (30°C)	3 hours	3 days

Amerlock 400 — Curing (DFT up to 5 mils)

Substrate Temp.	Dry to Touch	Dry to Handle	Full Cure
50°F (10°C)	24 hrs	48 hrs	21 days
68°F (20°C)	6 hrs	20 hrs	7 days
86°F (30°C)	3 hrs	12 hrs	4 days
104°F (40°C)	1 hr	8 hrs	3 days

PPG 861 (Amercoat 861) accelerator (1 pt per 5 gal) reduces all Amerlock 400 cure and recoat intervals to approximately half. US supply only.

📄 Immersion Service: Cure times for immersion service applications (tanks, pipes, and linings) vary by temperature and service conditions. Refer to the Amerlock 2 Product Data Sheet for full immersion cure schedule data.

Amerlock 2 in the Field — Case Study

Historic 1943 caboose restored with PPG Amerlock 2 epoxy and Amercoat 450H polyurethane topcoat — Erlanger, KY

📋 Historic 1943 Caboose Restoration — Erlanger, KY (2016)

Owner:: Town of Erlanger, Kentucky
Asset:: Historic 1943 railroad caboose, city center landmark
Challenge:: Previous coating had faded and started to peel due to years of outdoor exposure. The town wanted a longer-lasting system to restore and protect the historic piece.
System Applied:: Amerlock 2 (high-build epoxy, fast drying / self-priming) + Amercoat 450H (Gloss Aliphatic Polyurethane) topcoat for outstanding weather and corrosion resistance.
Why Amerlock 2:: Fast drying time and self-priming feature minimized downtime. The system extended the asset's service life and returned the caboose to the city quickly.
Result:: Town satisfied with the restored appearance and extended coating life. Amerlock 2 + Amercoat 450H delivered a durable, weather-resistant finish.

Source: PPG Case Study PM65866-USA (September 2016)

Good to Know Before You Buy

⚠️ Key Differences That Affect Which Product You Need

NSF/ANSI 61 scope is not the same — this is the most important difference. Amerlock 2 is certified for full potable water immersion: tanks, pipes, valves, and fittings. Amerlock 400 is certified for valves only. If your project requires tank or pipe lining under NSF 61, you must use Amerlock 2. Certification is valid for US-manufactured product only.
Cold weather: only Amerlock 2 cures at freezing temperatures. Amerlock 2 applies down to 32°F substrate; the PPG brochure notes application to 0°F with an ice-free surface. Amerlock 400 requires a minimum of 41°F. For winter jobs, Amerlock 2 is the correct choice.
Amerlock 400 gives you far more scheduling flexibility. Its maximum overcoat window is up to 3 months (vs. 1 month for Amerlock 2) when overcoating with epoxy. On phased projects or large structures, this significantly reduces the risk of having to abrade and re-prep areas that weren't topcoated in time.
Both products will chalk and lose gloss outdoors. Like all epoxies, these coatings are not UV-stable on their own. For any exterior application where appearance or long-term color retention matters, a polyurethane topcoat — such as PPG Amershield or Amercoat 450H — is required over the Amerlock base coat.

Frequently Asked Questions — Amerlock 2 & Amerlock 400

What is the difference between Amerlock 2 and Amerlock 400?

The most practical difference between these two products is how they behave at temperature — and that determines which one is right for your job.

Amerlock 2 cures fast. At 68°F it's dry to handle in 5 hours and fully cured in 4 days. It can cure at substrate temperatures as low as 32°F — making it the correct choice for cold-weather applications, fast-turnaround jobs, and any project requiring NSF/ANSI 61 certification for full potable water immersion (tanks, pipes, valves, and fittings) or FDA direct food contact compliance.

Amerlock 400 has a longer open time — at 68°F it takes 20 hours to dry to handle. That slower cure is actually an advantage in warmer ambient conditions, where a fast-curing epoxy can skin over before it fully wets out and levels. The 400 is better suited to hot-weather jobs, large maintenance projects applied in phases, and situations where you need more working time or scheduling flexibility. Its maximum overcoat window extends to 3 months (vs. 1 month for Amerlock 2), and it's compatible with the PPG 861 accelerator to speed things up when needed. Its NSF 61 certification covers valves only — not tanks or pipes.

In short: cold weather or immersion service → Amerlock 2. Hot weather, large-scale maintenance, or scheduling flexibility → Amerlock 400.

Which product is better for hot weather application?

Amerlock 400 is the better choice in hot or warm ambient conditions. Its longer dry time — 20 hours to handle at 68°F vs. 5 hours for Amerlock 2 — means the coating stays open and workable longer, giving it more time to wet out the substrate and level before it starts to cure. Amerlock 2 cures quickly, which is an advantage in cold weather and fast-turnaround situations, but in hot conditions a fast-skinning epoxy can trap solvents and produce a rougher finish. Amerlock 400 is also compatible with the PPG 861 accelerator, which can cut all cure times in half for situations where faster turnaround is needed even in warm conditions.

Which Amerlock product is NSF/ANSI 61 certified for potable water tank lining?

Amerlock 2 only — and only when manufactured at a US PPG facility. Amerlock 2 is qualified for ANSI/NSF Standard 61 covering tanks, pipes, valves, and fittings. Amerlock 400 holds NSF 61 for valves only. If your project requires potable water tank or pipe lining under NSF 61, you must specify Amerlock 2. Always verify the current NSF listing at nsf.org before ordering, as certifications can change.

What is the coverage rate for Amerlock 2 and Amerlock 400?

Both products have the same theoretical coverage: 341 ft²/gal at 4.0 mils, 273 ft²/gal at 5.0 mils, and 170 ft²/gal at 8.0 mils (based on 85% volume solids). Practical coverage is typically ~70% of theoretical; allow for loss in mixing and application, stripe coats at edges, and surface profile.

Can Amerlock 2 or 400 be applied over rust and old paint?

Yes — both are surface-tolerant epoxies specifically designed for application over tightly adhering rust and intact old paint when blast cleaning is impractical or impossible. For immersion service, full blast cleaning to ISO Sa2½ (SSPC SP-10) is required for carbon steel regardless. Surface tolerance is the key advantage for atmospheric maintenance work on bridges, tanks, and infrastructure.

How long can I wait before recoating Amerlock 400 vs. Amerlock 2?

Amerlock 400 allows up to 3 months (at 50–68°F) before overcoating with itself or another epoxy — giving maximum scheduling flexibility on large projects. Amerlock 2 allows up to 1 month at all temperatures. For urethane or PSX topcoats, both products have tighter windows. If the maximum recoat window is exceeded for either product, roughen the surface before applying the next coat.

Can I use the PPG 861 accelerator with both products?

The PPG 861 (Amercoat 861) accelerator is explicitly listed for Amerlock 400 only in the published PDS. At 1 pint per 5 gallons, it reduces all cure, dry-to-handle, and recoat times to approximately half — but also reduces pot life to half. It is available for US supply only. Amerlock 2's PDS does not list PPG 861 as an approved additive; contact your PPG representative before using any additive with Amerlock 2.

What is the minimum application temperature for each product?

Amerlock 2 can be applied with substrate temperatures down to 32°F, and the PPG brochure notes application to 0°F with an ice-free surface. This cold-temperature capability is one of Amerlock 2's defining advantages — it cures quickly even in cold conditions, making it the right product for winter jobs and cold climates. Amerlock 400 requires a minimum substrate temperature of 41°F and is designed for moderate to warm conditions, where its longer open time is beneficial rather than limiting. Both products require substrate temperature to be at least 5°F above the dew point.

What topcoats are compatible with Amerlock 2 and 400?

Both products are compatible with AMERCOAT 450 Series, SIGMADUR Series, SIGMACOVER Epoxies, AMERCOAT Epoxies, AMERSHIELD (aliphatic polyurethane), and PSX series topcoats. Amerlock 2 additionally lists PITTHANE ULTRA Series and DURETHANE DTM; Amerlock 400 additionally lists PSX 700. The combination of either Amerlock product with Amershield polyurethane creates the Lockshield system, which meets ISO 12944 C5-I High and C5-M High when applied to wire-brush-cleaned steel.