Premium Topcoat 501 · Finish Primer 442 · Protective Primer 161
Set your surface area or paint volume, pick spray or brush/roll application, and choose your product — get exact base, converter, and reducer amounts, plus accelerator dosing and estimated coverage, before you crack a can.
Measurement System
Sets the units used throughout.
Product
Sets the base mix ratio, reducer range, and whether an accelerator applies.
34
30%33.8%37.5%
Spray: 30–37.5% by volume of base + converter. Brush/Roll uses a different range and a different converter (C5012).
No accelerator-specific temperature ceiling is given in Alexseal's documentation. General application range: 60–85°F (15–30°C).
Note: Not recommended when applying directly on metal — use Protective Primer 161 as a first coat on steel or aluminum substrates.
Coating Area and Application Method
How much you're coating, and how you'll apply it.
Coating Amount
Enter surface area or the paint volume you plan to mix.
Enter the dimensions of the surface area.
Calculated Area: —
Application Method
All three Alexseal products support both Spray and Brush/Roll application.
Mix Result
Premium Topcoat 501 Base—
Topcoat Converter Spray (C5051)—
Reducer—
Accelerator (A5035)—
Coverage
Premium Topcoat 501 Base: —
Topcoat Converter Spray (C5051): —
Reducer: —
Accelerator (A5035): —
Related Products
(Disclosure: Contains affiliate links. We may earn a commission at no extra cost to you.)
Tips & Safety
Two-part coatings punish sloppy ratios — get the mix right before you spray.
Tell us what to fix or add — every report is read by the team behind ChemCalc.
How to Use the Alexseal Paint Mix Calculator
Alexseal topcoats and primers require precise mixing of base, converter, and reducer. Wrong ratios cause poor adhesion, slow cure, or a cloudy finish. This calculator gives you the exact amounts for your batch size.
Select measurement system — Imperial (ft², oz, qt, gal) or Metric (m², mL, L).
Select your product — Premium Topcoat 501, Finish Primer 442, or Protective Primer 161. Each sets its own base:converter ratio, reducer range, and whether an accelerator applies.
Adjust the reducer percentage — every product has its own range; Premium Topcoat 501's range also changes between Spray and Brush/Roll.
Add an accelerator, if applicable — Premium Topcoat 501's A5035 is spray-only; Finish Primer 442's A4429 works with either method and replaces the separate reducer amount when used. Protective Primer 161 has no accelerator.
Enter your coating amount — Give a single area or volume figure, or enter length × width and let the calculator work out the area. Set your input units and the units you want results in.
Choose an application method — Spray or Brush/Roll. All three products support both.
Read the result — Exact base, converter, reducer, and (where applicable) accelerator amounts. Results update as you type.
Premium Topcoat 501: Spray 1:1 base:converter (C5051) + 30–37.5% reducer. Brush/Roll 2:1 base:converter (C5012) + 16–33% reducer — a different converter product, not just a different ratio.
Finish Primer 442: 1:1 base:converter (C4427) + 15–25% reducer. Not recommended directly on metal — use Protective Primer 161 as a first coat on steel or aluminum.
Protective Primer 161: 6:1 base:converter (C1617) + 5–10% reducer (up to 25% for special application). No accelerator.
Coverage figures are factory ratings, used directly — not multiplied by a coat count. "Recommended coats" is shown as guidance text only.
Upgrade to Pro to access the full Repair Estimator with paint cost tracking.
How to Use the Alexseal Paint Mix Calculator
Alexseal topcoats and primers require precise mixing of base, converter, and reducer. Wrong ratios cause poor adhesion, slow cure, or a cloudy finish. This calculator gives you the exact amounts for your batch size.
Select measurement system — Imperial (ft², oz, qt, gal) or Metric (m², mL, L).
Select your product — Premium Topcoat 501, Finish Primer 442, or Protective Primer 161. Each sets its own base:converter ratio, reducer range, and whether an accelerator applies.
Adjust the reducer percentage — every product has its own range; Premium Topcoat 501's range also changes between Spray and Brush/Roll.
Add an accelerator, if applicable — Premium Topcoat 501's A5035 is spray-only; Finish Primer 442's A4429 works with either method and replaces the separate reducer amount when used. Protective Primer 161 has no accelerator.
Enter your coating amount — Give a single area or volume figure, or enter length × width and let the calculator work out the area. Set your input units and the units you want results in.
Choose an application method — Spray or Brush/Roll. All three products support both.
Read the result — Exact base, converter, reducer, and (where applicable) accelerator amounts. Results update as you type.
Premium Topcoat 501: Spray 1:1 base:converter (C5051) + 30–37.5% reducer. Brush/Roll 2:1 base:converter (C5012) + 16–33% reducer — a different converter product, not just a different ratio.
Finish Primer 442: 1:1 base:converter (C4427) + 15–25% reducer. Not recommended directly on metal — use Protective Primer 161 as a first coat on steel or aluminum.
Protective Primer 161: 6:1 base:converter (C1617) + 5–10% reducer (up to 25% for special application). No accelerator.
Coverage figures are factory ratings, used directly — not multiplied by a coat count. "Recommended coats" is shown as guidance text only.
Upgrade to Pro to access the full Repair Estimator with paint cost tracking.
Finish Primer 442: 1:1 base : converter (C4427) + 15–25% reducer. Not for direct metal application — use Protective Primer 161 first on steel/aluminum.
Protective Primer 161: 6:1 base : converter (C1617) + 5–10% reducer, up to 25% for special application. No accelerator.
A5035 (501, spray only): max 10 mL (1 cap) per 2 quarts of mixed and reduced Topcoat 501.
A4429 (442, either method): up to 12.5% of the catalyzed primer (base+converter), or 1 pint per mixed gallon — replaces the separate reducer amount entirely rather than stacking with it.
Coverage: factory ft²/gal ratings used directly, no coat-count multiplier. "Recommended coats" is informational text only.
Email results — Use the “Email Me Results” button to send a copy to yourself or your client.
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