Dip Coating Calculator
Calculate dip coating film thickness, paint consumption, and drain time for industrial immersion coating processes.
About this calculator
Dip coating film thickness is governed classically by the Landau-Levich equation for thin Newtonian fluids withdrawn from a bath, but that equation assumes low-viscosity coatings where the relationship between withdrawal speed and film thickness follows a clean two-thirds power law. Industrial coatings are usually thicker and non-Newtonian, so this calculator instead uses an empirical model better suited to that regime: wet film thickness scales with the square root of viscosity and withdrawal speed raised to the 0.6 power, both diminishing-returns relationships reflecting how a faster pull or thicker fluid doesn't proportionally thicken the film forever. Dry film thickness then simply applies your coating's volume-solids percentage to that wet figure, since the solvent portion evaporates away during cure. Paint consumption per part comes from that wet film thickness times part surface area, but the calculator subtracts a drip-loss factor that models how much wet coating runs back off the part before it sets — modeled as decreasing with viscosity, since thicker coatings cling to a part's surface rather than sagging and dripping off the way a thin, runny coating would.
Drain time is estimated similarly, growing with viscosity since a heavier coating needs more time to stop dripping before it can move to a cure oven. Daily consumption and tank turnover then scale these per-part figures by your shift throughput. Because the empirical constants here are tuned for typical industrial dip coatings rather than derived from your exact fluid's rheology, confirm predicted thickness against a physical measurement before committing to a production withdrawal speed — verify actual film thickness with a wet-film gauge on early production parts, especially if your coating is markedly more or less viscous than the 200 cps assumed as a baseline.
Inputs
Results
Dry film thickness (mils)
0.47
Daily paint usage (gal)
1.1
How to Use This Calculator
- Enter Withdrawal speed (in/min), Viscosity (cps), and Volume solids (%).
- Set Coating density (lb/gal), Part surface area (sq ft), and Tank volume (gal).
- Adjust Parts per hour as needed.
- Review Dry film thickness (mils) and Daily paint usage (gal).
- Use Wet film thickness (mils) and Paint per part (gal) to inform your decision.
How the result changes with Volume solids (%)
| Volume solids (%) | Dry film thickness (mils) | Daily paint usage (gal) |
|---|---|---|
| 23 | 0.24 | 1.1 |
| 34 | 0.35 | 1.1 |
| 68 | 0.7 | 1.1 |
| 100 | 0.93 | 1.1 |
What each input means
- Withdrawal speed (in/min)
- Speed at which parts are withdrawn from the coating bath.
- Viscosity (cps)
- Coating viscosity in centipoise.
- Volume solids (%)
- Volume solids percentage of the coating.
- Coating density (lb/gal)
- Weight of coating per gallon.
- Part surface area (sq ft)
- Surface area of each part.
- Tank volume (gal)
- Total tank volume in gallons.
- Parts per hour
- Throughput rate in parts per hour.
What each result means
- Wet film thickness (mils)
- Predicted wet film thickness at withdrawal.
- Dry film thickness (mils)
- Predicted dry film thickness after cure.
- Paint per part (gal)
- Net paint consumed per part.
- Drip return per part (gal)
- Excess coating that drips back to tank.
- Drip return (%)
- Percentage of applied coating that drips off.
- Drain time (sec)
- Recommended drain time before curing.
- Total cycle time (sec)
- Immersion + withdrawal + drain time.
- Daily paint usage (gal)
- Total paint consumed per 8-hour shift.
- Tank turnover (days)
- Working days to consume one full tank volume.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersWithdrawal speed (in/min) = 6, Viscosity (cps) = 200, Volume solids (%) = 45, Coating density (lb/gal) = 10 = 7 input(s) provided
- Calculate Dry film thicknessDry film thickness = wftMils * (volumeSolidsPct / 100)0.47 = 0.47
- Calculate Daily paint usageDaily paint usage = effectiveWetVolumeGal * partsPerShift1.1 = 1.1
- Calculate Wet film thicknessWet film thickness = k * sqrt(viscosityCps) * pow(withdrawalSpeedInMin, 0.6)1.04 = 1.04
- Calculate Paint per partPaint per part = wetVolumeGal * (1 - dripLossPct / 100)0.0045 = 0.0045
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does the calculator use a 0.6-power withdrawal-speed relationship instead of the classic Landau-Levich two-thirds power law?
The Landau-Levich equation was derived for low-viscosity Newtonian fluids, where wet film thickness follows a clean two-thirds power of withdrawal speed. Industrial dip coatings are usually thicker and non-Newtonian, so this calculator instead uses an empirical fit — wet film thickness scales with the square root of viscosity and withdrawal speed to the 0.6 power — that better matches how those heavier coatings actually behave.
How does viscosity affect both the film thickness and the drip-loss percentage, and do those two effects work in the same direction?
Higher viscosity increases predicted wet film thickness through the square-root term, but it also lowers the modeled drip-loss percentage (drip loss decreases as viscosity rises). Both effects point the same way: a thicker, more viscous coating clings to the part's surface rather than sagging and running off before it sets, so it ends up both depositing more material and retaining more of what's applied.
What's the difference between the wet film thickness and dry film thickness outputs?
Wet film thickness (WFT) is the calculated thickness of the coating layer immediately after withdrawal, while dry film thickness (DFT) multiplies that by your coating's volume-solids percentage, since the solvent portion evaporates away during cure. A coating with 45% volume solids will end up with a dry film only 45% as thick as the wet film measured right off the bath.
How is total cycle time per part calculated?
Total cycle time adds a fixed 30-second minimum immersion dwell, a withdrawal time based on a 24-inch part height divided by your withdrawal speed, and a drain time that grows with viscosity (30 seconds plus 0.1 seconds per centipoise). Slower withdrawal speeds and thicker, higher-viscosity coatings both lengthen the total cycle, which directly limits how many parts per hour the line can process.
Does Coating density (lb/gal) affect any of the results?
No. Coating density is collected as an input but the calculator does not currently use it anywhere — every consumption and thickness figure here is reported in volume (gallons) or thickness (mils), not weight, so changing this value alone leaves every output unchanged.
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