Professional Zinc Alloy Surface Finishing Solutions

Resin Dripping

Epoxy Resin Dripping — Crystal-Clear Logo Inserts & Nameplates for Hardware

Create high-gloss 3D logo inserts for zipper pulls, badges and nameplates using epoxy resin. AB ratio, degassing and curing — the complete guide.

The Epoxy Resin Dripping Process

Weigh → Mix → Degas → Fill → Cure → Demold — precision at every step

1AB Ratio Formulation

Epoxy resin (Part A) + hardener (Part B). Common weight ratios: 3:1 or 1:1 depending on formulation. Accuracy matters — ±2% ratio error changes viscosity, cure time and final hardness. Zero-conductivity measuring cup prevents bubbles.

Key Parameters

Common ratio: 3:1 or 1:1 by weight

Tolerance: ±2%

Mix time: 2–3 min slow stir

Pot life: 20–40 min @ 25 °C

Before

After

2Degassing (Vacuum or Still Degas)

Mixed resin traps micro-bubbles during stirring. Vacuum chamber at −0.08 to −0.1 MPa for 3–5 min pulls bubbles out. Alternative: let the cup sit still for 10–15 min — bubbles rise naturally, but slower.

Key Parameters

Vacuum level: −0.08 to −0.1 MPa

Vacuum time: 3–5 min

Still degas: 10–15 min

Result: Bubble-free clear resin

3Resin Dripping into Molds

Silicone mold with engraved logo cavitiy. Use a dispensing needle or syringe for precise volume control. Fill in one continuous motion to avoid trapped air layers. Allow 5 min still degas after filling for any remaining bubbles to surface.

Key Parameters

Mold material: Silicone rubber

Fill method: Needle / syringe

Fill speed: Slow, one continuous flow

Post-fill degas: 5 min still

4Curing — Room Temp vs Accelerated

Room temp (25 °C): 24 hours to demold, 72 hours full cure. Accelerated (60 °C): 2 hours in oven, then cool slowly. Fast heating causes thermal shock = internal cracks. Never exceed 80 °C — resin yellows.

Key Parameters

Room temp cure: 24 h demold / 72 h full

Accelerated cure: 60 °C × 2 h

Max temp: 80 °C (yellowing risk)

Cooling: Slow, in oven

5Demolding & Finishing

Peel silicone mold away. Examine for bubbles, incomplete fill or contamination. Crystal-clear result with >90% light transmission. Optional: UV-blocking topcoat to prevent yellowing over time.

Key Parameters

Light transmission: > 90%

Gloss (60°): > 85 GU

Yellowing resistance: Standard / UV-block

Touch-up: Clear coat on surface if needed

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Epoxy vs Other Clear Coatings

Why epoxy dripping gives the best 3D gloss for logo inserts

Property	Epoxy Resin	UV-Cure Resin	Acrylic Clear Coat
3D dome effect	Excellent	Good (thin only)	Poor
Gloss (60°)	> 85 GU	> 80 GU	60–75 GU
Full cure time	24–72 h	2–10 s	24 h
Hardness	Shore D 75–85	Shore D 80–90	HB–2H pencil
Yellowing resistance	Good (UV-grade)	Excellent	Fair
Bubble sensitivity	High	Low	Low
Max thickness per pour	3–5 mm (can layer)	0.5–1 mm	0.1–0.2 mm

📌 Resin Dripping Cheat Sheet

AB ratio tolerance±2% by weight

Vacuum degas−0.08 to −0.1 MPa, 3–5 min

Room temp cure24 h demold / 72 h full

Accelerated cure60 °C × 2 h

Light transmission> 90%

Gloss (60°)> 85 GU

Max pour thickness3–5 mm

⚠ Never mix AB ratio by volume — always weigh itEpoxy hardener and resin have different densities. A 3:1 ratio by volume can be 4:1 or 2.5:1 by weight, leading to soft, tacky or brittle cured resin. Use a digital scale with 0.1 g resolution. The pot life clock starts the moment you start mixing, not when you finish.

FAQ

Why does my epoxy stay tacky after 24 hours?

Wrong AB ratio — too much hardener or not enough. Check your scale calibration. Temperature below 18 °C slows cure dramatically. Heat the room to 25 °C for 4 hours and see if it finishes curing.

How to remove bubbles that form after pouring?

Bubbles that appear after pouring are usually from air trapped under the mold surface or released from the resin as it warms. Use a heat gun (700–800 °C) passed quickly over the surface — bubbles pop instantly. Or use a pressure pot (0.3–0.5 MPa) during cure to collapse bubbles.

Can I pour epoxy over painted surfaces?

Yes, but the paint must be fully cured and clean. Some paint chemistries inhibit epoxy cure (amine blush). Test on a sample first. A thin sealer coat of the same epoxy or a clear primer prevents compatibility issues.

How to prevent yellowing of clear epoxy?

Use UV-stabilized epoxy (aliphatic or cycloaliphatic hardener). Add UV absorber additive (e.g., Tinuvin) at 0.5–1%. Avoid direct sunlight exposure. For outdoor nameplates, specify a UV-block clear topcoat.

What is the maximum practical logo size for dripping?

Logo area up to 20 × 30 mm for single-pour. Larger than that → exothermic heat builds up and causes cracking. For larger logos, pour in 2–3 mm layers with 4 h between pours, or use a lower-exotherm formulation.

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Workshop Planning Data

Resin Dripping — Data Zinc Alloy Finishing Managers Need

Resin dripping (epoxy dispensing) creates crystal-clear domed logos, badges and nameplates on zinc alloy parts, protecting printed graphics while adding a premium 3D look.

220 m²Workshop Area

12 peopleTeam Size

70 kWInstalled Power

150-400k pcs/dayDaily Output (10 h)

Quality Inspection & Control

Check item	Method	Acceptance standard
Dome height & shape	Height gauge / visual	Uniform dome 0.8-2.0 mm, no air bubbles
Bubble control	Visual 10×	Zero visible bubbles after degassing
Adhesion	Cross-cut + tape	ISO 2409 rating 0-1
Hardness	Shore D	Shore D 75-85 after full cure
Transparency	Haze meter	Haze < 3%, water-clear
Cure completeness	Fingernail / MEK test	No tack after cure schedule

Workshop Layout & Floor Area

Zone	Area
Dispensing machines area	80 m²
Degassing & curing room	50 m²
Printing / preparation	35 m²
QA	20 m²
Resin store (cold)	15 m²
Utility & lockers	20 m²
Total workshop	220 m²

Manpower & Shift Plan

Role	Headcount
Dispenser operators	6
Printing / prep operators	2
QC inspectors	2
Supervisor	1
Maintenance	1
Total (2 shifts × 10 h)	12

Power & Utility Demand

Equipment	Demand
Dispensing machines (4 × 4 kW)	16 kW
Curing ovens / UV	20 kW
Vacuum degassing	8 kW
Air compressor	11 kW
Lighting & auxiliary	15 kW
Installed total	70 kW
Typical running load	≈ 52 kW

Production Flow Chart

Print / MaskScreen print logo, mask area

Mix & DegasResin + hardener, vacuum degas

DispenseAuto dispensing of resin dome

Level & CureSelf-level, oven or UV cure

InspectBubble, height, adhesion check

PackProtective film, pack

Daily Capacity — 10-Hour Operating Day

Parameter	Value
Cycle time	15-30 min (cure 60-120 min)
Pcs per dispenser per 10 h	40,000-100,000
Daily output (4 dispensers)	150,000-400,000
Monthly output (26 days)	3-10 million pcs
First-pass yield	≥ 97%

Output Value Estimate

Parameter	Value
Processing fee per piece	USD 0.01-0.03
Daily output value (10 h)	USD 2,500-8,000
Monthly output value	USD 65,000-208,000
Annual output value	USD 780,000-2,500,000