How to Repair Spider Cracking in Gelcoat

Introduction

• Presenter: Mark Corke from BoatUS Magazine
• Topic: Repairing spider cracking in gelcoat on boats
• Additional Info: Encourages viewers to like, comment, and subscribe to their YouTube channel.

Preparation Steps

• Cleaning:
  • Ensure the boat is clean.
  • Wash down the area and wipe with acetone to remove contaminants.
• Masking:
  • Mask off areas to avoid splashes on the rest of the boat.

Repair Process

Opening Cracks

• Tool Used: Dremel tool
• Purpose: Open up cracks to give the new gelcoat something to adhere to.
• Technique: Grind shallowly through the gelcoat to barely scrape the laminate underneath.

Gelcoat Preparation

• Material Used: Spectrum Color gelcoat
• Color Matching: Available in various colors; example used is Grand Banks white.
• Decanting Gelcoat: Use a syringe to transfer gelcoat into a paper cup.

Mixing Gelcoat

• Catalyst: Add catalyst according to manufacturer's instructions (2 drops recommended for small amounts).
• Working Time: Limited; best done on warm days.
• Thickening Agent: Use colloidal silica (wear respirator when handling).

Application

• Applying Gelcoat: Push thickened gelcoat into cracks.
• Smoothing: Use an old credit card or AARP card to smooth gelcoat.
• Curing: Leave overnight to harden.

Day Two: Finishing

Cured Gelcoat

• Waxed vs Nonwaxed Gelcoat:
  • Waxed gelcoat is not sticky after curing.
  • Nonwaxed requires covering to avoid stickiness.

Sanding

• Remove Masking Tape: Prevents blue tape contamination.
• Tools: Use 220 grit wet/dry paper followed by 400 grit for smoothness.
• Technique: Use a block of wood to maintain a flat surface.

Compounding

• Rubbing Compound: Use to remove fine scratches.
• Application: Apply with a rag and buff with a polisher.

Glazing

• Purpose: Provides a very fine polishing prior to waxing.
• Technique: Apply glaze and buff with a polisher.

Waxing

• Application: Use a wax polish applicator pad for best results.
• Final Buffing: Use a clean buffing pad for a smooth finish.

Conclusion

• Outcome: Achieved a nice, seamless, smooth repair.
• Further Resources: Check other gelcoat repair videos on their YouTube channel.