BoatworksTodayvideo
Making Custom Fiberglass Molds For Parts Doesn't Need To Be Difficult!
July 27, 2025 · 21 min · 17K views
What this video covers
Fabricating a custom fiberglass hatch for a Bertram 25 requires preparing a mold using OSB and chopped strand mat.▶ 0:20 To ensure the fiberglass lays flat, always request that suppliers ship fabric rolled rather than folded to prevent kinking or creasing the fibers.▶ 7:56 When prepping the mold, prioritize fairing and sanding the final part rather than the mold surface to save time.▶ 6:18 For the mold skin, flood the porous OSB surface with catalyzed non-waxed laminating polyester resin before applying the chopped strand mat to ensure a strong bond.▶ 9:31 Use torn strips of mat around the perimeter to create wispy edges that blend smoothly without creating hard humps.▶ 8:51 When working with polyester resin, spread the mixture into a thin film immediately after application to extend the working time and prevent the resin from overheating in the mixing cup.▶ 11:13
More from BoatworksToday
From BoatworksToday — see the channel’s boat, crew, and every analyzed video.
The Sailing Directory Newsletter
One email with the fleet's best finds — the moments, boats, and stories worth your watch time. Enter your own address to get your own copy.