Epoxycraft
Menu
  • Home
  • About
  • Epoxy Basics
  • How To
    • DIY
    • Artists
    • Board Sports
    • Woodworking
    • Boat Building
  • Trade Secrets
  • Projects
    • DIY
    • Artists
    • Board Sports
    • Woodworking
    • Boat Building
    • Motorsport
    • Aviation
    • Architecture
  • Meet The Maker
  • News
  • Contribute
  • Contact

Trade Secrets: TRADE SECRET: Wooden boat repair – rebuilding a plywood joint
29th May 2015

TRADE SECRET: Wooden boat repair –  rebuilding a plywood joint

Nobody wants a leaky boat. So when plywood joints start to deteriorate it’s time to start a wooden boat repair that will make sure your boat stays high and dry.

Modern boat builders are frequently looking to produce designs that are lightweight, fast and strong. It’s why many of them turn to plywood. But it’s also why these lightweight joints can be a source of problems.

These areas of weakness are put under a great deal of stress which causes them to deteriorate over time. Without proper care water often begins to seep on-board, causing damage to equipment, reducing buoyancy and even resulting in large-scale damage that can require extreme repairs such as hull replacements.

By following the steps below, you can avoid damage to your boat inside and out.

1. Clean out the joint

Clean out the joint by running a circular saw along the seam. The saw’s cut should be set to reach the full thickness of the plywood with the width of the blade set to shave the edges of both sheets of plywood at the joint and expose fresh wood on each edge. Make sure you remove any fasteners that could get in the way.

Drive the fasteners further into the joint and then sand a valley, roughly 100mm wide, using a disc sander. Make the depression about 0.75mm deep for each layer of 175g/m2 fibreglass tape that will be used to fill the joint.

valley sand

Finally, use a sander or a chisel to remove any additional damaged or rotted plywood around the joint. At each edge, use the sander with a roundover bit to round the corners. A 6-9mm radius should allow the glass tape to lie flat on the surface.

2. Seal the edges

To seal the edges, first wet out the seam and sanded area with resin/hardener mix. Then recoat the seam with epoxy, allowing it to be absorbed into the end grain of the plywood. You may also want to inject epoxy between any delaminated veneers that are still sound.

Apply the epoxy mix, thickened with WEST SYSTEM® 406 Colloidal Silica and mixed to a mayonnaise consistency, into the pre-wetted seam. Using a plastic squeegee, force the thickened epoxy into the wet-out seam and smooth the excess mix along the joint. Try to make sure the thickened epoxy is pushed into any voids and between delaminated veneers previously wetted out with resin/hardener mix.

3. Apply fibreglass tape

Apply a layer of fibreglass tape in the depression, along the joint. Using a squeegee, work epoxy into the fabric and remove the excess. Apply additional layers, if required, using the same method. Place the new layers 12mm to either side of the previous layer so the edges don’t fall directly on top of each other.

apply fibreglass tape

Apply epoxy thickened with 407 Low-Density Filler, mixed to a peanut butter consistency, to the joint. Use a squeegee to trowel on and shape the thickened epoxy slightly higher than the plywood surface. Allow to cure thoroughly and sand fair.

To find out more about the products used in this repair, visit the WSI product page.

Image credit: https://ow.ly/NLlZP


Share on


Back to trade-secrets

Subscribe to our newsletter
Our unique epoxy knowledge and experience, delivered straight to you

Events

Future dates TBC

What is epoxy?

Epoxy Projects

UK Chandleries Open – January 2021

As England, Scotland and Wales enter another lockdown, you may have started work on those home projects. Whether it’s boat maintenance and repairs, a restoration or a brand new build,

Creating an Artisan Gold Ring with Canadian Maple and Epoxy

You may be surprised to learn that the UK is home to some of the finest gold around. Mark discovered this as a child when his father, Edward, would take

Heritage 9.9

Castagnola Launch Heritage 9.9

Castagnola Shipyard has launched the elegant, custom-made Heritage 9.9. Able to reach a cruising speed of 34 knots, the 10.91m custom-built luxury yacht is a fine example of what happens

Nick Zammeti Gets Creative with Epoxy and Liquorice Allsorts

What happens when you give Youtuber Nick Zammeti lots of epoxy and bags of Liquorice Allsorts? You get one incredibly funky table! Nick is well-known and loved in the industry

Meet the Maker – The Resin Reserve

Resin artist, alchemist, resin-gineer. Kate Ede of The Resin Reserve has always kept us in awe of her marvellous and beautiful creations. Inspired by patterns in nature, Kate is a

Split Film Festival Trophies

Creating the 2020 Split Film Festival Trophy

The Split Film Festival is one of the oldest film and video festivals in Croatia, showcasing new films and radical works of all styles, themes and genres. The festival celebrated

Hot Box

How to keep your epoxy warm in winter: build a hotbox

Winter is a challenging time for epoxy products. Warmth is needed to keep the resin fluid enough for dispensing pumps to work well and cold ambient temperature can greatly reduce

How to Work With Epoxy in Cold Weather

The frosty mornings and dark evenings are drawing near. There are projects that need finishing, but what do you do when epoxy and cold weather don’t get on too well.

Mas Snowboard

Snowboard Enthusiasts Taking On The World With Incredible Designs

To many a holidaymaker, Turkey is a haven of golden sand beaches, historic landmarks and party towns. However, it’s not just those looking to top up on their tan that

Class Xero Yacht

Class Xero Combines Coffee and Epoxy in Sustainable Yacht Design

Image credit: Alec Smith - https://www.imagemundi.com Craig Palmer, based in Worthing, is looking at opportunities to bring the marine industry together in a collaborative way. In the middle of building

Craobh Woodwork

Bringing a New Lease of Life to Reclaimed Scottish Timber

Tucked away in the highlands of Scotland is the small village of Culbokie, home to Craobh Woodwork and artisan Bruce Neill. Specialising in producing bespoke timber products from the highest

Final Bar Design

Cheers! Leeds Furniture Maker Creates a Bar Worth Celebrating

James McKay has been a creator since his early years. His fascination for creativity guided his interest into art, design and technology during his school years. James went on to

  • Home
  • Epoxy Basics
  • Projects
    • DIY
    • Artists
    • Board Sports
    • Woodworking
    • Boat Building
    • Motorsport
    • Architecture
    • Aviation
  • Trade Secrets
  • How To
    • DIY
    • Artists
    • Board Sports
    • Boat Building
    • Woodworking
  • News
  • Privacy Policy
  • Contribute
  • Contact
West System
Pro-Set
Entropy Resins
Subscribe to our newsletter
Copyright © 2021 Epoxycraft | Website by MAA