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 – repairing localised dry rot with epoxy
31st March 2015

TRADE SECRET: Wooden boat repair – repairing localised dry rot with epoxy

Dry rot is the natural decay process that causes wood to discolour, crack, shrink and – worst of all – lose its strength. Fortunately, when the worst does strike, you can rely on epoxy to save the day.

In the bilges, behind cupboard doors, at the bottom of the chain locker or under the bunks; it’s a simple fact that wooden boats contain numerous small, often isolated areas with poor ventilation that are likely to trap moisture. Whenever that happens, dry rot is likely to develop.

It’s no wonder, then, that repairing small areas of dry rot is possibly the most common wooden boat repair.

When that happens, epoxy is the perfect solution. Not only does it restore the structural integrity of the material but it also totally replaces the water, forming a barrier against dry rot happening again in the future. In this respect, a dry rot repair made with epoxy can genuinely be ‘better than new’.

There are two filling methods which are recommended for treating localised dry rot. The method you should use depends on the size of your cavity.

This means that, before you decide, you need to excavate the area so you know exactly what you’re dealing with. Start by removing all of the wood which has been noticeably damaged by rot, making sure to extend well away from all sides of the apparent damage. A chisel is the best tool to excavate all the weak, crumbly wood. You should be left with a clean cavity with solid wood exposed on all sides.

The size of this exposed cavity will determine which of two filling methods is the most appropriate.

Method 1: Filling smaller cavities with epoxy

The simplest method is to fill the cavity with an epoxy/filler mix. This certainly saves time but is only suitable for small areas – approximately a 12mm layer or a volume the size of a golf ball. A larger volume will produce an exothermic reaction, causing it to heat up and significantly weaken the epoxy.
filling small rot with epoxy

  • Prepare the surface
    Once you’ve excavated your small cavity, prepare the surface as usual, making sure the area is thoroughly dried out to prevent any further moisture damage.
  • Wet out
    When you’re certain the area is dry, wet it out with a mix of WEST SYSTEM 105 Epoxy Resin® and 205 Fast Hardener®.
  • Thicken epoxy with high density filler
    Then thicken your epoxy with a high density filler. Adding 406 Colloidal Silica, 404 High Density Filler or 403 Microfibres will get your epoxy to a peanut butter consistency, which makes it perfect for gap filling, filleting, fairing putty and bonding uneven surfaces.
  • Apply epoxy / filler mix
    Next, use a squeegee or mixing stick to trowel in the mix. Make sure the cavity is filled with this thickened epoxy. Then smooth it flush with the wood’s surface and quickly remove any excess before the epoxy begins to cure.
  • Cure
    Finally, allow the mix to cure thoroughly and sand down your filled cavity. Do this only once it has had time to fully cure.

Method 2: Filling larger cavities with wood

Larger cavities need a more involved and labour intensive response. This second method involves carving a plug, or “dutchman” (wood shaped to fill the cavity), to the same shape as the cavity. This plug is then bonded in place using epoxy to create a repair that will restore the area’s original strength.
fillingwithwood

  • Prepare the plug
    Firstly, prepare the plug – if you have the same kind of wood available, it’s recommended to use that.
  • Carve the cavity, applying bevel to the sides
    Carve the cavity into a shape that will make fitting the plug easier and bevel the sides of the cavity. The longer the bevel on the sides running across the grain, the stronger the repair will be. An 8-to-1 bevel (8cm long for every 1cm deep) or greater will get you closest to the original strength of the wood. Then check the plug for fit. A perfect fit isn’t entirely essential, as your thickened epoxy will fill fairly large gaps. Now you can prepare the surfaces for bonding.
  • Wet out
    Wet out the bonding surfaces of both the cavity and the plug with a mix of 105 Epoxy Resin and 205 Fast Hardener or 206 Slow Hardener®.
  • Thicken epoxy using high density filler
    Then thicken your epoxy using a high density filler. Add 406 Colloidal Silica, 404 High Density Filler or 403 Microfibres to get your mix to a moderately thickened, mayonnaise consistency. This blend is recommended for any general bonding, filleting or hardware bonding making it ideal for this application.
  • Apply epoxy / filler mix
    Using a mixing stick, apply the epoxy to the cavity’s surfaces. Make sure that you apply enough of the thickened compound to fill any gaps.
  • Fix and clamp plug
    Insert the plug into the cavity. Any excess epoxy should squeeze out of the joint. Clamp the plug into position and remove any excess epoxy before it starts to cure. If you need to hold the plug in place use weights or staples.
  • Cure
    Finally, allow the mix to cure thoroughly before removing any clamps. You should always sand down your filled cavity, but make sure to do this once it has had time to fully cure.

The ability of epoxy to protect wood structures from water has made modern wooden boats almost immune to dry rot and WEST SYSTEM® epoxy is unequalled as a moisture barrier. To find your nearest stockist and start your repairs, click here.

 

photo credit: https://www.westsystem.com/


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