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Sealing Buffalo Board

Edge Sealing Buffalo Board To Enhance Life

High durability boards such as ATP’s Buffalo Board are regularly used in harsh environments  where water and other contaminants will be found. The tough phonolic film surface on the plywood resists attack from many common chemicals and offers a waterproof finish.

However, the boards will have to be cut to size, or joined together, and this action will expose the high quality plywood substrate to attack by the elements, Sealing Buffalo Board cut edges will be required to maintain the full life of this product.

Using Smiths Clear Penetrating Epoxy Sealer to Seal Buffalo Board Cut Edges


A customer was using Buffalo® Board on the deck of his boat, and was worried about the edge sealing. Whilst other sources recommend sealing with paints or thinned varnishes, neither of these will offer anything like the same level of protection to the plywood as the phenolic surface that you are paying for with Buffalo® Board. In order to obtain the full life of this premium product our customer asked if Smiths CPES could be used to seal the edges.

Sealing with Smiths CPES

The ability of Smiths CPES to deeply penetrate the edges of plywood and to seal it against the elements are well documented, and it’s performance on the high quality ply base found in Buffalo® Board will be excellent.

The real question was ‘will the solvents that carry Smiths CPES deep into the timber damage the phenolic surface’, we decided to find out:

  1. The cut edge of the Buffalo Board was immersed in Smiths CPES for 5 minutes. This will give significant exposure of the board and phenolic coating to the CPES. With large boards you would just paint the CPES on with a paintbrush. Saturate the plywood, wait till the solvents have evaporated, and then paint to saturation again. The high quality plywood used in Buffalo® and other Phenolic Boards is normally very well protected after 2 saturating applications.Sealing Buffalo Board By Immersion
  2. The board was then left to evaporate and dry out for half an hour
  3. Two more cycles of soaking (5 minutes) and drying (30 minutes) were then performed
  4. The board was then left for the CPES to cure, another 3 days

The phenolic surface on the board had suffered no damage whatsoever from the application of the Smiths CPES.


Sealed Buffalo Board Edge Sealing Phenolic Board EdgesSealing Buffalo Board

Our sealing Buffalo board edges was complete. No damage at all had occurred to the phenolic surface of the board, and the vulnerable edges had been protected by the CPES.

Caulking the edges of the Buffalo board.

Under some circumstances the waterproofed edges may now be required to be sealed to make a watertight join. Prior to performing any operation like this, please remember to allow sufficient gap for thermal expansion and contraction of the boards, which must be taken up by compression or expansion of the chosen sealant.

The Smiths CPES will offer an excellent base for permanent sealants, such as Everbuild Stixall or 3M 5200, if the boards are to be sealed to another board or alternative surface to provide a watertight  seal. All modern polyurethane sealants adhere permanently to Smiths CPES, but please ensure the solvents have fully evaporated first, as alcohols in the solvent blend can damage the setting of one part polyurethane adhesives.

If required these may be purchased along with CPES in our timber crack repair kits at a discount, or obtained at most reputable builders merchants.

Protecting the edges of the sealed Buffalo Board from UV Light

In short – No Epoxy Resin has UV tolerance itself. UV blockers are sometimes added, or provided by top coatings.

A customer asked if the sealed edges would necessarily need painting afterwards, as he didn’t want to get paint onto the top surfaces while painting the edges.

Because the CPES doesn’t have UV tolerance, the CPES in the top fibres of wood will be broken down by sunlight over time. How quick this is and how deep it goes depends on how much sunlight it gets.
You still however get significant protection with no coating. The boat gents often treat a deck, and then wipe the top fibres clear with solvent to get a grippy surface so they can walk on it, and still gain significant benefits from the penetration of CPES into solid wood. This trick is described here maintaining a natural finish while protecting wood. Penetration into end grain on plywood is of course deeper still than that – so you will make a massive difference even if UV nibbles a bit at the surface.
In summary – paint if you can paint easily – but don’t bother if you can’t.

Read here for more information on how well CPES Seals Plywood edges .