Sealing WBP plywood

[pocketslint]

Hello all, I am new to the site and I would appreciate some help and advice please. I am making a cross/marker for an unmarked family grave that I located for an aunt of mine. I intend making this by laminating 5 layers cut from a sheet of 18mm WBP plywood. I am going to seal it with a propriety sealer/stain and finish it with a coat or two of Yacht Varnish. I was wanting to know if I should seal/stain each individual layer before I glue them together. Would this add to its water/moisture resistance? and would it affect the property of the adhesive? which I would also want some advice on. I don't expect this to rival the Taj Mahal but I do want it to last a few seasons at least. Thanking you all in advance, WW.

 

[Rob Platt]

no glue them all together first or they probably wont glue successfully. seal afterwards
all the best
rob

 

[pocketslint]

Thanks Rob, can you recommend a particular type of adhesive? WW.

 

[Rob Platt]

evostick exterior wood glue blue bottle or titebond 2 or 3 clamp it tight and leave it for 24 hours in the clamps if its as cold and damp as it can be at this time of the year.
all the best
rob

 

[Benchwayze]

Pocket,

Welcome aboard.

To save time clamping, screw the layers together as you go, with plenty of weather resistant screws. Screw each layer down, as you go, onto what is to be the shown face, leaving it clear of any evidence of the screws. At the back, you could countersink well, and fill over those screws. The screws act as clamps of course.

HTH

 

[hunggaur]

if it were me i would use epoxy then when finished give it a couple of coats of clear epoxy to finish it off (the same as you do when you make a boat) should then be 100% waterproof and last for years

jon

 

[srp]

If it was me I wouldn't use ply at all, or varnish. Having owned and maintained a variety of boats for too many years I can tell you for nothing that varnish will not last any longer than one year outside. WBP will start to deteriorate as soon as the varnish film degrades. Epoxy resin is not UV resistant, so would need a UV resistant varnish coating, which again would only last a year tops.
Your best bet would be to use a durable hardwood like English Oak, teak (if you can afford it), or iroko, and leave it unfinished. It will weather to a silver grey colour. Avoid any sort of glue and join the two pieces with either stainless or silicon bronze screws.