Marine ply wood

[smiffy]

The roof of my boat is constructed of 3/4 t&g boards covered with 6 mm marine ply, after nearly 25 years the ply now needs replacing. What would be the best ply to use Gaboon, Okoume or Teak. Also between the t&g and ply there is rubber /bitumen type membrane any idears on a suitable replacement Thanks Mike

[Guest]

The roof of my boat is constructed of 3/4 t&g boards covered with 6 mm marine ply, after nearly 25 years the ply now needs replacing. What would be the best ply to use Gaboon, Okoume or Teak. Also between the t&g and ply there is rubber /bitumen type membrane any idears on a suitable replacement Thanks Mike

Donkeys years ago, the marine ply I used was mahgoany to BS 1088. This probably changed years ago.

I wonder if neoprene fish pond liner would be suitable for your membrane? Easily available in large pieces.

[Steveo0750]

Hello. I would rip off all the old ply and upstands for hatches etc and plain/gring off all the old membrain/soft bits you find and allow to dry. Remove rubbing strates. For the ply I would use WBP, which use's the same glue as marine ply but WBP in not Lloyds approved. That will save you about 3/4 the price. Although, I would use 9mm ply as this would be strong in its own right with the aid of the camber. When deck is ready trim into coachroof etc and leave plenty of over hang so someone can pull down whilst you screw into beam shealf. To stick the ply down I would use Polyuraphain glue. The gold colour stuff that foams up. This will go into all the t&g and any other bits that have been ground out and is salt water proof, flexable and strong. When gone off trim up, put upstands back on and round over edges and put epoxy fillets on any joints then epoxy shieve onto coach roof (rebate could be added for this or prep and glass the lot) and 1" 0r so down hull. This is the fastest and easiest way of putting on a new deak that will last indefinatly if all deak fittings are bonded down correctly. Hope this helps, but rember if you ask 10 diffrent people, you get 10 diffrent answers.

[ChrisPy]

I use Eidai WBP ply from Robbins. Only drawback is that it doesn't have a nice veneer for varnishing.

[David Schweizer]

I support the recommendation to use WBP ply which uses . Marine ply uses Mahogany veneers, which is a sea water craft specifictaion. Using it on an Inland Craft is a pointless (and Expensive) extravagence.

 

However I would also recommend that you source the ply from a reliable Merchant, such as (Robbins of Bristol) to ensure that the bonding specification is the same as that for marine ply, otherwise you may find air gaps in internal veneer layers.

Edited April 19, 2009 by David Schweizer

[Guest]

I support the recommendation to use WBP ply which uses . Marine ply uses Mahogany veneers, which is a sea water craft specifictaion. Using it on an Inland Craft is a pointless (and Expensive) extravagence.

 

However I would also recommend that you source the ply from a reliable Merchant, such as (Robbins of Bristol) to ensure that the bonding specification is the same as that for marine ply, otherwise you may find air gaps in internal veneer layers.

Exactly the problem with my NB floor. You will hate me for this, but I believe green chipboard would have been a better floor than the stuff used in my boat. It seems that there is WBP, and there is WBP if you see my meaning. I am not suggesting that the poster does his roof in chipboard BTW, just agreeing to make sure the WBP is of a good quality.

[ChrisPy]

Exactly the problem with my NB floor. You will hate me for this, but I believe green chipboard would have been a better floor than the stuff used in my boat. It seems that there is WBP, and there is WBP if you see my meaning. I am not suggesting that the poster does his roof in chipboard BTW, just agreeing to make sure the WBP is of a good quality.

agree.

 

Robbins sold me some "WBP" stacked in the main shed, about £36, that was rubbish; when cut in half you could see the wavy lines of the plies, and many voids.

Then I spoke to the right man at Robbins, who put me on to Eidai which is hidden away in a side shed. About £55 for a sheet of 18mm.

[Steveo0750]

Go to Edens or jewsons and you can get good quality 18mm WBP for about £26, 9mm for about £18. Without voids in the middle when you cut through. Dont use over rated marine stockists. They get it from the same place as every one else.

[David Schweizer]

Go to Edens or jewsons and you can get good quality 18mm WBP for about £26, 9mm for about £18. Without voids in the middle when you cut through. Dont use over rated marine stockists. They get it from the same place as every one else.

WBP ply is manufactured in Europe, South America, North America, Africa, and Asia, and most of them export to the UK, but they do not all comply with the British Standard.

 

It is quite commonplace for Ply to be sold as WBP that does not comply with the requirements, however it would appear that as long as it is not actually marked as complying it is not illegal to sell it. You should always ensure that the ply is clearly marked as complying with BS1088 or BS6566 (this BS is no longer current but is still used by some importers)

 

I have never sought to purchase WBP ply from Jewsons, but if you can get it for £26 a sheet, I can get it for considerably less, as I have an account. I will be surprised if it complies with the British Standard, but will be checking, because, if it does comply, at that price it is very good value.

[smiffy]

Thanks for all your advice I will make some inquires regarding price and quality of all the recommendations .

[David Schweizer]

I was in Jewsons yesterday, ordering some materials and enquired about their WPB ply - The material they had that complied with BS 1088 was £40+VAT a sheet, (Trade) that will work out about £60 over the counter. The stock they had was from Brazil, which is better than Indonesia where the laminating process can be of inferior standard.

 

The stuff they had for under £30 was exterior grade ply which is basicly veneered shuttering. The 18mm stuff had only three structural ply veneers and large voids visible on the edges. Ok for Sheds and chicken houses but not for any structural work on a boat.

Edited April 22, 2009 by David Schweizer

[DHutch]

Robbins sold me some "WBP" stacked in the main shed, about £36, that was rubbish; when cut in half you could see the wavy lines of the plies, and many voids.

Then I spoke to the right man at Robbins, who put me on to Eidai which is hidden away in a side shed. About £55 for a sheet of 18mm.

That supprises me slightly, as ive never bought anything from Robbins that ive not been very happy with, all be it often having paid for it.

- That said, i guess they cater for many markets, and i do always ask them to make a suggestion for what material would be best even if i have a good idea of what i want.

 

http://www.robbins.co.uk/

 

 

 

Daniel

[smiffy]

I When to Goldbergs in Uxbridge today and they stock marine ply B S 1088-1-2003 mel exterio class 3 BS EN314 Gaboon throughout with Lloyds type approval for £46.67 per sheet plus v a t and the quality looks very good so I will use this rather than something cheaper but of lesser quality .Mike