VicMallows
Well-Known Member
Obviously some cost-cutting in later years
..... all 3 original washboards on my S29 (1984) are solid teak.
Is Marine Ply real?
- Thread starter richardabeattie
- Start date
Obviously some cost-cutting in later years
..... all 3 original washboards on my S29 (1984) are solid teak.John the kiwi
Well-Known Member
My whole boat is glass over ply so this is a question that interests me a little.
My Boat is now 30 years old. As i make repairs and modifications, i have had to cut into the original plywood on a number of occasions. e.g Most recently i cut some holes in Bulkheads for speakers.
I have to say that the offcuts from the original 30 year old ply appear to be infinitely better than the "Marine Ply" i can source locally today.
The original stuff is voidless, fine / tight grained and cuts cleanly with minimal splintering.
Don't know what it was but i would like to buy some.
Cheers
John
My Boat is now 30 years old. As i make repairs and modifications, i have had to cut into the original plywood on a number of occasions. e.g Most recently i cut some holes in Bulkheads for speakers.
I have to say that the offcuts from the original 30 year old ply appear to be infinitely better than the "Marine Ply" i can source locally today.
The original stuff is voidless, fine / tight grained and cuts cleanly with minimal splintering.
Don't know what it was but i would like to buy some.
Cheers
John
prv
Well-Known Member
AntarcticPilot
Well-Known Member
BS 1088 ( the British standard for marine plywood) says the following (quoted from Wikipedia, but it appears to be a fair representation is the actual standard, which of course is copyright and not free).
There's a lot more than that, but that covers the things most people care about!
Note that there is no requirement that the face veneers be decorative. I've bought BS1088 plywood from the local reputable builders' merchant (Ridgeons of Cambridge), and it is a) stamped BS1088 and b) appears to to adhere to the specification above (I haven't tried boiling it
). However, the face veneers are just a plain white wood with little grain pattern. Doesn't matter for me - I'll paint it. But for a place where you want a nice wood appearance, it wouldn't do.Note that plywood that is sold as BS1088 marine ply and doesn't adhere to the BS specification should be reported to trading standards; people may be relying on the specification in safety critical applications (like the hull of a boat!)
oldharry
Well-Known Member
There's a lot of ply being sold as 'wpb', exterior grade , marine or BS1088 that just isnt, particularly by the DIY superstores, and many builders merchants, who really should know better. I have worked with the stuff for over 40 years in various boats and this is what I have learned, not only at first hand, but from years of hunting up the 'best' for the job I am doing.
'Ordinary' plywood up to around 12mm usually consists of one or two core sheets of softwood, with a very thin veneer. Glues are rarely waterproof, and there can be large voids in the core, where the inner laminates join in manufacture. Because of this it has ver little strength. Thicker panels may have 3 or even 4 cores, but always of inferior and soft timber. It will not tolerate even getting damp, and will turn to cardboard after the first shower of rain.
Exterior grade or wpb, is similar construction: two or three thick cores with a thin veneer, but with (marginally) better glues which are supposed to be waterproof, but will not take prolonged damp. Even if the glues survive, the veneers and cores often will not. Again there is no control over the size or extent of voids in the inner cores which means that as a structural material it is highly suspect.
BS1088 is the UK standard for marine ply. It specifies that all the core sheets and veneer facings must be of uniform thickness and quality, and sets a minumum standard for the glues. It also sets the maximum width and number of joins in the core veneers, ensuring the board conforms to strength standards Unfortunately most BS1088 stamped board from the far East (the main source) does not comply. They get round it but using BS1088 as a stock control mark, tradename or similar, and not applying the official kite mark. Worse still, many manufacturers use a trade mark that looks very similar to the BSS kite mark, so that you have to examine the stampings quite carefully. usually they are blurred and faint so that the detail isnt properly visible. True BS1088 MUST have the BSS Kitemark with the relevant BSS numbers clearly dispalyed (and sorry, I dont now remember what those numbers should be, offhand)
How to tell the difference between Scam board and real BS1088? Check the thickness and quality of the internal veneers. Check also for the presence of voids or gaps in any veneer along the cut edges, no void should be more than a couple of mm wide. Even so it is not always easy to tell whether you are buying real 1088 or Scamboard. Most (but by no means all) scamboards will be glued using the same or similar glues to real BS1088, but will have inferior wood in the cores, and be far too thin on the facing veneers. Also there will be many more and larger voids than true 1088. Not to be relied on for structural work but maybe OK for furniture and possibly seats, if the edges are properly sealed. The real problem will be the very variable strength of these boards, and how well they tolerate getting wet. I recently built a new engine case (inside the cabin for my boat using what appeared to be good quality WBP from a reliabale source. It is delaminating already after just 6 months. I will be having words with the supplier.
Marine Ply: good quality marine ply is costly, and is usually well above BS1088 minimum standards. You can nearly always see the difference straight away. All the veneers will be of the same thickness, including the facing veneers, and will be the same timber (no white wood veneers!). Nowadays it is quite difficult to source real marine ply.
Marine ply of 40 years ago is of significantly better quality timber than nowadays: I was repairing a 60s plywood Bell Seamew some years ago, and the quality of the original ply was vastly better than the best I could obtain nowadays. Quite simply, the timber to make it to that quality is just not available. Lovely straight close grained wood, making even Bruynzeel or Robbins best look poor quality alongside it!
'Ordinary' plywood up to around 12mm usually consists of one or two core sheets of softwood, with a very thin veneer. Glues are rarely waterproof, and there can be large voids in the core, where the inner laminates join in manufacture. Because of this it has ver little strength. Thicker panels may have 3 or even 4 cores, but always of inferior and soft timber. It will not tolerate even getting damp, and will turn to cardboard after the first shower of rain.
Exterior grade or wpb, is similar construction: two or three thick cores with a thin veneer, but with (marginally) better glues which are supposed to be waterproof, but will not take prolonged damp. Even if the glues survive, the veneers and cores often will not. Again there is no control over the size or extent of voids in the inner cores which means that as a structural material it is highly suspect.
BS1088 is the UK standard for marine ply. It specifies that all the core sheets and veneer facings must be of uniform thickness and quality, and sets a minumum standard for the glues. It also sets the maximum width and number of joins in the core veneers, ensuring the board conforms to strength standards Unfortunately most BS1088 stamped board from the far East (the main source) does not comply. They get round it but using BS1088 as a stock control mark, tradename or similar, and not applying the official kite mark. Worse still, many manufacturers use a trade mark that looks very similar to the BSS kite mark, so that you have to examine the stampings quite carefully. usually they are blurred and faint so that the detail isnt properly visible. True BS1088 MUST have the BSS Kitemark with the relevant BSS numbers clearly dispalyed (and sorry, I dont now remember what those numbers should be, offhand)
How to tell the difference between Scam board and real BS1088? Check the thickness and quality of the internal veneers. Check also for the presence of voids or gaps in any veneer along the cut edges, no void should be more than a couple of mm wide. Even so it is not always easy to tell whether you are buying real 1088 or Scamboard. Most (but by no means all) scamboards will be glued using the same or similar glues to real BS1088, but will have inferior wood in the cores, and be far too thin on the facing veneers. Also there will be many more and larger voids than true 1088. Not to be relied on for structural work but maybe OK for furniture and possibly seats, if the edges are properly sealed. The real problem will be the very variable strength of these boards, and how well they tolerate getting wet. I recently built a new engine case (inside the cabin for my boat using what appeared to be good quality WBP from a reliabale source. It is delaminating already after just 6 months. I will be having words with the supplier.
Marine Ply: good quality marine ply is costly, and is usually well above BS1088 minimum standards. You can nearly always see the difference straight away. All the veneers will be of the same thickness, including the facing veneers, and will be the same timber (no white wood veneers!). Nowadays it is quite difficult to source real marine ply.
Marine ply of 40 years ago is of significantly better quality timber than nowadays: I was repairing a 60s plywood Bell Seamew some years ago, and the quality of the original ply was vastly better than the best I could obtain nowadays. Quite simply, the timber to make it to that quality is just not available. Lovely straight close grained wood, making even Bruynzeel or Robbins best look poor quality alongside it!
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ripvan1
Well-Known Member
Fond memories of Bell Seamew, my first boat and surprisingly strong and nimble. Banged my head fair few times tho'
blackbeard
Well-Known Member
I once had a dinghy - just a small rowing boat, used as a tender - which lay afloat and consequently often had rain water slopping about in it.
The floor was in a bad state so I replaced it, using cheap exterior plywood from a well known DIY supplier. No paint or varnish. Would do for a few years, I thought.
Sure enough, it didn't delaminate. But by the end of the season, it was too rotten to bear my weight.
Being wet, or (worse) damp, for much of a season, and in rain ie fresh water rather than sea water, is a severe test.
Nevertheless. You have been warned.
The floor was in a bad state so I replaced it, using cheap exterior plywood from a well known DIY supplier. No paint or varnish. Would do for a few years, I thought.
Sure enough, it didn't delaminate. But by the end of the season, it was too rotten to bear my weight.
Being wet, or (worse) damp, for much of a season, and in rain ie fresh water rather than sea water, is a severe test.
Nevertheless. You have been warned.
PhillM
Well-Known Member
We bought from Lathams. I was told that it was top quality marine ply and at £240 per sheet I really hope it is. Apparently there is a 20 year guarantee on it.
http://www.lathamtimber.co.uk/ProductCategory.145.html
http://www.lathamtimber.co.uk/ProductCategory.145.html