Marine ply

[Theo]

I am about to start a much needed project. My wooden side doors have reached an advanced state of decomposition and need replacing.

 

I am planning to use t&g (not v) softwood with vertical boards. This will give the outside effect that we would like. The inside will be smooth so I was thinking that it would be sensible to screw a 6mm thickness of ply over the whole. I hear that all modern ply is made with waterproof glue. If this is the case, do I need to use marine ply or will bog standard stuff do?

 

If I am using the ply will I need to brace the door? Is it likely to dish if I don't?

 

I am sure that there are lots of experts used to working in wood out there who will tell me what is advisable and what not to do.

 

I look forward to comments.

 

Nick

[frangar]

Whatever wood you may use I would recommend coating it with an Epoxy system like the West System

 

http://www.westsystem.com/ss/the-105-system/

 

I have used this to good effect on my wooden exterior woodwork such as handrails and hatches....you can just lightly sand and paint over it.

 

HTH

 

Gareth

[Timleech]

Whatever wood you may use I would recommend coating it with an Epoxy system like the West System

 

http://www.westsystem.com/ss/the-105-system/

 

I have used this to good effect on my wooden exterior woodwork such as handrails and hatches....you can just lightly sand and paint over it.

 

HTH

 

Gareth

 

Proper marine ply is hard to find and V. expensive.

There is stuff sold as 'marine ply' in big timber yards which in my experience is not much better than the ordinary cheapish hardwood faced stuff. Whatever you use it is very important to seal the edges, but the cheaper the ply the more important this becomes.

International now do a 2-pack clear primer which should be good for that - I have been using it recently but no long-term experience with it yet. It can be used as a primer for varnish.

 

Tim

[Chris Pink]

I am about to start a much needed project. My wooden side doors have reached an advanced state of decomposition and need replacing.

 

I am planning to use t&g (not v) softwood with vertical boards. This will give the outside effect that we would like. The inside will be smooth so I was thinking that it would be sensible to screw a 6mm thickness of ply over the whole. I hear that all modern ply is made with waterproof glue. If this is the case, do I need to use marine ply or will bog standard stuff do?

 

If I am using the ply will I need to brace the door? Is it likely to dish if I don't?

 

I am sure that there are lots of experts used to working in wood out there who will tell me what is advisable and what not to do.

 

I look forward to comments.

 

Nick

 

 

....don't understand why you want the ply (birch faced is cheaper than marine but I don't know whether you can get this in 6mm). The traditional way is to put two short pieces of T and G top and bottom at 90° ( 4 pieces total), with chamfered edges. This will look right as it seems that's important to you.

 

I also notice (from another project) that pitch pine is available in t and G (again?) go for this rather than cheapo red pine.

[bizzard]

I am about to start a much needed project. My wooden side doors have reached an advanced state of decomposition and need replacing.

 

I am planning to use t&g (not v) softwood with vertical boards. This will give the outside effect that we would like. The inside will be smooth so I was thinking that it would be sensible to screw a 6mm thickness of ply over the whole. I hear that all modern ply is made with waterproof glue. If this is the case, do I need to use marine ply or will bog standard stuff do?

 

If I am using the ply will I need to brace the door? Is it likely to dish if I don't?

 

I am sure that there are lots of experts used to working in wood out there who will tell me what is advisable and what not to do.

 

I look forward to comments.

 

Nick

Good quality marine ply is iffy these days unlike years ago when it was made from Aframosa the Mahogany substitute.

I'd say a decent piece of WBP ply would be ok as it will be inside,but i'd be inclined to use much thicker, if possible 15mm or even 18mm to brace the T&G to prevent warpage,and glue all over and clamp them together.Being thicker would also give better purchase for fittings too.

[bizzard]

Before GRP boats really came on strongly people built small cruisers and dinghies from marine ply,either from kits or from plans.

I personally in my younger days built an 18' Lysander sailing cruiser and two sailing dinghies from plans with the old good quality marine ply.Glue and screw and stitch and glue ''glass and resin''.

[Ex- Member]

I am about to start a much needed project. My wooden side doors have reached an advanced state of decomposition and need replacing.

 

I am planning to use t&g (not v) softwood with vertical boards. This will give the outside effect that we would like. The inside will be smooth so I was thinking that it would be sensible to screw a 6mm thickness of ply over the whole. I hear that all modern ply is made with waterproof glue. If this is the case, do I need to use marine ply or will bog standard stuff do?

 

If I am using the ply will I need to brace the door? Is it likely to dish if I don't?

 

I am sure that there are lots of experts used to working in wood out there who will tell me what is advisable and what not to do.

 

I look forward to comments.

 

Nick

 

Hi Nick

 

Marine ply is pricey very pricey, I would use hardwood ply WBP of course glued and screwed to at minimum 15mm T&G 20mm better. You can trim the edges of the ply back and affix some hardwood strip Oak or other suitable hardwood. You can incorporate this into the T&G also so sandwiching the softwood and ply leaving no edges exposed especially end grain on the T&G Also a very nice durable finish.

 

I've used hardwood ply for my engine room door it's been there 7 years and hasn't moved or warped, this is sometimes described as marine ply but in reality isn't much of it comes from china but it is good stuff and probably around £35.00 per sheet. I bought mine at Avon Plywood Keynsham Bristol, I was lucky enough to come across a part sheet that suited my needs so got it cheap.

 

http://www.avonply.c...SP/Plywood.aspx

 

Engine room door 25mm ply bordered with 9mm Oak and edges trimmed with 10mm Redwood. Door is solid and hasn't moved a mm

 

 

ETA if you do this with T&G you need to let the wood dry out over a few weeks in a warm place otherwise it will shrink after being affixed to the ply and the joints will widen. Clamp the boards together you intend to use, it will reduce warping whilst drying out. Best bet though is go to a reclamation yard or get some old T&G from somewhere, it will already be dry and have that aged look to it.

Edited May 21, 2012 by Julynian

[Theo]

Hi Nick

 

Marine ply is pricey very pricey, I would use hardwood ply WBP of course glued and screwed to at minimum 15mm T&G 20mm better. You can trim the edges of the ply back and affix some hardwood strip Oak or other suitable hardwood. You can incorporate this into the T&G also so sandwiching the softwood and ply leaving no edges exposed especially end grain on the T&G Also a very nice durable finish.

 

I've used hardwood ply for my engine room door it's been there 7 years and hasn't moved or warped, this is sometimes described as marine ply but in reality isn't much of it comes from china but it is good stuff and probably around £35.00 per sheet. I bought mine at Avon Plywood Keynsham Bristol, I was lucky enough to come across a part sheet that suited my needs so got it cheap.

 

http://www.avonply.c...SP/Plywood.aspx

 

Engine room door 25mm ply bordered with 9mm Oak and edges trimmed with 10mm Redwood. Door is solid and hasn't moved a mm

 

 

 

ETA if you do this with T&G you need to let the wood dry out over a few weeks in a warm place otherwise it will shrink after being affixed to the ply and the joints will widen. Clamp the boards together you intend to use, it will reduce warping whilst drying out. Best bet though is go to a reclamation yard or get some old T&G from somewhere, it will already be dry and have that aged look to it.

 

Ax alway,s heaps of good advice. Thanks all. What's WBP, Julynian? Is that £35 for an 8' x 4'?

 

Nick

Edited May 21, 2012 by Theo

[Ex- Member]

Ax alway,s heaps of good advice. Thanks all. What's WBP, Julynian? Is that £35 for an 8' x 4'?

 

Nick

 

Hi Nick

 

 

Weather & Boil Proof

 

Better not quote me on the cost per 8x4, it was a long time ago I last bought ply and prices have rocketed.

 

This will give you an idea, but prices quoted here would be hard to find in a local builders merchants. There are companies who will cut to size but delivery is usually. B&Q should stock hardwood ply too, thay will cut to size also but you'll have to buy the full sheet if half sheet isn't sufficient. This ply will always come in handy though if you're boat building. If it's a one off project though might pay to buy just whan you need cut to size delivered.

http://www.discountbuildsupplies.co.uk/shopdisplayproducts.asp?id=81&cat=Hardwood+Throughout+Exterior+WBP+Plywood

 

 

[system 4-50]

Hi Nick

 

 

Weather & Boil Proof

 

Better not quote me on the cost per 8x4, it was a long time ago I last bought ply and prices have rocketed.

 

This will give you an idea, but prices quoted here would be hard to find in a local builders merchants. There are companies who will cut to size but delivery is usually. B&Q should stock hardwood ply too, thay will cut to size also but you'll have to buy the full sheet if half sheet isn't sufficient. This ply will always come in handy though if you're boat building. If it's a one off project though might pay to buy just whan you need cut to size delivered.

http://www.discountb...ior+WBP+Plywood

 

 

 

Be very careful buying boards at B&Q. I have come across instances where buying half and quarter size boards has been almost as expensive as buying the full board!

[Neil2]

Fyne Boat Kits sell proper marine ply and yes it is very expensive but I've used it and it is top quality stuff. Don't know how it compares with the ply of bygone days but it is lovely to work with. I think they sell half sheets but don't know what delivery is (I used to live nearby). I believe Robbins timber have a good reputation too.

[FORTUNATA]

Unfortunately the glue used in plywood can be toxic to fibreglass if the glue comes directly into contact with polyester as it sets. Even though, plywood is an old standby as a core in fibreglass moulding.

Yes, the edges are what give most problems. I like to coat the edges in a marine grade sealant before painting over.

 

Before GRP boats really came on strongly people built small cruisers and dinghies from marine ply,either from kits or from plans.

I personally in my younger days built an 18' Lysander sailing cruiser and two sailing dinghies from plans with the old good quality marine ply.Glue and screw and stitch and glue ''glass and resin''.

 

Before GRP boats really came on strongly people built small cruisers and dinghies from marine ply,either from kits or from plans.

I personally in my younger days built an 18' Lysander sailing cruiser and two sailing dinghies from plans with the old good quality marine ply.Glue and screw and stitch and glue ''glass and resin''.

[bizzard]

Unfortunately the glue used in plywood can be toxic to fibreglass if the glue comes directly into contact with polyester as it sets. Even though, plywood is an old standby as a core in fibreglass moulding.

Yes, the edges are what give most problems. I like to coat the edges in a marine grade sealant before painting over.

The glue used in proper marine plywood would be Epoxy similar to Araldite.so once cured i doubt would react with Polyester resin.

The term ''stitch and glue'' really means ''stitch and Polyester resin''reinforced with glass fibre tape. The hull panels are drilled frequently along mating edges,then stitched with copper wire to hold them together and shape, then finally glassed over with the tape and resin. As per wooden Mirror sailing dinghy kits.

[onionbargee]

B & Queue ply is made of sponge cake mix, avoid it.

 

The old indestructable marine ply your talking about is found when old boats do a refit, they throw it all out, not realising it's real good stuff, and now costs a fortune. It's like armour plate !

[ditchcrawler]

The glue used in proper marine plywood would be Epoxy similar to Araldite.so once cured i doubt would react with Polyester resin.

The term ''stitch and glue'' really means ''stitch and Polyester resin''reinforced with glass fibre tape. The hull panels are drilled frequently along mating edges,then stitched with copper wire to hold them together and shape, then finally glassed over with the tape and resin. As per wooden Mirror sailing dinghy kits.

O the good old days

[Teadaemon]

The glue in WBP plywood can be either melamine or phenolic based. It certainly isn't epoxy. It also doesn't react with polyester resin, although polyester resin does not stick very well to any kind of wood (or indeed to much else at all, including cured polyester resin).

[bizzard]

The glue in WBP plywood can be either melamine or phenolic based. It certainly isn't epoxy. It also doesn't react with polyester resin, although polyester resin does not stick very well to any kind of wood (or indeed to much else at all, including cured polyester resin).

I disagree. If dry plywood or cured Polyester resin is scrupulously roughed up and most importantly thoroughly degreased with spirit it sticks very well indeed. Have you ever tried to take a Mirror dinghy's hull apart.

[bowten]

IROKO timber is excellent for outside use and can be got in t/g,use a good weather proof varnish,you can't go wrong.However the colour is like a dark oak and you may not want this.Most wood glue is waterproof just check the container.

[smileypete]

The glue in WBP plywood can be either melamine or phenolic based. It certainly isn't epoxy. It also doesn't react with polyester resin, although polyester resin does not stick very well to any kind of wood (or indeed to much else at all, including cured polyester resin).

There's a primer for wood which allows polyester resin to stick much better. But for small areas epoxy might work out cheaper and much easier.

 

cheers, Pete.

Edited May 21, 2012 by smileypete

[Richard T]

Nick as you are based in Leicestershire try Harlow Brothers at Long Whatton as a source of decent quality ply see link My linkThey may well cut it into manageable sizes for you. Stay away from B&??? ply it may say its WBP but it failed on our boat when used as locker lids after 3 years. We replaced it with hexagrip which is much better but very expensive.

[ChrisPy]

There's a primer for wood which allows polyester resin to stick much better. But for small areas epoxy might work out cheaper and much easier.

 

cheers, Pete.

polyester resin isn't suitable for anything apart from GRP mouldings.

epoxy is miles better for repairs, sheathing, stitch & glue, etc.