Making a door

Paulg25

Paulg25

Well-Known Member
Joined
20 Oct 2019
Messages
2,038
Location
Afloat
Visit site
Hi All. The front doors of my boat are an appalling fit so I want to replace them with a single door. What is the best sheet material to make it from, bearing in mind it needs to be about 20mm thick? I was thinking plywood but have read it is bends and twists too much and something called BWP blockboard is better. Trouble is it doesn't seem to be available in the UK. Any ideas? :) (y)
 
Do not use block board. I was always told that WBP used to stand for water & boil proof
The glue is not of marine quality & the core will have voids & it will be of a low quality timber
Not recommended for exterior use
Use marine ply as suggested above
 
Proper marine ply is of course costly and not all that easy to come by (but entirely possible). If it is interior and properly sealed and dont see marine ply is essential.

By front door you might mean effectively wash boards or a door exposed to the elements in which case marine ply may be worth while.

However, presumably it will either be painted, or you may want to use a varnished ply with a veneer surface, in which case it will either be veneered ply of some type or ply and you will buy seperately and bond the veneer.
 
I used 12mm (or thereabouts) teak-faced marine ply for forepeak doors, but for various reasons ended up making half-height double doors down to the infill rather than the more usual full-height bi-fold doors (that suited well the layout and our use of the forepeak). So there’s less height to reveal any warping, and they are held in position by both a tight fit and by opposed neodymium magnets set into the doors and the infill and upper frame - but they have not warped noticeably at all.

I suspect that solid teak edging glued and pinned all around the varnished ply helps a little by adding rigidity orthogonal to the sheet and - more so perhaps - by sealing it against moisture. I doubt that a good quality non-marine ply treated similarly would have warped badly either, but that’s a guess.
 
I have ca 1/2" thick two marine ply doors in my boat that are 53 years old and they are not warped. Beware of veneering just one side though, as that can cause warping. Mine are just painted.
 
I'm not sure what it is you are referring to as block board. If it is the type of sheet material that is made up of a laminated solid wood strip interior with some type of veneer either side, then I would not recommend it, for as Daydream Believer says, it is not waterproof.

If the doors you are referring to are interior ones, they do not have to be made explicitly of "marine ply". Other than for structural elements regular waterproof glued ply is acceptable in what used to be marked as AW 100. The difference between this and "marine" was not the glue, but the choice of material for the inner veneers and the assurance that all voids have been filled.

The best and fairly easy way to build doors is to use solid wood for the stiles and rails with a veneered ply fill.
 
Daydream believer said:
How big are these doors?
When you say "front " doors do you mean those inside into an area towards the bow, or the main entry hatch from cockpit into the main saloon?
Click to expand...
External doors. The opening is 1830mm x 620mm.

BWP blockboard is Boiling Water Proof... all to do with the resin used I understand. As with ply, different qualities are/were available. Allegedly it is more stable than ply. :)
 
Why not use acrylic (perspex) or even polycarbonate (depending on UV I guess...)?

I’m planning to replace our m Perspex washboards with doors (like on the new Benes). Wouldn’t consider wood or anything opaque. Much nicer to have the light come in and see what’s going on inside/outside.
 
Daydream believer said:
Do not use block board. I was always told that WBP used to stand for water & boil proof
The glue is not of marine quality & the core will have voids & it will be of a low quality timber
Not recommended for exterior use
Use marine ply as suggested above
Click to expand...
WBP stands for Waterproof, bonded ply, referring to the glue used. Buildbase hardwood exterior ply is excellent. RGB ply is total rubbish. Exterior ply, properly protected will be fine.
 
Hacker said:
No, it stands for water and boil proof.
Click to expand...
Thankyou
As a young lad in the building industry my father had a joinery works & the joinery foreman always referred to it as water & boil proof.
Google will tell us no such thing existed but it stands for weather & boil proof. Something which I have only learned today after having a reasonably productive joinery & fit out company for 35 years, which I sold 20 years ago
I used to buy sheet materials by the lorry load & NEVER heard the term Weather & boil proof. But we learn something every day
Anyway, to answer the OPs query DO NOT use blockboard for external doors.
I seem to recall marine ply stamped BS 1088 but even then quality varied from ( generally)low grade Philippine to better Israeli & some Brazillian products. One needed to pick the supplier. ie James Latham or W T Eden as examples of those with wider range of quality
 
Last edited:
Paulg25 said:
External doors. The opening is 1830mm x 620mm.

BWP blockboard is Boiling Water Proof... all to do with the resin used I understand. As with ply, different qualities are/were available. Allegedly it is more stable than ply. :)
Click to expand...
At this size I would assume that it is a wheelhouse door, rather than a companionway hatch, and definitely needs to be constructed more rigidly than can be done solely with sheet material which will inevitably warp. In short it needs to have a proper timber framework with inset panels, possibly solid at the bottom and transparent at the top, such as you would find at the back door of a house.
Unless the you have consummate woodwork skills and the necessary toolsI would recommend that you find a joiner, or similar, to construct it for you.
 
PCUK said:
WBP stands for Waterproof, bonded ply, referring to the glue used. Buildbase hardwood exterior ply is excellent. RGB ply is total rubbish. Exterior ply, properly protected will be fine.
Click to expand...
I decided to settle this for myself I have a copy of Specification 1963 as well as documents from the Timber Research & Development Association. I have dug up sections of BS 1203 1954 from whence it came. this BS refers to glue standards
According to the Timber Research & Development Association ( Whose expertise I would take above any on this forum) the WBP definitely stands for Weather & Boil Proof.
I will endeavor to retrieve the full BS from my store later when I warm up.
 
Last edited:
You must log in or register to reply here.

Share this page

Top