Teak decks again

[Petercatterall]

I am repairing the teak decks on my 32 Atlanta. I have been able to simply re-seal the side decks but have to strip off the foredeck as the plywood sub deck is too far gone.
I am working out of doors so have to work within weather windows. I have considered a'tent' but am concerned that the Ardrossan gales would rip it off!!
I propose to replace the Plywood and seal it by wetting out then epoxying,I will then have a waterproof deck.
The difficult bit then follows( for shear practicality I would forget the teak but I feel that I must preserve the classic looks) .. My problem concerns fastening the teak to the epoxyied plywood. The reclaimed strips were screwed so there is an immediate problem with the existing holes and as I would be perforating the nice sealed plywood with 500 screw holes. I could use glue or epoxy but will these adhere to the epoxied ply?
how would I hold the strips down untill the glue dried?
The teak has been sanded over the years and is now about 3/8 thick, enough for wear but many of the screw holes are now insufficiently deep to take a teak plug on top of the screw. I wonder if I can counter sink them further but am concerned that there is insufficient wood for this.
One idea is to use a glue and just use a few screws to hold them while the glue sets, I could increase the countersunk depth on the other holes and use plugs to seal them off.
I guess that my questions concern recommendations about glue to epoxied surfaces and if 3/8s teak strips will take screws and have sufficient depth remaining for plugs, is ther a tool which would help give a well controlled counter sunk hole? also what glue for the plugs, epoxy or what?
I am trying you classic boat guys as I am sure ther will be a million experts happy to help on this!!

 

[PBrooks]

I have experience of new decking - though with Pitch Pine rather than Teak. I think these pointers may be helpful, but others may have more specific experience when it comes to replacement.
1) Epoxy the ply thoroughly - particularly the edges.
2) Epoxy sticks very well to itself provided you've washed it down and abraided the surface (this is because there's a by-product on the surface - an amine blush).
3) You can fill the screw holes in the teak with bungs epoxied in after you've fixed the planks down. I wouldn't worry about screw holes in the surface of the ply under the teak - though make sure you don't go through to the other side. (N B If the screw holes in the teak are not completely round (or were damaged when you took the planks off), drill out to the next size. If you can't do this, you'll have to consider new teak planking - this may not be a bad idea anyway, depending on the condition of your planks). You'll need a pillar drill with a good stop to drill to exact depths

4) With 3/8 teak you are on the border line of what will stick with epoxy on its own - according to the West Brothers it should be a maximum of around 5mm (whatever that is in old money). This is because the contracting / expanding forces when the wood dries / gets wet could overcome the glue with anything thicker than 5mm. If you can get around this by sanding / planing the boards down, then you could just glue them down, using screws & washers going through the grooves between planks (or throught he old holes), in places where weight alone won't work - I used battens and house bricks to hold my planks down and this was fine.

5) If you want to keep the planks at 3/8, you'll probably need to fix with screws and here, I'll hand over to anybody else you has experience in this area. I expect you would have to seat the planks in polyeurathane sealant rather than rigidly glue with epoxy to allow for some movement.

6) If you opted for the thinner planks and used screws and washers in the grooves, take these out after the epoxy goes off (use a soldering iron on the head to break the bond) - wait at least a week for it go off.
5) Fill the groove with polyeurathane (Sp?) such as Sikaflex or Purflex.
5) Fill the old screw holes with plugs using epoxy. The plugs are easy to make with a pillar drill and cutter and some scrap (?) teak.
6) Belt sand after allowing to dry for at least a further 8 days
7) Problems: Doing this outside in a Scottish winter will be no fun at all. Epoxy needs to be at around 12 deg C to go off (though there is a low temp version). Equally the polyeurathane needs to be warm (around 19 deg) to dispense properly. The whole lot needs to stay dry until the epoxy has gone off for several weeks (it can take this long to achieve full strength). I'd go so far as to say it'll be pretty well impossible without cover and some heat.
8) Although it sounds complicated, it's a fairly straightforward job, if somewhat time consuming. Also, be wary of epoxy in confined spaces (particularly if you've set up a low cover) - I wear gloves and a charcoal mask. There are several books and leaflets around that would be worth reading first - Robbins has a useful leaflet on teak decks and West produce leaflets and a good book which covers the thin strip technique.
Good luck!
Best regards Paul

 

[PBrooks]

Just to add a correction to what I posted earlier. On reflection and after reading a recent post on the Woodenboat forum (www.woodenboat.com), when fixing screws into the ply, I would coat them with epoxy / sealing compound (whichever you are using to bed the planks) as you're putting them in. This is just to make sure that moisture can't get into the ply if the bung / sealing compound fails. If the screws are being put in temporarily, don't coat in this way, but fill the hole with epoxy after removal, then use the sealing compound.
Best regards
Paul

 

[Petercatterall]

Paul, Thanks for the detailed tips.
U want to retain the old teak as I was able to repair the side decks withoit stripping off the teak and a patch of new teak at the front would look somewhat odd!
I have read that after drilling into the ply I should pour in some thin eoxy to wet out the area around the hole and use thickened epoxy or sealant as the screw is put in. .
Yes I can see that temperature will be a problem! I will cut the ply then take it home to epoxy in the warm garage. I will still h seal any gaps between the plywood and the rubbing strip on site though and will just have to pray for a warm day!
On the side decks I heated up the Purflex in hot water , with a towelling jacket around the tube this worked well if one was quick (manufacturers have OKd this)
Inspection of the old 'caulking' suggested that most of the failures were where the sealant had not adhered correctly to both sides of the teak, there was no 'breaker tape' in the bottom of the cracks which would have contributed to the loss of adhesion. I followed Robbins's suggestions to de-oil and seal the teak sides and to use a breaker strip to allow the sealant to stretch in the seam, I am fairly confident that it should work ok.
In fairness the boat is 27 years old so the original workmanship can't really be criticised!
Again, thanks for the comments.

 

[Petercatterall]

Another point and another question!
The original strips appeared to have been glued down with a hard setting black glue or even tar/bitumen, it was certainly effective as the teak brought off the top ply laminate as it was removed.
Concerning the plywood, is sensible to epoxy both sides or just the top and edges ((plus, I guess, the underneath bit wich sits on the side bits (beam hangers?))??
Basically I'm asking if it is better for the plywood face in the cabin area to breath or be sealed?

 

[PBrooks]

All sounds sensible and some good solutions to inclement weather. I epoxied all sides of the ply as this is what the designer recommended (and I thought it would prevent mould / rot taking root if there is any condensation. However, I'm not sure you'd need to - as long as you keep an eye on it all for damp / mould.
Best regards
Paul

 

[Petercatterall]

Thanks Paul,
I will post up the results of my experiences when I have recovered from the task!