Wood to Metal

[touchstone]

We have two metal opening doors at the front of our boat and the inside of the doors have been finished with plywood and varnished. When fitted out, timber battens had been glued to the inside face of both doors. Ply wood facing was glued and screwed to the battens to finish the job off.

Overtime, the glued battens have broke away from their glued position on the metal doors and it all needs to be refitted.

I would like to do away with the idea of battens and ply and replace it with some form of solid material about 18mm thick which which would be glued directly to the inside metal of the doors much as it is now.

The question is what material to use? Is MDF a suitable material bearing in mind it would on occasions get wet (if the wife forgets to close them in the rain).

B&Q sell exterior ply in sheet form of the thickness I need, but would it do a decent job?

The sheets I have looked at appeared to have a nice top grained finish which I thought would look OK when varnished. The other point in their favour they can cut the sheet into the size I can handle and the price is about what I can afford.

Any suggestion about the above and also about gluing/fixing the sheet material (whatever it is ) to the metal would also be welcome.

[Arthur Brown]

If you are not using a solid hard wood then proper marine ply would be a good idea maybe even with a hardwood veneer.

 

This area will see rain water and condensation dampness much of the time.

[dmr]

If you have 18mm then I might be tempted to try to put in a bit of insulation, maybe 6mm of polystyrene then 12mm of ply on top?

Rather than use glue you could drill a few countersunk holes in the sides of the door and screw into the plywood. Screwing into the edge of plywood is not ideal but is ok if done with care. As said above, its difficult to keep all the condensation out, we remove our wooden panels every few years to check for any rust, especially at the bottom of the doors.

[Neil2]

I believe a lot of fitters use Gripfill to fix internal battens to the cabin/hull sides for fixing linings to. I have used it for all sorts of things and it is amazing stuff - I used it as a temporary fix when our garden fence blew down about four years ago and it's still holding.

 

I'd be inclined to use epoxy though, with marine ply, definitely not MDF. You could epoxy coat and varnish the surface and that would seal the ends too, but this sort of job always looks neater with some sort of edging

[Ex- Member]

All our doors were done basically the same as you describe. All the doors lined with standard WBP 18mm ply out profile battening though was in MDf, reason being it ready to paint after being Routered, We applied plenty of paint to all doors, however even over a short period of time the stern doors is already swelling, not the ply just the MDF

 

This happend also to the side doors, so I removed the MDF and replaced with Hardwood routered out in the same way.

 

Basically MDF won't cut the mustard on doors, a lot of the time they're open when raining, especially stern doors. Also our side doors were originally very close to the gunwale so close that capillary attraction caused moisture to cling to the underside of the door edge eventually soaking into the ply via the tiniest crack.

 

Basically I would say ply is best for the actual lining, but use hardwood for any profiling on top of that.

 

I would also add to use a good quality ply that doesn't warp. Our front steel doors over 5 f/t tall both bend slightly fortunately in the same direction, this is caused by the plywood. Better quality hardwood ply marine grade will have more lamination will not do this. I bought some a while ago trade @ £75 per sheet but with an Oak finish one side.

 

http://www.mcilvain.com/plywood/

[onionbargee]

B & Queue ply is lowest quality known to man, avoid. MDF even exterior is an absolute no. WPB ply should do, if you seal the edges.

 

Evostick "sticks like s**t" or similar is better than Gripfill, if you put it on with that ( correctly prepared steel ) the worst that can happen is is falls off in 10 years time. which is better than having screw holes in your doors.

[Neil2]

B & Queue ply is lowest quality known to man, avoid. MDF even exterior is an absolute no. WPB ply should do, if you seal the edges.

 

Evostick "sticks like s**t" or similar is better than Gripfill, if you put it on with that ( correctly prepared steel ) the worst that can happen is is falls off in 10 years time. which is better than having screw holes in your doors.

He's probably right but Gripfill is a gap filling adhesive which. like epoxy, actually likes a little "give" between the surfaces so you don't have to worry too much about 100% contact. I think when joining sheet materials there's a lot to be said for gap filling glues.

[Captain Fizz]

Mdf has no place on a boat, period. It is the work of Stan.

WBP plywood or hardwood or marine ply is fine, gripfill or epoxy resin as an adhesive.

[Phil Ambrose]

Sticks Like Sh¤t is also gap filling and has superior adhesive properties as well as remaining flexible.

Phil

[Ex- Member]

He's probably right but Gripfill is a gap filling adhesive which. like epoxy, actually likes a little "give" between the surfaces so you don't have to worry too much about 100% contact. I think when joining sheet materials there's a lot to be said for gap filling glues.

 

Gripfill type adhesives tend to dry brittle and do not cope well with expansion & contraction, especially between wood & metal. We initially used Gripfill and it failed in several places inside a year and completely failed in adhering batten to under the gunwale. Fortunately we used screws as well as Gripfill everywhere else otherwise the linings would now be hanging by now.

 

Since then we've used a product called Stixall, It's some kind of polymer I recall and dries like rubber so so copes well with movement. no failures in many different applications even metal to glass.

[Alastair]

B & Queue ply is lowest quality known to man, avoid. MDF even exterior is an absolute no. WPB ply should do, if you seal the edges.

 

I've had WBP stuff (yeah, from BQ) delaminate in a couple of months. It was really well varnished, the glue was obviously not water resistant at all.

 

If you can suggest a source or brand near York, I'd be damn grateful.

[blackrose]

I believe a lot of fitters use Gripfill to fix internal battens to the cabin/hull sides for fixing linings to. I have used it for all sorts of things and it is amazing stuff - I used it as a temporary fix when our garden fence blew down about four years ago and it's still holding.

 

I'd be inclined to use epoxy though, with marine ply, definitely not MDF. You could epoxy coat and varnish the surface and that would seal the ends too, but this sort of job always looks neater with some sort of edging

 

Gripfill has limited flexibility and may not cope with the differential expansion and contraction of steel and wood. I knew a bloke who used Pinkgrip and his linings fell off. Epoxy is a bit OTT and is also not flexible enough. Much better to use Marineflex to stick battens to cabin sides.

 

http://www.marinemastics.com/marine-flex.html

 

My doors on my boat came with some sort of oak-faced MDF linings and somewhow they'd sealed the edges with a brown finish. 8 years on they still look fine, but if I was relining them I'd stick a piece of 12 o 20mm thick Cellotex on the door, run a thin hardwood frame around the perimeter and then just stick some sort of lining over the top - perhaps painted T&G or thin marineply.

Edited October 5, 2013 by blackrose

[blackrose]

 

Since then we've used a product called Stixall, It's some kind of polymer I recall and dries like rubber so so copes well with movement. no failures in many different applications even metal to glass.

 

http://www.everbuild.co.uk/stix-all

 

Looks like this may be a cheaper alternative to marineflex. My only reservation would be the manufacturer as I once used some Everbuild silicone and it was rubbish. Since then for me Everbuild has been synonymous with cheap crap.

Edited October 5, 2013 by blackrose

[Ex- Member]

 

http://www.everbuild.co.uk/stix-all

 

Looks like this may be a cheaper alternative to marineflex. My only reservation would be the manufacturer as I once used some Everbuild silicone and it was rubbish. Since then for me Everbuild has been synonymous with cheap crap.

 

Yeah Marineflex, clever name!

 

Unfortunately it has it's limitations though, requiring very expensive primer for certain applications, and only comes in 3 colours.

 

Also the fact Marineflex seems to feel the need to produce several other different products as well, doesn't give me much confidence as to the durability of their main product, where Stixall can and does everything those products do in a single tube at a much cheaper cost. Reading the spec on Stixall confirms it is clearly a far superior product.

 

I'm always suspicious of products like Marineflex. Not that there's anything wrong with the product, but not knowing who manufactures it.

 

I've never been able to find out who manufactures Marineflex??? So never used or would trust such a product. Marineflex is just a clever brand name slapped on a tube of glue/sealant of unknown origin, and of course anything with marine in front of it is always going to be more expensive, so it has a clever name, by some clever marketers. However It it's very likely to be exactly the same stuff as many bog standard sealants/adhesives made for the sheds, or anyone else who wants to put their name on a standard product like plubming suppliers, Ironically it could even be made by Everbuild the UK's largest independent manufacturer of Sealants, Adhesives. who knows!

[smileypete]

Marineflex and Sikaflex should be fine when used in the proper way.

 

I'd expect the vast majority of problems are down to 'application errors'

 

I phoned up their tech support ages ago and they were clearly very knowledgeable about the product.

 

cheers, Pete.

~smpt~