mdf v plywood

[londonron]

time moves on and products improve. Whats wrong with using MDF to line a boat especially if you use the water resistant one?

[Grace and Favour]

Marine ply is better

[The Bagdad Boatman (waits)]

Ordinary mdf is compressed paper and swells if wet. Try dropping a sample of waterproof? mdf in a bucket of water for a month.

[londonron]

i could drop a piece in there for a year. However all that would prove is that it is no good for that application. I was wondering what the drawbacks would be for the application i am using it for. A well vented narrow boat interior that doesnt get wet.

Edited May 6, 2013 by londonron

[ditchcrawler]

i could drop a piece in there for a year. However all that would prove is that it is no good for that application. I was wondering what the drawbacks would be for the application i am using it for. A well vented narrow boat interior that doesnt get wet.

I have used the waterproof type on the ceiling of our Narrowboat, its been up 12 years at least and not had any problem, had some laying around outside at home for years and didn't change at all. I always find that the grain lifts on plywood at the edges.

For lining out it wouldn't be to good to fix to IMO

[Guest]

MDF is banned in some parts of America you know

 

I used ordinary oak faced MDF for my bulkheads which have managed to survive for 9+ years (as have I). The so called WBP plywood floor is delaminating.

 

I have never tried waterproof MDF for lining a boat, but did panel a kitchen with some (looks like T&G). An offcut lay in my trailer outdoors for a winter, and was fine when I eventually chucked it. I think if a NB gets that amount of water in it that the lining is wet, we may have serious problems.

 

I remeber when marine plywood in a boat was the work of satan, and the old boys wouldn't use it at any cost.

[stagedamager]

Modern day WBP ply is utter garbage. Both on a boat and on land it fails.i have sent numerous sheets back to suppliers due to poor quality finish and massive voids. Birch ply wins for me every time and although I pay a tiny bit more in time I will save by not replacing! !

I have seen boats lined out, very well in MDF and no swelling over several years....it can be done!

Dan

Edited May 6, 2013 by stagedamager

[fudd]

I have used mdf that is guaranteed against failure for 50 years. You can't buy ply with that sort of guarantee. You don't have to use that stuff. It's very expensive. Don't use cheap stuff either. Medite is a good one. Mid priced and won't fluff up when it's machined.

[Mike Jordan]

My take is that veneered MDF is fine for used where it is contained as in door panels which are framed by solid timber. You should never, ever, see the actual MDF core, only the veneers on the faces. Using veneered MDF by machining the edges and allowing them to show is the mark of a yard with a CNC machine and little regard for quality!

It is increasingly difficult to get thinner plywood with a veneer on both faces, most suppliers only offer these with an MDF core,

Any savings you may show in fitting out a single boat with cheap materials will be easily offset when the final value of the boat is assessed.

[Bee]

I think I`d be wary of using it below the gunwhale of a boat on those dark badly ventilated bits behind beds, cupboards etc but as said, time moves on and it`s really only the edges that soak up water and the same goes for end grain in ply and solid wood too, it should be ok for most interior uses.

[Guest]

I am surprised at the replies so far! I put a similar reply about using MDF in my boat (not lining) on here some years ago (I'll guess nine years) and a priest was immediately sent around to exorcise my boat.

 

When some people realise I have used MDF they have commented "It'll swell if the boat ever sinks/takes a lot of water." Having helped to deal with a boat many years ago that did sink on the L&L, it needed guttiing and refitting to get rid of the awful stench and of course the beautiful wooden interior was badly stained..

 

Interesting post about WBP ply; the stuff I used for the floor is utter crap. Green chipboard would likely have fared better. I am told that even BS 1088 marine ply isn't as good as it once was? I would be interested in opinions on that.

[smileypete]

WPB ply is extremely variable these days, I'd never order it sight unseen. Seems the world is running out of available rainforest to chop down... it ticks me off when I see decent new WBP used for walling off building sites.

 

Both WPB and MR-MDF can be checked by boiling an offcut in water for a while. And with either, the hidden backs and especially edges should be well coated with something like a protective stain or paint for all-over protection. Not doing so is common corner cutting on some supposedly 'quality' fitouts.

 

cheers, Pete.

~smpt~

Edited May 7, 2013 by smileypete

[Danny1234]

Hello

Have been shopping around for timber boards of various kinds a fair bit these last few months.

As mentioned, the quality of WBP varies enormously.

Word of caution with regards to Moisture Resistant (MR) MDF, ...... MDF can be quite nasty stuff to work with, recognised as a carcinogenic by the more forward thinking associations/bodies, .... Proper masks and dust extractors really are a must. Other thing, it's bleeding' heavy. About 40kg a sheet, approx double the weight of standard ply type sheets. Have you tried lifting 2 sheets of ply at once?. Maybe you're a 6'4" bodybuilder type and that really isn't a problem. It's pretty hard to lift around with a comfortable level of control and not bang the edges/corners.

If in doubt, depending on how much time you have available, you can seal/paint the edges of the boards. Through as I'm sure you're aware, dealing with the condensation and moisture before it gets to the stage where it may start damaging boards is probably the most important issue to consider/deal with.

 

Regards

Danny

[Ex- Member]

I have used some MDF here and there and didn't bother with the waterproof stuff either. It's been fitted well over 7 years now and has no problems what so ever. I wish now I had used it more as we eventually painted over Oak faced Ply as we were fed up with so much wood finish everywhere. Had we lined the upper cabin sides with MDF it would have saved a good few quid.

 

At the end of the day, a good majority of the board is a very hard resin and quite water resistant anyway especially if painted, I wouldn't hesitate to use it under the gunwale either but would probably go for 15mm thick and make a good solid job of it.

 

On some MDF I fitted I used proper MDF white primer which really does adhere really well and gives some additional moisture resistance.

[Guest]

Hello

Have been shopping around for timber boards of various kinds a fair bit these last few months.

As mentioned, the quality of WBP varies enormously.

Word of caution with regards to Moisture Resistant (MR) MDF, ...... MDF can be quite nasty stuff to work with, recognised as a carcinogenic by the more forward thinking associations/bodies, .... Proper masks and dust extractors really are a must. Other thing, it's bleeding' heavy. About 40kg a sheet, approx double the weight of standard ply type sheets. Have you tried lifting 2 sheets of ply at once?. Maybe you're a 6'4" bodybuilder type and that really isn't a problem. It's pretty hard to lift around with a comfortable level of control and not bang the edges/corners.

If in doubt, depending on how much time you have available, you can seal/paint the edges of the boards. Through as I'm sure you're aware, dealing with the condensation and moisture before it gets to the stage where it may start damaging boards is probably the most important issue to consider/deal with.

 

Regards

Danny

I agree that MDF can be heavy to lift.

I have cut loads at work and agree that a face-fit mask and LEV is essential. That said many hardwoods carry exactly the same and even greater risks in some cases. Sanding of same can be very hazardous.

[Chalky]

I used MDF for come of the engine room cupboards and also to line the rear doors. This is a wet area and after cutting the panels they were given a couple of coats of thinned varnish to seal them. This was then smoothed and the whole lot grained / painted to give the feel of a traditional back cabin (bit limited since there's an engine under the floor!). It's been rained on for a couple of years without any problems. As a precaution I always touch up any chips with varnish to prevent any moisture ingress..

[OldPeculier]

I lined my bathroom at home with http://www.wickes.co.uk/mdf-beaded-panel-6x607x1220mm/invt/190140/ Has had ten years of kids splashing, steam and condansation and hasnt suffered at all.

[Guest]

I lined my bathroom at home with http://www.wickes.co.uk/mdf-beaded-panel-6x607x1220mm/invt/190140/ Has had ten years of kids splashing, steam and condansation and hasnt suffered at all.

That looks like the stuff I spoke of that was lying in my trailer for ages in all weathers. Easipanel is the name that Homebase use for it. Expensive i thought, but very effective and weather resistant.

Edited May 8, 2013 by Guest