MDF vs. Plywood

[Henri]

I've done a bit of looking around on the site and can't find any related topics...

 

I'd always assumed that i'd use veneered plywood for the cabin linings, until I happened a professional builders yard, and when having a nose around their latest boat and asking many questions of one of the builders (who was very friendly and helpful) he told me he was using veneered MDF for both the linings and partitions. I was a little surprised at this as i wouldn't have thought it suitable in damp conditions, but he claimed that as well as being cheaper, it was more stable and easier to work with than ply.

 

Any thoughts, is MDF a big no no, what are the advantages of using ply??

 

Thanks in advance for any answers!! I hope its not cheeky me asking questions like this?!?

[bottle]

Name: -Medium Density Fibreboard (MDF)

 

Sources: -MDF is a type of hardboard, which is made from wood fibres glued under heat and pressure.

 

Advantages: -There are a number of reasons why MDF may be used instead of plywood or chipboard. It is dense, flat, stiff, has no knots and is easily machined. Because it is made up of fine particles it does not have an easily recognisable surface grain. MDF can be painted to produce a smooth quality surface. Because MDF has no grain it can be cut, drilled, machined and filed without damaging the surface. MDF may be dowelled together and traditional woodwork joints may even be cut. MDF may be glued together with PVA wood glue. Oil, water-based paints and varnishes may be used on MDF. Veneers and laminates may also be used to finish MDF

 

Disadvantages: -MDF can be dangerous to use if the correct safety precautions are not taken. MDF contains a substance called urea formaldehyde, which may be released from the material through cutting and sanding. Urea formaldehyde may cause irritation to the eyes and lungs. Proper ventilation is required when using it and facemasks are needed when sanding or cutting MDF with machinery. The dust produced when machining MDF is very dangerous. Masks and goggles should always be worn at all times. Due to the fact that MDF contains a great deal of glue the cutting edges of your tools will blunt very quickly. MDF can be fixed together with screws and nails but the material may split if care is not taken. If you are screwing, the screws should not be any further than 25mm in from the edge. When using screws always use pilot holes. Urea formaldehyde is always being slowly released from the surface of MDF. When painting it is good idea to coat the whole of the product in order to seal in the urea formaldehyde. Wax and oil finishes may be used as finishes but they are less effective at sealing in the urea formaldehyde

 

 

This was obtained from this site Design Technology

 

Personally would not have it anywhere near me or my boat.

[GUMPY]

All the partitions on Parglena are veneerd MDF and the below gunwale linings are ordainary MDF. Where the origional builder used ordainary MDF there have been a few spots where widows leaked over time that I have replaced with Ply

However all the veneerd stuff has been fine and survived as well as ply does, even next to the shower that had a leak it has only discoloured and not "blown".

 

In the extensionn to match the grain and "feel" I have continued with veneerd MDF.

Its much easier to source than vennered ply and easier to work, however ALL my cutting has been done outdoors whilst wearing a mask to minimise the health risks.

 

Oh and by the way the dust is carcenogenic..................

 

J

[Guest]

We used WBP veneered ply for all linings, and veneered mdf for partitions and furniture.

 

To throw the cat amongst the pidgeons as it were, we use a lot of MDF at work and so have investigated the dangers of this material. After advice from HSE etc, there was no evidence available that this nmaterial is any more hazardous than other manufactured boards. I would be very interested in any information to the contrary as I use the stuff daily.

 

Thanks

[david and julie]

 

I'd always assumed that i'd use veneered plywood for the cabin linings, until I happened a professional builders yard,

 

Professionals would usually only build for their particular market. I doubt that high end builders would use MDF(except for templates).

 

The only MDF on our boat are the radiator frets. I was reluctant with these, but couldn't source them in anything else. They are quite easy to replace though, should they fail.

 

You can use either faced 18mm blockboard or 4mm ply bonded onto 18mm WBP ply for the bulkheads.

 

For doors you can bond two sheets of 9mm faced ply, back to back.

 

18mm faced ply is harder to find, but is definately available.

[Richard Bustens]

I have never seen anything conclusive printed in this country, but in the USA they consider it to be carcinogenic and there is plenty of stuff on the net saying so.

 

So i usually work on the principle if in doubt don't use it.

[Gary Peacock]

I aren't too fond of MDF personally but from a production point of view I can see why it is gaining popularity, it is a very easy and quick material to work with. The Heron boats we have here are nearly a 100% MDF fit out but the finish they achieved is very good.

 

I think in years to come you will see MDF becoming more accepted

[Bullfrog]

Urea formaldehyde is always being slowly released from the surface of MDF.

 

Personally would not have it anywhere near me or my boat.

 

Oh my God! I spent most of Sunday in Ikea while Mrs Bullfrog chose new wardrobes and stuff for home. Think of it - a whole humungous wharehouse full of it - all exuding urea formaldyde at the good people of Croydon and surrounding areas.

 

David

 

PS I've just had a thought - Croydon Ikea is on an old power-station site, where they have retained the whacking great big chimneys poking up into the sky-line. Perhaps that's where they are pumping the gas?

Edited June 6, 2006 by Bullfrog

[Henri]

Fair enough...

 

To ask another daft question or two...

 

Specifically why is it that high end boatbuilders don't use it, and why are you not fond of it Mr Peacock???

 

Do people not touch it because its somewhat dangerous, or are there other performance advantages gained from using plywood?

 

Or is it not used because its MDF, has a negative reputation, and hasn't been the material of choice in the past few years? Could you ever see yourself using it in the future Mr Peacock??

[Gary Peacock]

Fair enough...

 

To ask another daft question or two...

 

Specifically why is it that high end boatbuilders don't use it, and why are you not fond of it Mr Peacock???

 

Do people not touch it because its somewhat dangerous, or are there other performance advantages gained from using plywood?

 

Or is it not used because its MDF, has a negative reputation, and hasn't been the material of choice in the past few years? Could you ever see yourself using it in the future Mr Peacock??

 

I don't like MDF purely because of the way most boat builders use it, I aren't a fan of the routered edge effect that is rapidly becoming the norm along with surface mounted MDF doors on cabinets.

 

We have used MDF on occaisions normally on hire fleet and community boats built to a budget, if we were to enter the arena of the budget boat then there would be no alternative to use it if there was to be any chance of being competitive.

 

We do use a form of MDF in some very exspensive boats in that the Kronospan sheets we offer as a linning option is basically MDF with a melamine laminate. The stick in the mud narrowboaty types would die with one leg in the air at the thought of it but we don't really aim at that market anymore, and customers seem to like the Kronospan option.

[Henri]

Okay thanks very much (everyone), i think that kinda helps me out, i guess its time to get on the phone and do some ringing around for prices!!!

[Guest]

I have never seen anything conclusive printed in this country, but in the USA they consider it to be carcinogenic and there is plenty of stuff on the net saying so.

 

So i usually work on the principle if in doubt don't use it.

To be fair Richard they said that for years in the 'states about microwave ovens. How many of us would not use one of those now?

[DHutch]

And titaium.

- Every time i get anything with titanum in it from the states it has a orange sticker stating "this product contains substatces know to thw state of calafornia to cause cancer" yay!

 

Where as in the UK to get a sticker like that it has to be aspestose or somthing!

 

 

Daniel

[ChrisPy]

I saw a report that calcium silicate was found to be carcinogenic. As a result US authorities believed they should put health warnings on builder's sand and public beaches

[wrigglefingers]

To be fair Richard they said that for years in the 'states about microwave ovens. How many of us would not use one of those now?

 

I don't use one and neither do the kids at school because they encourage the development of poor cooking skills, the use of expensive and less healthy ready-cooked foods (which are loaded with cheap fat and make a huge profit for food manufacturers) and can lead to dangerously under-cooked food because some users don't understand how they work or how to use them effectively.

 

But then I am a bit of a food obsessive.

 

Jill

[DHutch]

I fear where drifting, but i would like to add that microwaves can have there place.

- We have at home and its great, we use it reguarly, if not frequently.

 

We've never used it from microwave meals, ever, but you can use it for many other things, warming wine, making custard, heating tins of soap, speeding up baked potaotes, defrosting bread, melting butter (for aspagus), or just softening it. Also melting chocolate onto mousetraps!

 

 

Daniel

[wrigglefingers]

I fear where drifting, but i would like to add that microwaves can have there place.

- We have at home and its great, we use it reguarly, if not frequently.

 

We've never used it from microwave meals, ever, but you can use it for many other things, warming wine, making custard, heating tins of soap, speeding up baked potaotes, defrosting bread, melting butter (for aspagus), or just softening it. Also melting chocolate onto mousetraps!

Daniel

 

Now I've got home it's occurred to me that I've not been at my most sunny today. Apologies. I'm intrigued by the melting chocolate onto a mousetrap idea - why?

 

To drag the thread back again, we don't use MDF in school because the dust shed when it's cut can affect children who struggle with asthma and other respiratory illnesses. There's no warning in place for finished MDF (and indeed some of the lavs at school wouldn't have useable doors most of the time). My feeling is that as long as you take sensible precautions that veneer-faced MDF would be suitable for lining but may be considered undesirable by a future buyer. Moley used OSB in his re-fit and that would be my choice for a refit.

 

Jill

Edited June 6, 2006 by wrigglefingers

[DHutch]

Now I've got home it's occurred to me that I've not been at my most sunny today. Apologies. I'm intrigued by the melting chocolate onto a mousetrap idea - why?

Because they like chocolate, and if you melt it on the buggers cant pinch it!

- You try using cheese or ham and the little darlings pinch the cheese/ham without geting there selfs traped.

 

 

 

Daniel

[Amicus]

The scare with MDF, I take it, is from the glue used in the manufacture, That being, what is the glue used in ply, block-board or OSB, even chipboard?

 

 

As an aside I work with a lot of MDF and have heard all the scares so I have chased all I can find on t’internet, I have the HSE publication at hand. The upshot seems to be that MDF lies between hardwood and softwood for nastiness.

Having said that, ALL particulate is a hazard.

[Guest]

The scare with MDF, I take it, is from the glue used in the manufacture, That being, what is the glue used in ply, block-board or OSB, even chipboard?

As an aside I work with a lot of MDF and have heard all the scares so I have chased all I can find on t’internet, I have the HSE publication at hand. The upshot seems to be that MDF lies between hardwood and softwood for nastiness.

Having said that, ALL particulate is a hazard.

Correct, all the research we have done shows that the hazards are no different than any other manufactured board. You should wear a mask when cutting and especially sanding many wood based materials. I have heard the stories that it is "banned in some states of America" but never seen any proper evidence. Apparently in one state of America the smoking of cigars on a Thursday by dogs is banned.

[Cafnod]

I have been using some Brazilian manufactured WBP for the hull lining and it gave off some very nasty nffs when I touched it with the jigsaw. Masked up before proceeding. I assume that was the glue........

All of these things can be dangerous, but it is like anything, weigh up the risk, take precautions and proceed with care and attention to what is going on.

[Hairy-Neil]

To be fair Richard they said that for years in the 'states about microwave ovens. How many of us would not use one of those now?

 

Me for one, though the bigger health risk with a microwave oven is not the radiation emitted but the high saturated fat and sugar content of the average ding-meal. I find it hard to believe that people really buy microwave ready beans on toast..............

[DaveR]

What about the special primer sold for MDF.

 

Is this to seal in the glue used, special because of the absorbing properties of the board or another money making scheme by the DIY industry?

[Guest]

What about the special primer sold for MDF.

 

Is this to seal in the glue used, special because of the absorbing properties of the board or another money making scheme by the DIY industry?

Personally I would be far more concerned by what is present in the various insulation materials that we use, than anything found in MDF and other timber related products.

[Moley]

Moley used OSB in his re-fit and that would be my choice for a refit.

Correct. I had to buy most of my sheet materials from B&Q. Even though I've got an Alhambra (/Sharan/Galaxy - all the same) I can't get 8x4 sheets in my car, and it was more convenient to have B&Q cut to required sizes (I've since been told by a builder that he buys his sheet materials there, cheaper than most timber merchants).

 

I couldn't see the sense in buying their top grade ply when it's not going to be seen, and their mid-range plys seemed rubbish. OSB is unsightly, but exterior grade, stable and relatively cheap. I'm covering that with flooring laminate below gunwhales and bonding on 4mm ash faced ply above.

 

But, the laminate is MDF based, though it's a far higher density than the standard sheet materials. It's also coated both sides.

 

I have used MDF for my bulkheads, because it's cheap, stable and easy to work with (using a good dust mask of course). This has been primed and Duluxed one side, bitumined and tiled inside bathroom.

 

Other than that I wouldn't touch the stuff. Any offcuts left down my cellar really soak up the moisture.

 

Can you actually get proper wood veneered MDF or is it all plastic wood-effect, and how dense is the backing?

 

Thinking about it, the laminate flooring (job-lot special offer from B&Q again, £2.99/m2) was made by Kronospan, so Gary, even though you're flogging it to the upper end of your market, is it still plastic-coated tat?