Vennered MDF inside boats .

Captain Coochie

Captain Coochie

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Has anyone used veneered MDF inside a boat ? Myself i cant see why it would be a problem for things like tables and interior doors cabinets that are free standing or not likely to sit in any water for any length of time .
 
I am not sure if some of the volume manufacturers are using MDF in boats, but I do not think it is at all suitable. If you wet MDF it can absorb a lot of water, and it will swell up. Veneered plywood is a much more acceptable material. For anything structural or external marine ply is required, but ordinary good quality ply will work well for non stuctural items provided it is well sealed with varnish. I once made some casting patterns from MDF, and the quantity of varnish they absorbed was quite amazing. The cut edges took about six coats to seal them.
 
But if the edges are sealed and lipped with solid timber then no moisture will get into the MDF so no problem .
BTW if you filled the edges first with dry lining filler it would have only needed one coat .
I know there are tried and tested materials that are used such as ply but ply rots , ive never seen MDF rot .
 
I wouldn't work with MDF onboard though... apparently the dust can 'explode' and destroy wherever it is... so best to destroy your garage as supposed to the boat.... /forums/images/graemlins/grin.gif
 
All dust can explode , static can set it off so be careful next time you use the hoover !
You beat me to it /forums/images/graemlins/grin.gif
 
MDF on a boat? Waste of time. If you want to be cheap use exterior grade ply. Otherwise use marine ply.
Any wood will rot given the right (or is that wrong?) conditions. Plywood is no more susceptible than mahogany. MDF is NOT a boat-building material.
 
Cheap ply £15 veneered MDF £45 -£60 its not about the price its about will it do the job . Plywood is more prone to rot as it has voids . Marine ply BS1088 has voids so anchor marine is the best bet if you can afford it .
Why do you say MDF is not a boat building material ?
 
Re: Veneered MDF inside boats .

I would not use standard MDF in boats for 2 reasons. It will absorb moisture and expand eventually, even if sealed. Also it is very heavy compared to other materials. If weight is no problem then use moisture resistant or better still exterior grade. Unfortunately the core of veneered boards is always standard grade MDF. You could always veneer exterior grade MDF yourself if you are keen to try it !
Best use for MDF on boats is for making templates for bulkheads, shelves etc. Use 3,4, or 6mm.
 
The humidity inside a boat due to its proximity to the sea will be absorbed through a veneer and into the MDF, popping the veneer from teh MDF surface from the MDF swelling from the edges inwards.
 
It does that to vennered ply also but that is still used . I agree that normal MDF is used for vennered boards but have you tried and tested it ?
 
Ive not seen that /forums/images/graemlins/confused.gif
Ive seen it swell up to three times its size but has never fallen apart .That was left outside not inside a boat .
 
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Myself i cant see why it would be a problem for things like tables and interior doors cabinets that are free standing

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Too heavy?
 
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I am not sure if some of the volume manufacturers are using MDF in boats, but I do not think it is at all suitable.

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I doubt it, it is a useless material on a boat.
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For anything structural or external marine ply is required, but ordinary good quality ply will work well for non structural items provided it is well sealed with varnish.

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I think the AWB industry uses WBP ply which is a bit cheaper than marine ply but is still pretty substantial stuff, WBP indicates water proof to boiling point.
 
Seaspray111 - you seem convinced it's fine, so go ahead and use it. My personal experience is that MDF absorbs moisture over time. While you don't like ply, it has the advantage that moisture can only wick along one plane, whereas for MDF it can enter at any point.
A hi-speed cat built here in QLD in the mid 80's used extensive "marine grade" mdf panels - I'm told the cost of repairs, eventually removing all MDF exceeded original build costs.
 
Im not convinced its fine i just thought it was an interesting question and seeing as everyone has a mid 80's opinion on MDF i thought i best give a 2006 opinion on it . Ive used exterior MDF for external joinery and have had no problems .
BTW i also think Asbestos is good for fire proofing /forums/images/graemlins/grin.gif
 
Mark has some on his barge Lodestar and was less than impressed but I don't know which grade. Have a look next time you're down on Eel Pie.
 
I wouldn't use interior grade mdf, unless you could soak it with resin first, but there is an exterior grade that is completely waterproof. I don't have it any more but a few years ago, Classic boat did an article showing where it had been used on a big boat restoration (no, I don't think it was an April issue /forums/images/graemlins/smile.gif ). They also showed articles on a seaside ice cream kiosk that had been made from it, a few years previously. The difference is that is is made up with a waterproof glue, but the bad news is that it is more expensive than marine ply, hard though that is to believe. Like the standard stuff, it is also a lot heavier than ply. Its main use was in fancy cut-out or fretted designs that are too tricky to do well in ply, and a nightmare to do in solid wood, hence the use in a high quality restoration. If I find it again I'll post you the reference.
 
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