MDF vs. Blockboard

Hi there,

Bit of a noob question....

I have designed all of the flatwork for my office project in 18mm sheet material... but I now have the vexed question of ply vs. MDF.

It's all going to be in Sapele Veneer, finished with Sapele Face Frames.

There seems something really ersatz about MDF, and a bit concerned about all the formaldehyde emissions e.t.c. but with blockboard, I am worried that the edges are going to be hard to finish. When I have been to some professional cabinetmakers building repro furniture, it seems as if everything is crashed out in MDF... but I am thinking maybe this is for commercial reasons, rather than making a quality product.

The blockboard will be a bit more pleasant to lag up the stairs, wont sag under weight.... it just seems like the better solution..

Also, what thickness Ply for the rear board of my bookshelves... They are going to be big old shelves... 8ft high, 80cm wide. I was wondering would 12mm be overkill?

Advice welcome.

Gavin
 
Gavin,

We don't see much Blockboard on this side of the pond. I put that link in just so people can see what it is. I've personally never noticed it for sale here.

If they're not using some kind of secondary wood, I think most people veneer with MDF. If you're doing large amounts, it's probably worth setting up some kind of vacuum contraption...

Thanks,

Bill
 
Thanks Bill - that is interesting to know - indeed, we don't see tons of it over here either; but Timbmet in their catalogue seem to think it is an under-used product.

I can buy blockboard or MDF pre-veneered with Sapele veneer. I have some thin birch-ply which my Uncle veneered with me on a big heated 10' x 4' heated press! He really is a legend... it's been sitting in his factory for ages, and I need to hurry up and order the rest of the sheet so it is out of his hair!
 
Well, as I understand it, MDF makes for a very stable base for veneer? How does blockboard move? How does veneer like a blockboard base?
 
Hey All,

Thanks for the great response.

Wish me luck! - Just ordered the board eek - see my post in the introduction section.

I think I saw this book in the library and photocopied a few pages when I did the Kevazingo -thanks for the recommendation.

I managed to find someone who had worked with blockboard - an ex school design & technology teacher, and I've seen some for myself. I'm confident it's the way to go now on the grounds of strength and weight. We shall see...
It also "sounds like wood" when you tap it, and doesn't have all the formaldehyde - so trying to make something "authentic" I feel it's the way to go.

The pine strips are laminated between two very thin pieces of plywood - so the veneer "keys" onto this well and it's a smooth surface. In terms of movement, I am told it is quite stable - like a plywood, only the middle section of softwood is chunky.

It might be fun for small quantities - but I'm looking along the lines of 15 8x4' boards in 18mm and about 10 in 9mm.... so it would be a big bag press and a lot of practise!

I would be trying my uncle's patience to ask him to do the sapele veneered boards, as I couldn't

I suppose if I am buying veneered boards, the finish will be superb as it is coming from a supplier - I don't have the confidence to get it quite right myself at these sizes.

The kevazingo sheets we did looked amazing when they came out of the press - I can't wait to see them as they have been stored a couple of months, so we shall see if they stand the test of time. They were veneered with PVA and a little heat in a high-pressure press.

The only one detail, on a couple of the sheets, we may have applied a tad too much glue (went on very very thin so as not to bleed through) which then adhered to the fibres of the paperboard we sandiwched them in the press with.
 
Having taken five people to get the wood from the top of the delivery lorry onto the ground; with the heavy-MDF falling like a stone; I'm convinced the blockboard was a smart move.

It sounds like wood when you tap it, is nice and light to handle; smells like nice softwood when cut - and the dust is nicer by a mile than MDF.

On the disadvantages; some of the edges of the pre-cut stuff have "voids" along the edge, where the cut has co-incided with one of the glue joints between blocks. Knowing how I am going to cover these edges, I am heartened - as I don't think they will need filling, and there are "other bits of wood" along the length which will support the edge mouldings. I think a thixotropic moulding glue should also fill in the gaps a little?

All in all, I'm feeling really pleased I plumped for the blockboard over MDF - and I'm sold on the tag-line in the catalogue that it is a now under-used product that should be considered more carefully.
 
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