Using veneered plywood

[stuartpaul]

I'm about to consider what to me is the heresy of using veneered plywood, - mahogany in particular. Don't ask why, - it's just to me solid wood is the 'proper' way to dot it!!

However, - costs and availability dictate I consider it's use. I can't believe you can get the same finish as with solid wood. For example and lipping is surely going to look like, - well lipping!! This for me sort of blows the concept.

What about weight 'bearing'? Thickness for thickness is plywood as strong as solid? Building a long case clock and some of the weights are quite heavy.

I know there will be some out there who think I'm daft for not using it but we're all different aren't we?

Any thoughts, hints or tips much appreciated, - just be gentle with me!!

Edited to add: Any details of suppliers in the Dorset/Somerset/Devon area would be great. I don't need a lot so if anyone does half sheets even better.

 

[garywayne]

Hi stuartpaul.

Regarding strength, thickness for thickness, I think you will find that plywood has more elasticity, and is stronger, and will hold more weight than solid wood.

I hope this is of some help.

 

[George_N]

Plywood is more stable than solid wood and veneered MDF even more so. It won't detract from your project to use veneered sheet goods for panels and they will be substantially more stable. After all, furniture makers have been putting exotic veneers on common woods for centuries.

 

[Scrit]

As per the comments above

I can't believe you can get the same finish as with solid wood. For example and lipping is surely going to look like, - well lipping!! This for me sort of blows the concept.

That depends on the class of work. If you lip the MDF/plywood first then veneer the faces the result is much less noticeable and with a thick enough lipping profiled edges become possible. Veneered work has always been highly regarded from Ancient Egypt onwards as it allows you to make pieces which would otherwise be completely impossible. As a more "mundane" example take a look at a Rolls-Royce dashboard and you may see what I mean - you'd simply never find enough solid walnut burr to make all the dashboards and door cappings in Rollers. Veneering also allows you to "stretch" a show timber further. Without it Ruhlmann could not have done some of his brilliant pieces back in the twenties with, for example, the amboyna burr accents,

because amboyna is a tiny tree (in comparison to a mahogany), the burr is quite rare and the veneer leafs are rarely more than 6 to 8 inches across when you do see it.

If you are going to pre-veneered MDF then your design choices will inevitably be a little more limited, but for the most "seam-free" appearance I'd either opt for a veneer edging or a V-grooved solid lipping, both of which will produce a barely noticeable transition if done well. If you are concerned about the use of a thin (0.4 to 0.6mm) knife-cut veneer edging you can always obtain constructional veneers in thicknesses up to about 2mm or even go to solid wood lippings available in rolls and between 2mm and 3mm thick.

Scrit

 

[stuartpaul]

Thanks all.

Does it matter if I go for ply or MDF? I have absolutely no experience in this area at all. Cost of course is an issue (isn't it always?!).

Scrit, - I was intending to use pre veneered sheets and apply a solid wood lipping (say 12mm or so). If I'm careful are you saying I can get an almost invisible joint? A sort of T&G approach? Not quite sure what you mean by 'v grooved'?

 

[jasonB]

Mahogany is not that readilly available in pre veneered sheets, Sapele will be the closest.

The 12mm ply will cost more than 13mm MDF and the ply will only have face veneer on one side with a balancer on the reverse, the MDF will be veneered in the same wood both sides though on eis oftem slightly better than the other.

A thick lipping will look more obvious than a thin one, I would go for iron on real wood veneer edging.

Jason

 

[woodbloke]

I understood that ply, used in the correct way is incredibly strong - I am no expert on this but have heard that a marine ply hull in a boat is stronger than the equivalent made from steel. I also agree with all of the comments to date but would add that when a lipping is applied and then the show veneer over the top, the lipping can sometimes shrink a fraction which then 'telegraphs' through onto the surface of the veneer as a slight shadow all round the piece, which is annoying to say the least. This can be somewhat nullified by lipping the edge and then veneering twice, the first veneer at right angles to the final show surface. The alternative is to use a much thicker constructional veneer and veneer just once, but then you are limited to the type of timber and grain pattern available - Rob

 

[Scrit]

I was intending to use pre veneered sheets and apply a solid wood lipping (say 12mm or so). If I'm careful are you saying I can get an almost invisible joint? A sort of T&G approach? Not quite sure what you mean by 'v grooved'?

I hope the following diagrams will assist:

The thick lipping is very obvious, whereas the V-groove one isn't that visible and can be cut on a table saw. As Jason says sapele is easier to obtain mahogany in pre-veneered and mahogany veneered hardwood plywood will be a bit of a hunt to track down. I know of one supplier who sometimes has some (Lawcris in Leeds - a tad far off methinks), but the last lot I saw was a very insipid pink colour indeed.

I understood that ply, used in the correct way is incredibly strong

Yes, Rob, but do you need that much strength in a piece of furniture?

....(I) would add that when a lipping is applied and then the show veneer over the top, the lipping can sometimes shrink a fraction which then 'telegraphs' through onto the surface of the veneer

If you get the lipping into equilibrium with the veneer and the ground and then use a low-moisture content, resin-based glue such as an RF (resorcinol formaldehyde) glue then it is highly unlikely to happen.

Scrit

 

[Roger]

Stuart

Plywood or MDF at least 1/2" is ample for a longcase clock. The weight of the movement and actual weights is all supported on the seatboard in any case and transmitted to all four sides. The actual construction of the various 'boxes' can be done with either material - edged with the solid wood to match the veneer and jointed in any way you see fit.

There is very little 'strength' needed in any of the particular parts, other than decent balanced construction.

 

[Nick W]

If you are building load carrying shelves (e.g. a bookcase) then MDF will sag under the initial load and then continue to creep. The workround for this is to add lippings (and fairly deep ones at that) to the MDF. The cure is so use ply, or better yet blockboard - IF (and thats a big if) you can find any pre-veneered, or are prepared to veneer it yourself, or get it veneered.

Other advantages of blockboard are that it is considerably lighter than the other two options, and doesn't produce the nasty dust that MDF does when cut. You do still need and edging of some sort for cosmetic reasons, but the thin iron on stuff will do.

 

[Scrit]

Other advantages of blockboard are that it is considerably lighter than the other two options, and doesn't produce the nasty dust that MDF does when cut. You do still need and edging of some sort for cosmetic reasons, but the thin iron on stuff will do.

Unfortunately some blockboards/laminboards do have a tendency to telegraph through with age..... there's really no ideal solution . For any of them, though, the amount sag in load bearing situations can be calculated using the Sagulator :lol:

Scrit

 

[engineer one]

have to say that my experience with mdf bookshelves is that if they
are not too wide and deep they can carry quite heavy loads with
no real sagging. [-(

in principle the un coated stuff i made over 15 years ago is no wider
than 600 by 300 deep and carries many BIG books so i think it is
often over emphasised, whilst i agree that edging does help.

paul :wink:

 

[engineer one]

having made the bald statement thought i had better check

so in my practical experience you can make a 1200 x610
bookcase out of 18mm mdf with three book spaces up to 310 high
and they will take up to 24 books that are hard back and over 300 high.

i know this because i had done it, and just re measured the shelves.
maybe they don't make mdf like it was, but using one of my
engineering straight edges, i got no discernible space under the whole
length of an 18 in edge. also it did not rock at all.

so maybe i have just been lucky, but it kind of makes a point doesn't it??? :twisted:

one final point though i made those bookcases with bottom, and
two intermediate fixed shelves, and an open top. but the back is
screwed on 6mm mdf on the outside, not in a rebate. and across
the top i put an 2440 board since i had more of these bookcases
in the space.

also floating in the air i have another box which is 950 unsupported
wide, and 500 back to front. same kind of age, and no discernible
sag, actual overall width is 1200, so am not sure what that proves,
but it is an interesting piece of factual not dream information.

paul :wink:

 

[George_N]

For your particular application (long case clock) I would envisage most of the veneered sheet goods, be it ply or MDF, to be used as panels in solid wood frames. If that is the case then lipping or edge banding would not be required. A lot depends on your design and whether you can match your solid wood with the veneer. In a long case clock edges can often be dressed with decorative mouldings to disguise the fact that you have used a veneered board, again a lot depends on the design. I watched Norm Abram :norm: make a clock a while back and he used his favourite, cherry veneered ply, for the panels. I don't remember many/any instances where he had to apply a lipping that would be obvious, even on close inspection.

 

[Woodworm99]

Hi

I'm a newbie. I'd like a mahogany bookcase (or that depth of colour at least) and I'm considering veneered MDF but leaning towards veneered Ply for strength. I've been told finish is often a problem with veneer as it can have issues when planing or cutting. What would you suggest?

I personally don't know why it would need planing but I've been told by a carpenter that it's something to consider.

 

[custard]

Don't build bookcases out of MDF, at least not the shelves. MDF isn't very stiff, it sags noticeably under weight and a shelf laden with books is very heavy. You can beef up an MDF shelf with extra thick lippings front and back, but as a woodworking newbie securely and accurately attaching thick lippings might be a step too far.

When designing shelves "The Sagulator" is your friend, if a shelf sags by even 3mm across a 1200mm run it looks pretty tacky, where as you want your first jobs to look super spiffy so that Mrs Woodworm 99 will enthusiastically support your plans to build a shed and fill it with exciting tools.

http://www.woodbin.com/calcs/sagulator/

Good luck!

 

[RobinBHM]

Hi welcome to the forum.

Is that a record resurrecting a 10 year old thread!

Mdf veneered boards are easier to source. Sapele is the timber you need for a mahogany look.

Mdf however does tend to sag, so if you use it for shelving I would use a solid timber lipping at the front and possibly back. If you can design the shelving so the uprights are fairly close all the better. It can also make bookcases more interesting.

If you are going to stain the work, be careful with glue. Pva glue especially will seal the grain and appear as white marks when the stain is applied.

I wouldnt say there is a real problem with finishing veneer, just dont sand through it!

 

[Benchwayze]

Depends how thick the veneer happens to be; as to whether or not you can safely plane it.

These slopes were made with laminated Luan board, (Similar to block-board core) dovetailed , and veneered over with 3/16 walnut, which could be planed of course. (The elm burl was just the usual thickness of veneer; like paper!

Sorry about the quality of the pics.


John (hammer)