Replies

1. 
   WillGeorge | May 19, 2010 10:19pm | #1

   Veneer Core plywood over Lumber Core.  ?? Not sure exactaly what you mean. OK, I'm old and loose track of what I see in print.

   I have never used 'lumber' core plywood so I cannot comment (Except in doors). I use MDF and veneer core often. I find that the veneer wood on MDF usually has less 'checking' along the grain than with veneer core. Not sure if that is always true. Just from looking at many different sheets in the bins during selection of what I purchase.

   I have no real experience but would not lumber core be prone to warping over time? And then again I have installed many solid lumber core doors that have never warped if finished properly on all edges and faces. I would assume that lumber core would hold fasteners better and be lighter in weight than most MDF core. Not sure.. If well made, I would think either is OK.

   Well made plywood is hard to find these days, even with Marine grade that is much more expensive. I have seen voids in the layers of quality marine grade plywood but much less that common so called quality furniture grade.

   Only my opinion which was free advice.....

1. 
   JimmyD3 | May 19, 2010 11:22pm | #2

   Veneer Core vs Lumber Core

   Thankyou for the reply Will, I appreciate your input.

   From what I understand from one of my suppliers here in DFW, lumber core has less voids than veneer core, which is always a plus. I do suspect though, that lumber core is not as structurally strong as veneer core. I have tried to locate someone here in our area that sells Quality Cabinet Grade Plywood, but no one yet.

   Thanks again for the input, hold the faith.

1. 
   Lataxe | May 20, 2010 05:56am | #4

   J,

   You write: "From what I

   J,

   You write: "From what I understand from one of my suppliers here in DFW, lumber core has less voids than veneer core, which is always a plus. I do suspect though, that lumber core is not as structurally strong as veneer core".

   In practice the two types of man-made board vary a great deal in quality, just as with other man-made stuff.  Generally, you gets what you pays for.  Voids and strength vary in both plywood and lumbercore boards, as do their other qualities.  I've used both plywood and blockboard (as lumber-core is often called here in Britain) for furniture and quickly learned to avoid the inexpensive stuff.  Although the latter may be fine for mere construction work that is invisible once a piece is made.

   With plywood its best to go for what is often called birchply or (as I recall) applecore (in the USA).  These are plywoods made with high quality internal veneers and have more layers-per-thickness.  The best are guaranteed void free.  The many layers, as well as the better quality timbers in them, usually make for a better board.  Any surface veneer is generally of good quality too - no checks from the veneer-slicing machine, no wild colour variations and so forth.  Such plywood is often heavy, compared to the cheaper stuff - perhaps a reflection of its content: birch rather than unnamed (and often very soft) softwoods.

   Blockboard also varies in quality but I'm not aware of a "type" or brand-name that is of best quality (doesn't mean there isn't such a brand).  Personally I prefer blockboard to plywood for making furniture (as opposed to build-ins) because it can be worked as though it were solid timber; although don't try planing the veneer.  :-)  You can make dovetails and M&Ts with it, assuming you can hide any lumber-core parts exposed by the joint cutting. You csan screw into it as though it were solid wood. Often, it is lighter in weight for a similar thickness/stiffness, compared to plywood.

   Feastures to watch out for in blockboard are:

   * Are the blocks glued up without voids, loads of knots, splits, skinny/fat/short pieces or other defects?

   * Are there two adequate veneer layers - the thin "show" veneer and a thicker one to stop the block pattern telegraphing through to the show veneer? (See below)

   * Is the block pattern such that it adds to the stiffness of the board?  Blockboard can be a lot stiffer than plywood, if it has a block pattern chosen by the manufacturer for that purpose.

   ****

   I've made a goodly number of cabinets and such using blockboard.  With the higher quality stuff it is impossible to tell which parts are solid wood and which blockboard, once a piece is completed.  To get this effect you must avoid rotary-cut show-veneers in favour of a veneer pattern that looks like glued-up planks - bookmatched veneer slices generally look most like solid timber, as though you had resawn a thick plank. 

   In addition, beware the dreaded telegraphing.  I once made a piece with maple-veneered blockboard that seemed to have an adequately-thick "under" veneer between the show veneer and the blocks.  However, that under-veneer was too soft a wood and despite being nearly 1/8" thick, the blocks telegraphed anyway.  It was a very slight effect only visible in a strong raking light; but it was unmistakable.  Doh!

   Although I manage to scavenge all my timber free, I have to buy blockboard.  A full sheet (8' X 4') of 3/4" good stuff can cost over £100 ($150) in Britain.  However, this gets you very high quality veneer, usually on both sides.  To buy similar quality of grain/colour in solid timber would cost a great deal more.   A sheet of 8' x 4' goes a long way in a cabinet as there is (with careful planning) very little waste.

   Lataxe

1. 
   JimmyD3 | May 20, 2010 08:19am | #5

   Veneer Core vs Lumber Core

   Lataxe

   Thankyou for the in depth reply, very informative. I will discuss the quality issues with my supplier or get a different source.

   JimmyD

2. 
   JimmyD3 | May 19, 2010 11:52pm | #3

   Information Source

   Found this in "Knots" 

   https://www.finewoodworking.com/Materials/MaterialsPDF.aspx?id=2395

   This answered a lot of my questions. Seems I didn't dig deep enough.

3. 
   hammer1 | May 20, 2010 08:15pm | #6

   Lumber core plywood is for interior use only. It's typically used where the edge of the plywood will be seen or sometimes shaped. It's light weight, high quality, expensive, holds fasteners well, especially on edges.

   Veneer core runs the gammit from construction to furniture. Some is exterior rated. It can also be expensive depending on the species and cut of the veneer. In cabinetry and furniture, it's often used for carcasses, shelving and when the edges are covered. Fasteners on the edges can cause splitting of the veneers.

   Due to the cost and limited availability of lumber core, it's reserved for special circumstances, not as general use sheets.