Questions for Lignum about veneering

[echnidna]

In another thread Lignum said,

Cliffie--- Try a torsion box with pine ribs covered in some 6mm ply or mdf. Its 10 times STRONGER than solid timber and it WONT move, and with care in the edging you CANNOT tell its veneered. And with a 2100 x 1000 x 35mm top you can have an extra 5 or 6 - 30mm x 2.1 planks to play with? Now if that dosnt get you excited nothing will:cool:

An interesting excersise---- Next time you thickness up some boards for your top, disconect the extraction and when you have finished stand back and weep at all that saw-dust that should be still happily together in the form of a veneer or two:(

I like the torsion box idea for table tops. Very strong yet much lighter and far more stable than using solids. Would also take crossbanding work and inlays much better than solids.

I have been thinking of veneered tables but was thinking of using formply, there are advantages in torsion box that are well worth considering.

Considering the sheer abuse a tabletop can be subjected to isn't a 6mm top substrate a wee bit thin.?
Could the top be say 12mm and the bottom 6mm?
What are your thoughts about using cd construction grade ply for the torsion box instead of mdf?
If I use handsawn veneers say 2mm thick would you apply it as leaves say 70 to 100 wide or would you suggest gluing them into wide leaves?
What traps to watch out for doing this.
Any recommended books on the subject?
Anything else you can comment on.

[Greg Q]

In another thread Lignum said,
....

I like the torsion box idea for table tops. ...

Considering the sheer abuse a tabletop can be subjected to isn't a 6mm top substrate a wee bit thin.?..
.

FWIW, I made one using 3mm skins two years ago-its still working as the kid's desktop. Cross-section anything from IKEA and you'll see their real genius-they sell cardboard and air wrapped in thiiiiin veneer.;)

[Auld Bassoon]

Hi Bob,

Sorry to butt in!

I use veneers quite a bit, generally resawn from rough sawn boards after jointing an index edge & face.

Thicknesses that I use range from <2mm to 6mm+; I don't see any reason why one couldn't apply the same approach with, say, 10 ~ 12mm "veneers" - just don't try and bend them much!

In fact, one of my next projects is to make up a whole wall "entertainment centre" for a big screen TV, the DVD, Hi Fi, etc. from Red Gum - but kept fairly simple; not ornate at all, and I'll be using this approach as I don't want to use up my stock of RG just for the sake of building to the required strength, so I'll use laminated stock, veneered with, probably 3 ~ 4mm RG on both sides, and a face frame construction in RG.

For the cabinet back, I'll take a slightly different tack, I think, and use ship-lapped 6mm RG planking; this because it'll be wvisible from the fron when the doors are open, and I want a uniformity of colour and texture.

Cheers!

[echnidna]

Hi Steve,
I meant 12mm ply substrate not 12mm veneer which is so thick there'd be movement problems.

[Auld Bassoon]

Hi Bob,

Probably me, as I've had to read so much today I'm seeing double...

Anyway, with a 12mm substrate, a veneer of 2 or 3 mm on top would be fine. Very limited (if any) movement, easy to do, and would look like solid timber - but be stronger.

The biggest challenge with veneering is making the two mating surfaces clean and smooth, with just a bit of grooving in either one to help the glue. Then clamping after having rolled (or hammered with a veneering hammer) the surfaces together with plently of cauls.

Cheers!

[Lignum]

Considering the sheer abuse a tabletop can be subjected to isn't a 6mm top substrate a wee bit thin.?
Could the top be say 12mm and the bottom 6mm?
What are your thoughts about using cd construction grade ply for the torsion box instead of mdf?

Howdy Bob:) I like 9mm but i find it harder to get for some reason so 6mm both sides more than adequate as its the quality of the ribbibg inside that gives it the strength. The more ribbing the less hollow it appears when tapped. You can get special resin impregnated cardboard but unfortunatly i havnt used it yet, but i hear its fantastic to use. Keep the skin thicknesses the same. A 30mm top with 2 x 6mm skins gives you 15mm ribs which is as thin as you would want to go on a table top for maximun strength. you can go thinner, just increase the amount of ribbing.

And i dont like c/d grade as it has to many hollows through out and it will show up in the surface especialy if you put it in a vacume bag. The only time MDF is any good is for this purpose. Flat, hard surface and easy to glue and cheap:D


If I use handsawn veneers say 2mm thick would you apply it as leaves say 70 to 100 wide or would you suggest gluing them into wide leaves?

I like to saw up out of a 150 board usualy getting 145 out of it, and thickness to 1.5. I glue in to a sheet the traditional way by jointing, then drawing together on the under side with masking tape, then turning over and aplying veneer tape, after that has dried take the masking tape of and presto:D a nice sheet of hand scliced veneer:o :o :o :o love it:o


What traps to watch out for doing this.

Main one is in the construction of the torsion. Iv seen people make the ribbing directly onto one side of the skin, gluing it on as they go:eek: when they finish and glue the other side on, whilst still a torsion, it WILL sag:eek:

For a 1000mm wide table I make the ribbing seprate on a dead flat surface with 8 pine ribbs, 19mm x thickness (thickness = minus the two 6mm skins for overall top thickness) spaced around 119mm apart running length wise. Then cross sections snugly fitted around 200 apart inbetween them. when dry clean up any bumps or lumps as it will show when veneered up, then press on the skins. If their is the slightest twist, bend or whatever in it now it WONT come out after its all glued up, so be carefull-keep it flat.

If you arnt vacuming, glue and press on a skin with weights one side at a time. When dry, trim and square up. Then glue on 10mm edge strips in the same material as the veneer (thicker if you intend routing profiles) ---- all done... time to lay-up the veneer:D


Any recommended books on the subject?

Of hand they dont come to mind, but Neil Erasmus has writen excelent articles in AWR. check em out as he knows his stuff;)


Anything else you can comment on.

Yes, just before glue up have ALL materials you need ready, glue clamps, newspaper, clamps, cauls, waterbottle with glycerine etc, and MOST important, have a cold VB just prior to glue up to settle the nerves.... Happy veneering:D :D :D



Forgot to add.... Veneer the underside same thickness as the top but with some crapier timber.

[Lignum]

Hi Bob,

Thicknesses that I use range from <2mm to 6mm+; I don't see any reason why one couldn't apply the same approach with, say, 10 ~ 12mm "veneers" - Cheers!

Steve trouble is when you go above 2mm the veneer isnt veneer it becomes solid and the movement creates havoc with the joins. Im not saying it wont work, but i wouldnt sleep at night if i sold something to someone with veneer any thicker than 2mm.;)

[Greg Q]

Yes, just before glue up have ALL materials you need ready, glue clamps, newspaper, clamps, cauls, waterbottle with glycerine etc, amd MOST important, have a cold VB just prior to glue up to settle the nerves.... Happy veneering:D :D :D

.[/QUOTE]


Do you use hide glue for this?

Greg

[Lignum]

Yes, just before glue up have ALL materials you need ready, glue clamps, newspaper, clamps, cauls, waterbottle with glycerine etc, amd MOST important, have a cold VB just prior to glue up to settle the nerves.... Happy veneering:D :D :D

.


Do you use hide glue for this?

Greg[/quote]

I use urea with 5-10% pva put on with a squeege just on the substrate, soon as i lay the veneer lightly onto it, i quickly spray the out side of the veneer with water and glycerin to counter the moisture on the glued surface:)

[echnidna]

And i dont like c/d grade as it has to many hollows through out and it will show up in the surface especialy if you put it in a vacume bag. The only time MDF is any good is for this purpose. Flat, hard surface and easy to glue and cheap:D


I thought 2mm veneer would overcome cd face side irregularties even though the back may need any voids patching.

[Lignum]

I thought 2mm veneer would overcome cd face side irregularties even though the back may need any voids patching.

the hollows to watch are internal, surface imperfections arnt so much a problem as they can be filled/ sanded. A vacume will suck down very very hard and when its polished they can show up. Standard .5 veneer is a no go and 2mm Veneer helps, but its not worth it with all the trouble you go to;)

[echnidna]

So it could work ok with a mechanical press instead of a vacuum press?

[Lignum]

So it could work ok with a mechanical press instead of a vacuum press?

Yep i rekon that would be fine. Mechanical or cauls would be ok. Its just habbit i think vacume.

If you ever want to get a great DVD http://www.vacupress.com/videos.htm vacupress has "working in a vacume" FANTASTIC i also have "working with veneer" its an introduction, but if you get working in a vacume it will cover the other. Both cost me $56.75 and was delivered within a week of order from the USA ... Well worth it:D :D :D :D :D

[echnidna]

Is it necessary to veneer both sides of the substrate or is it only necessary to veneer the top and bottom of the torsion box?

[Shedhand]

G'day all
Check out this guys work AND check all the bloody Bessey clamps...lucky bastard.:o
http://www.raygirling.com/sawtable.htm

[Lignum]

Is it necessary to veneer both sides of the substrate or is it only necessary to veneer the top and bottom of the torsion box?Well the "skin" wether its mdf, or ply when put on the ribbed framing needs veneering on top and bottom, good stuff on top not so good on bottom, as long as they are the same thickness. :)

[Greg Q]

[[/quote]

I use urea with 5-10% pva put on with a squeege just on the substrate, soon as i lay the veneer lightly onto it, i quickly spray the out side of the veneer with water and glycerin to counter the moisture on the glued surface:)[/QUOTE]


Thanks, lignum. Is the urea that you use Unibond 800 as in that website you linked? Can this stuff be had locally?

Greg

[Lignum]

[

I use urea with 5-10% pva put on with a squeege just on the substrate, soon as i lay the veneer lightly onto it, i quickly spray the out side of the veneer with water and glycerin to counter the moisture on the glued surface:)[/quote]


Thanks, lignum. Is the urea that you use Unibond 800 as in that website you linked? Can this stuff be had locally?

Greg[/quote]

Greg, i use AV201 from AVSyntec with the liquid hardner and drop in around 10% pva as it gives it more elasticity and a longer open time. In Melbourne get it from them at 30 futura rd Keysbourough --- PH-9798 4944 :)

[Greg Q]

Thanks, Lignum.

I'm going to get some of this and try it on my next project.

I hope to have my vacuum press finished :rolleyes: (started, I meant to say)soon. I'll try a few crapiata panels first, then go to the real thing. This should be fun. Thanks again for the info.

Greg

[Lignum]

Thanks, Lignum.

This should be fun.

Greg

Well people here must get sick of me going on and on about veneering, but it IS FUN

Watching laminations or veneers being sucked down over a curved former creating shapes with such ease is pure joy. It adds such an extra dimention to the craft we all love:o :o :o :o :o :o :o :o :o :o :o

[echnidna]

Well people here must get sick of me going on and on about veneering, but it IS FUN


Well its very good for the forum members that we have so many people highly specialised in various aspects of wood working.
e.g.
Lignum for veneering
Iain and fxst - scrollsaw
Wayne Davey - dust extraction
Derek Cohen - hand tools
- Turning & moderation
Christopha & Journeyman Mick - General
Major Panic & Different - fine stylish furniture
Sturdee the jig man
Rocker the laminator

In fact there are so many skills represented on this forum that its truly impossible to list everyone and their specialities.
I apologise to all of those fine woodies I have left out.

[silentC]

Yes you're right Bob and I just wish I had more time to tap into it.

This veneering thing has me intrigued at the moment. I'm certainly becoming more aware of it and find myself deliberately wondering if a certain piece has been veneered or not.

I'm still not certain I'm ready to leap into it though. Most of the solid wood I use is either found or very cheap - a lot is recycled. If I start making projects by veneering man-made boards, the costs will skyrocket because MDF and ply is way more expensive than what I'm spending now. On the one hand, it would be good to make what I have got stretch further, on the other a lot of things would not get done if I had to buy ply and MDF to make them.

[Lignum]

Yes you're right Bob and I just wish I had more time to tap into it.

This veneering thing has me intrigued at the moment. I'm certainly becoming more aware of it and find myself deliberately wondering if a certain piece has been veneered or not.

I'm still not certain I'm ready to leap into it though. Most of the solid wood I use is either found or very cheap - a lot is recycled. If I start making projects by veneering man-made boards, the costs will skyrocket because MDF and ply is way more expensive than what I'm spending now. On the one hand, it would be good to make what I have got stretch further, on the other a lot of things would not get done if I had to buy ply and MDF to make them.



:D :D :D Go on - jump in i dare yu :D :D :D



Also 3 weeks ago i got half a cube of blackwood for a job. their was one board that had 800mm of the most sensational quilting, absoulutly STUNNING. that is now in my "select" pile that will be sliced for veneer. i can see 4 of the most awsome door panels in the making...... now just have to think of something nice to go around it:rolleyes:

[echnidna]

I've rescued some nice fiddleback messmate from the firewood heap, picked up a couple of nicely figured blackwood and hakea etc logs that will make some nice furniture by veneering.

I'm just wondering where the heck I can put a veneer press in my confined space.

[Lignum]

I've rescued some nice fiddleback messmate from the firewood heap, picked up a couple of nicely figured blackwood and hakea etc logs that will make some nice furniture by veneering.

I'm just wondering where the heck I can put a veneer press in my confined space.

thats the beauty, you dont need space. the gear is easy to store and as long as you have a 2.4 x 1.2 top to lay it up on, bobs ur uncle. that fiddleback messmate would make great panels:D

Cloudmaker sell the litle 1000 x 1300 kit you hook up to your air compressor for just over 400 bucks. cant do table tops but can do every thing else

[echnidna]

I was looking at a s/h vacuum table top last weekend but it was only 1600 x 1100 and not big enough for table tops
Reckon I might have to make a torsion box veneer bench so it can be packed away when not in use. Probably go for mechanical (or pnuematic) operation so I can use cd ply as substrates.

[silentC]

The WorkBench Book (my favourite coffee table book at the moment) has details of a veneering bench. It's basically a flat workbench and a torsion box panel the same size. You sandwich your substrate and veneer between the bench and the panel. You have a heap of plywood cauls as long as the bench is wide which you clamp over the torsion box panel, one clamp on each side. There's a bit more to it than that but that's the gist of it. Obviously only good for flat panels and you need a heap of clamps to use it.

[Clinton1]

Probably me, as I've had to read so much today I'm seeing double
Steve - and your typing has suffered as well.
Should it be "Probably me, as I've had so much red today, I'm seeing double...? :-)

[Lignum]

The WorkBench Book (my favourite coffee table book at the moment) has details of a veneering bench. It's basically a flat workbench and a torsion box panel the same size. You sandwich your substrate and veneer between the bench and the panel. You have a heap of plywood cauls as long as the bench is wide which you clamp over the torsion box panel, one clamp on each side. There's a bit more to it than that but that's the gist of it. Obviously only good for flat panels and you need a heap of clamps to use it.

sounds like a great idea, but once you have used a vacume the thought of using cauls is as apealing as seeing how sharp your saw blade is by putting you finger into it (very popular in Tasmania i hear) When veneering time is crucial.... Vacumes are fast, cauls very slow. And 1600 x 1100 is an odd size but if it was cheap go for it.

If you have a 2.4 x 1.2 bench that is flat, you can use that by having a hole for a inlet and routed grooves for air extraction (a seperate 12mm melamine cover sheet with grooves 4mm deep would be fine) make up a frame that is suspended above it via pulleys, and laying whatever is to be veneered on the table, throw a 30ml vinyl sheet over it and lower the frame over so it goes over the side and is sealed (rubber is good) then clamp it to the bench and turn your vacume on.... Bingo:D Its that simple;)

[echnidna]

Trouble is I just dont have 2.4 x 1.2 space for another bench unless I throw out my near finished cnc router. (this only needs about 3 weeks and it would be going but its been like that for a few years)

I wouldnt go normal cauls I'd use pnuematics - lay flat hose in a channel and blow it up with the compressor

[Lignum]

Trouble is I just dont have 2.4 x 1.2 space for another bench unless I throw out my near finished cnc router. (this only needs about 3 weeks and it would be going but its been like that for a few years)

I wouldnt go normal cauls I'd use pnuematics - lay flat hose in a channel and blow it up with the compressor

Is their anywhere in your house! maybe suspended up in the living room or something. it wont be used all the time so it wont get in the way when the fam are watching telly.

[silentC]

The idea of this bench was that it is your workbench but you can also do veneering on it. Trouble with that is you would have to clean it off first. :p

[Termite]

Trouble with that is you would have to clean it off first. :p

:eek: :eek: :eek:

[echnidna]

So if I decided to build a very big table say 2400 or 3000 by 1200 what is the best way to apply the glue, roller or spraygun. Is there enough time to glue the bottom veneers on and the top ones on in the same gluing process?

The only downside I see about veneered torsion box is construction time.
I used to build a 1800 x 900 solid table in 6 hours plus 2 hours to turn the 4 legs. I reckon the veneered torsion box is going to take 15 to 20 hours.
But I still like the stability issues and lower weight which is important with big tables.

[Auld Bassoon]

Hi Lignum,

I'd agree if it were on a curved surface, but on a flat face, I've had no issues (to date!) with movement, especially as I allow for some movement anyway in the frame.

The little hall table I recently made didn't have any veneer thicker than around 2mm.

Cheers!

[Auld Bassoon]

Steve - and your typing has suffered as well.
Should it be "Probably me, as I've had so much red today, I'm seeing double...? :-)

:D He he, at that time no; later, well ahem!

My typing is always rotten:o

Cheers!

PS I was waiting for that one!