|
|
Post by karatestu on Jan 23, 2021 15:32:59 GMT
Searching the back of a barn I found these "boozing tables" made in the early 1930's. They are made of some lovely solid oak. They are perfect to build my speakers "into" if you know what I mean. I was going to use the tongue and groove boards that made the table tops to fill in the four sides as far as the leg cross braces. Then fit a top and bottom baffle for my up and down firing mid bass. Will oak this old still expand and contract across the grain with change in humidity ? If it does then I can see a problem with cracking and bending as if the woòd is tight jointed and glued then it has nowhere to go. I can't make it loose jointed as it won't be sturdy, will rattle and won't be air tight. Are there any ways around this ? If not I will have to go to plan B which is use the oak legs and do the rest in birch ply which does not move. I would keep the splayed nature of the legs. Many thanks in advance.       |
|
|
|
Post by MikeMusic on Jan 23, 2021 15:51:47 GMT
Good question.
I'd like to know too !
|
|
|
|
Post by speedysteve on Jan 23, 2021 16:11:38 GMT
If they have been stored in a dry place they will be fine.
If they are wet or damp then you want to let them dry slowly.
Bringing them in from a damp shed to modern centrally heated home could cause warping etc.
If wet/damp Wrap in polythene not too tight with a few pencil size airholes to breathe and see how things look after a couple of weeks.
That gives a controlled moisture reduction over some time.
Oak is pretty good at ageing. We have 300yr old beams in our cottage (new build 2015) no problems!
My ebony importer gets in 'wet' fresh ebony from Africa, 1", 2" and 3" thick planks, all wax sealed!
The rule is 1yr to dry for every 1" thick!
You remove some of the wax and let it dry slowly.
Hope that helps.
|
|
|
|
Post by petea on Jan 23, 2021 16:13:33 GMT
If the room is dryer than the barn then it is likely to shrink even though old. This will be more so in the transverse section than the length though and so the distance between the legs will only change minimally. You could allow it to acclimate in the room for a month before starting the build and maybe use oak veneered particle-board for the infills rather than T&G board (which would probably have to be loose to prevent splits). One of my hobbies was cabinet making for many years (until I ran out of things to build!) and I built a kitchen and several bits of furniture from old 1930s oak wardrobes (I still have some on the rack in the workshop!). And the missus is a timber technologist working for the German Federal Testing Institute! Nice tables though!  |
|
|
|
Post by ant on Jan 23, 2021 16:15:37 GMT
The oak will be fine, the top if softwood will keep expanding and contracting for years after it is cut, personally i would use ply its much more stable.
Id be tempted to dismantle the frame, rout a groove in the faces of the legs where the ply needs to go, glue and clamp the structure, sans the top or bottom, and when dry use some sealant or decorators caulk on the inside of the joints. That way if it does crack its joints for some reason it will stay sealed.
Put the top or base on with screws and a gasket made of rubber. Epdm pond liner is good for this, or flat rubber strips, when you screw it down it will crush the rubber somewhat and force it into any voids to make it airtight
|
|
|
|
Post by petea on Jan 23, 2021 16:19:34 GMT
I live in a C17 cottage in the UK and cracks in the beams and some gaps in joints increased markedly after central heating was installed. Nothing structurally threatening, but even quite old oak can change dimensionally as its moisture content changes and certainly better shrinking than expanding!
What do you use the Ebony for, Steve?
|
|
|
|
Post by karatestu on Jan 23, 2021 16:23:32 GMT
If they have been stored in a dry place they will be fine. If they are wet or damp then you want to let them dry slowly. Bringing them in from a damp shed to modern centrally heated home could cause warping etc. If wet/damp Wrap in polythene not too tight with a few pencil size airholes to breathe and see how things look after a couple of weeks. That gives a controlled moisture reduction over some time. Oak is pretty good at ageing. We have 300yr old beams in our cottage (new build 2015) no problems! My ebony importer gets in 'wet' fresh ebony from Africa, 1", 2" and 3" thick planks, all wax sealed! The rule is 1yr to dry for every 1" thick! You remove some of the wax and let it dry slowly. Hope that helps. Thanks for the help Steve. They have not gotten wet at any point but the agricultural shed is damp like any unheated outdoor building and they have been in there over 30 years. I will try and dry them slowly. |
|
|
|
Post by karatestu on Jan 23, 2021 16:31:20 GMT
If the room is dryer than the barn then it is likely to shrink even though old. This will be more so in the transverse section than the length though and so the distance between the legs will only change minimally. You could allow it to acclimate in the room for a month before starting the build and maybe use oak veneered particle-board for the infills rather than T&G board (which would probably have to be loose to prevent splits). One of my hobbies was cabinet making for many years (until I ran out of things to build!) and I built a kitchen and several bits of furniture from old 1930s oak wardrobes (I still have some on the rack in the workshop!). And the missus is a timber technologist working for the German Federal Testing Institute! Nice tables though! Thanks Pete, Yes the room will be central heated and much dryer. I wasn't actually going to use the tongue and groove parts - they would be cut off. As they are the T&G boards are slightly warped. I read that they can be straightened by use of a wet towel on one side and a hot iron on the other (along with a bit of pressure added). I wanted to try and use as much of the original wood as possible, mainly for keeping it original but also for cost savings and I like recycling. I am open to alternatives if I have to, such as baltic birch ply. |
|
|
|
Post by karatestu on Jan 23, 2021 16:40:49 GMT
The oak will be fine, the top if softwood will keep expanding and contracting for years after it is cut, personally i would use ply its much more stable. Id be tempted to dismantle the frame, rout a groove in the faces of the legs where the ply needs to go, glue and clamp the structure, sans the top or bottom, and when dry use some sealant or decorators caulk on the inside of the joints. That way if it does crack its joints for some reason it will stay sealed. Put the top or base on with screws and a gasket made of rubber. Epdm pond liner is good for this, or flat rubber strips, when you screw it down it will crush the rubber somewhat and force it into any voids to make it airtight Hi Ant,thanks for the advice. I wasn't intending to use any softwood at all. The original plan was to do as you suggest and continue the groove that ìs in the legs already to the depth I need and use the oak T&G cut to size and the tongue and groove bits cut off. They are 20 mmboards the same as the pieces that join the legs together. Good tip about the epdm pond liner, thanks. Question to all- If using Oak boards do you think I can stop the movement by gluing the oak to a sheet of 3 mm mild stee or aluminum, or will that make thing worse ? |
|
|
|
Post by petea on Jan 23, 2021 17:00:07 GMT
Depends in part on how strong the bond is. You could still see the wood splitting if movement occurred. A thin oak panel fixed to the steel with a flexible adhesive?
|
|
|
|
Post by ant on Jan 23, 2021 17:27:27 GMT
|
|
|
|
Post by ChrisB on Jan 23, 2021 18:42:13 GMT
Handheld moisture meters are notoriously inaccurate. The only way of reliably testing wood is to stick bits of it in a bomb calorimeter.
12% moisture content is not attainable by air drying - you have to put it in a kiln to get it below ~17%.
Once it's been kiln dried as low as that, the MC will then rise until it reaches equilibrium with the atmosphere it is stored in.
|
|
|
|
Post by ChrisB on Jan 23, 2021 18:46:56 GMT
If you're going to use steel, then why not make the cabinet airtight with that and stick the oak on top as a cosmetic skin? Cut the edges of the boards at an angle and glue them to the steel, but not to each other. That way they can overlap, but not touch & they can breathe a little.
|
|
|
|
Post by ant on Jan 23, 2021 19:19:30 GMT
Yes i know they are pretty inaccurate, but its adequete as a guide. its just something ive always done with this meter when i use old reclaimed wood
If ive bought new stuff i dont bother, i just leave it stood for a week or so before i use it
|
|
|
|
Post by Slinger on Jan 23, 2021 21:11:45 GMT
Amazing. The stuff you learn on hi fi forums, eh?  |
|
|
|
Post by karatestu on Jan 23, 2021 21:19:09 GMT
Aren't you in bed yet Paul ?
|
|
|
|
Post by Slinger on Jan 23, 2021 21:22:30 GMT
I get to stay up late on Saturdays, Stu.  |
|
