Warping

[c00]

I'm having some fairly bad problems with some wood I bought last week.

I'm making a small cabinet, and bought all the wood from Wickes. (Previously I've gone to a timber yard, but the nearest one recently closed down). This was standard PAR pine stuff. Most of the planks (which are either 20mm x 145mm or 20mm x 95mm) have warped, which first became noticeable just one day after getting the wood home.

I checked the stuff in the shop (and put back some planks that already looked bent), so I'm fairly sure that it was okay when I bought it. The wood was in the back of my car for about 4 hours during the afternoon, which was reasonably cold (probably about 3C - 4C I would think), but I didn't really expect that to cause problems.

I've tried to have the wood laying flat in a pile on the floor (although obviously they'd all been stored up on end in the shop) as I had hoped this would help, but it doesn't seem to have.

I'm now having a devil of a job trying to get the cabinet together. Most of the sides/shelves are made from 3 80cm lengths of the 145mm wood glued side to side - as I glued up the planks with the grain in opposite directions, the result is now slightly wavy panels (like this: ~ )

Does anyone have any ideas what could have caused this - could the wood have got cold or absorbed moisture and then warped due to drying out too quickly at home?

I'd be grateful for any opinions on this or advice which could stop it happening again!

 

[masona]

I was in Wickes the other day and saw most of the wood are twisted or warped, I'm afraid most timbers haven't been air-seasoning and this is what you're experiencing because of difference temperature of moisture contents in the wood. They don't have time to air-season anymore as the timbers are shipped in straight away and ready to sell. More information if you do a search on timber air-seasoning. I'm afraid there is not a lot you can do other than to take it back. I always go to timber merchants that sell timbers in open air which minimise the problem.

 

[big-all]

heeelllooo coo

changes in temprature and moisture content will cause distortion just depends on the inbuilt stresses within the wood!!!

you will get this a lot especialy at this time of year
wood from the sheds[wicks b&q ect]is off lower quality
i also dont think it helps that they clingwrap it which traps in moisture

i personaly dont cut wood that has been in store at home for less than a week [or thats the ideal]

somtimes i do for example glue on tops that are wavey onto cabinets because the structure can hold the uneveness in check

if the timber starts to move before you work it[twist or warp]leave it for a few days to settle down

if youve cut it to size and it starts to move before assembly the quicker you finnish assembly the better

if good quality is important go for properly seasoned or kiln dried wood and when youve picked yourself off the floor at the price
just buy 50% more timber from wicks than what you need and select the best bits

 

[c00]

Thanks for the replies big-all and masona.

i personaly dont cut wood that has been in store at home for less than a week [or thats the ideal]

somtimes i do for example glue on tops that are wavey onto cabinets because the structure can hold the uneveness in check

if the timber starts to move before you work it[twist or warp]leave it for a few days to settle down

Big-all, are you saying that it's more prone to warping once it's been cut? (I did most of the cutting on the first night after getting the wood home) - do you think it would have been better to leave it for a week then?

Also, when you talk about letting the wood settle down, should I just leave it stored flat, or would it be better held in some sort of clamp to try to straighten it out?

As I've started assembly, I think I'm going to have to try hammering it into submission and hope that, as you say, the structure will hold it together okay.

To be honest, I had no idea that the wood in Wickes (or any other DIY store) hadn't been properly dried. Do you know if the stuff from a timber yard would have been?

Thanks again.

 

[big-all]

its a slower proccess in a timber yard wood has a chance to settle down its also better quality in general

cutting timber in its self doesnt aggrivate any twisting
its just trying to stop it twisting any more by assembling and trying to stop it mooving further

if a bit off wood is going to warp its going to warp

the tend to convert the timber too soon before its had a chance to settle so any stress will come out later in twisting ect

if your timber is already twisting you are pretty much stuck with it

if you can assemble your work by pulling the wood strait dependent on construction it may be ok or distort the whole thing
you would never put twisted wood into a door for example

 

[carpenter les]

hi ,now you know why MDF is widely used and loved

 

[gord55]

hi ,now you know why MDF is widely used and loved

Hear, hear. Small section softwood is not of the quality to stay flat these days (unless you pay a lot for the best redwood)... wrapping it in film or leaving it on the rack in a timber yard hardly prepares it for a centrally-heated environment! It's always best, but not always possible, to hold it or pull it straight (as big-all said) by screwing cleats (battens) across the backs.
Also, I think leaving it a room to stabilize will do just that - it will stabilize, but not in the shape you wanted!

 

[gord55]

c00 - I see you've used 20mm finish boards. Would it be possible for the jointed panels to be thinner? If so, take them to a joiner with a panel sander and have them sanded flat - if you're lucky you may end up with 15 or 16mm, especially as you jointed them correctly (end grains opposite ways). Guess you may have to redesign your cabinet though...

 

[c00]

Also, I think leaving it a room to stabilize will do just that - it will stabilize, but not in the shape you wanted!

Hmm.... I think you're right there - perhaps I should have designed an oval cabinet instead.....

c00 - I see you've used 20mm finish boards. Would it be possible for the jointed panels to be thinner? If so, take them to a joiner with a panel sander and have them sanded flat - if you're lucky you may end up with 15 or 16mm, especially as you jointed them correctly (end grains opposite ways). Guess you may have to redesign your cabinet though...

Sadly it's too late for that (and I think it might have impacted my budget for the job too much anyway ). I've got as far as getting most of the main structure together (ie the two sides and three shelves). Much muttering and swearing ensued. In places (due to warpage) I've got gaps of up to 2mm between the end of the shelf and the side of the cabinet. It looks like it won't be too bad from the outside though - I'll just have to hope no visitors to the house have cause to look inside the damn thing.

 

[big-all]

another way round the cupping problem is to rip the wider boards down the middle and reassemble with alternating cup up and cup down [as you already do] dont forget each cut will reduce your wood by about 3mm!!!!

or if the top is cupping you run a series of cuts underneath 1 to 2 "apart 3/4depth before assembly stopping short of being visible from the exterior and if your worried about it showing on the inside cover with ply or other material

 

[Ukwoody]

Big-all, just for once for may disagree with you! I was under the impression that cutting the wood, could create a bit more warping, as you're taking the strength out of the remaining (now shorter) grain).
isn't that why if you're in a joinery shop, you have to get really seasoned timber? If you just get standard whitewood/redwood from the merchants and start running it through the old thicknesser etc, it often causes a warp?

When I was at a large hospital, one of the guys got some Maranti in to make a door with. It was fine 'til he cut and planed it, the next day it was like a dogs back leg.

I should at this juncture just say I am not a joiner, and in real terms have very little machine shop experiance, only working in them when I had/have to. I'm just a poor (very poor!) chippy trying to earn a crust to get by on - donations welcome.!

Woody

 

[big-all]

heeelllooo woody

please disagree with me at your pleasure
we are all still learning and i certainly am
i often explain badly but that is probably just my age
not quite sure which point your asking about
if its about the series of cuts underneath i should have said they are along the grain so you are now reducing the surface to about 6mm thick which allows the surface to flatten easier with only the outside edges being stiffer and less easy to flatten

i have actualy had a bit of 10" by 2" i cut 3 x3" strips from it
the next day i had a relativly strait bit a bow and a boomerang from the same piece of wood the tensions in the relevent parts off the wood were amazing you dont normaly expect such differences in one plank of wood but they happen