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Forum topic by fiddlebanshee posted 05-03-2010 03:26 PM 1373 views 0 times favorited 19 replies Add to Favorites Watch
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fiddlebanshee

195 posts in 2411 days


05-03-2010 03:26 PM

Topic tags/keywords: question warped wood mitered frame

I just signed up for LJ but have been reading the forums for a while. I am just getting started with woodworking and my first project is to remodel a shed into a chicken coop. The first task, while I am waiting for delivery of the shed, was to make 4 windows with plexiglass to give the chickens some light and ventilation.

I have a sliding compound mitersaw (Makita 10”), so I cut all the frame pieces out of 1×3 pine to the exact dimensions (or so I figured). I had plexiglass rectangles that are the standard 11×14”. I also have a router (milwaukee, 1.75 hp) that I used for the first time, to cut grooves in the inside of the frames to receive the plexiglass. So far so good, I could’ve done a better job of the routing. I don’t have a router table so I did this handheld and didn’t hold the router perfectly horizontal, so there was considerable burning (to the extent that. even though I was outside but near to the door, that the fire alarm went off. But that’s a lesson learned and I should next time either make a jig to keep the thing horizontal or to invest in a router table. This was not the real issue. This was:

I assembled the frames with a kreg pockethole jig set. This worked fine once I found out how far away from the joint to position the jig. I assembled everything, put some silicone in the grooves to hold the plexiglass and to shield that from the weather. THen I let them stand vertically overnight. I had not noticed anything wrong with them so far. THey were square (as in the diagonals matched) so I was happy.

So here’s what then happened and what concerns me:

Next day I lay them flat on my workbench to sand and prime them for painting. Two of them will not lay flat, one corner will come up from the worksurface by about a quarter inch. What caused this to happen? Was this there already yesterday and I just didn’t notice, being so focused on getting them square on the diagonals? Did something warp overnight, and if yes, what could I have done to prevent this? Is there anything I can do about it to correct this?

By the way, since I don’t think the chickens will mind a bit of extra ventilation I’m not overly concerned for this particular project, but I want to know what happened so that I can learn and prevent this in the future.

Your insights are appreciated.

-- As if I needed another hobby!


19 replies so far

View Mark Shymanski's profile

Mark Shymanski

5314 posts in 3178 days


#1 posted 05-03-2010 03:48 PM

My guess would be that the pine moved over night, especially since you’d just cut the material and then assembled it into your frame. Pine will warp or twist quite a bit as it dries, or as internal stresses are relieved as when you cut it. You probably got a bit of both happening as the interior wood may be moister than the exterior and a fresh cut will allow this to dry, and of course with a fresh cut the stresses are relieved as well, changing the shape.

What you can do to minimize this is to cut your wood a bit oversize on the initial cuts, let them sit for a while to acclimatize/dry/de-stress and then mill them to final dimension.

Welcome to Lumberjocks!

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

View PurpLev's profile

PurpLev

8523 posts in 3114 days


#2 posted 05-03-2010 03:54 PM

1.were the frames glued? or only screwed together with the pocketholes?

2.assuming it was glued – were the frames left over night to dry with clamps to keep them square? or did you only rely on the pocket screws to hold it together?

3. pictures might help

my guess is that your mitersaw is not setup perfectly, or the parts werent held properly which caused the cuts to be off from a perfect 90 degree angle, and overnight they slipped off from the square position you put them. but that is just a guess. take a 1×3 board, cut it in the middle on your MS, place both pieces on the workbench, and flip one top to bottom so that the cut is not reversed between the parts – and put them back together. if the MS is tuned well, those 2 parts will mate perfectly into a straight board (although cut in half) but if not, you’ll see it fairly easily.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View fiddlebanshee's profile

fiddlebanshee

195 posts in 2411 days


#3 posted 05-03-2010 04:00 PM

PurpLev,

The frames were only screwed together, not glued, because I had the silicone in there already. The miters were perfect, I don’t think I can blame it on the saw. The warping that occurred was not that the frame is no longer square, the diagonals are still identical, and the miters meet each other perfectly. The warping occurred in the vertical dimension if you understand what I’m saying. So it twisted rather than went out of square.

If I clamp it to another perfectly flat surface for a couple of days, would that twist it back?

-- As if I needed another hobby!

View David "Lucky Dawg" Brown's profile

David "Lucky Dawg" Brown

440 posts in 2457 days


#4 posted 05-03-2010 04:08 PM

Sounds like a moisture problem!
What mark said is true!
When I use pine I buy what I need and let it sit
i my shop a couple days before I cut it up!
The humidity of a temperature controlled store
or a outdoor lumberyard is not the same as my
tin barn shop.

-- dumpster diver delux

View Gene Howe's profile

Gene Howe

8256 posts in 2894 days


#5 posted 05-03-2010 04:11 PM

Mark is right on, IMO. Are these opening windows? if not, you’d probably be OK in setting them in place and forcing them plumb as you fasten them into the openings.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View PurpLev's profile

PurpLev

8523 posts in 3114 days


#6 posted 05-03-2010 04:11 PM

I understand the twist. and I was referring to the miter cutting the lumber at a slight bevel – since those are miter cuts which are obviously not cut at 90 to the long grain.

unless you are going to glue the frames, clamping them down for a couple of days won’t make much of a difference, since the moment you’ll release the clamps, the screwed construction will just follow the cut ends and will retwist back into it’s old self again.

my recommendation – check the cut as I suggested. you may or may not find the culprit to this issue is indeed related to the saw – maybe not- but my point is- this is an easy thing to check, and will affect all future cuts.

after that – dissassemble frames. glue the joints. screw them back together, and clamp to a flat surface- let dry for a day.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View NewPickeringWdWrkr's profile

NewPickeringWdWrkr

338 posts in 2478 days


#7 posted 05-03-2010 04:12 PM

yeah, unless pine is thoroughly dried, it will move and quickly. I had some 2×4’s in my shop for almost a year and used one to make a very simple mitre key jig. Basically a single piece of 2×4 surfaced on 3 sides with a 2.5” deep notch. I then cut a groove down the length for the table saw blade to slide through. In 1 day only, the pine moved clamping the blade groove closed. Turned it into a throw away.

-- Mike - Antero's Urban Wood Designs http://anterosurbanwooddesigns.com

View fiddlebanshee's profile

fiddlebanshee

195 posts in 2411 days


#8 posted 05-03-2010 04:16 PM

They are designed to be opened, with hinges at the top (like a hopper window) and some sort of stick propping them up. Then when I close them I’ll have to come up with some sort of closing device, perhaps at both lower corners to keep them closed tight. I’ll have hardware cloth in the opening in the wall so I’m not so concerned about raccoons and other critters trying to get in.

I had had the pine for a while basically sitting in an unairconditioned shed. The day I cut the lumber the air humidity levels changed dramatically (it got really hot and humid here in VA over the weekend) so that might have played a role in this too, and perhaps what Mark mentioned that the stresses in the wood got relieved by cutting them.

-- As if I needed another hobby!

View PurpLev's profile

PurpLev

8523 posts in 3114 days


#9 posted 05-03-2010 04:17 PM

disclaimer – I haven’t worked often with pine, and was not aware it can move this much this fast. so based on other’s input here -this may be a very highly possibility.

regardless – checking the MS for square (non beveled) cuts is an easy test to run. worth the while. :)

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View fiddlebanshee's profile

fiddlebanshee

195 posts in 2411 days


#10 posted 05-03-2010 04:20 PM

PurpleLev,

Good suggestions. I hadn’t thought about the bevel. I still think they butted together good, but I’ll check. I’m not sure I will go through the trouble of un-assembling them at this point, as I (and the chickens) can live with the results, but I’ll make sure to check next time when I make the frames for the ventilation openings (which are going to be screwed directly to the panel of T1-11 siding that I will cut out of the wall, and they are also hinged so that I can open and close them.

Thanks everyone for your suggestions.

-- As if I needed another hobby!

View mrg's profile

mrg

659 posts in 2464 days


#11 posted 05-03-2010 04:22 PM

The problem may have occurred from the drastic swing in temperature hear on the the east coast. If I read the post correctly the windows had been built outside and assembled, then stood vertical overnight. Change of temperature, hot to cold change in humidity caused the wood to swell and twist. You may try laying them on a flat surface face or back down and taking a heavy object and laying it on top to flatten.

PurpLev beat me to the solution.

-- mrg

View Gregn's profile

Gregn

1642 posts in 2448 days


#12 posted 05-04-2010 05:17 AM

Pine can be finicky and should have time to accumulate before use. Pine is harvested quickly today and drying times are often rushed whether its air or kiln drying. You don’t even have to cut pine for it to move. I have bought pine lumber straight as the day is long. To only go out to the shop in the morning to find it warped and twisted. I tend to buy my lumber from the local lumber yard over the big box stores. Your local yard can give you more information about their lumber than a big box store will. For this purpose your right the chickens won’t know the difference. If you plan to use pine for projects you might want to get a moisture meter to check before purchasing. For pine you want the reading to be from 6-8% leaning closest to the 6% mark when ever possible and then let it accumulate to your shop for a couple of weeks before use, as you should with any lumber you bring into the shop. I hope this helps to understand wood movement a little bit.

-- I don't make mistakes, I have great learning lessons, Greg

View woodnewbee's profile

woodnewbee

76 posts in 2571 days


#13 posted 05-04-2010 05:45 AM

had a time like that as well with a shadow box of pine. finally used buscuits to hold miters where I wanted them. Also made a silverware box with my son as a 4-H project that acts as a hygrometor. When the humidity rises the corners of the lid rise, when it dries down they lay back flat.
Have windows on garden shed that the trim moves around as well.

View EZzinger's profile

EZzinger

8 posts in 2413 days


#14 posted 05-04-2010 07:00 AM

This is just your first learning experience in examination and judging the quality and condition of your lumber supply. You need to learn to study the grain at both ends of each piece to be used, and when cut & assembled, clamp them in a stack to a very sturdy & flat surface to allow cure time. When you release the clamping & they remain reasonably flat, then you need to seal all surfaces as soon as possible to maintain the resisdual moisture level. Then they will usually cure long term installed and hold their shape if your wood has reasonable quality. Visit as many local suppliers as you can find time and examine their inventory so you will be better prepared in the future. You will also need to study the use of appropriate materials for each job.

View fiddlebanshee's profile

fiddlebanshee

195 posts in 2411 days


#15 posted 05-05-2010 01:41 AM

Thanks to all for the comments and thoughts. I think the most likely thing is a combination of operator error (me, the pocketscrews and the mitersaw) and the sudden humidity change. The humidity has gone down today and two most pronounced victims were a bit more straight this evening when I gave them their second coat of kilz, so I’m almost sure that it does have to do with humidity. And since these suckers are going to be outside—well, me and the chickens, we’ll have to live with it.

I’m thinking of some kind of a rail (like a 2×4 or a 1×4) that would sit at each end of the row of windows in a bracket and slide over the bottomframe of the windows in the winter to keep them tightly closed, with some weatherstripping between the siding and the window edge. They will be hinged at the top. In the summer they’ll be open anyway, so then I don’t care what the wood does. Eventually if this gets worse and I can’t close them anymore, the worst that can happen is that I’ll have to make new ones.

-- As if I needed another hobby!

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