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Discussion Starter #1
I have a couple cedar boxes that have been in use for just under a year. I was cleaning them this weekend because I need to sell them. I was surprised to find them cracked and cupped, rather badly. They have been properly painted on the outside before they were used. The cupping explains why the frames were not sitting properly.

Always thought that cedar is a superior timber for hives, so I’m baffled with this. On the other hand, pine boxes that are now in continuous use for 4 years are still in perfect shape.

I don’t know much about wood, but could this be because the timber was not dried properly at the kiln before manufacture? Or is this a common issue?
 

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Never had a problem with cedar. We have white cedar here which we have used for fence post for as long as I can remember. Not being properly dried would likely do that.
 

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Honeyeater, I can fix all your Flow Hive problems with a single match...:D

Cedar is rot resistant, which makes it ideal for beehives. As far as warping, that has more to do with the growth ring orientation and moisure content at the time of milling.
 

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Discussion Starter #4
I was thinking that myself :)

I didn’t want to mention the brand again...... can’t wait to get them out of my sight to be honest.
 

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look at the cupping, if the "fat side" is the inside then the painted surface is not absorbing moisture and the unpainted is.
If you find this consistent with your cupped boxes, then either paint both sides or do not paint any sides. then moisture uptake and let out should be more or less the same for each side inside and outside.

I use cedar, have some painted and some not painted, mine was only air dried and they seem to be fine. "michigan white cedar"
I use screws and do not glue, FYI , 3 per corner in a medium and 4 in a deep, butt jointed. cedar does seem to strip out easier so I use 3 inch, pre drill the outer board. I like them, as they are a bit lighter than the pine.

JWP I disagree with "moisture content at the time of milling." most wood is milled "green" then either air dried or Kiln dried or both.

I guess if you built them green and painted one side, they could later cup do to different moisture release factors.
Could have been a timber-bined tree , but likely not all the boxes were from 1 tree so If the cupping has the C shape to the outside, it is a paint vrs non paint factor,, moisture absorption factor. try to well dry the boxes Honeyeater if most of the cupping goes away then there you have it.

GG

GG
 

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I would like to see pictures of the distortion and view of the end grain that would show orientation of growth rings. The heart side should not be to the inside. Every example I have seen of splayed out frame rests was the result of this error. Picture below is classic example.

That said, cedar and white pine are usually considered less prone to warping than many others.
 

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GG, I am thinking cut green, stickered, and allowed to dry, then milled (planed). Could be wrong.
 

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GG, I am thinking cut green, stickered, and allowed to dry, then milled (planed). Could be wrong.
been doing it that way for many years. With cedar I would think you could let the log dry for a year then saw. Other species will by then have post beetles.

I have 10,000 feet of white pine I had milled this spring, is now stickered, still deciding if I want to kiln it. The sap would rosin and the bug eggs/larve would be killed, molds as well. But the mold and mushroom thing is showing some benefit so who knows. If I can find a cheap kiln, easy location then I may, else I may not.

I am leaning also to not planning this batch, rough sand with like 80 or 100 grit and let it go. As long as the Inside dimension is held constant via a jig then to me a mil or 2 is not an issue to worry about.

GG
 

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Discussion Starter #9
Ok... I think that this is not even cedar (invoiced as Red Western Cedar). I have another one of these supers and it is waaaaay lighter. This super was already replaced for other defects and I suspect the replacement was Araucaria. Bummer. It also had a layer of mould, while the true cedar one doesn't.

The belly bulge it towards the outside which I think it is odd. Looks like it is getting drier on the inside.

Maybe my quilt box is working too well and is kiln drying the inside of my box :)

I wouldn't worry too much if it was a brood box, but with FlowHive supers, the frames have to sit exactly in place to align with various bits. I tried to raise this on the Flow forum but I have been suspended, they don't like criticism.

 

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Sounds as if the wood was not properly equilibrated before it was milled. Once dried properly and allowed to re-equilibrate to more or less static moisture content it shouldn't move a huge amount. That said, depending on the mill and how it was handled, it might have been pretty wet when milled or stored -- I've seen lumber stored in half sheds open to the rain on windy days too many times.

Usually the bees waterproof the inside of the boxes fairly quickly, certainly by the end of a summer they will have an even coating of propolis and wax, and after a few years it will be a heavy coat. This is why keeping the outside well painted is important -- sealed on one side the wood will gain and lose moisture from the atmosphere only on the unsealed side, and will warp, twist, and split.

As noted, heart side of the wood must face out -- this causes the top and bottom edges to push inward when the wood moves. Other way 'round will open the joints and let water in, prompting rot much faster.

I've found that well made box joints, fully nailed, will give you the strongest boxes with the least movement. A fully nailed box joint is pretty tough -- if you don't believe me, take one up on the roof of the house and fling it into the air. It may distort a little when it hits, but unless the wood actually breaks, it will stay together and very close to square. Rabbet jointed boxes will shatter when they hit. Carefully screwed might be as strong, but screws pull out more easily than nails, especially if turned one turn too many going in -- that strips the wood out of the hole.

Properly dried and milled cedar should last a long time. Big box store pine does fine for me, never had an issue so far, but commercial Ponderosa pine boxes are prone to rot if the box joints are completely glued and painted.
 

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Discussion Starter #11
Thanks for that info. I thought that would be the case.
I was thinking whether the box can be made right but being glued it is very difficult and I’m sure that if I try to put any pressure it will continue to crack.
 
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