Beemaster's International Beekeeping Forum

BEEKEEPING LEARNING CENTER => EQUIPMENT USAGE, EXPERIMENTATION, HIVE PLANS, CONSTRUCTION TIPS AND TOOLS => Topic started by: jmblakeney on March 17, 2013, 12:55:59 am

Title: How do you keep plywood tops from warping?
Post by: jmblakeney on March 17, 2013, 12:55:59 am
I have several of the DCoates nuc boxes that have the plywood tops.  Some painted some bare.  I always have problems with the tops warping.  Even some of my 10 frame Langs has 3/4" ply tops and they warp as well.  I have to keep some heavy blocks/bricks on each corner to keep them manageable.  The nucs I have screwed down on each corner to keep them straight but this is not convenient at all. 
What are some of your practices to keep them from warping?

Thanks,
James
Title: Re: How do you keep plywood tops from warping?
Post by: Joe D on March 17, 2013, 11:55:42 am
Mine are treated telescope covers, about forgot, my bee yard is covered so probably no help.  The hives I bought a few years ago had the top nailed down, not nearly as easy to get into though.  Good luck




Joe
Title: Re: How do you keep plywood tops from warping?
Post by: Rex Smith on March 17, 2013, 12:33:45 pm
James - On the lids - do you have a rim that hangs down all around the lid?  I do on my hives as well as on my nucs and that (helps) to prevent warping.  If the lip is only on the front/back, then yes it will definitely warp.  I basically added 1" all the way around to my hive tops and used a piecce of 1" (3/4" - or close) stock/scrap for the lips that offer structural support to the lid.

Delaminating - the only thing I know of to prevent delaminating would be to use an exterior paint on all the edges of the ply.  I (obviously) have not made time to paint mine as yet...

Rex's Lids (http://www.bohemianutopia.com/bees/lids/)
Title: Re: How do you keep plywood tops from warping?
Post by: hardwood on March 17, 2013, 12:55:14 pm
I use 3/4" form plywood (faces are covered with plastic) and don't have a problem with warping. Don't run edging on all 4 sides if you're not using inner covers. You'll have a hard time prying them off the propolis.

Scott
Title: Re: How do you keep plywood tops from warping?
Post by: Rex Smith on March 17, 2013, 01:09:43 pm
Good point, Scott!

My hives in East Tx are in the piney-woods area - and get HEAVILY propolized.  However, my hives in N Texas (North of Dallas) generally have comparatively little propolis that is gathered.
Title: Re: How do you keep plywood tops from warping?
Post by: bailey on March 17, 2013, 02:48:56 pm
I paint both sides of my d coats nucs tops.  It doesn't bother the bees if the are cured well and if it warps I just flip it over.
I also make a few extra tops to replace those that aren't manageable.
Bailey
Title: Re: How do you keep plywood tops from warping?
Post by: Moots on March 17, 2013, 03:09:37 pm
I'm afraid the short answer may be, you don't!  :-D

Although I'm thinking certain things will help postpone it.  My first two Nucs I used either 1/4" or 3/8" plywood and put a support board in both the front and back.  Primed the top and all edges and followed with two coats of exterior latex....and they warped in a matter of weeks.  :(

The ones I've built since then, I've avoided plywood.  However, I'm thinking using a thicker sheet of plywood would certainly help...More layers, less prone to warping.  Along with Bailey's suggestion of painting the inside of the cover, I definitely think that would make a difference.

Lastly, I assume you could run some board supports on the two sides, placing them on top instead of the bottom to avoid not being able to remove the cover.  However, it may look a little strange and you have to ask yourself, how much extra effort is it worth to be able to use plywood?
Title: Re: How do you keep plywood tops from warping?
Post by: jmblakeney on March 17, 2013, 08:42:13 pm
Thanks all.  I do have a rim on the front and back but not on the sides.  Mainly because I like to overwinter nucs with their sides touching and a rail on the sides would allow a space in between them.  I suppose I could put them on the top for a trial run. 
I have not tried painting them on the underside in addition to the top side.  May give that a try as well.

James
Title: Re: How do you keep plywood tops from warping?
Post by: AllenF on March 17, 2013, 09:06:29 pm
My tops I made for dcoats nucs are made out of scrap 3/4 plywood.   I salvaged a bit of it out of it out of an office one day.   It was painted up thick on both sides already.   I put front and rears on the tops out of the scrap 3/4 also.   Not much warping out of these.   
Title: Re: How do you keep plywood tops from warping?
Post by: specialkayme on March 18, 2013, 08:42:45 am
I must be lucky, as I don't have issues with warping on plywood (much, at least).

I use plywood for inner covers, telescoping covers, migratory covers, solid bottom boards, and D coates nucs. I make sure to cover all of the edges (when possible) with pine wood, securing it with a liberal amount of Tightbond III glue. Then I make sure I cover all exterior edges (and usually a little bit on the inside edges) with two coats of very nice, exterior, durable latex paint. I prefer Sherwin Williams' Duration. It's significantly more expensive than "oops" paint, but you can find it on sale for 50% off or more. At that price, it still isn't cheap, but it's worth every penny in my opinion. I can get 2x or 3x the life out of a piece of equipment with that paint as opposed to the cheapo stuff. Considering that cheap paint will run you about $15 a gallon, if this stuff is $50 a gallon, and I can coat about 24 bottom boards with a gallon, and each bottom board costs me about $8, and with cheapo paint I can get 5 years out of it, and with good paint I can get 10 years out of it, by spending the extra $35 on paint I save $192.

Sorry for the rambling.

But I had a DCoates nuc that I left outside year round in a damp area with extra shade for 14 months now, and it hasnt shown any signs of warping yet.
Title: Re: How do you keep plywood tops from warping?
Post by: Michael Bush on March 18, 2013, 11:31:51 am
I boil mine in beeswax and rosin.  But dipping in paint would help... or painting on both sides to equalize the absorption so the top isn't absorbing more water than the bottom and in dry weather, vice a versa.
 
Title: Re: How do you keep plywood tops from warping?
Post by: JPBEEGETTER on March 18, 2013, 04:39:33 pm
I use inner covers banded with cypress, slotted 1/4" groove 1/2" deep 3/4 x 1 1/2" with 1/4" plywood in center.. Telescoping cover -cypress rim 3/4 X 2" ,top is 1/4" plywood covered with alumn. flashing cover.. no warping,  no moisture.. little more trouble but worth it to me... JPP
Title: Re: How do you keep plywood tops from warping?
Post by: Moots on March 18, 2013, 04:56:17 pm
I use inner covers banded with cypress, slotted 1/4" groove 1/2" deep 3/4 x 1 1/2" with 1/4" plywood in center.. Telescoping cover -cypress rim 3/4 X 2" ,top is 1/4" plywood covered with alumn. flashing cover.. no warping,  no moisture.. little more trouble but worth it to me... JPP

I'm pretty sure you must be talking about your hives and not Nuc boxes here???  :?
Title: Re: How do you keep plywood tops from warping?
Post by: JPBEEGETTER on March 18, 2013, 04:59:45 pm
 ;)On nucs  I use 1 piece 3/4" pine, or cypress. no plywood, now on swarm traps plywood is ok because don't stay out long on a tree..
Title: Re: How do you keep plywood tops from warping?
Post by: capt44 on March 25, 2013, 12:20:25 pm
Building my tops I use frame boards 3/4x3inches then put 3/8 plywood on top of that.
I glue and nail all pieces.
I then use aluminum flashing for a cover with 1/2 inch overlap on each side.
When I paint the top I turn it upside down and use a good exterior latex paint letting it run under the flanges on each side.
So far mine are not warping, some have been out there 4 years now.
Title: Re: How do you keep plywood tops from warping?
Post by: Moots on March 25, 2013, 12:33:02 pm
Building my tops I use frame boards 3/4x3inches then put 3/8 plywood on top of that.
I glue and nail all pieces.
I then use aluminum flashing for a cover with 1/2 inch overlap on each side.
When I paint the top I turn it upside down and use a good exterior latex paint letting it run under the flanges on each side.
So far mine are not warping, some have been out there 4 years now.

Capt.
Sounds like you're describing a telescoping top for a regular hive, I think the OP was specifically asking about Nuc tops.
Title: Re: How do you keep plywood tops from warping?
Post by: gov1623 on March 25, 2013, 11:36:05 pm
on my plywood nucs i glue and nail a 2 x 3/4'' strip of pine in the middle from front to back on the top of the lid. This stops them from curling up.
Title: Re: How do you keep plywood tops from warping?
Post by: Michael Bush on March 26, 2013, 10:54:36 am
Lots of bricks helps... Pile them up on any corner that is curling up, or in the middle if it is bulging...
Title: Re: How do you keep plywood tops from warping?
Post by: gefdef on March 27, 2013, 09:32:09 am
I don't have plywood. I use polystyrene sandwich ( as used in cool rooms) for lids.  would also help you with winter insulation.  I make a ventilation frame to go under the lid.

Title: Re: How do you keep plywood tops from warping?
Post by: JPBEEGETTER on July 08, 2013, 12:11:58 pm
How do you keep your tops from warping ?  Don't use plywood...
Title: Re: How do you keep plywood tops from warping?
Post by: cbinstrasburg on August 13, 2013, 12:52:45 am
I have come across a sheet of 1" and 1 1/2" styrofoam with a foil backing...could this be used for a hive cover with an upper entrance and inter cover?
thanks
Title: Re: How do you keep plywood tops from warping?
Post by: BlueBee on August 13, 2013, 01:58:16 am
Plywood = warp due to unequal stresses in the wood layer sandwich. 
OSB = less warp due to random orientation of stresses, but it falls apart after too much fun in the sun.
Polystyrene = works great as long as the ants don’t find it.

Most of my hive tops are polystyrene.  However you still need something under those tops or the bees will try to glue the poly tops down to the hive body.  I use a sheet of plastic (like 3mil stuff) for my inner covers.  Bees propolis doesn’t stick to polyethylene.  Polystyrene also lacks protection from UV.  It needs to be painted/coated with something or else the UV will turn about 4mm of it to dust every year until it is all gone.
Title: Re: How do you keep plywood tops from warping?
Post by: Santa Caras on August 13, 2013, 11:25:37 am
I think one of the joys of beekeeping is the woodworking that is required. I'm learning that bee's really LIKE wood and all the componets that go along with that. If plywood is used with the pine framing, with the correct joints and glue, painted and protected from the elements (mainly moisture) then even 1/4 will lay straight and last for years. yes...I even like telescoping covers for a nuc......protects it and you can use it over and over for many years.  While I dont have many beehives, I've built many other things over the years thats sitting outside and if done right.....they last. Of course I'm not building hundreds of these so I dont have that worry.
Title: Re: How do you keep plywood tops from warping?
Post by: capt44 on August 13, 2013, 05:18:40 pm
On my Nuc Hive tops I use aluminum flashing just as I would for a telescoping top for a regular hive.