What have I done wrong?

[Weekend_Woodworker]

We have had rats in our compost bin, so we had them rebuilt out of concrete blocks with stainless mesh for the floor. I then found they were going over the top, so have built a bifold lid with a wooden frame and some polycarbonate sheeting in the middle. The wood frame is just some decking boards chopped down with a rebate routed in and joined with some dominoes in the corners. I then gave the wood a couple of coats of Cuprinol garden colours which has worked pretty well on other things. However from the photos hopefully you can see that most of the corners are starting to split after a couple of weeks. So the question is what did I do wrong, and more importantly how should I correct it?

 

[Trevanion]

There are a lot of different possibilities, the timber may have been a little high in moisture content when it was made and when it's been put outside in the harsh sunlight it may have reacted adversely. Perhaps cutting the timber from larger pieces of decking boards may have released stresses that manifested slowly, which has caused cracking in the finished piece. The polycarbonate might be a very snug fit in the grooves which when it expands in the sun considerably it is putting a lot of force on the joints.

 

[Cabinetman]

Shame, I think it’s the softwood trying to shrink but the dominos being dry and hard are staying the same size- something had to give!
Without rebuilding it I can’t think of a way around, suggest you just fill and repaint the damage. Ian

 

[Doug]

I’d have thought that the heat from the composting material & the build up of heat through the polycarbon would have played a big part as would the higher moisture level inside the composter.

 

[Mike G]

I think you have nicely illustrated, Steve, that sunlight is a bigger threat to timber than water.

As an aside, you may not have created the best environment for composting. The process needs air to work well. Mesh sides would have been better.

 

[AndyP]

I rely on worms and bugs and creepy crawlies to do the composting of my kitchen waste and some greenery from the garden. These are enclosed dalek type bins with no ventilation but in direct contact with the soil underneath.
I have two large cages for leaf composting which are just fenced on three sides and open to the elements.

Both systems provide good, but different compost. I pee on both systems regularly

 

[RogerS]

.....
Both systems provide good, but different compost. I pee on both systems regularly

You're now officially BFD

Big Friendly Dragon or

Bob FlowerDew :lol:

 

[AndyP]

.....
Both systems provide good, but different compost. I pee on both systems regularly

You're now officially BFD

Big Friendly Dragon or

Bob FlowerDew :lol:

I’ve often thought of trying his “growing spuds in car tyres” technique. :eusa-think:

 

[SamQ aka Ah! Q!]

I pee on both systems regularly

You're now officially BFD

Big Friendly Dragon or

Bob FlowerDew :lol:

Nah, Roger. Andy's in France innit? Clochmerle!!

 

[RogerS]

I pee on both systems regularly

You're now officially BFD

Big Friendly Dragon or

Bob FlowerDew :lol:

Nah, Roger. Andy's in France innit? Clochmerle!!

Mange tout...mange tout.

 

[AJB Temple]

There is no way that rats can be 100% eliminated from a rural garden environment. Probably less so from an urban one.

We use a fully enclosed hot composter for all kitchen waste except oil and bones. It includes any uneaten cooked food - it all goes in, with some torn up cardboard, loo rolls and paper napkins. There is obviously minimal air flow, but it has a small roof vent. It gets very hot and is very fast, also producing literally hundreds of worms. Easy to make one as basically a wheelie bin with a bottom grating and insulated with polystyrene would do the job.

Ours empties from the bottom, so you just take out the fully rotted stuff and the rest drops down. I would expect to get two wheelbarrow loads out of it today.

Everything else apart from perennial weeds goes on the open compost area. As there is no foodstuff there, rats are not interested.

 

[Weekend_Woodworker]

Thanks for all the replies. I looked up the temperature stability of polycarbonate, and for the size I have 10 degrees change in temperature would account for about 0.3mm of movement, so I don’t think that’s the problem. As Ian suggests I think it must be the softwood shrinking, although I didn’t think it was damp when I used it. Clearly I was wrong. I think now I’ll leave it and see how long it lasts and if need be I’ll have to find some better wood and remake them.