My recent project to build a cold frame. Ordered the aluminium cold frame and then started thinking about how and where it was going to go. I could have just placed it directly on the floor and it would be done in a day, but disadvantages are; being low down, it inevitably gets shaded by something, it gets splashed by rain bouncing off the floor, it’s a pain bending down to look into it and not easliy accessible. Also, raising it, allows the area underneath to be used for overwintering plants and keeping them dry. Raising it up is where all the work and fun begins.
To increase the interior height, I ordered 3 levels of a raised bed. These come with 6 pieces of wood to make the construction. I had to discard these and made my own long ones to elevate the frame. I had 50mm square machined down and then screwed on 35mm square to make a section for the floor to sit on. At the bottom of the legs, I screwed in 6" hot dipped special galvanised bolts to make adjustable feet, screwed in coated with silicone grease.
Construction of the raised bed wood and legs proved very tricky, as getting everything level, straight and square when you have no starting point is fun. The answer is to do every stage slowly, methodically and check at every tightening.
Stainless screws screws used throughout the whole project and this is where using No.12 instead of the usual No.10 helps. They grip better and the head is more firm on the surface.
Every joints had to be absolutely perfect. If it was 1mm out, I’d plane down or reject the piece and cut it again. I didn’t want any piece pulling in or forcing out the construction.
The distance between the cross struts needs to be this, as even 19mm ply sags if the gap was much larger.
All the wood used in the project has been treated with 3 coats of Ronseal multipurpose wood treatment, with all ends being soaked for 3 hours each. Then follwed by 4 coats of clear Barrettine decking oil.
Level, level and level again and make all feet have the same pressure.
Fitted auto louvre. Polished the aluminium and wiped every piece with camellia oil.
Made these end pieces to cover water ingression and it looks prettier. Ribbed wood gives nice finishing touch.
The floor is marine grade 19mm ply treated with Ronseal multipurpose wood treatment followed by 2-part flexible epoxy boat paint. This was trickier than I had imagined. Once mixed, you have about 30 mins to apply, but as it’s very thick, it’s a slow process and difficult. It’s literally like painting on Araldite. Then it takes days to dry properly on the surface, so you have a 6’x4’ sheet of plywood that you can’t touch and need to keep dry, upright and dust free. Pain.
Added strengthening struts. The whole structure doesn’t move at all when pushed.
Added draught excluder underneath
…and made aluminium angle brackets to add excluder inside at the frame junction. All bolted on in case need to remove.
…and between glass using 9mm siliconised fibres on the best 3M 9448 Adhesive backing.
Added velour to the glass partitions to stop scratching each other when they slide.
Painted piston white to improve temperature measurement on the auto louvre.
Putting a circulation fan inside. Tried another fan that got good reviews and it was absolute junk. That’s reviews for you. This Blauberg has been excellent up to now. Cut some pvc tube and made this rivetted aluminium bracket to house it.
The fan is plugged into a wifi plug device that allows me to adjust the speed from my phone in 1 % increments. This is great to adjust the ideal amount of breeze.
Made this polystyrene housing for the temp/humidity guage. It connects via wifi to my phone and is set to alert me if temp goes over 35c and also allows me to follow the stats on a graph.
It’s all to house a collection of rare carnivorous plants. The machining of the wood legs at the start, allows 6 x 24" square trays to be fitted to within a few mm. I changed the aluminium shelf brackets by making deeper ones. This makes the shelf slighly more rigid.
Finished.
Good opportunity to take a break now. We’ll all recommence in 45 mins for a question/answers session.
