Invent Design Make

Step 14 – Going Composite & Adding Insulation

Ok this is where things get even more unusual.  Using the drill again we make a whole series of holes along the length of the outer door frames and fill them with recycled ground cork.  These parts of the doors are the thickest bits, so will be the heaviest and most prone to letting through the heat.

To make them nice and insulated, without unduly weakening them, the holes are not made in a continuous line, but a series of staggered lines.  This way, for the heat to escape, it has to travel a long wiggly path around the cork sections.

As you can (just about) see, by marking up carefully beforehand we can make sure that we don’t drill into any bits that are required to mount door hardware.

Drilling such large holes is MUCH more effective with vacuum extraction. It prevents the holes from clogging and keeps the bit much cooler (and thus it stays sharper).

My dad rescued this industrial grater from the landfill and I use it to grind up some wine bottle corks – I have collected quite a few.

Assemble the insulation ingredients: PVA and the fruits of the grater.

I nearly fill each hole, and then put a good bit of PVA on top.

I then push on some more ground cork and wait for the glue to dry.

Upturned, the loose cork falls off and is collected up.

Any protruding bits sanded off (I did use the dust extractor with this – a staged photo I am afraid).

For big glue-ups like this, I assemble all the little bits (to spread the clamping loads) ready (you can see them on the left). Time to glue it to the door – quite a major glue-up.

On the last one I found myself struggling against the clock, and fiddling trying to get it straight. So for this one I used biscuits to help with alignment. Put little or no glue on the biscuits here, or they will swell up and split the wood (as I discovered on one section – luckily I could put it right quite easily).  Here’s the final view of some nice looking (to me at least) joints.

Clamps in full affect – glue my pretties! Glue!

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