Saturday, 23 January 2010
MYOG. Not Quite Sub 150g
I ordered 3mm closed cell foam from Needle Sports to make protective covers/cosies for my sub 200g cooking set-up. The foam arrived yesterday and I started to make the cosies last night.
I had tested different types of adhesive to see what worked best on closed cell foam and found that 'Evo-Stik Impact' was perfect. I measured and marked out the required pieces and set about glueing them. I used a strip of masking tape on the inside of the seam to hold the pieces in position this allowed me to keep the edges aligned but open. I simply put a line of adhesive down the edges, closed them briefly to spread the adhesive to both sides then let the seams stay open for 10 minutes or so before closing the join. As it's an impact adhesive you only get one chance at making the join, as the tape was already in place it was quite easy. I used 8mm closed cell foam for the circular bases but couldn't really allpy the adhesive to both the inside of the cylinder and the edge of the base so I only applied adhesive to the inside of the cylinder, this worked fine but took longer to fully set.
I decided to make the outer cosy 2 piece so cut it in half and added another base. The cosy for the 330ml mug needed to be foldable so once it was glued together I simply cut a cross in the base, this allows me to fold and roll it to store it inside the mug.
I had overlooked one thing when considering the inner cosy, the one I intended to place the pot in once I removed it from the stove. The heat of the pot would melt the closed cell foam so I had to line the inside with aluminium tape which added a bit of weight although it still weighed a little less than the one made from alu bubble wrap.
The complete set of cosies ended up weighing 32g against 53g for the bubble wrap set.
I added a 2mm dyneema cord to the pot to allow me to lift it off the burner by piercing 2 small holes in the rim of the pot but they're slightly too close to the top as the knots prevented the original lid from sealing properly, in addition the small part of the lid that opens fell off leaving too big a vent hole so had to make a new lid by forming a piece of aluminium flashing using jam jar lid and a piece of steel pipe. I drilled a few vents and punched a hole to add a piece of 2mm dyneema as a handle, it's a bit rough but it'll be fine.
The entire set didn't quite make it under 150g so I made a new permanent match using a 1g TN ti tent peg and drilled the handle of my spoon. It wasn't quite enough though, the set weighs in at 149g but adding the stuff sack takes it up to 157g, although not strictly nescessary the stuff sack makes it easier to store.
It isn't without compromise, for example the windshield is shorter than I'd ideally like and as such requires me to use the 5g ti skewer but overall it's pretty light yet still provides me with everything I need. I tried it outside today and using both inner and outer cosies kept the water hot for quite a while. The benefit of having the outer cosy in 2 parts is that each half serves as a bowl/support/insulator for a meal in a ziplock bag. It'll be easy to add more protection/insulation if needed by simply making an additional sleeve to fit over the outer cosy or alternatively by making the outer cosy from 8mm closed cell foam.
I'm going to use this set-up next time out and see how it performs.