Material Science

My new isopropyl alcohol sanitiser arrived last week and I've been playing with resin again, but in controlled conditions so as to see whether the allergy returns. I didn't use gloves, but minimised touching any of the resin. I did, however, use the hand sanitiser liberally on my hands, which did cause a flare up around the eyes, which I cut short with antihistamines.

It would appear that I've developed an allergy to isopropyl alcohol - an allergy which was not there before. I found a paper on it here. Apparently it's possible to develop an allergy to something you've used all your life.

There are 2 solutions - either wear gloves and avoid needing to use isopropyl alcohol at all, or switch to acetone (nail varnish remover) to dissolve the resin on my hands. Knowing my luck, I would probably develop a reaction to acetone. Gloves seem to best solution, but what a thing to become allergic to in a pandemic!

My sister-in-law, on seeing the lamps I made, asked me to make a couple for her in the cheetah print material. I dug out the remnants of cheetah print I had and started to cut out two 55cm squares, but there wasn't enough material. This got me to thinking about a more efficient use of cloth by adapting the size of the squares to the standard size of bolts of cloth. 

It turns out that thinner, cotton-based cloth comes in bolts of 1.10m width (1.09m when measuring to the pattern, as there's usually a white border). 55cm squares are not the most efficient use of the material, when allowing for a fudge factor. A better size is 50cm x 50cm, which allows me to buy 1.5m of cloth and guarantee to get 4 squares from it. 

I also investigated a new technique to prevent me getting loads of resin on my hands and therefore having to use vast quantities of sanitiser. This involved clingfilm under and on top of the resined cloth and allowing it to fully cure before  removing the clingfilm and draping the cloth over the silicone former with the aid of a heat gun. 

The cat in the background is not ours, but one of the interlopers that take advantage of our underfloor heating.

The experiment didn't work so well, as it proved impossible to remove the clingfilm from parts of the resined sheet - it tears too easily. What's needed is a couple of silicone squares, about 1mm thick, from which the cloth can be more easily peeled. 

Additionally, it's difficult getting heat into the sheet when fully cured, so it doesn't drape well at all and the chance of creases increase. You need something like 10 hands to keep one side draped while trying to drape the other side. The cloth has to be very pliable when placed on the former so it falls correctly, which means semi-cured, despite that meaning there's a large risk of the folds sticking to themselves and me having to intervene manually at various stages of curing to unstick them.

Stop Press: on forming the lampshades for my sister, I used no hand sanitiser whatsoever. I also used gloves, but did touch the resin occasionally while it was curing. I now think I'm allergic to the resin, or the catalyst, rather than the isopropyl alcohol..