Here's a kit I put together for diluting 40% permethrin to treat clothing and gear.
In the past I've used Sawyers and Repel Permanone products. The Repel product just didn't last very long. Last year I treated my gear with 10% permethrin purchased at Tractor Supply. It worked but the scent of the petroleum distillates was pretty strong (at first).
This year I saw 40% permethrin at Tractor Supply. My thinking was that by using a more concentrated permethrin, there would be less distillates in each batch, so less smell.
Since 40% is 80 times more than the 0.5% used for treating clothing the product needed to be diluted at an 80:1 ratio. The Sawyer dunk product comes in 6oz bottles. Converting to metric, that's 180mL per bottle. 180mL/80=2.25mL, which is the amount of permethrin in the Sawyer bottle. But for dunking Sawyer has you dump the contents into a bag and the fill the bottle with water twice more, dumping that into the bag as well. 3x6oz=18oz of total liquid to treat one set of clothes.
I found a syringe from an old inkjet printer refill kit and used it to pull 2.5mL out of the 40% permethrin bottle. Rather than add that to a 6oz bottle and then need to dump two more 6 oz bottle of water in, I simply shot the permethrin into a 20oz Coke bottle filled with water.
To have some 0.5% around for spraying, I added 10mL of permethrin to a 24oz spray bottle and labeled it accordingly. EDIT: Per Oh-No, Permethrin has very limited shelf life once mixed with water, so only mix when needed.
Just treated three sets of clothing and a couple of hammocks. There is definitely much less smell in the fabric using this method.
Here's the kit.
Here's the Sawyer dunk product label.
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Last edited by Knotty; 05-20-2011 at 00:40..