shuter Posted September 13, 2019 Report Share Posted September 13, 2019 I just wanted to post that I found an easy to find, easy to use replacement product for Butyl/Toluene as dope for our speaker surrounds that I’ve never seen mentioned. The product is Lexel. It’s an elastic synthetic rubber caulk with properties I believe meet and exceed the Butyl Rubber that KLH used to dope the surrounds in our speakers. Butyl Rubber is a synthetic rubber falling into a classification of an elastomer (elastic+polymer) which includes natural rubber and synthetic rubbers. There are two main properties of elastomers that we are most concerned with, elasticity and hardness. After as much research as I could dig up, the butyl rubber caulks that we can get have an elasticity fully cured of around 200-250%. This means you can stretch/displace it to twice the size and it will rebound to it’s original size. Lexel has a listed fully cured elasticity greater than 400%. Twice as elastic as butyl. As to hardness, the butyl caulks I researched list a hardness, on the “Shore A” scale of around 60. This is compared on most charts to the hardness of the tread of a tire. A pencil eraser is about a 40. Lexel has a “Shore A” measured hardness of 25. Very soft. That’s means it will remain twice as soft as butyl fully cured and is compared to a rubber band on most charts. Lexel (clear) contains only whatever synthetics rubbers they are using (they don’t say) and two solvents for ease of application that evaporate away. Naphtha and Toluene. It should be easily thinned by adding some more of either or even just some mineral spirits. Best thing is it is readily available at Lowes or Home Depot and a 5 oz. tube costs about $6. Having a clear is also important to me as my surrounds are the yellow/orange color of the early manufacture and I’d like to keep them that way vs black or white. I’ll be using it this weekend on my 60’s vintage 17’s but I only have my ears to measure the effectiveness. I’d love some comments or if someone can experiment and measure that would be great too. P.S. I did find a manufacturer that specializes in commercial butyl rubber sheeting that has a butyl product of Shore A hardness as low as 40 and elasticity of 500% but that still doesn’t match Lexel. Quote Link to comment Share on other sites More sharing options...
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