probably try shiny magazine covers I s'pose. When you do get to somewhere you can look for something decent - a good engineering supplier should be able to get you nitrile infused gasket material - the problem with ordinary gasket material is that when it is used in raw water
systems the salt
water/zinc oxide mix osmoses causing that ugly white powdery mess around the galleys. I've found the nitrile stuff is effective in stopping this, whats more it seems to work better dry - ie no sealant/gasket goo/hylomar/whatever you may be using.