I always makes to put a DS1820 series inside a 6” of ¼ copper tube. 1mm of ds1820 will remain out from tube to other end, After i seald with Mseal or M-Seal Easimix - 20 Epoxy Putty.( That uneffected withstands temperature up to 180°C ) and avilable in only in 0.37$ in india into tube formate.
one tube is sufficient for about 50 nos. 1820 sensors.
see property of epoxy putty http://www.pidilite.com/productinner...65&subcat2=184