This disclosure presents a streamer filler material that is a low density gel formed from a two-part, mix-curable polymer, and methods of making streamers using such materials. One embodiment of the filler material features a two-part silicone gel mixed with a paraffinic oil. The two-part silicone gel can make up 15% to 25%, by weight or volume, of the mixture. Methods of making such materials include forming a first unreactive mixture having a first reactant, promoter, and/or catalyst and a second unreactive mixture having a second reactant, promoter, and/or catalyst and mixing the first and second mixtures in a paraffinic oil system to make a gel. The streamer can be loaded with the filler by pumping or extruding the mixture.