The abilities of three classes of low molecular weight, metal-based, associative compounds to thicken high pressure ethane, propane or butane have been assessed with a close clearance falling ball viscometer. Tributyltin fluoride (TBTF) does not require a heating/cooling cycle to attain dissolution, and at a concentration of 1 wt% in ethane, propane or butane yields 70-100-fold viscosity increases at 25 degrees C. Increasing temperature substantially reduces TBTF's thickening ability. Although hydroxyaluminum di-2-ethylhexanoate (HAD2EH) is insoluble in ethane, it does dissolve in liquid propane or butane after mixing at similar to 100 degrees C and cooling to temperatures as low as 40 degrees C. HAD2EH induces small viscosity increases in propane, but is a very effective butane thickener. Increasing temperature causes a relatively small decrease in HAD2EH's thickening performance. Combining a phosphate ester and a crosslinker in ethane, propane or butane yields a translucent liquid with viscosity increases that are significantly less than those attained with TBTF or HAD2EH. (C) 2016 Elsevier B.V. All rights reserved.