Please help me understand the clearest way to increase and decrease density as well as stretchy lava in vintage lamps!

[VintageK]

Hi gang, it's been far too long! I have been busy collecting older lamps when I can and have a few that need help.  I have two that have had the "chunky" lava issue that older lamps that have sat around tend to have. I have found with that that cycling them many times seems to eventually fix that issue. What I need your help with is what is the best chemical to add to the liquid to give a little bit more lift to older lava that seems to need too much heat. (I use dimmers on all of my lamps as NYC fluxuates too much temperature-wise) but a few of my lamps are needing too high of a wattage so I would like to add what I am hearing to be Glycerine? to increase the density a bit and that this will not affect the surface tension of the lava?

Regarding surface tension, to get a better, stringy-er flow (like the great older lamps) what do you suggest I add? I have heard one of the dish soaps can work (Dawn? or is it another?)  I had luck I feel with Dawn in one of my lamps and then tried a drop of Palmolive in my Consort and it was ruined...  Other commenters have said Propolyne Glycol to get the lava to stop creating just tight balls and to stretch nicely. (ignore the joke there.)   What have you found?

Can anyone give a semi definitive list of options for these chemicals and which have proven to work the best?  Thank you!

Trying to go with the FLOW! ;)

[Keith]

Propylene Glycol increases the density of the water, and sometimes it doesn't take much.  I have used fog machine fluid which is 50% PG and 50% water.  

Sodium Lauryl Sulfate is a surfactant that is used to help stretch out the flow, as well as prevent wax sticking to the side of the globe.  It can be found on ebay:  http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2054436.m570....

or you can use bubble blowing stuff but some of those can cause clouding.