Sciencemadness Discussion Board

Water-based lubrication

Melgar - 2-6-2010 at 06:32

Let's just say someone (me!) has a girlfriend who he wants to surprise with an inflatable kiddie pool and about a quart of water-based lubricant. Only issue is, water-based lubricant tends to come in tiny little bottles, and it'd be really expensive to buy a quart of it. So, a little research revealed that most varieties of this stuff are comprised mostly of glycerin and/or propylene glycol. A little more research revealed that glycerin on its own is no good -- it can provide food for certain vaginal bacteria that are not the type you would want to feed. Propylene glycol on the other hand seems to have a mild disinfectant effect.

Any reason I couldn't just use straight propylene glycol mixed with water? IIRC, glycerin is a bit thicker, and has a sweet taste, but now I'm wondering if it's actually necessary. I know she doesn't have any allergies to either of these chemicals, and both are more or less nontoxic. So, anything I need to do before buying a nice big bottle of propylene glycol? ;)

densest - 2-6-2010 at 08:38

The propylene glycol (PG) evaporates relatively quickly at skin temperature and isn't that viscous. Some food grade or food/cosmetic grade polyethylene glycol (PEG) 400 or polyvinyl alcohol (PVA) 400 will thicken it and slow evaporation significantly. A water/pr.g./peg mixture should be slippery & persistent.

There must be water in the mix to prevent osmotic drying of skin.

Cautions: plastics may be softened and paints may be removed by PG, PEG, or PVA. Mold can grow on these compounds. Very small amounts (0.01% - 0.05%) of mold inhibitors - often substituted NH4+ compounds - will preserve the mixture. The mixture will taste slightly sweet. All sources I've read say it's not harmful, but it would be wise not to gulp it down.

The numbers after the PEG or PVA names specify how big the molecules are on the average and therefore how thick or solid the material is. I suggest a small (1-5%) amount of a moderately thick to almost solid variety rather than a lot of a thin variety.

not_important - 2-6-2010 at 12:03

The commercial veterinary lub J-Lub is PEO/PG based, as denset suggested using. Generally some propylene glycol is added, it or glycerol help maintain lubricating effect when the water content evaporates. Dipropylene glycol is also used instead of or along with propylene glycol and/or glycerol; it has much lower volatility than propylene glycol and is slightly more slippery.

Other things that work include mixtures of xanthan and guar gums in water, generally under 1% total. Both are used in baking, particularly for gluten-free goods, and so are easily available in food grade; shops specialising in baking supplies almost always carry it.

Combining these with PG, combining several chain lengths of PG, and mixtures with small amounts of alginate (too much makes a firm gel), and/or carboxymethylcellulose, are all done. There is a bit of an art in getting desirable properties; in the early 1970s a friend got into small scale manufacturing of such, and she did ... extensive "research and testing" to develop mixtures targeting differing specific uses.


Note that most of these can have a laxative effect if consumed in sufficient quantity. Propylene glycol seems to have a species-specific toxicity in cats, you may need to take that into consideration.

None of these mixtures will last very long without mold or bacteria growth. Use good cleanliness procedures, and store refrigerated (microwave on low to warm). Parabens, as methyl parahydroxybenzoate or the ethyl, propyl, or butyl esters, help retard fungal growth; some people don't want them in products they use. Benzethonium chloride is the most common of the NH4+ compounds mentioned by densest. Triclosan is also used. Health food types say to use grapefruit seed extract, however testing has shown that at least the majority of the preservative effect of commercial GSE products came from one or more of the aforementioned preservatives, not from anything from the grape seeds.

Getting the PG/PEO and the gums to disperse well can be a bit tricky, but there's plenty of online information between the manufacturers and bakers.

Melgar - 10-6-2010 at 16:51

Hmm, my girlfriend is already apprehensive about my chemistry experiments, and I'm not sure how keen she'd be on slathering a homemade concoction all over herself. Thanks a lot for the info though! I actually got two serious replies. :)

This led me to do some searches on eBay, figuring someone out there must be filling the need for large quantities of water-based lubrication. Sure enough, I got a pint of the stuff for about $15 with free shipping. But if I ever need a lot more than that, I now have all the information I need. Thanks!

Sedit - 10-6-2010 at 16:56

I do admire your enthusiasm for chemistry Melgar I give you that. Chemistry always makes life better:D

The WiZard is In - 11-6-2010 at 07:14

Quote: Originally posted by Melgar  
Let's just say someone (me!) has a girlfriend who he wants to surprise with an inflatable kiddie pool and about a quart of water-based lubricant.


------------
I would go with the rubber sheets and a gallon of mayonnaise.

The answer to your question - can be found on Wiki Pedia.



djh
----\
If the county pervert posse
call's - you never heard of me.

Hoveland - 23-7-2010 at 01:26

"The answer to your question - can be found on Wiki Pedia."


Or on "wipipedia"...

http://www.londonfetishscene.com/wipi/index.php/Lubricant


zed - 23-7-2010 at 01:50

What's wrong with Jello? It's pretty inexpensive, and if it doesn't work quite right, you can eat your mistake.

Warm, full fat content, yogurt.....at room temperature, is another possibility. Has a nice texture, and it is swarming with benevolent bacteria. Generally, about 2 to 3 dollars a quart.



[Edited on 23-7-2010 by zed]

The WiZard is In - 24-7-2010 at 06:37

Quote: Originally posted by zed  
What's wrong with Jello? It's pretty inexpensive, and if it doesn't work quite right, you can eat your mistake.

Warm, full fat content, yogurt.....at room temperature, is another possibility. Has a nice texture, and it is swarming with benevolent bacteria. Generally, about 2 to 3 dollars a quart.



--------
Me thinks what with the sugar in Jello and a plethora of
microbes in yogurt ..... the possibility of she developing
a yeast infection ......! However, you may find one that
glows in the dark attracting.

zed - 25-7-2010 at 10:36

Yeast infection from yogurt? Not likely.

Actually, one of the most serious possible problems, is your having a rebel girl on your hands.

Young women that resent their mothers, may find it amusing to blow you, while talking to mom on the phone. This is not without its merits, but the behavior of such girls must be monitored carefully.

Depending upon her current level of rage, she may decide that the somewhat used, residual Jello or Yogurt, from your little experiment, would be a good item to serve to her overbearing mom at lunch.

This is not legal, and it's over the line. You must explain to her, that while it is amusing for the two of you to eat the yogurt, while her mom is present at lunch.....It is not kosher, to feed the same yogurt to her mom.

[Edited on 25-7-2010 by zed]