The polymers used in making bubble juice often clump or fail to fully-hydrate if you simply dump them into water and stir. Each polymer has its own special needs which are usually quite simple. All of the recipes provided on the recipes page provide instructions for the mixing of the polymers. This article provides some general guidelines for mixing.
Different polymers have different mixing needs and methods. Some polymers may need cold water for mixing and others hot water. What works for PEO may not work for CMC or HEC. It is important when following a recipe or the instructions below that the instructions be carefully followed. They are usually quite simple but ignoring any part of the instructions may lead to a failed mix. Most reports of problems on SBF, the Soap Bubble Fanciers Yahoo Group, are due to people ignoring one or more parts of the instructions.
[THIS ARTICLE IS STILL ROUGH. BUT THE INFORMATION SHOULD BE HELPFUL NONETHELESS]
Typically, there are technically a few stages involved in dissolving a polymer. (Technically, most of these do not dissolve but form a suspension of some type.) The usual stages are:
- Dispersion. The powder is dispersed so that it does not clump. Sometimes this is done by mixing with a slurry. Sometimes this is done by mixing with another powder to separate the polymer grains. Some polymers are dispersed in water with particular temperature or pH characteristics. For example, some HPMC is treated so that it is effectively insoluble in cold water. Such a polymer can be stirred into a small amount of cold water to disperse the grains; then, hot water is added to the mix to begin hydration.
- Wetting. The powder becomes saturated with water and the grains start to swell. This usually happens as part of the dispersion and hydration. Some polymers are most effective if thoroughly wetted before hydration and stirring begin.
- Hydration. The polymer swells and unravels and dissolves or forms a suspension. Usually, the solution is stirred to encourage proper hydration. Some polymers will thoroughly hydrate with little or no stirring while others require constant or periodic stirring until hydration is complete. Different brands of the same polymer may be treated differently and hydrate differently. The commonly used versions of PEO, for instance, will create a nice suspension with a fairly brief stirring/agitation -- a minute or two is generally sufficient. Even though a PEO solution's viscosity will continue to build for up to 24 hours, once the polymer has been dispersed, wetted, and its hydration started with a few minutes of stirring, it can be left alone. By contrast, many brands of HEC, need up to 40 minutes of constant or occasional stirring to ensure that the suspension remains stable.
Slurry Mixing - GeneralEditA slurry is a mixture of a polymer powder and a liquid that does not hydrate the polymer. The polymer becomes dispersed in the slurry so that it does not clump when the slurry is added to stirred water or (in some cases) when water is added to the slurry. The slurry generally does not hydrate the polymer or hydrates it only very slowly which prevents clumping. Generally, you do not want to leave the slurry sitting around for too long as clumping can happen with some combinations of polymer and liquid if left too long.
Most of the polymers used for making bubble juice are insoluble in dry alcohol (see below), glycerin (glycerol), and propylene glycol. A few of the polymers can even be slurried with detergent (more on that below).
Some polymers are more sensitive to how they are mixed than others. Here is the general technique for mixing using a slurry:
- Make the slurry. Put the dry powder in a container and add enough slurry liquid to cover the powder
- Combine with water. Combine the slurry with stirred water of the appropriate temperature (and/or pH). In some cases, it makes a difference as to whether you add the water to the slurry or the slurry to the water.
When using gycerine, it can be useful to warm it up so that it is not too viscous. Glycerin's viscosity changes quite a bit between 60F and 100F for instance. It can be pretty viscous at room temperature but pours readily when warmed to 100F (38C)
Add slurry to water or water to slurry? It depends on the polymer and your technique. In many cases, you can start stirring the slurry and pour the water into the container and avoid clumping. For other polymers, it is best to slowly pour the slurry into water that is being stirred. If you are not sure which method to use, use the latter (adding slurry ot stirred water).
If using alcohol, you sometimes need dry alcohol (alcohol that contains very little water). If you need dry alcohol, make sure that it is at least 90% alcohol. Standard American rubbing alcohol has too much water in it to be used for making slurries with WSR301, for instance. 90% (or higher) isopropyl is generally easy to find. Make sure to check the label. For some polymers (such as guar gum), rubbing alcohol is fine.
PolyOx WSR301 will not slurry well with rubbing alcohol but J-Lube will slurry fine. You might be able to add an inert powder (such as sugar) to your WSR301 if you need to slurry with alcohol and are having trouble with clumping. (J-Lube uses a 3:1 sugar:PEO ratio).
For some polymers, dishwashing liquid may be used for making a slurry. In some cases, you must used chilled detergent. Details are found in the article Slurry-Detergent.
The most common forms of PEO encountered by bubblers are Dow PolyOx WSR-301 and J-Lube. The methods given below work for both types except where noted. The BLM mixing method does not work with WSR301 as WSR301 responds differently to water temperatures that approach boiling.
See the the Slurry Mixing section above. Use glycerine, propylene glycol or very dry alcohol or even detergent for the slurry. WSR301 requires very dry alcohol (at least 90% pure) while J-Lube can be slurried with rubbing alcohol.
If you experience clumping using dry alcohol, chill the alcohol in the freezer and clumping should be eliminated due to the reduced solubility at very cold temperatures.
(2016) Detergent works as a slurry liquid too (at least Dawn Pro and its equivalents) but requires a little more care than when using dry alcohol or glycerine or propylene glycol. See Slurry-Detergent for details.
Pouring back and forth. This is a simple reliable method for mixing/hydrating PEO. Experiments seem to indicate that this method develops the viscosity (and self-siphoning) of the polyer mix at least as well (and usually better) than other methods. It is convenient for mixing up enough PEO for gallons and gallons of bubble mix. This works with all types of PEO including J-Lube
- Put your powder in a beaker or glass. Call this "Glass 1".
- Optional: add a little more glycerine or dry alcohol (i.e. "dry" alcohol has a 91% or higher percentage isopropyl or methanol or ethanol. If you use alcohol that has less than 90%, you are likely to get clumping due to the water) than is needed to cover the powder. Stir it to make a slurry. (Amount of liquid needed is on the order of 2 to 3 times the amount of powder)
- Put some warm water in another beaker or glass. Call this "Glass 2".
- Pour the water rapidly from Glass 2 (just water) into Glass 1 (the PEO slurry)
- Pour the water back and forth between the two glasses until the solution is smooth. Typically this takes about 2 minutes.
The amount of powder, non-solvent (the glycerine or alcohol), and water depends on the percentage solution that you want. For a 1% PEO solution use:
- 4 grams of J-Lube (this amount contains just 1 gram of PEO) or 1 gram of WSR-301
- 8 grams of glycerine or dry alcohol (91% alcohol or great by volume -- see note below)
- 88 grams of warm water
You can scale up the amounts if you need more.
ALCOHOL NOTE: When using alcohol for slurries, you need to use "dry" alcohol that has little or no water. Alcohol that is 90% alcohol or greater by volume works well. If you use alcohol with a lower percentage of alcohol, you are likely to get clumping.
Fizz-mixing is a a convenient way to mix PEO with just a mixing vessel (often a tall glass), baking soda, citric acid, your polymer and a stirring rod (or chopstick or fork). And, it is kind of fun. Watch the video to see it in action. See this thread.
Mechanical Stirring Using a Drill and Paint StirrerEdit
[POLISH THIS SECTION. Add note about using dry diluent such as glycerine, PG, or dry alcohol to make slurry.]
Attach a non-aerating paint-stirring attachment to an electric drill.
Put water in the mixing vessel.
Start stirring the water and let a nice vortex build but don't use a higher rotation speed than necessary.
Slowly pour your powder into the vortex.
Reduce the speed of the stirring once all the powder has been added as PEO can be damaged by the high-shear stirring.
Many (but not all) types of HEC are surface treated to be cold water dispersable with delayed hydration. The hydration phase can be started by elevating the temperature or raising the pH (or alkalinity) for many types of HEC (such as Natrosol and Cellosize). If nothing special is done, hydration will eventually begin. Unlike some other polymers, HEC requires that the solution be stirred (at least intermittently) until hydration is complete or near complete.
If your water has a pH less than 8, baking soda (sodium bicarbonate) can be used to safely raise the pH enough (in most cases) for complete hydration. (The Ashland and Dow data sheets recommend sodium hydroxide which is a fairly unfriendly chemical and is unnecessary for our purposes.) As noted below, baking soda can speed up hydration even if your water's pH is higher than 8!
Cold water dispersible or not. Many versions of HEC are specially treated to be dispersible in cold or room temperature water. These types of HEC do not need glycerine or other slurry liquid other than cold water). It seems that the most commonly available version of HEC are treated this way. Cold water dispersible HEC includes the Natrosol 250 series when 'R' is in the name -- such as 250HR -- and also CelloSize QP100MH and most of the CelloSize that I have encountered. If you have cold-water dispersible HEC, use the Cold/Hot mix method: add the powder to some cold water for dispersal and then stir in hot water to hydrate. See the detailed notes below.
Hydration versus dissolution. With HEC, it is important to realize that there is a difference between hydration and dissolution (dissolving). The HEC may appear to be completely dissolved shortly after the powder's dispersion into water. Even though the HEC appears to be completely dissolved, it will take some time -- even with constant stirring -- before hydration completes and the viscosity has built to its full potential. If you stop stirring before the hydration is complete, the HEC may coalesce into a distinct gel layer that is difficult (sometimes impossible) to incorporate back into solution. This is (at least in part) because most HEC is manufacture for the hydration to be delayed in order to assure easy dispersion without clumping. During this delay, the grains of HEC swell and unfurl. Even with continuous mixing it can (depending on the brand, the water temperature, and solution pH) take up to 40 minutes for the solution to be hydrated well enough that you can stop stirring.
HEC can be hand-stirred, but a mechanical mixer or magnetic stirrer is often convenient for this method. If hand-stirring, you will want to stir periodically until the solution is completely (or almost completely) hydrated and has reached almost full viscosity.
Hand stirring. If you are hand-mixing, stir for a few minutes then stir for a minute or two every five minutes until the solution has cooled to room temperature OR has become clear and ghost free. At this point, there should be no 'ghosts' visible in the mix.
Some brands of HEC hydrate relatively quickly and will be shelf-stable after 5 to 10 minutes of occasional stirring. Others take longer to fully-hydrate and require constant or occasional stirring (occasional is usually fine) for a full 20 to 40 minutes in order to ensure that the HEC does not settle out as a distinct gel layer.
Baking soda. Adding baking soda can speed hydration even if your water is already alkaline. If your bubble juice recipe calls for baking soda, add it while the HEC has started hydrating and you may notice an acceleration in the hydration rate. Do this after the HEC has dispersed and after adding the hot water if using the cold-hot method.
Debugging. If your HEC comes out of solution and forms a gel layer, you need to make sure to stir the mix over a longer period of time. Continuous stirring is not usually necessary. It is generally sufficient to stir a bit every several minutes until hydration is complete.
Cold/Hot Mix NotesEdit
Steven L's mixing notes:
HPMC is generally quite easy to hydrate. The exact method to use will depend on whether you have cold-water-dispersible (CWD) HPMC or untreated HPMC. The popular MethoCel K15M comes in both CWD and non-CWD forms.
If you are not sure if your HPMC is a CWD-type, sprinkle a little onto some cold water. If the HPMC clumps, it is not cold-water dispersible.
See also: MethoCel K-Type Food Gums (on the Dow MethoCel site).
Hydrating Untreated HPMCEdit
Untreated HPMC is not very soluble in very hot water 80-90C (176-194F). There are a few methods for easy hydration. All work well, use whatever is most convenient.
- Heat 1/5-1/3 of your water until is very hot (80-90C or 176-194F).
- Add your powder while stirring/agitating and continue stirring/agitating until the powder is well-disperse with little or no clumping.
- Add the remaining water as cold water while stirring vigorously. Continue stirring as solution cools it will become viscous and should be clump free.
- Add your powder to enough of a non-aqueous liquid such as glycerine, propylene glycol or very dry isopropyl alcohol (greater than 91% alcohol) to make a slurry. Make sure that there is enough liquid that the slurry is not paste-like.
- Add cold or warm water and stir until the solution is viscous and clump free. If there are tiny clumps, it is ok. They will resolve themselves over time.
Hydrating Cold-Water Dispersible HPMCEdit
Cold-water dispersible MethoCel can be added directly to cold water without clumping as long as you perform the hydration within a reasonable amount of time. To hydrate it, you can either raise its temperature or the pH of the water. Here are two methods for preparing a solution with cold-water dispersible MethoCel.
Method 1 for CWD HPMC (cold/hot with a microwave)
- Add the powder to a microwavable container that contains full amount cold water in which you intend to dissolve the HPMC
- Put the container containing the water into a microwave and heat it until the temperature reaches about 160F (71C)
- Stir until the solution is clear (it may already be clear when you remove it from the microwave).
- Replace any water that evaporated during microwaving.
Method 2 for CWD HPMC
- Measure a portion of the water (about 25-50% should be good) that you intend to use into a container for mixing (such as a glass measuring cup). This water should be cold.
- Heat the remaining water until it is hot.
- Add the powder to the cold water and stir to disperse it.
- While stirring the cold water, gradually pour in the hot water and continue stirring until the hydration is complete.
For more tips on HPMC mixing see this post on SBF. Hot/cold mixing works well with the MethoCel that is not cold-water dispersible -- and variations of it work with versions that are cold water dispersible -- i.e. disperse some MethoCel in a portion of the water and some hot water while stirring. Then add room temperature water while stirring.]