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Looking for a poor man’s mixer/blender (< $100)
Hello, Chemists/Formulators!
I am using a $12 paint mixer, fitted with a .75 in. dia. drink mixer attachment. See images below. Using an emulsifier at 3-4%, I can make stable 40-50 g. test formulations. My concern is air bubbles. I understand I can use a stick blender. Is there anything anyone could recommend that’s less than $100 and that I don’t have to hack? Thanks.
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18 Replies
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The answer depends on what you are making the formulas for.
If you are making product that you wish to sell, then neither the mixer your using or a stick blender would be appropriate. A stick blender is strictly a hobbiest tool.
If you are just making product you want to use for yourself, you can probably just keep using what you’re using. But you need to make larger batches than 40 or 50g. At minimum you should be making 400 - 500 g batches. You can put the finished product in a warm water bath overnight to let the air bubbles resolve.
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Thanks, Perry. Would a 40 C water bath suffice for removing bubbles?
When considering the very final formulation, is the use of hobbyist tools distinguishable from that of high-end homogenizers and high shear mixers?
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When considering the very final formulation, is the use of hobbyist tools distinguishable from that of high-end homogenizers and high shear mixers?
Not if the mixer really is high shear. Some stick blenders are, many are not. It depends on the design of the blade / surround. -
A 40C water bath might work. You have to test it and see.
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Thanks, Perry and Belassi. Here’s my before and after, per heating an arbitrary formulation for several hours. The pictures don’t do my testing justice—flash washing things out. If anything, the bubbles appear smaller. I’ve tossed these results, and have another formulation with bubbles, in a 40 C water bath, which has been going for > four hrs. I’ll check it in about another four hrs. BTW, the formulation pictured contains Carbomer 940 at ~ .08% and Xanthan gum at ~ .10%. Regards.
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Why are you using Carbopol 940 in this?
Carbopol 940 is a grade specifically designed for extra clear compositions. In order to do this, some other properties of the product type are sacrificed - e.g intolerance of other materials especially ions.
It may not be of particular significance in your current problem but it is something to be aware of.
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Is that $12 any good? Just curious.
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@Bernie_X - What size batch are you making? It looks so small.
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I’m still a believer in using vacuum to remove bubbles. There are inexpensive hand-held manual pumps that work on a small scale.
An inexpensive electric drill can sometimes substitute for a mixer also.
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@johnb I am using Carbomer 940 as a thickener that helps prevent creaming; are you referring to its intolerance to acidic solutions?
@em88 for $12, it’s great!
@Perry for the test, I used a 10g sample
@Bobzchemist although I have a manual pump for vacuum sealing, I can’t conceptualize using it as part of formulating; is there something you could refer me to?Thanks.
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Many homecrafters who make batch sizes of less than 300g use one of these mini mixers successfully to create the emulsion:
UK/Europe:-
https://www.amazon.co.uk/d/Blenders-Mixers-Food-Processors/Bosch-MSM2623GGB-Dips-Dressings-Hand-White-Green/B01HODZ19K (use the white attachment for batch sizes of less than 300g and the normal metal attachment for more than 300g).The above mixers are more powerful, giving higher shear than the norpro white mixer you have which is sold in various places such as Brambleberry and on ebay/amazon etc. For obvious reasons, please do not use a normal coffee frother - the one with the wire whisk type round head!
The trick to avoid incorporating air bubbles is to hold the head of the mixer deep inside the emulsion and hold the mixer still and upright/vertical. You will need to make a larger batch size than the one in your photo to be able to do this and you can also try a smaller diameter beaker! Do not move the mixer around too much otherwise air will be introduced.Good luck
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As I pointed out, the 940 grade is a special modification intended for crystal clear products. Your pictures indicate a preparation which is far from clear so, that being the case, you are possibly unnecessarily sacrificing product stability, ease of manufacture and cost.
I know my comment was off-topic. Just trying to make things easier for you.
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@MakingSkincare Thanks, Jane. Your insight is very helpful.
@johnb Thanks for your expertise on carbomer. I now understand its senstivity to metal ions. I also think it’s the root of my issue, as stated in Chemistry and Technology of the Cosmetics and Toiletries Industry (http://bit.ly/2tplLx9). For kicks, I’d like to try opaque carbomers (i.e., carbomer 934); however, 940 is the only one I’ve been able to purchase.Regards.
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On your scale, make batch as usual. When batch is between 30C and room temperature, put beaker containing batch into vacuum chamber and apply vacuum. Entrapped air bubbles will slowly expand and burst. Release vacuum. Repeat cycle until all air is out.
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The blade assortments available look like this would be a worthwhile investment if you are going to make larger batches.
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@Bobzchemist Excellent. Thanks, Bob.
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The only way for you to avoid air bubbles with any carbomer cream is to ensure that it’s hot process and get bubbles out while the product is still hot (and thin). 940 is excellent for this. I have at least two carbomer creams (0.3% of 940) and no trapped bubble problems. It MUST be hot process - or forget it.
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@Belassi Thanks, for that. I vaguely recall a lower incidence of bubbles while an emulsion was hot. I guess I would need a mixer with a very low RPM when adding miscellaneous phase.
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