Dawn dish soap has worked for me.....adding glycerin helps. I have made those giant bubbles with a homemade bubble wand. They are made with a dowel, piece of cord and a small plastic ring. It's hard to describe, but you start out with the cord closed and dipping it in a bucket of bubble solution. When you lift out the cording you slide open a loop you have made....
The reason I am describing this is because it is a bit difficult to do and it stilled worked with homemade solution. I may have read somewhere that a corn syrup could be used as a thickener....but maybe I am dreaming that up! Good luck!
I never have had much luck with homemade bubbles, but as previously mentioned Dawn is supposed to be the go-to soap for bubbles (and just about everything else too:. Don't know what they put in that dawn soap but it is in many recipes for HM cleaning solutions as well.
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