So we looked at hand crank machines such as the Wonder Wash, but we weren't totally excited to cough up 50-60 bucks for one. So my genius husband went to Lowe's and figured it out for himself!
So now, I am going to attempt to explain what he did.
5 gallon Bucket
Paint stirry thing aka mortar mixer
various PVC connectors
First, he drilled a hole in the bucket to fit the mortar mixer.
Then he used E6000 glue to affix a PVC endcap to the bottom of the bucket. This helps keep the stirry thing off the bottom, which allows for more agitation and keeps the mortar mixer in place.
The next few pictures show how he used the PVC bits to make a handle for the mortar mixer. He used E6000 glue to attach it all together.
For ease of stirring, he put some bigger PVC pieces around the handle.