Comparing boric acid prices. you can easily wholesale quality boric acid at wholesale prices on made-in-china. wholesale price. sign in. join free for buyer. search products & suppliers product directory supplier discovery post sourcing request ... cheap boric acid powder; cheap borax decahydrate; For this experiment you will need borax (disodium tetra borate) and conc. hydrochloric acid. take 25 ml of hydrochloric acid and dilute it with 75 ml of water. next take 67 gms of borax and dissolve it in boiling water. now add equal amount of hydrochloric acid. crystals of boric acid will start forming. they are completely insoluble in cold water. For a completely non-toxic roach killer, use food grade diatomaceous earth. roaches crawl through the boric acid powder and the tiny particles cling on to their bodies. when they clean their bodies by licking themselves clean, they ingest the boric acid (which acts as a stomach poison). they die shortly after.