Ko te kōwae muka karaehe whakaahuru he hua whakaahuru hou hei whakangawari me te tere ake i te hanga oumu me te whakapai ake i te pono o te arai.Ko te hua, ma te ma, te rahi noa, ka taea te whakanoho tika ki runga i te punga o te peera rino o te oumu ahumahi, me te pai o te ahi ahi me te whakamaarama wera, e whakanui ake ai i te pono o te whakamaarama o te oumu, me te whakapai ake i te hangarau arai oumu.Ko te pāmahana whakarōpūtanga (Mai i te 1050°Cto 1600°C).