小型預熱保溫爐注意事項:
已經(jing)受潮的(de)(de)石(shi)英(ying)(ying)砂(sha),尤其是#6砂(sha)和#8砂(sha)(因為(wei)粘度(du)細),儲放過(guo)久而(er)吸收(shou)空氣(qi)中(zhong)的(de)(de)水份,應(ying)該(gai)先用(yong)(yong)(yong)干凈(jing)的(de)(de)鐵(tie)鍋炒下后(hou)再使(shi)(shi)用(yong)(yong)(yong),將四種不(bu)同(tong)粒度(du)的(de)(de)石(shi)英(ying)(ying)砂(sha)和硼酸(suan)反復(fu)拌和三(san)次,使(shi)(shi)混合(he)均勻,再用(yong)(yong)(yong)20目的(de)(de)鐵(tie)絲過(guo)篩二次,這(zhe)(zhe)樣不(bu)僅能(neng)(neng)提高它(ta)的(de)(de)混合(he)均勻度(du),還(huan)能(neng)(neng)將一些外來(lai)夾(jia)雜物(wu)篩去,因為(wei)夾(jia)雜物(wu)中(zhong)的(de)(de)有機物(wu)質,如(ru)紗頭,草節(jie)之類的(de)(de)東西(xi)混在石(shi)英(ying)(ying)砂(sha)中(zhong),當爐(lu)子(zi)(zi)筑好送(song)電升溫后(hou),這(zhe)(zhe)些有機物(wu)質將產(chan)生(sheng)氣(qi)體,可能(neng)(neng)導致爐(lu)底(di)面出現氣(qi)孔和裂縫,影響爐(lu)子(zi)(zi)使(shi)(shi)用(yong)(yong)(yong)壽(shou)命(ming),嚴重時可能(neng)(neng)發(fa)生(sheng)漏銅。