1. Xaiv cov hnab looj tes vuam raws li koj qhov chaw ua haujlwm. Piv txwv, cov welders xav tau tuab dua thiab ntev dua cov hnab looj tes vuam. Thickness tuaj yeem tiv thaiv lawv...
Cov hnab looj tes txiav tuaj yeem ua tau theem 5 tuaj yeem raug txiav cov khoom tsis haum, thiab puas tuaj yeem qib kev txiav cov hnab looj tes-tawv haum ua tau raws li qhov yua...
