Sub Bordures()
Dim r As Range, i As Byte
Application.ScreenUpdating = False
Cells.Borders.LineStyle = xlNone 'RAZ
On Error Resume Next 'si aucune constante
Set r = [B3:B65536].SpecialCells(xlCellTypeConstants)
For Each r In r
With r.CurrentRegion
For i = 7 To 10
.Borders(i).Weight = xlMedium
Next
End With
Next
End Sub