Solder (4)
I believe the answer is:
weld
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">solder</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for weld that I've seen before include "Solder" , "Unite metals by heating to melting point" , "Fused metal joint" , "Join together; dye plant" , "Join (metals)" .)