Along with what has already been said in this thread, you also need to contact the manufacturer of the WOL. Each manufacturer has their own specification of how much weld is required based on what size WOL you are using. We have used WOI and Bonny fittings recently and they are similar, but not the same. Both companies have a recommended guide on their website that shows you what you need to know (if you are using one of these companies WOL's).