There are a couple ways to weld up your spiders. You can tack-weld them inside the case and then remove them to be fully welded. However, there’s a slight chance the heat from welding could cause them to cock, making reassembly difficult. We normally just weld the gears together inside the case, making sure to get as much weld coverage as our MIG gun will allow. Don’t forget: If you’ve got C-clip axleshafts, don’t weld the cross pin to the gears. It may also be a good idea to protect the cross pin with some aluminum foil to keep any large weld boogers from sticking that would prevent the pin from being removed. Otherwise, you won’t be able to get your C-clips back on your axleshafts.