Welkin Mechanical LLC. Welkin Mechanical LLC. Search | Advanced Search | New Members | Coupons and Discounts | All Categories Other >> GNYWC Welkin Mechanical LLC. 1010 Northern Blvd, Suite 204Great Neck, NY 11021 | View on Google Maps Keith Cappuccio (718) 554-2957 | fax: (718) 554-2839 Visit Site