Birchwood Casey Perma Blue Liquid Gun Blue Bottle 32oz. It will give a non-streaky even blue-black finish to steel (except stainless). both perma blue liquid gun blue and paste gun blue provide great blueing to metal that has already been thoroughly cleaned and is free of rust. Perma blue paste gun blue is slower to darken than liquid gun blue but will build up a denser finish. Note: perma blue liquid gun blue will not blue stainless steel aluminum or non-ferrous metals. Specifications for Birchwood Casey Perma Blue Liquid Gun Blue Bottle: Manufacturer: Birchwood Casey Fabric/Material: Steel Quantity: 1 Included Accessories: Standard Volume: 32 oz Package Contents: Birchwood Casey Perma Blue Liquid Gun Blue Bottle Standard Birchwood Casey BC-13132: Perma Blue Liquid Gun Blue Bottle 32oz