I know its not important for most of you, but i thought id give you a little insight into the various methods for weld testing.... Besides just hammering it to death!! There are a lot of ways to test welds, but some are specialist and expensive, such as xraying etc. They are generally set into two categories, 'Non Destructive', and 'Destructive' A very rough way of testing is just to knock it about for a while, held in a vice. Great for first time welders that want to make a noise!! This would be a destructive weld test! Root bend. A slightly more technical way is a 'root bend' test. Do a weld, then cut a portion out of it, say 40mm wide. Then bend it between 2 blocks in a press, with the root facing down. If its okay it will bend nicely without the underside of the weld cracking. Dye Penetrants. Dye penetrant testing is another simple way to check for cracks and holes that you cant see. Its a three part kit, a cleaner, dye (flawfinder) and a developer. First clean the weld area, then sprya on the dye. Allow it to dry then clean of the surface. Then spray on the developer, this reacts with the coloured dye and make it very easy to see and defects. Can be handy to use before sending stuff for xray. Magnetic powder. The area is magnetised with an electromagnet, then the powder is spread on the surface. Any defects are shown up by concentrated areas of the powder. Xraying/Radiographic. Xray or Gamma ray testing is used on a lot of things, the defects will show up as light areas on the film. Ultrasound. Works in very much the same way as an ultrasound in a hospital. The waves are reflected back at varying frequencies, allowing you to build up a picture of what is being tested. Macro Etc. This test allows you to see how the weld material is deposited onto the parent metal. A slice is taken through the weld, then polished. When the surface is smooth, a mixture of Nitric acid and alcohol is then wiped onto the surface. This darkens the weld material, allowing it to stand out fromthe parent metal. Good for checking penetration.