Tech Talk - Sand Blast Kits
Commercial Sand Blast Kit
These kits are used with a pressure washer to deliver a water sand mix to the surface being worked at high impact. The resulting abrasive force removes graffiti or can be used for paint preparation on hard surfaces. The kit includes a probe that is inserted into the sandblast medium, a pick up tube that transports the sand to the head, and the head assembly. The head assembly is typically constructed of aluminum with a carbide tip. The carbide is hard and holds up best to the abrasive action of the water and sand mixture. The head assembly is plumbed to a trigger gun with a lance. The lance should be long enough to keep the operator far enough away from the area of impact so that they aren’t hit by too many flying particles. It is important to be close enough to watch the progress closely. Some kits require a separate high-pressure nozzle that is installed into the head assembly. When using the Hydro Sandblast Kit, success or failure depends on whether or not the operator follows a few important rules. The first rule is that the sandblast material must be kept dry at all times. Without taking precautions, the material gets wet very quickly. The sand is usually sold in paper bags. If using the sand directly from the bags, be sure to elevate the bags so they are out of any water that is running on the ground. A plastic bag should be turned upside down and placed over the sand bag. The probe should then be jabbed through the bag and the packaging material into the sand. Make sure the probe is dry before insertion. Make sure that the plastic bag isn’t collapsed down around the probe. Pull it up so any water that hits it runs off and not in. Another method used to help protect the sand is to transfer it to dry five-gallon pails with no lids, then cover them with the plastic bag and insert the probe. With the pail the problem of ground water affecting the material is eliminated. Next rule is to check to make sure the pickup tube connections are tight so there are no air leaks. The pickup tube enters the head assembly at a fitting that comes off the head at a 45-degree angle. It is an absolute necessity to always keep this angle and the pickup tube on the top when working. Keep the “Y” towards the sky, or else water will enter and clog the pickup tube. Some kits have an air adjustment screw on the head, the less air allowed in at the adjustment, the more sand is drawn. The last advice on hydro sandblasting is that you need to watch very carefully to avoid damaging the surface that is being worked.