Sandblast Pot Troubleshooting – A Complete Guide
Your sandblast pot can be critical for you on the job to get a surface prepped for paint. When an issue occurs with your sandblast pot, it can cause you to lose time and money. While proper sandblast pot maintenance can help reduce problems from occurring with your sandblast pot, there is still a chance that issues will occur despite your maintenance efforts. Knowing how to troubleshoot a broken sandblast pot will help you reduce downtime and ensure you get back to work as quickly as possible. This guide will aim to cover common sandblast pot problems and how you can fix them.
How a Sandblast Pot Works
To better troubleshoot your sandblast pot, it can be helpful to have a general overview of how a sandblast pot works. A sandblast pot ultimately mixes a high volume of air under pressure through a hose where blast media is mixed. For the air to be pressurized you need the sandblast pot to close off. Additionally, you have to have a way to stop the sandblast pot in case of a hose blowing off the blast pot, getting out of the operator's hands, Closing off of the pot and stopping of the pot in case of emergency are controlled by a handle at the end of your blast hose. It is triggered by air or an electric option depending on the type of remotes you choose with your sandblast pot.
Air or an electric single from the remote at the end of your blast hose goes back to the inlet valve and pushes the valve opening allowing air into the sandblast pot. Simultaneously air pushes the exhaust valve (the valve at the top of the blast pot) closed preventing air from escaping the sandblast pot. The trapped air then forces a valve called the pop-up valve to close the sandblast pot off. At the bottom of the sandblast pot an abrasive metering valve allows you to control how much sandblast media is in your sandblast air stream.
When you are finished sandblasting letting go of the handle by your sandblast nozzle the reverse set of events occurs. Air pressure is released that was helping hold the exhaust valve closed which lets air escape from the blast pot. Additionally, the air inlet valve returns to the closed position preventing further air from entering the blast pot. The pressure in the blast pot is then released and the pot depressurizes.
Common Sandblaster Problem # 1 – Your blast pot Will Not Pressurize or Maintain Pressure
If your sandblast pot is not able to build any pressure there are a few reasons that this could be occurring. Problem areas that could cause your blast pot from not pressurizing include having a malfunctioning air inlet valve, worn pop-up valve seal or pop up valve, a malfunctioning air outlet valve, or a malfunctioning air exhaust valve on the blast pot. Both air inlet and exhaust valves have o ring seals and springs that are typically accessed without removing the entire valve. These are good first places to check if the o rings or the springs appear worn this can be the cause of the blast pot not pressurizing. If the inlet and exhaust valves on the sandblast pot appear ok then you should check the gasket and condition of the pop up valve. If the pop up valve is missing the gasket or worn either may need replaced. You should also check to make sure you have enough CFM of air being delivered by your air compressor as the pop up valve requires a certain volume of air to seal. Additionally, if you are using to large of a nozzle and your compressor cannot provide sufficient compressed air then their will never seem to be any pressure to your sandblast pot. For more on compressorsma and sandblasting you can refer to this guide. A final thing to check is the functioning of your safety handle (often called a deadman). If it is properly functioning you should feel air coming out of the handle until you push the lever out of the way and push the handle down. If you do not feel air beneath the handle you squeeze you should review the way the two hoses are connected to your blast pot and the safety handle. You should also check the hose out to the handle and back for any signs of leaks. If you have an electric safety handle you will want to review the other problems areas and then evaluate the dead man safety handle and line for any issues.
Common Abrasive Blast Pot Problem # 2 – My Blast Hose Is Slow at Moving Blast Media and Won’t Deliver Consistent Pressure
Another common problem with a sandblast pot is often referenced as the blast media spits or chugs out of the blast pot. While this often will happen when you first put compressed air to the blast pot as you purge any remaining blast media from the blast hose, it should stop after a minute or two. If your blast pot continues to spit and chug then it is important to check a few potential problem areas. First is to check to see if you have any blockages in your blast pot. Blockages, whether at the blast nozzle, media outlet valve, or anywhere will stop the proper flow of air which can create media piling up resulting in a chugging sound. You can also check your sandblast pot media valve. Typically a sandblast media valve should allow you to adjust the amount of blast media in your air stream. If your air stream is heavily darkened or is not changed by adjusting the media valve, this can cause issues with chugging or slow blast media movement. Fortunately it is often possible to rebuild your blast media valve.
Common Abrasive Blast Pot Problem # 3 – My Blast Pot will not release pressure when Im Done
If your sandblast pot is not relieving the pressure built up pretty quickly after you release your deadman safety handle, you should check the exhaust air valve, the air inlet valve, the abrasive trap screen, exhauster, and umbrealla. Specially for the umbrella, inlet, and outlet valves, and exhauster review to ensure that they are not sticking or working properly. Additionally check to make sure your abrasive trap (right before the exhauster) is empty of sandblast media. If the abrasive screen fills up with media, it will slow down or potentially prevent air from escaping from the blast pot well.
Ultimately proper blast pot maintenance and having a quality sandblast pot can go a long way to reducing any potential issues that you may have with a sandblast pot. If you have issues with your blast pot, you can also refer to this troubleshooting guide for practical advice on how to fix your abrasive blast pot.