Abrasive Blasting 101
If you’re struggling to decide whether it’s time to upgrade a sandblasting cabinet we understand your dilemma. There are no-brainers like needing additional part processing capacity, meeting increased demand on existing machinery, and changes in applications. Unfortunately, there are less clear-cut situations where your current machine is falling short but you aren’t sure exactly what will alleviate your pain points.
Often, we hear these complaints from people who purchase the small, less expensive blasting cabinets found all over the internet today. These machines use less compressed air, have minimal dust collection with no abrasive recycle separator reclaimers, and claim to be “HEAVY DUTY” machines. They appear to be the solution people are asking for, a low cost blasting cabinet that operates on the small air compressor available in a home shop.
ProTip: Light use blasting cabinets can be OK tools, but manufacturers are often competing for the lowest possible cost at the expense of the user. Often these machines are associated with a messy work area, slow cleaning speeds, and very poor overall performance.
FACT: 220-volt single-phase power is incredibly limiting for compressor operation. It results in slow cleaning speeds due to the reduced cfm produced using lower amperage available for single-phase compressor motors. Regardless of what the motor says for horsepower, there are 1, 2, 3 and 5 horsepower 220-volt single-phase motors. This is an amp factor vs. the size of the copper windings needed to make the motor and if the motor says 8 hp and it runs on 220-volt single-phase power it’s a 5.
A huge compressed air tank means nothing when the pressure drops below 100 psi. The difference between 50 psi and 100 psi is 4 times cleaning speed, coefficient of frictions being squared. It’s almost the same with air volume used.
ProTip: Increased frictional heat and the amount of abrasive delivered are what decrease processing speed when you use a larger cfm gun size.
To make matters worse, duty cycle on these smaller air compressors is measured in 10 minute cycles. If you have a 60% duty cycle you need to let it rest for 4 minutes out of every 10 to cool or the warranty is void. This means much slower cleaning speeds, and operating the machine longer to clean parts.
ProTip: Light duty machines are meant to have a duty cycle of about 5% per day, about 20 minutes) or the features are a mismatch. If 11 cfm cleans the part in 10 minutes, 22 cfm cleans the part in 3-1/2 minutes, 44 cfm cleans the part in 1 minute 20 seconds and 90 cfm cleans the part in 40 seconds. Now project to 8 hours of blasting!
If you need more help with compressed air, check out these blog posts:
Air Compressor 101
Air Compressor FAQs
5 Things to Know Before Buying an Air Compressor
How to Size a Piston Air Compressor for Blast Cabinets
5 Compressed Air Factors For At-Home Sandblasting
Operating a machine with an inadequate dust collector, limited dust storage, and low cfm blower will create a real mess unless you clean the dust collector every 10 to 15 minutes.
Even if you find a way to increase the cfm your machine uses, it’s likely your dust collector can’t handle the increased processing capacity. If you could originally run the machine for an hour of blasting, increasing your cfm can quickly reduce operation time to 20 minutes, 7 minutes or 2 minutes before the low-quality dust collector creates a mess or bad visibility.
You may think the quality of your abrasive isn’t very important, but you are dead wrong. Slags, Cull Beads, and limited mesh sizes have a very poor recycle rate and they can quickly plug up the dust collector on low cost machines. Cabinet manufacturers that sell poor-quality abrasive usually know their machines don’t have the recycle capacity or dust removal separators to warrant using expensive media. Said another way, if a car leaks and burns a quart of oil a day why use good oil?
Inexpensive blasting cabinets typically put price and budget first, and the machine’s application second. They are made to look like a large tank on an air compressor by having a large cabinet size, include “HEAVY DUTY” in the product description, and list very little about the dust collector, separator reclaimer and features.
If the above description sounds like the machine driving you nuts, it might be time for you to upgrade to another sandblasting cabinet – we know and we can help! You are wasting money trying to upgrade an inexpensive cabinet, they are missing more than a few features.
Media Blast & Abrasive has been manufacturing sandblasting cabinets since the 1970s. We make more than 50 models totaling 180 individual cabinets with some models available in as many as 13 different sizes. In addition to a comprehensive list of included features, we offer more than 80 optional features for increased productivity, durability, and operator safety. Give us a call or visit our Buying Guide to find the right machine for your needs.