In-House Sandblasting v. Outsourcing Sandblasting

We recently received an email from someone who wanted advice about sandblasting bicycle frames for profit. That might sound like an easy task, but deciding whether to process parts in-house or outsource sandblasting comes down to some very real factors. These five sandblasting considerations can help you to decide what’s the best choice for your business.

In-House Sandblasting Factors to Consider:

1. One of the hardest shapes to sandblast is a round tube about one inch in diameter. You’ll have to approach the blasting process just like eating an ear of corn. This means rotating the bicycle frame many times to process the full 360 degrees around each tube in every location. Your sandblasting cabinet will have to accommodate the size of the frame and allow every inch to be perpendicular to the blasting nozzle… this means a very large cabinet and lots of part rotation and endo-flipping!
2. Start researching the compressed air required for your application and whether that’s available to you at your location. Think of the blast nozzle as an electric sander, the harder you push down on the sander the more frictional heat you produce and the faster you sand. With compressed air, the more air volume you use, the more frictional heat increases again and again. It’s possible that epoxy paints and powder coatings may require compressed air volume usage at 80 to 100 cfm, normally a 30 hp air compressor, before the frictional heat is high enough to remove these coatings. If you cannot operate your sandblasting cabinet with the necessary compressed air to complete your task, you’re going to be very frustrated. With air compressors operating on 220-volt single-phase power, you can expect to find no air cfm volume more than about 24 to 25 cfm.  To have more you must have access to 3-phase electrical power.
3. Are you blasting for fun or profit? Face facts, if you take all day to blast a bicycle frame profit is not your motive. You’ll also need a really good blaster with a very large dust collector, or you will have more abrasive on the ground than in the machine. Remember as the gun cfm gets smaller so does the dust collector and the machine cost. Now you are taking 8 hours to do 30 minutes of work, which is not profitable and ends up being a real mess.
4. Choose the right abrasive for cabinet blasting. Garnet and slag are normally abrasives you reuse a maximum of only three times because they are soft and have lower maximum impact velocities. For this reason, and a few others, they aren’t typically used in cabinets where the objective is to reuse the abrasive many times over. Blasting cabinets use harder abrasives like aluminum oxide and silicon carbide that remove the paint while bouncing off the frame. Blast rooms use softer abrasive because they quickly get contaminated with lots of trash and it’s better to purge the room than try to recycle the abrasive.
5. Sending bicycle frames to a shop using a 50 hp air compressor, 200 cfm, will take about 5 to 15 minutes to process each bicycle frame – depending on the blasting gun nozzle size. Price out the hourly cost of having a job shop process your parts compared with you doing them in-house and you’ll likely find you are better off out-sourcing the project and doing other things related to the business.

Sandblasting Cabinet Tips if You’re Blasting In-House: 

1. The fastest way out of the painting business is to show up to paint a complete house with a one-inch brush! Make sure you buy a machine with compressed air and a nozzle that is the right size for your application.
2. If you are blasting bicycle frames inside a blasting cabinet make sure the cabinet is large enough to flip the frame while inside the cabinet. The cabinet should be about 1-1/2 times wider than the largest frame and high enough to allow complete frame rotation.
3. Your arms can only reach about 18″ with both hands in the work ports, so reaching the part with the blast nozzle will be limited. Using a direct pressure abrasive delivery will extend your reach because it holds the blast pattern tight and reaches out 12 to 18 inches still having great abrasive velocity, and speed, making your reach longer.

To Sum It Up

If you are just having fun and want to blast something – find a square part, it’s much faster to sandblast than anything round. Get the biggest cabinet possible to allow rotating the part inside the cabinet. If you’re limited on air compressor volume, use direct pressure abrasive delivery to increase your reach inside the cabinet. Finally, you can’t have a big enough dust collector because you’ll need the capacity when it takes all day to process powder-coated or epoxy-painted frames.

We do offer two machines for both bicycle and motorcycle frames, allowing all the above: the PowerStrip or Hailstorm. These are designed for plastic bumpers with two front staggered operation ports and one end port using a direct pressure delivery with pneumatic conveyor pressure pot reloading. This is not an inexpensive machine but it does keep you outside the room using street clothes.

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. If you’re not sure whether the PowerStrip or Hailstorm is the right fit for your needs, give us a call or fill out our contact form.