An inexpensive media blast box, with removable ends to accomodate longer items, is a very handy addition to any workshop. Built-in gloves would be a simple and necessary addition with heavier media but so far I've been using baking soda from the supermarket bulk bins. Other than being a bit dusty, there is no problem
The unit is perfect for a lot of clean-up work but especially for carbs. Strip carbs and soak them in Pine Sol overnight, rinse in fresh water, blow dry, then soda blast them. This brings the aluminum parts up to a bright "as new" burnished finish. Old carbs that have corrosion from old gas or water inside clean up very well, as do small brass parts like pilot screws, jets and needle seats. Getting these parts clean by brushing or sanding manually is very difficult. With a soda blaster, it is quick and easy. There is far less risk of damaging the delicate parts. When the blasting is done, rinse the parts off in a bucket of fresh water and blow dry.
I also do aluminum polishing. Final polishing with cloth wheels is often preceded by sanding with increasingly fine grades of wet/dry sandpaper & WD40. I will experiment soon with doing similar prep with a variety of media. So far, the soda blaster has done an good job of cleaning corroded or weathered parts.
The box took about 2 hours to build, then I coated it inside and out with Kilz primer, and again in the morning. It is constructed with salvaged 1/2" plywood about 14" square on ends and 2 feet long. There is 2X2 reinforcement at the edges of top and bottom, providing a good backing for the plywood to be screwed into. The end panels have the end blocking attached. They are a tight fit into the body, but can be removed if you need to work on a longer item. In that case, just use a piece of tarp or poly secured, with duct tape
or what-have-you so it does not blow off.
The top is salvaged plexiglass that just happens to have a 3/4" lip on front edge (handy but not required). It just sits on top but it could easily be fastened in place. The arm holes are 4" diameter, cut with a jig saw. A 2" hole in the top of the right end panel allows the air and media siphon hose to enter the box and a 2" hole on the back connects an old shop vac hose used as a vent.
I use a simple Campbell Hausfeld media blast gun from KMS Tools - about $18. Sixty psi is fine for most work, especially delicate parts. Higher pressure cuts a bit better but you sacrifice compressor efficiency as you increase working pressure.
The pictures show the box, the gun and the siphon which sits in a coffee can filled with soda.
The box is extremely efficient. I have be re-using the same 5 pounds of soda over and over. Eventually it will not cut as well, but I have so far done three Honda 4 carb banks and numerous aluminum parts for polishing. I store the gun, media cannister and hoses in the box when not in use. It is important to keep soda dry while in storage.
My only beef is that the siphon tip sometimes hollows out a hole in the soda, which does not always sluff in, so you have to tap the can to cause the soda to fall down. I plan to use a piece of 4" plastic pipe capped on one end and about 20" tall as a replacement to the can, and perhaps the problem will be solved.
Following the KISS principle, I just wear an old workshirt and the sleeves plug the holes pretty well. I wear a pair of unlined work gloves when blasting small items like carb jets. Not shown in the pictures, I added a boot made of inner tube on the hoses entering the box, to stop dust exiting there. Likewise I have an old shopvac hose on the back. Using soda on small parts did not create a lot of dust so initially I ran the box without these features. And I use the beast outside
For small jobs,
a small compressor is fine - just take your time and do your best to ensure your system is tight. Siphon guns leak a bit, so connect it only when you are blasting, not when you're waiting for the compressor to catch up or if you are arranging work.
You can do well even on larger parts, even with a small compressor, by attaching an auxiliary tank. Ensure that all connections between compressor and tank are tight. Leave tools disconnected and charge up the tank. If need be, stop the compressor and let it cool, then continue. Connect your hoses and tools (the things most prone to leaks) only when needed.
You can buy a media box for about $120 but this homemade version is very functional at a fraction the cost.
