How to Build a DIY Soot and Dust Trap for a Shop Vacuum Cleaner

A store bought dust trap can be pricey and a soot vacuum is even more expensive, but you make one yourself for next to nothing. You can scavenge most parts and you might already have some of them collecting dust in the garage. The idea is make a water trap to collect any dust and soot that is small enough to pass right through the filter on a common vacuum cleaner. I built my soot vac from a 5 gallon plastic bucket, but any other container with a locking lid can work. A tall thin bucket should work better than a short fat bucket. The tall bucket can catch more dust because the dust will be in contact with the water longer. My bucket is short, but I choose it because it has a screw on lid. Soot can be very messy and I did not to risk making a splash when I popped the lid off of a standard bucket.

I cut two holes in the lid of the bucket. I used a $3 harbor freight hole saw kit, but a razor knife will work if you are careful. One hole is for the hose from the vacuum and the other to suck up the mess. The hoses need to fit tightly into the holes. Electrical or foam tape can be used to take up any play and provide a good seal. The hose from the vacuum should only pass about 1 inch through the lid while the other hose needs to reach the bottom of the bucket. Any large diameter hose can be used. I had some corrugated black plastic hose for a sump pump from a left over project. It's cheaper than most hose for a shop vac, but it's smaller and cuts down the air flow a bit. Just fill the bucket about 2/3 to 3/4 full of water and attach the lid. You need to leave some room in the bucket because the water will bubble and foam. If you overfill the bucket water will be drawn into the vacuum.

To use the water trap just attach the suction hose to any standard garage vacuum. Normally I remove the filter from the vacuum if I'm working with water because a wet filter is a ruined filter. A dry filter can be banged out and reused, but if any dust gets through the water trap I want the filter in place as a back up. If you have ever tried to clean up after sanding down some newly hung drywall you know how fast your filter can clog with dust. Some of the dust is small enough to make it right through the filter and your vacuum will blow the dust all over the house. Cleaning a dirty boiler furnace or oil burner can be even worse. You would need a vacuum with a special filter to catch the soot. This water trap will work very well for both jobs. You do loose a bit of suction through the extra hose and the water. You might not pick up small stones or screws like you would without the water trap, but there is plenty of power to get the job done when it comes to collecting dust and soot. Remember to keep an eye on the exhaust port of the vacuum to make sure the water trap is working. If it's not working there will be visible dust blowing from the vacuum. Stop to check your hose connections and water level. Also remember to replace the dirty water with fresh water. If you have a lot of dust to clean up the water will turn thick like pancake batter and stop working. A larger bucket will need to be emptied less often than a smaller one. Carefully disconnect the hoses and carry the unit outside when you are done. Dust and soot can drop out of the hoses and make a mess in the house.

Locating the parts.

A new 5 gallon bucket can be purchased from your local Wal-Mart or home store, but a contractor, handyman or bakery might get you one for free. Hot water and a rag will quickly clean out an old sheetrock joint compound bucket, even if the compound is dry. The bucket I used was for swimming pool chlorine and it had a nice screw on lid. You can use shop vac, sump pump, swimming pool or any other 1-3 inch hose to connect the water trap. Swimming pool hose is often tossed out if it has a crack or pin hole. It can be cut where it is cracked and used for this project. As you can see in the photo I had to use foam to seal the hole where my vacuum hose entered the lid. I was using a shop vac with a larger hose before, but I switched to my small Dewalt vacuum for this boiler cleaning. This isn't rocket science as long as the dust is bubbled through the water this will work for you. Locating and sealing any leaks will increase your vacuum power.

Be sure to view all of the photos attached to this article. I have an article of this soot vac being put to good use cleaning my tarm wood, waste oil heater.