Potentially Simple Alternative

[ChemE75]

Ran into this info after I decided to try making a collector for my old 2.5" rigid vac. Most all my tools with dust fittings directly fit my shop vac 2.5" hose. I'm retired and not in business so it's not a daily usage, sometimes it goes weeks unused. So I wanted to keep my cost down.

My first collector try was based on a YouTube video showing two 5 gal buckets slipped together after cutting top ridge off of one. The end facing up is cut for the hose fittings. Even with an entry pipe fitted with elbow and 45 to direct the stream down and around the inner circumference, I got a lot of short circuiting to the exit vac line so not very efficient. To be fair to the guy in the video, he was using a much smaller vac with 1.25" or 1.5" fittings. Plus I felt the limited usable capacity would a pain to constantly need to be dumped. Looking at around $50 for a tiny cyclone also did not seem like an efficient solution.

I felt a larger collection vessel with larger diameter top would help by allowing better separation between inlet and exit. Better yet if it was somewhat tapered to encourage a cyclonic action. I got lucky, found a local guy selling surplus 35 gal plastic drums with top closure rings. They even have a bit of taper from top to bottom without ridges, clean and smooth inside and out. I cut a new top from some 7/16 osb scrap I happened to have on hand.

Now, before I saw this idea which does seem effective, I simply used the 5 gal bucket from my first try with the exit pipe coming up through the center so it hangs inside the from the top and acts as both an inlet cyclone enhancer and as an exit air baffle. Initial results are looking great. I saw no new dust in the vac. I just recently used it for finer dust from my RO sander and so far it seems effective. I just got a new vac filter so will install it soon to better test it for carry over. Photos aren't great but get the idea across. I figured if it's not effective, then I'll make a baffle plate. But I had the bucket that already had the hole for the pipe so figured it was easiest thing to try it first. So far, so good.