Thread: Shop Vac for Sanding

Those mini cyclones are available in AU for reasonable cost, bought two a year ago for around $30 each delivered, absolutely fantastic and worked way better than I thought it would or should, still nothing in the external mounted Shop VAC after all this time -> (EDIT) -> This is used for general clean up and floor vacuum, NOT fine dust collection - hence very little fine dust in the material, a 3HP DC takes of that. The cyclones are only around 300 mm high and 150 mm wide at the top, very compact.

I made a simple waterproof enclose for VAC and placed a large intake slot in the bottom. I have the mini cyclone inside the workshop mounted on round thick plastic bin 900 mm high ($20), a deep bin worked better than a small shallow one for me and reduced the swirl action in the bin that can cause fine dust to hang around the lower cyclone port. The noise from the cyclone is the same as the noise from the ducting, virtual nil. Ducting runs of 50mm are not as restrictive as bigger diameter DC runs, especially with hard ducting. One of the most used devices in workshop and keeps those floor shavings, general dirt, rubbish and metal drilling and sanding remnants out of the main 3HP DC bags, one of the reasons our small workshop is kept so clean.

I'm using this setup. It's a 20lt paint tin (bought from a paint shop) that's totally sealed. Mounted on top is a dust deputy cyclone and a Pullman industrial shop vac. I already had that shop vac, I didn't pick it specifically. I agree the cyclone works brilliantly. It traps the greater majority of dust & chips. I do still clean the filter, just not as much.

I'm still looking at a plumbed solution for this application tho. I'm interested in putting it in my dusty enclosure and running 50mm pvc as Bob recommends. I'm just waiting to hear how much 50mm I can run.

all the shop vacs i've seen from Bunnies have a 36mm diameter. should i be looking for 50mm? they don't seem "cheap" or readily available.. but i might be looking in the wrong places...

Mine is 36 but it seems to work well with 50mm flex

Originally Posted by johnredl

Mine is 36 but it seems to work well with 50mm flex

Ahh sweet... I thought I was missing something.

Don't use more flex than u need as it cuts down airflow

I run 4m of 65mm duct off a Festool CT26 vac with no appreciable loss (i.e. still plenty of suck). From the end of that I might have 2m of 50mm flex or up to 7m of 36mm flex. When the 7m length is on there is some noticeable loss, but not too bad and after all it is going through 11m of flex/duct - certainly plenty to vac up the deck outside the shed, but capturing fine dust would be diminished (say for sanding). For the sanding station I have a separate branch of duct for about 3m and then about 3m of 36mm flex. The suction on the end of that is pretty fierce. Everything is controlled by homemade blast gates.

I had a thread on it but the pics got nuked, although they are still in my library, but without explanatory notes. If requested I can comment on them. Those pics do not show the latest version of the ducting, but the functionality is the same.

Here is the back end of the system:


With the flex you need as smooth a wall as possible - i.e. don't use pool hose. The corrugations will knock the power off the suction quite significantly and they also accumulate dust.

The total length you can run also depends to some extent on what you are doing with it. I don't use the VAC for dust collection, only for the previous posted clean up, and cleaning tools and machines when needed.

I have the VAC mounted on the outside of the workshop wall, there is a short 50 mm pipe through the wall, one side goes straight into the VAC intake. Inside the shed, the cyclone and bin are connected to the wall fitting by a short 200 mm piece of flex. I have a 4 metre length of quality flex that reaches everything needed and also a 1.5 m hard extension floor vacuum than extends that length to 5.5 meters, most of my machines are moveable and on big locking castors. I cannot notice any loss over the length as far as chip and cleaning goes, however it may be noticeable if you are forced to use this system for any form of limited dust collection.

BTW If I remember correctly, BobL may have carried out measurements on Vacuum cleaners and flow rate loss in small VAC ducting. Might be worth search BobL posts.

EDIT: If you look at the picture in the previous post above, that looks identical to the flex I used, it was the smoothest "internal" walled flex I could find and is the same quality as the short 100 mm and 150 mm flex I use occasional.

Originally Posted by Dibbers

all the shop vacs i've seen from Bunnies have a 36mm diameter. should i be looking for 50mm? they don't seem "cheap" or readily available.. but i might be looking in the wrong places...

The ShopVac brand comes with 35mm hose and fittings BUT the inlet is actually 50mm with a reducer. Pull out the reducer and you have a 50mm inlet

IMG_0954 (Edited).jpgIMG_0955.jpg

Also has a 50mm outlet that I run outside the shed

Here is the thread I mentioned in post #24. Flow loss using a Dust Deputy

This is page 2, where Bob tests the loss through a DD mini cyclone. It's worth reading the thread from the start, as usual in these threads there is the usual misinterpretation of short post material (we all get that) and some "slightly" heated exchanges, but it's worth the read with some valuable real world testing being carried out. Be careful when reading these posts as certain assumptions are made, by all, this can be confusing for those new to dust collection and extraction, but keep at it and you should be able to come to grips with it.

NOTE: The correct mini cyclone to get has an intake ramp, not the older style with the straight intake and no ramp, this was mentioned in a previous post.

Mike.

This is usually glazed over in many threads, but I did some testing with a low height 300mm bin and bins between 600mm to 900mm in height. The results indicated that over time, a shorter bin has more fine dust suspended in and around the cyclone dust exit port causing more fine dust to be pulled up into the VAC.

With a 600mm or higher bin and an old pleated filter on the shop VAC and mini cyclone with ramp intake and 900mm bin, there has not been a single chip in the VAC bin. The filter after 6 months had a slight amount of fine dust (not visible) when I put the filter in a bag and hit it a few times there was almost nothing in the bag. I have also pulled the VAC down to check the motor and foam filters with the same result, virtually nothing after 6 months of use in our workshop.

Even more surprising, a particle counter mounted inside the VAC outdoor weather proof housing showed only a small change in particle counts when cleaning up dust shaving and material from below the lathe and general floor and workshop cleaning.

This is mainly due to the fact that this system is NOT used for Dust extraction of tools or machines, it's not subject to very fine or invisible dust. This is an important distinction as fine dust would pass through the VAC filter and also contaminate the VAC internally in a much shorter time if this were the case.


FYI found a link to cyclone in AU: https://www.ebay.com.au/itm/Industri...item4656e3d208