The Ridgid Shop Vacuum WD19560 was testing and compared to three other shop vacuums. The Ridgid came out on top, but we learned some tricks on how to dramatically increase the performance of shop vacuums when you need it.
The Ridgid Shop Vacuum Model WD19560 was tested against three older shop vacuums using an inexpensive setup and methodology that can be easily duplicated. Two inexpensive instruments, the Kill A Watt meter and the Smartphone Anemometer provided all the electrical and flow information needed for accurate comparison of four shop vacuums. As you will see the Ridgid Shop Vacuum WD19560 is a wonderful machine that clearly met the manufacturer’s performance specifications, and in some conditions exceeded them. The Ridgid Shop Vacuum met all of the performance requirements for digging holes with a Holey-Moley Digger.
- Shortening the hose length from 7 feet to 3 feet doubled the material pickup rate for all vacuums.
- Smaller Shop Vacuum performance improves up to 150% with larger diameter (2-½ inch) and shorter hose length. In some cases the 8 Amp Shop Vac out performed the 12 Amp model.
- Increasing hose diameter to the largest diameter the shop vacuum will allow increases flow rate.
- Removing the air blower cap improves intake airflow rate
- Dirty filters decrease performance.
Finding the right vacuum for digging fence post holes
I was in the market for a new shop vacuum for powering my line of Holey-Moley Fence Post Hole Diggers. These diggers, are incredible tools that can feed a shop vacuum with dirt, sand, and gravel, and any number of other things dug up, at rates measured in pounds per second. These hard to believe rates push shop vacuum operating limits and demonstrate a new realm of usefulness for these amazing machines.
My best choice
After following my own recommendations on Selecting The Best Hole Digging Shop Vacuum, I purchased a Ridgid WD 19560 Wet/Dry Vacuum. The 6.5 HP Ridgid is rated at 12 Amps, the maximum allowed for an appliance. This tells us the unit should be at the high end of the performance curves. I also wanted the highest air flow (CFM) available and the Ridgid is right up there with over 200 CFM. Large wheels on the rear, a sturdy frame, a stainless steel can and a removable handle were important if I could find it.
The Ridgid WD19560 was my choice for several reasons
- The Ridgid has a respectable 203 CFM airflow rating, just what I was looking for.
- It has large sturdy wheels and a 16 gallon tank that will easily hold everything a five foot deep hole can produce, it is made of non-rust stainless steel, and there is more than enough room for storing the hose inside the tank when finished. When digging 6-inch diameter holes, in dry sand and clay, two gallons of soil will be produced per foot of depth and each gallon weighs close to 10 pounds. See the blog article Hole Volume Calculator to determine the weight of various materials removed from any size hole. A five foot deep hole can easily produce over 100 pounds of material, a serious amount of material for a shop vacuum to hold.
- A strong removable handle on the Ridgid WD19560 was a plus. This is a very attractive attribute especially when putting it into the back seat or trunk of a car. It will also store under a bench without the handle. This compares to the 90L650A 14-gallon Shop-Vac I purchased at Lowe’s a few years ago (#2 in the photo below) that doesn’t have a removable handle. It won’t fit into my car trunk. This makes traveling a pain as it will only go in the back seat. When looking for a space to store the Shop-Vac, it seems the handle is forever getting in the way. The Ridgid handle has a 90 degree bend to the rear which provides good leverage and a good stand off distance for pushing or pulling without having your feet hitting the wheels.
- The Ridgid Shop Vacuum has a 20 foot cord that is very handy which eliminates the need for an extra long extension cord. At my home the entire property is accessible with the Ridgid and standard outlets.
- The blower port on the Ridgid Shop Vacuum comes in handy for blowing off the outside of the unit and blowing out hoses and cleaning off equipment. This was not one of my criteria for selecting a shop vacuum, but when I started using it to clean up equipment as well as my clothes, I found it to be very handy.
- The plastic and stainless construction of the Ridgid Shop Vacuum allows for a complete wash down. There is nothing like being able to wash dirt and damp soil off of a piece of equipment before transporting it. It can be wiped down with an old towel in minutes and it is ready to go.
- One of the best surprises associated with Ridgid Shop Vacuums is the new washable CleanStream Filter available right next to the vacuums at Home Depot. This filter is good for wet and dry use and is easy to wash off. From their web page it looks like they have filters now for Shop-Vac units. It is real handy to be able to wash a filter off, especially after working with fine materials such as cement and drywall dust.
- Ridgid has a Limited Life Time Warranty on the Shop Vacuum. This covers unexpected early failures and defects in materials and workmanship however it does not cover misuse or normal wear and tear.
I compared this new Ridgid WD19560 to three other vacuums that I’d been using for digging holes. One, the Dayton, is over 20 years old so it was fun to add it in on the testing to see how well it performed.
The Ridgid Shop Vacuum Three Other Test Vacuums
- Ridgid – Model WD19560 12 Amp, 6.5HP, 16 gallon – New 2016
- Shop-Vac Model 90L650A 12 Amp, 6.5 HP, 14 gallon – Approximate 2005
- Shop-Vac Ultra Plus Model 87M300, 8 Amp, 3HP, 6 gallon – Approximate 2005
- Dayton Model 2Z205G, 6 Amp, no HP rating, 5 gallon – Approximate 1996
The four Shop Vacuums were tested for their ability to pickup 15 pounds of mixed gravel and 25 pounds of mixed dirt, sand, and gravel. In addition, the airflow rate, amperage, voltage, and wattage were measured with the hose full open to the atmosphere and again fully closed to the atmosphere the highest static suction pressure condition. Finally, the initial flow condition was measured using 7 feet of 2-½-inch vacuum hose (standard with the Ridgid) and a clean filter. The 7 foot hose was used in the pickup tests as well. The same tests were repeated using a 3 foot section of 2-½ inch hose to see how hose length affects flow and pickup rates. The shorter hose allows for high airflow rates (if the vacuum can produce it) and thus a high amperage load.
The test units (7) were run with either a 7-foot length of 2-½-inch hose (9) or a 3-foot length of 2-½ inch hose (8) connected to a 4-foot long flow section made of two feet of 3-inch diameter pipe (4) transitioning to 2 feet of 4-inch diameter pipe (3) opened to the atmosphere at the end to achieve smooth flow across the opening of the pipe. This is where flow measurements were taken (2) with the ABM Smart Tool Anemometer. Location (1) is where the Kill-A-Watt EZ meter readings were taken. A dirty filter (5) and a clean filter (6) were used in various tests.
The flow rate was measured at the end of the pipe using an ABM-100 Smartphone Anemometer connected to an iPhone. There were several reasons to use a flow section. First, the air velocity in 2-½ inch hoses exceeded the capacity of the meter and second the need for smooth laminar flow across the airflow inlet. The flow section provides both of these and works very well with the ABM-100 Anemometer.
During the 30 second flow measurement period, Amps, watts, volts, and frequency were measured using a P4460 Kill-A-Watt EZ meter by P3 International. This same information can also be obtained with the P4400 Kill A Watt meter.
Kill A Watt EZ inline power meter
Shop vacuums use the most amperage when running with a full open hose. This is because the units are moving the maximum amount of air. Under a full closed vacuum, there is very little air for the turbine to work on and thus the current is much lower. In our testing we were interested in the amperage and airflow when the hose was 100% open (full flow), and how this compared to the Manufacturer’s sticker (Amps) and airflow (CFM) ratings. The data is summarized in the table below:
Test Results – Flow
- The brand new Ridgid Shop Vacuum Model WD19650 lived up to expectations with a measured flow rate almost exactly the same as the manufacturers sticker rating.
- The 12 Amp Shop-Vac 90L650A surprisingly exceeded the manufacturers specification. The screw-on plug that blocks the blower port was removed. This increased the airflow by 12 CFM or 6.7% above the manufacturer’s specification. This vacuum came standard with 12 feet of 2-inch hose, so the 7 foot 2-½” hose provided significantly more airflow.
- The Shop-Vac 87M300 produced 136 CFM 6.2% below the 145 CFM rating, even with the blower port plug removed. The bearings in this unit failed by the end of the testing and this may have been the reason for the lower than expected flow rate. (see note 1) This unit came standard with a 1-½ inch hose, but was tested here with the same 7-foot, 2-½ inch hose that plugged right into the unit. This gave us a direct comparison to the other vacuums tested.
- The Dayton shop-vacuum, used for digging holes for nearly 20 years. This vacuum produced 108 CFM which was 18.2% lower than the manufacturers specification. This vacuum initially came with a hose that was about 6 feet in length which is 16.7% shorter than the hose used in the test. I suspect that the vacuum is right on, meeting the manufacturer’s requirement. This simple vacuum has continued to perform well over many years.
Because the larger diameter hose allows for more airflow for the same HP, using the 2-½ inch hose provided an opportunity for the two Shop-Vac’s with smaller hoses to out perform the manufacturers specifications and the Shop-Vac 90L650A did just that.
Test Results – Gravel and Rock Pickup Rate – 7 foot hose
All four test units were timed for their ability to pickup 15 pounds of mixed gravel and rock and 25 pounds of gravel, sand and dirt. This was an excellent test to check vacuum performance which pushed the units to their performance edge. The following chart shows the results using a 7 foot 2-½ inch diameter hose. The Airflow measured was lower than initial flow test results because slightly dirty filters were used. Instead of new filters being used for each test, filters were banged off and vacuumed off a bit to bring them back to a neutral position for the next test. This seemed to give consistent results. The 25 pound load is 66% more than the first 15 pound test and we would expect the pickup time to also be approximately that much longer.
- The Ridgid Shop Vacuum (16 gallon tank) with the higher recorded airflow rate of 204 CFM had the fastest pickup rate. The surprise was the 95% increase in time between the 15 pound sample and the 25 pound sample. This can be attributed to the fine dust that started clogging the filter and the amount of time it took to pull down a vacuum on the 16 gallon tank when a suction demand was required to move the sand and dirt piling up along the hose. The Riddgid pulled in 15 lbs of mixed gravel in 22 seconds. The pickup rate was 0.68 lbs/sec.
- The Shop-Vac 90L650A with the second highest flow rate of 140 CFM (22% lower than the flow test) came in second on the speed pickup test. What was interesting was the 120% increase in time between the 15 pounds and the 25 pounds. The 77 seconds for 25 pounds was the longest time of any of the units. This Shop Vac has been my favorite for a number of years for digging holes. Based on the performance drop of the Ridgid I expected to see a similar drop in the Shop-Vac. However, coming in 25% below the Ridgid was unexpected. The pickup rate was 0.429 lbs/sec.
- Finally, the Shop-Vac 87M300 had some impressive results pulling in the 15 pounds in 33 seconds. The pickup rate was 0.455 lbs/sec.
- The Dayton did came in 4th with 15 pounds in 51 seconds. The pickup rate was 0.294 lbs/sec.
Test Results – Gravel and Rock Pickup Rate – 3 foot hose
The flow rates of the four vacuums were measured using 6 feet of 2-½ inch hose. This was then compared to 3 feet of 2-½ inch hose. In both cases clean filters were used. The following flow changes were seen when cutting the hose length in half.
- Ridgid 12 Amp decreased 41 CFM from 247 to 206 CFM, a drop of 16.5%
- Shop-Vac 12 Amp decreased 23 CFM from 215 to 192 CFM, a drop of 10.7%
- Shop-Vac 8 Amp decreased 23 CFM from 159 to 136 CFM, a drop of 8.2%
- Dayton 6 Amp decreased from 4 CFM from 112 to 108 CFM, a drop of 3.5%
The following chart shows the increase in time to move 15 lbs of mixed gravel when doubling the hose length.
Summary Test Results – Pick up rate
When moving mixed gravel and dirt with a shop vacuum, air flow rate (CFM) is the major factor. Which one moves the most pounds per second of material is the best test. When we look at the chart below three things pop out.
- CFM is the prime mover that moves dirt, the more the better.
- Dirty filters decrease the flow rate.
- Decreasing the hose length by half will improve the material flow rate by over 100%
- It appears that smaller tanks recover static vacuum quicker. When needed this helps make up for some of the losses due to having less volumetric flow rate.
- The Ridgid Shop Vacuum was able to move 15 lbs of mixed gravel at an incredible 1.36 lbs/sec.
The Ridgid meets all the criteria
There is no doubt that the Ridgid Shop Vacuum Model WD11950 met all of my criteria. The next step was to see how well it performed on the job. I connected the Ridgid Shop Vacuum to a Holey-Moley Fence Post Hole Digger to see just how fast I could dig a hole. In conclusion, the Ridgid Shop Vacuum, handled all the dirt that the digger could throw at it. I was able to dig a 4-½ inch diameter hole, 40-inches deep in 3 minutes. Consequently, the weight of the soil removed was approximately 36 pounds. In addition, the rate was roughly 12 lbs per minute or 0.2 pounds per second. This was working at roughly ⅓ the measured capacity in 6 foot hose. See the Holey-Moley 4-½ inch Post Hole Digger video to see this tool in action.
The photo below shows the Holey-Moley Fence Post Digger hooked up to the Ridgid Shop Vacuum. The combination of the two tools makes digging fence posts a breeze.
(1) I called Shop-Vac Customer Service and was able to purchase a replacement motor for $40 which included shipping. They shipped it out right away from stock. This unit was out of warranty but still serviceable. Spending some time shopping around I may have been able to do better than this.