Brian I have never seen a speck of dust come from the exhaust of my bee vac that was visible to the naked eye. I have however seen a lot of dust come out of the exhaust of a regular shop-vac when vacuuming sheetrock dust or other types of dust when a large amount is hit at one time, even with the manufactured filter attached. (Many times). Though it might have happened, I have never heard of shop-vac catching on fire when used in nasty-dusty construction circumstances, no matter what source of dust material was being vacuumed. Where I have made cutouts I have yet to find a numerous amount of dust except for bits and pieces of loose derbies caused by deconstruction when making or cutting my way in to reach the hive. I have never found "bees wax dust". I have however, found (bits of insulation inside the catch box) though rarely, I have found very small pieces of comb from time to time, very small because I have my suction set for picking up very light objects such as bees. Anything heavier is not picked up by my vac. As stated before, (Reduced Suction) is the key to not killing bees.
No derbies are found at the top of my catch box where the screen is located. Never have I found any insulation, or anything else on, or stuck to the 16" wide by 19 7/8" long catch box screen. Adding I have ran this vac for as long as 3 hours straight, numerous times, when doing a difficult cutout, I would be afraid to guess how many hours this vac has ran. Hours upon hours all total, counting a few cutouts and several swarm recoveries, at least 30-40, and no sign of motor failure or fatigue is present. But if it would ease your mind, lol, I could easily attach an adapted filter to the bottom of the cut off vac housing made of Shop-Vac filter material in a few minutes easily, 🙂flush so nothing changes the results or dynamics of this bee-vac.
Being you are experienced with vacs etc I am surprised you are missing the point of this design. Perhaps you need a clearer description on my part to relate the set up to you. The motor is on top with a sheet of pegboard beneath. Their is an empty space between the motor and the pegboard 16" wide by 19 7/8" long where there is nothing. Not a thing, only empty open hollow space. This hollow space between the two, allows suction build up for an even suction across the entire pegboard. Which equals an even suction through the peg board holes, which equals a equal suction through the catch box screen. As stated, the pegboard dimensions are 16" wide by 19 7/8" long, same as a langstroth bee hive. Each individual peg hole is a suction inlet in itself, independent of the other, with an evenly distributed suction through the individual peg holes throughout the entire top of this set up. There are hundreds of these peg holes in this vac pegboard, making hundreds independent suction inlets to the vacuum motor itself. Beneath this, is the screen, which is attached to and independent catch box, same size, 16" wide by 19 7/8" long. The vac box with the peg board is set on top of the catch box/screen with a perfect union fit, and an added seal from the diameter of the rim of the pegboard where the two meet, now making one joined unit.
A hose hole is in place at one end of the catch box for the benefit of the suction hose attaching. Suction friction is a constant equal throughout the hose travel from the time the bee enters the hose to the time the bee exits the hose into the catch box. Once the bee and or a derby reaches the catch box as described, pressure is instantly relesed inside the catch box because of the design of the many suction access holes of the peg board before reaching the suction of the motor. (Physics) The scution of each of these hundreds of peg holes are greatly reduced individually. The bees come in for a soft easy landing. This is why no foam is needed for the opposite end of the inlet box. Bees do not need protecting from crashing or being banged around or against the other end of the box. Nor are there any derbies coming crashing in, banging against the opposite side of the inlet box or the screen for the same reason. Bees come in for a soft easy landing. Whatever you may vacuum instantly settles to the bottom of the box. Derbies large enough to bee vacuumed, such as a bee for instance, are not (pulled) to the top because of the greatly reduced inside pressure of the design, (thanks to the peg board). Now, If we were to purposely cover X numbers of peg holes then things might start changing if enough of the holes were purposely plugged. Slowly increasing the suction pressure of what is in the catch box, If enough of these holes were reduced to an area equal to the area of the size of the vacuum hose openiing, then we would have that same pressure inside the catch box, but we don't because of design.
As far as the pool hose I agree, the smoother the better. The pressure relief valve that Jim and I are talking about if for the benefit of the reduced suction, With my design it is mainly for hose pressure suction reduction. As 2Sox stated to many bees coming in at one time could cause clogging. You can read the following from post 38 where smooth hose was mentioned and covered.
"For my hose, I searched for a pool vac hose, and not just any pool hose. I have found that though (ridged) on the outside, some brands are almost smooth on the inside, which is just what we need in my opinion. I found this "perfect hose" at either Lowes or Home Depot, I am thinking it was Home Depot. 50' I cut it 20'/30' giving me two hoses."