Tales from a Ventilation Lunatic

[rvpopeye]

The links worked for me too.
They didn't work for you Cammie ?


Try this one.
https://www.ebay.com/itm/2-Pack-HEPA-Car...SwaJ9cRzQe

[sternwake]

I wrapped delta hepa with the charcoal pre filter.

did a quick side by side 20 gallon trashbag test, dialing in same wattage of papst and delta fans.
The delta fan wins easily in the flow department, the papst.is.much quieter and maxes.out at 2.2 amps.

The delta.fan hepa dialed up to at 2.2 amp draw, fills bag nearly instantly and rips it off.
It will draw in excess of 3 amps.turned all the way up, but is LOUD!
Ill estimate 85 to 100 cfm at max speed.

The Delta HEPA is much lighter and smaller, easier to hang up out of the way, And it.does not screw.uo with my vhf hi tv reception, like the buck/boosted papst fan does, at higher rpms.

[sternwake]

Well, I noticed that I was not awaking with a stuffy nose, attributing it to my new magical filter, then on night 3 one nostril said Ha Ha futhermucker.  It might help in this regard, it might not.

I removed my  3 fan, acrylic intake shroud, in order to retint that conversion van window.  Long ago, 2007 and perhaps even earlier, I used Nylon screen and backed that up with fine mesh galvanized chicken wire, for security.

I noticed last year I had to dig out and vacuum away,  some white powder from base of mesh, from outside, and when I removed fan shroud the white powder was everywhere along the bottom like somebody got some of that just add water filler powder that turns to rock, and forced it in with a putty knife.

The aluminum window frame, basically dissolved in portions.  The little rubber strip that one uses a roller to push into the gap to install the screen, had turned to this white rock.  It took me a few hours, sharpening  and resharpening dental pics to get all the old rubber out, and then I busted out the dremel and wire wheels and drill bits and cut off wheels and carbide burrs to attack the rest of the white rock.

Everywhere adjacent to where the aluminum had dissolved, was super soft and the carbide burr/ drill bits on dremel, just turned it into a fine white powder.

There was even a hole rotted in the sliding track,  so any water in the window track would just drop inside, and the steel below rusting.

The metal body of the Papst fan is also showing some white corrosion.

The galvanized mesh  has dissolved in parts as well.

I've ordered some stainless steel mesh and will likely forgo the bug screen.  I think I will attach the mesh  to the acrylic fan shroud, rather than the window frame, and beef up the shroud and attach it more securely.

  This will allow for making  better seal around the acrylic shroud and window frame, and also pushing the mesh a bit further from the back of the fan blades, reducing resistance,  increasing flow.

Glad the weather has been nice and cool and I don't need the intake shroud, but I still miss levitating my bedding.


   
   
   

[rvpopeye]

It's always something...more fun than mowing lawns though.
I wonder if those low temp propane torch melt aluminum brazing rods would work without lighting it all on fire ?

[GypsyDogs]

It looks like you had gremlins chewing on it! Weird. Glad you caught it. Any other windows going to need attention too?

[Cammalu]

Stern what on earth could have caused that? It wasn’t touching dissimilar metal somehow?

[sternwake]

My window opposite the dissolved aluminum one, seemed OK regarding corrosion the other week when I cleaned its track.
It is closed 99.99% of the time. My feet at night are in close proximity in this area at night, and even the thinner fans would be in the way.

There has to be some sort of dissimilar metal thing going on, enhanced by the consistent nightly moisture, and the fact that salt air and whatever else gets stuck onto galvanized mesh from fans pulling so much air through it, as well as the nylon screen, gets concentrated at the bottom which was most degraded/dissolved.

Also with these 3 fans on their relatively tightly fitting shroud, they are able to force so much air inside, to the point it makes it difficult to close the side door without slamming it, that some of the high pressure air does seek the path around shroud's edges, especially at bottom. Extra oxygen forced through to increase rate of oxidation and perhaps concentrate possible dissolving catalysts. I do leave this window open when driving so any and all road dust in teh area gets pushed through, and without the shroud int eh window air would enter these windows at highways speeds. more so with front windows open.

I went through some ancient pics, and the galvanized mesh/ tight pore chicken wire that I used, was installed in 2002, but I did not start force feeding this window with fans for several years. They were just passive vents often left open. I did paint the mesh black several times over the years, but it flakes off. The mesh individual wires would turn white and I'd use a fine wire brush to clean it and open up the pores, whenever I cleaned it.

I did shatter the one window once a while back, slamming it, and replaced it with 1/4" thick smoked acrylic , that is now showing its age through crazing and scratches.

Could a swore I ordered a 12x24 piece of stainless steel mesh, but 12x18 arrived and is what I clicked,grrrrr, and is just not quite enough for the plan. Which is to make it look like it is securely attached to the window frame instead of shroud itself.

Buyer pays return shipping....... which is just about half of what it cost. Oh well. Ordered a bit smaller pore 12x24" SS mesh which should be a bit easier to work with.

I intend to have new SS mesh attached to acrylic fan shroud, instead of window frame with better gravity assisted moisture deflection, and no more dissimilar metals in direct contact with each other, other than SS screw to aluminum frame holding white oak tight against interior van body. No way around that, and the SS screws themselves did not show any corrosion, once cleaned up of the white powder on the threads.

I suspect the galvanized wire mesh was at the root of the dissolving aluminum window frame. But perhaps SS and Aluminum react with each other too with moisture present and enough time and oxygen.

No more permanent nylon screen in the equation, but can always be added should I enter a small buggy zone.

New plan presents opportunities, and issues. I can push the mesh further from back of impellers now for lesser resistance to flow, and lesser noise, but the mesh was part of the shroud's retainment method previously, and without the mesh, it does not quite fit right, and lower oak window frame needs some more wood and epoxy.

Also, the galvanized mesh, attached to window frame itself gave more security than the acrylic shroud by itself will, as is, so I am going to beef up the acrylic in the weakest areas, and hold it to window frame in more places. Not impossible to get through it to steal fans and whatever can be reached, but likely the same effort and noise levels as smashing a window to get in.

The acrylic shroud has been painted black. The acrylic solvent glue requires both bonding surfaces be free of paint and saw/ sanding block grooves, and fit perfectly together, and it basically solvent melts one piece into the second. This perfect mating surface, is a pain in the keester to achiev, and any gaps, do not get filled, but stay as gaps, weakening it.

I found I can achieve an excellent bond of acrylic, with my epoxy, but the mating surfaces need to be very rough, which is much easier to achieve than perfectly flat and smooth.

But epoxy is not really happy above 160f, and not happy with UV light beating on it either.

Every freaking project...... complicated to the N th degree.

This started with a dental pic and a vacuum picking out white powder, and now I am rebuilding the whole freaking window frame and redesigning the shroud.

As long as I can do it without adding a HEPA filter, I should be OK.
Maybe.

[rvpopeye]

Situation well in hand.

[sternwake]

The 12x24" #8 mesh I ordered second, from E bay, arrived in less than 24 hours from the time I ordered it.

Also, 30cm= 23.6 ish inches, and it is advertised as both 12x24" and 30x60cm.

Glad I do not need the full 24 inches.  When I first unrolled it, it was less than 23.5 inches but flattening it, removing the rolled up memory,  stretched it almost 1/4 inch.

The 24 wire mesh is the same wire and pore size as the 18" wide piece ordered from different seller, but the stainless is slightly different color, though both claim to be the 304 stainless alloy.   Neither are slightly magnetic like some 400 series alloys can be.

The 18" arrived in a flat cardboard backed padded envelope, the 24 came rolled up into a box 3 inch x 12" square box, and took significant effort to straighten and flatten, but was also 10$ cheaper than the 18".

The SS is much stiffer and stronger  and with larger pores than the old corroded galvanized mesh.  It should still prevent most larger bugs from being sucked inside, provide a smidge more security, or at least appear to, and present less resistance to air flow.

I'm thinking of JB welding some SS  machine nuts to some aluminum instead of previous fastening system which relied on custom shortened screws to grab the two sides of the screen track on top an one side.

But more importantly I want the freaking fans back in the window and operating.  The  forced influx of fresh air is sorely missed.  I can open the window and crank up the exhaust fans to pull fresh air through the aperture, at a decent rate, but it is nowhere near as effective as even just the Papst fan at its minimum speed.

I'd also grown in the habit of making my bed while brewing coffee, and hooking the bottom fitted sheet over the edges of the fans, turning them to medium speed or higher, and the bedding lifting off the mattress like a bouncy house.  I will also just do one layer of bedding at a time, increasing fan speed for each layer as needed to keep bedding levitating.

Not having this ability to force all stale air and body condensation from sheets and blankets, is sorely missed.

Its kind of strange that at first, the air forced through bedding is not so pleasant smelling, but after a period of time starts smelling like laundry detergent, instead of human, and sheepdog.

[Cammalu]

I think I’d like to see how you are doing the sheet airing. That must be a trick. Great idea