new air conditioner for brunnhilde - part 6

I has been pouring rain here. Early on Halloween day I woke up with a cold sweat because I realize I was a dumb ass. I cover the 15x24" opening with 2 sheets of polyethylene remodeling clear sheet and duct-taped around the raise frame. I didn't think of when the rain water accumulates it becomes a bowl. The weight of a few quarts of water is significant.


I went out and check at 4 AM. Sure enough huge amount of water had collected on the plastic sheet . I push the wrap from under to pour out the water. Problem there was may be 2 quarts of water between the two layers because the outer layer has a small hole. A bit of water did get in but no damage was done.

later that day we had our biggest downpour of the year; soon the street begun to flood as the storm drain was overwhelmed by the amount of water

the stupid Portland Trimet driver (and the supervisor he consulted) was stupid and reckless enough to cross a flooded spot under an overpass and flooded the inside of an electric transit train

there were many pounds of water collected

I took the dry break and cut a piece of artist cardboard foam sandwich and put another layer of plastic on top. That would make me sleep better the next few nights.

this is a much better design

there are a lot to consider for the planned installation of the Mach 8 Cub air conditioner due to a lot of difficult constraints

considering some preliminary ideas of the plenum design

While I set myself a goal to take the trip to purchase sheet aluminum, the day will past with the goal unfulfilled. Only until I felt I have a good final plan as well as the exact outer dimensions of the material needed that I took the trip to a local metal supplier. One reason is to avoid the need to trim the sheet aluminum down to size by specifying the correct one and have it cut by the suppler.

my work-in-progress scale dimensional drawing for the aluminum plate

Went to shop for AL sheets today. I went with 1/8" 5052 AL. I bought a 32"x45" and an 15 1/8" x 27". Went to the metal shop nearby but the smallest edge bend they can make is 5/8". They also want too much money for the 3 bends I want, so I said I would pass.

Fortunately I went with 1/8" and they should be stiff enough without the folds. I also had been thoughtful to plan for the width - with folds and without folds without having to trim for the latter.

Got busy that late afternoon to round off the corners of the top sheet and smoothed out all the sharp edges. I am ready to carefully start marking the cut lines of the 13 5/8" AC opening.

BTW, I realize I can use the Kerstner AC's 6 mounting holes to locate them onto the top AL sheet. They are not the most precise as the holes may be a bit on the large side but should save a lot of time and effort.

The price of the AL is quite reasonable when I told him I want to pay cash.  Cut to exact dimensions I need. 12.9 sq ft of 1/8".

I will attempt to do with only the top sheet, but would use the lower sheet with sandwich construction if needed. Right now I feel that just the top sheet may be adequate as there is a lot of meat on all four sides at the 13 5/8" sq aperture.

i had never noticed that the industry use color code at the end of the stock to denote thickness

finding a tin can with the right diameter to mark the rounded corners

fortunately I had not thrown away the wooden skit the Mach 8 Cub AC was shipped with

ominous sky with spots of clearing

i made the ground corners and smoothed out all the sharp burrs

rain was forecasted for the next few days so I moved the work into the garage

i managed to move the AC from the backyard all by myself

Fewer and fewer dry days now, and the temperature is dropping fast. I was intimidated by the thought of taking out the Kerstner's plastic raised bracket. Once it is removed, failure to install the AC is not an option.

I just remember a joke. "Failure is not an option, it is bundled with every Microsoft product."

Tomorrow we would have one dry day, and I was thinking about crossing the Rubicon. Actually If I could just carefully locate the 6 mounting holes of the AL plate, and fasten it down and seal the existing rectangle opening with Sikaflex 715 I could still close up the small openings against the impending rain the next few days.

This night I worked a few hours in the Garage and made some good progress of things that needed to be prep'ed for tomorrow.

I had the following done:
1) made the metric thread stylus for locating the 6 mounting holes.
2) drilled the 4 mounting holes that pull down the mounting foam - I am likely to use the angle aluminum John Olsen suggested. The alignment of the 4 holes is perfect when I mated against that of the AC threads of the mounting u-channels.
3) cut down to half the thickness of the foam spacers on the leading edge.
4) prepared 2 counter sunk holes for two bolts for holding down the leading edge. I found some big 2.5" metal washers to spread the stress on the plastic pan.

Once the AL plate is secured and seal against the high top, mounting the AC should be trivial - if I have planned and execute every step right.