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dbc

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Posts: 249
Reply with quote  #21 
Another busy weekend with just a little time for the ZP project.  I did manage to cut the polyiso back panels - pulled the top sections off the 2 2x8 frames and carefully slipped the polyiso in to check the fit.  I also verified that I really could put the tops back on with the back in place.  I was pleasantly surprised that everything fit well without much trouble - no slop, no binding.  I'm getting to know these frames on a first-name basis.

Here's a couple pictures of one of the frames.  The front face of the polyiso just meets the bottom of the end slots (I'm building the collector in 2 sections):

Back in frame, 060516.JPG 

Back with slot, 060516.JPG 

Greg - are you building a 20 ft. collector in one piece?  If so, I am curious how that is going.  I definitely think one piece is the way to go if the collector is built right on the wall, like Bert's, but I would need it to be free-standing, and not have an unintended 'hinge in the middle', since the polyiso, plywood, and other sheet stock all comes in 8 ft. lengths.  I want to try a one-piece next time, so I'm on the lookout for good ideas.  My installation requirements are closest to yours, although I won't have to take it down in the summer.

Right now, I think I need some sawhorses - beats doing everything on the floor.


gbwillson

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Reply with quote  #22 
Don-

Nice to see your ZP coming together. Right now any solar projects are on the far back burner with so many other household and garden projects to tend to. As much as I'd like to have a one piece collector, the fact that I have to move it seasonally prohibits that. I could probably handle a one piece 2x16 or 2x20, but if it were 4x, the collector would be so heavy and bulky that I would need help moving it. I thought about trying an ultralight 4x16 collector, but the idea of it folding in half during a move quashed that foolish thought in a hurry. If only I had a location for a permanent install...SIGH![frown]

I purchased a really nice set of sawhorses last fall after an old horse up and died. Best investment for the workshop in a long time. They are sturdy as heck, height adjustable and have several really handy functions, including the ability to connect the stands together with a pair of 2x4's to make a really sturdy work table. My back loves the height adjustment the most! They're $50 each, but are worth every penny many times over. Make sure to read the reviews!

http://www.homedepot.com/p/TOUGHBUILT-5-51-in-Adjustable-Folding-Sawhorse-TB-C700/205870356?MERCH=REC-_-PIPHorizontal1_rr-_-205068379-_-205870356-_-N

Greg in MN


dbc

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Posts: 249
Reply with quote  #23 

 

Worked on the back pieces - cut the aluminum flashing to go on the back side of the polyiso and cut 6 inch holes for the duct ports (actually 5 7/8 inch for a snug fit), and glued the flashing to the polyiso with Liquid Nails.  Here is my clamping setup:

Back, clamped, 061816.JPG 

After the glue driied, I cut out the holes in the polyiso to match the flashing.  Here's a couple shots of the back.  I lapped 6 inch and 20 inch flashing to get the required width:

Back, 061816.JPG 

Back closeup, 061816.JPG 

On the front face I glued on some 12 inch wide pieces of 0.019 inch aluminum sheet, after marking and cutting the 6 inch holes.  These pieces are a little thicker than the flashing, because they will be the attachment surface for the duct ports and the snap switch bracket.  I glued these with silicone.  I have come to the conclusion that liquid nails is mildly toxic, so anything getting glued from now on inside the polyiso will be with silicone.  It just doesn't smell as bad for as long.

Anyway, after the inside pieces were dry, I put foil tape all the way around the edge of the plates.  Here is a picture of the front.  The aluminum sheets are cut 1/2 inch in from the edge of the polyiso to give the tape something to stick to:

Front, 061816.JPG 

So - now I have to decide what needs to be attached to the frame before the back goes in.  I will probably attach some angle brackets to hold the collector to the mounting frame and some more to join the two halves together.

Also - I am still trying to come up with something better than metal angle pieces screwed into the frame to hold the glazing on.  So far I haven't come up with much that seems build-able.  I got some 8-32 T-nuts which I may still use - drill a hole through from the outside for the 8-32 screws, then back-drill through the plywood only for the t-nuts.  They need to go into the wood from the inside, so if I go that way I need to do it now.  Gonna sleep on that a little bit.







gbwillson

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Reply with quote  #24 
Nice Clamps!

I have a set just like those. I used basically the same setup with mine. No amount of hand clamps will hold down a large flat surface better than your setup. The overlapping flashing should work well too. Be careful with the t-nuts. When I used them for my prototype ZP, I intended to make the screen gap adjustable. But the t-nuts easily tore out of the soft pine. It might have worked with hardwood reinforcement. But these were the pine screen frames made of 1x2's.  I used galvanized flashing for thicker and stronger reinforcement points, like your attachment L-brackets.

Greg in MN


dbc

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Reply with quote  #25 
Greg,

I'm surprised the t nuts pulled out on your frames.  I wonder if we are talking about the same thing?  Here is what I mean:

120c4156-9ea3-4bfb-af9d-aafc308267a9_400[1].jpg 

That's a big picture - oh well.  Anyway, the whole plate would have to pull through the wood (the screw threads into the small end).

I still wish I could figure out a better way to hold the glazing on than screws through angle stock and into the side of the frame, whether with t nuts or just into the wood itself.  Seems like a lot of holes in the frame.  Maybe still use the angle but hold it tight with some type of clamps.  I remember we talked about this before, and I guess we are both still looking for the right thing.

I only thought of t nuts in the first place so the screws could be removed and replaced again if necessary.  I didn't think 3/8 inch plywood would be good for more than 1 time with just wood screws.

Bert

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Reply with quote  #26 
If you wanted to use angle over the glazing and you don't think the thin track will hold, what about rivnuts
https://www.amazon.com/20Pcs-Steel-Rivnut-Insert-Nutsert/dp/B00W8YJ9SA/ref=sr_1_3?ie=UTF8&qid=1466613351&sr=8-3&keywords=threaded+insert+for+metal

May be a lot of work, but should hold well. You could put bolts in or out from the outside.




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gbwillson

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Reply with quote  #27 
Don-

I originally tried to use regular nuts inserted and epoxied into a shallow hole. But this didn't last at all. Each nut stripped out almost immediately. To be honest, the t-nuts did hold to a point when epoxied in place. I didn't use the t-nuts for the outside frame or glazing, but used them so I could make adjustments to the screen gap. One screen frame was fixed in place near the back wall of the collector. The upper screen frame had a nut in each corner with a bolt from the outside back of the collector. By screwing this bolt in or out, I could precisely, and externally, adjust the gap between the screens, until I found the "optimal" screen gap. But with every adjustment, the T-nuts would loosen a little bit more, even with the spikes and epoxy. One completely stripped out of the frame and I ended up having to stick my hand through the back of the collector for adjustments. Again, my screen frames were made from the softest, cheapest pine. I could dent the wood with my fingernail. But if the T-nuts were used simply to hold down the glazing, they should hold tight for several years, depending on how much internal cleaning and maintenance your collector needs.

Greg in MN

Regular nut glued in place
IMG_0265.jpg 

Nut stripped out of wood
IMG_0264.jpg 


T-nut ready to go
IMG_0271.jpg 


T-nut glued and inserted, screen cut away from opening
IMG_0285.jpg 





gbwillson

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Reply with quote  #28 
Don-

I've been trying to think of a way to hold the glazing and frame since last year. Since you are using stud track for your frame, could you modify(bend) small sections of stud track to clip over the sides of the frame and glazing? Think of how a C-clamp holds something. It's adjustable. But you wouldn't need any adjustment, since your clamp or clip could be a uniform size. I essentially made the same thing last Winter when my glazing had a blowout. At first I used a bunch of C-clamps, until I could make up some cheap clamps out of a chunk of wood and a couple of brackets. It got me through the winter just fine. I'll still have to make repairs to the collector this fall.

Just a thought...

Greg in MN

Incidentally, Krautman held his one piece frame/glazing assembly down by drilling holes all the way through the frame/glazing and collector box frame. He simply stuck stainless steel bolts through everything from the back and attached a nut. Simple, but not the most attractive having a nut on the face of the collector, but it works! And being that his latest collector will be up on the roof, it will never me noticed.
gbwillson

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Reply with quote  #29 
Bert-

I think something like that could work. Here is a link to Plusnuts, which is from the same company. Plus nuts legs expand outward and are design to use with thin sheet metal. Kinda pricey, but they do look like the right kind of fastener. I think you could figure out a way to use them without having to purchase the expensive installation tool.

Greg in MN


http://www.rivnut.com/plusnut-products-tools.html
dbc

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Posts: 249
Reply with quote  #30 
Thanks everybody for the feedback.  Some good stuff to consider.

Bert - I thought abut using RivNuts in the frame for the glazing hold-downs.  I have used them before (installing FM 2-way radios in fleet vehicles back in the olden days), and I still have the tool and some 1/4-20 rivets.  Rivnuts would work especially well if there were no plywood stiffeners in the frame.  I considered that too, but the 25 ga. track was so flimsy I ended up putting in the plywood.  PlusNuts may work even better in the thin sheet metal.

I never thought the track alone would hold a screw for long, but figured the track and plywood together might.  Palram (others too) sells some coarse-thread screws with metal/neoprene sealing washers that work well screwed into milled lumber, but plywood?  I don't know.  Mranum used some pole barn screws (into 1x lumber) which look similar to the Palram.  That's what led me to T-nuts, anchored into the plywood.  Better than nothing, but still kind of 'fussy' to use.

Greg - I see now why you had trouble with the t nuts stripping out.  Any time you apply a force that pushes the teeth back out of the wood - such as with your adjustable screen - the t nut wants to lose its bite and eventually chew away the wood.  Maybe you could fit a small plate with a hole in the middle over the t nut, permanently screwed to the frame, to keep the t nut from backing out.  That was a slick idea though to have an adjustable gap.  (I take it that was on your original test ZP.)

I like best the idea of slip-on clamps.  They would need to have the exact right span, even better would be slightly over-bent with a rolled edge, to apply tension to what is clamped within.  Something like stud-track, only about 7/16 in. wider (5/16 for the twinwall + 1/8 for weather stripping).  Not sure how to make that out of normal track; may be easier to bend it from scratch out of some sheet metal.

I came up with something similar made out of PVC trim-wood.  Something like this:

PVC trim clamp, 062616.JPG 

There's no spring tension - it would just have to be a real tight fit to slightly compress the weatherstripping.  By the way, I forgot the weatherstripping in the sketch; it goes between the frame and glazing.  I may try some mock-ups of both ideas.  May also just install the t nuts anyway.  Don't have to use them if the clamps work out.  I can seal the holes in the frame, and they will be covered by the angle pieces, which then would have no holes.

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