Hoop Bender

Lost Creek Bender
I just formed my first test hoop on the Lost creek hoop bender and I must admit that it was really easy. I used .065-wall thickness 1 3/8” top rail, which is heavier than recommended. The bar bent a little bit (not the bender in the pictures but the lever) but that’s my fault for using heavier tubing. I have no doubt that if the recommended wall thickness tubing was used the lever bar would have worked just fine.
I made a stronger bar and completed the bend with no problems. I am old and slow but hopefully I can get this thing built before the first frost.
Oldude

http://i24.photobucket.com/albums/c47/karpes/12Hoop9-29-07003.jpg

http://i24.photobucket.com/albums/c47/karpes/12Hoop9-29-07002.jpg

http://i24.photobucket.com/albums/c47/karpes/12Hoop9-29-07001.jpg

Cool! My brother made me a really nice jig for my grhouses out of plywood that he curved and added a bent metal pole at the base to stick the pipe into. He had wooden rims at the top to guide the pole, sanded it all down. Really nice ( he traced it off another jig that we borrowed for the day) and then I lent it to someone who lost it! How can you lose something that big?? It was a bit larger than yours. When I have to make repairs to the bows, I am going to have to make another and hope that I can trace it off one of my poles.

I finally got started and decided to go 20'x20'. These are the laid out tubes after bending.

Base boards using U bolts . Need to trim later.

Hip boards Using U bolts.

Ok, I didn’t get all of this done today, but this is about four Saturdays of work. I realized that I could not finish the greenhouse before the first freeze so the pace has slowed down.
Here is a shot at the end of today. Gees, I am tired!
Oldude

Lookin' good, ol'dude!

You should feel good with your work!

Shoe

Ok, I finally finished and this is my first day operating a greenhouse. Oh boy I am totally ignorant about this. I put all of my effort into building the thing and very little into actually operating it. I would really appreciate any help that you can give me. Ok. Here’s what happened today.
The day started out at 46 degrees with the door open and side curtains rolled up. At noon it’s 78 degrees ambient and the fan comes on at 90 degrees inside the greenhouse. The fan ran for a while (temps rising 95 degrees) then I realized that it’s sucking air directly from the sides with the curtains rolled up. Quit laughing!
I then rolled down the curtains and closed the door and the temperature is holding at 90 degrees with the outside temp at 79 degrees. I then remember this misting thing so I pressured up the old garden sprayer and started spraying inside the greenhouse. Duh, the fan quit running, (within seconds) for a while so this misting really does work! Not for long because 8 minutes later the fan is going again. Now it’s 4:15 PM, still 80 degrees ambient and the greenhouse temperature is stable @ 90 degrees and the fan is off.
My question is about misting. The greenhouse is 20’X20’ and 10’6” tall, so how many misters GPH do I need to maintain a 85 degree temperature with an ambient of 95 degrees.
Can I use a thermostat to turn on the misters when the inside temperature reaches 85-90 degrees? I have 60 pounds water pressure that runs through a water softener that I can further filter.
Oldude

Sorry I cannot answer your question, but awesome job on the manufacturing!

If you have the option of thermostatic controls, I would say definitely investigate that. The exhaust fans I have on my greenhouse would be way more effective if I didn't have to manually plug them in, though, they are intended to be controlled by thermostat.

You've created an excellent growing space for yourself!

[pats back]

I don;t think that I would rely on the misting system to keep the temps down in the grhouse as they would be on alot when the sun is out and that would create a very wet environment in your grhouse. I think that that would really invite root rot and fungus of all kinds.

I would set your fan thermostat down to 85 and forget the misters through the winter. I am not a big fan of misters except for use for propagation, as your biggest enemy is going to be too much moisture. You esp don't want your foliage being wet going into nighttime. Also, the roots in your container plants need to dry out occaisionally or they may rot.

Another thing that I would do soon is go around the base of your grhouse and fill in with dirt all the space under the wood. When the fan comes on, it is sucking air from under there and cutting back on its effiency. It will bring more air through the grhouse faster if you do that.

Not sure how cold it gets there at night in the winter, but you may find it more economical to add a second layer of plastic with a small squirrel cage fan blowing air between the two layers of plastic. As long as the space between the two layers is anywhere between .5" and 4", then you will gain about 10 degrees more warmth at night which will definitely save in heating costs.

Is that the shutter or the fan in the picture?

Looks like you did a great job building it-you are going to love it! Nothing like being in a grhouse in the middle of the winter-when its so cold outside and so warm inside!

That’s the exhaust fan at the fore front of the picture and the inlet is on the bottom far side next to the door. Yesterday the ambient temp reached 81 degrees clear skies ,with the fan running, the inside temp was approaching 103-104 degrees. I installed the 50% shade cloth and this dropped the inside temperatures to 98-99 degrees. The fan ran for 7 hours.
My winter ambient temperatures average in the forties at night and in the seventies during the day with occasional high temps in the lower to mid eighties. We can also get down to the mid twenties occasionally but very rarely anything near or below 20 degrees.
What are the other options other than misting if any?
Oldude

The only other options are to put a larger fan in (thats why I asked if that was the fan-off the top of my head-it looks pretty small for that size grhouse-but Stressbaby could help with the numbers better than me).
Also-I think you said that you only had one shutter? It will get much better draw if you have two (most larger grhouses have two) and putting the shutters up higher helps-for two reasons. One is that hot air rises and that is the air that you want to move out and your shutter being so low is not doing it that well. Two-you get better, unobstructed air movement when the shutters are higher and don't have to compete with the plants/shelves etc. As well-in the winter, the air is cold outside and you don't want that blowing on your plants. My shutters are about 5' off the ground and on either side of the door.
Hanging a fan or two , either halfway down the grhouse or if two, then 1/3 and 2/3's down will also help to move the air.
Filling in all the holes under the base of the grhouse will also help.

Your fan is going to constantly be on during the day on sunny days-I
don't even think about it, its a given.


I have never used a shade cloth on my grhouses and I generally use them from now until mid May-then I empty them out. Shade cloth will cut down on the fan use, but it also makes for more leggy plants.

Hope this helps.

Thanks tigerlily
I will seal off the base boards this week to see if that helps. The fan was sized to move one exchange of air per minute and it is a 24” 4,800 cfm with a 36” motorized vent.
http://davesgarden.com/community/forums/t/886387/
Oldude

24" should be big enough for that size house. Looks are deceiving-it looked smaller. Another thing that I forgot is that the fan should have been put in the center of the gable end-would draw better from both sides than having it on one side. Wouldn't be hard to move.
You can just use dirt and shove it up under the base board-pack it in. Also, next time that you cover, let the plastic go all the way to the ground so it covers the baseboard totally and that will help if you have more space under the board.. I don't think that you ever roll up the plastic on the sides anymore, unless you can roll it up way higher than you have it now.

Tigerlily
I had some time to play with the greenhouse today and the dirt along the sideboards definitely helped. I put thermometers at four inside locations and there is definitely a dead spot where air is not moving well. Looks like I will need another vent.
Now I have to install a time delay for the fan because the vent will not open with the fan on at full RPM. It will open with the fan at half speed but this will not be enough flow on an 85-degree day. Other than a time delay really, do you know of an easier way to delay the fan for 10 seconds while the vent opens?
I was surprised that so much air was leaking in but when you calculate a small crack times 80 feet of baseboard, it adds up to quite a bit.
Thanks, I appreciate the help.
Oldude

Oldude-not sure what is happening with your shutters not opening when the fan comes on full strength ( esp the RPM bit).

I am not even sure that I have RPM option (?) on my fans. I know that they are hooked up to the thermostat and when that hits the right temp, it turns the fan on and a few seconds later the draw from the fan opens the shutters at the other end. It takes a few seconds as the grhouses are long (100'), but if the belt is tight and no leaks anywhere-when that fan comes on-it can slightly move the grhouse and the shutters fly open.

Given that the stronger the draw-the faster/fuller the shutters open, it doesn't make sense to me that the shutter doesn't open at full strength and only at half strength. I do think that moving the fan to the center of the back gable will help-esp if you are adding a second shutter.

I am not understanding your question of trying to delay the fan coming on until the shutters open-with my grhouses, the shutters will only open when the fan comes on, and they drop shut when the fan turns off. I don't have the shutters on a thermostat though, and maybe you do. I have never seen the need for that-extra expense, I guess. the fan does a good job of opening the shutters, and just having the shutters open does next to nothing to cool the grhouse down, without the fan.

Its a good idea to always have a backup fan belt, or do preventative replacing every year ( or less). Nothing like noticing in the middle of the day that the fan belt broke and you can;t get in there to fix it until the grhouse cools down! Also periodically tightening the belt will help with the draw of air.

The fan motor is guard mounted (variable speed) with no belts and the vent is motorized to power open. These vents work just the opposite of yours in that any air flow works against them opening when they are trying to open. With the leaks under the base boards eliminate the fan exerts so much force on the closed vent that it cannot over come and open. If the vent would open a few seconds before the fan comes on it would eliminate this problem.
The only two options that I have now is to use a time delay relay which would allow the vent to open a few seconds before the fan comes on. After reading the net last night I came across the use of a two-stage thermostat ($75) that would open the vent 4-5 degrees before the fan comes on. I guess a third option would be to have a vent like yours that opens with the flow of air.
It’s extra expense but I view this as a good problem since I know that the airflow will be sufficient to cool the house.
Thanks Oldude

It might be an extra expense-but not a very expensive one-I think that the shutters that I have are probably the cheapest option-no motor attached, no thermostat. they work great. every once in a while I grease the hinges One pair is over 17 yrs old and still works fine.
I think there is a shutter where you can have a thermostat attached to it that you could set for a lower temp than the fan and that would open it-but I think you could get two shutters like mine ( 24") for under $ 75, which is the cost of the thermostat (which wears out in a grhouse and would have to be replaced)

oldude, is it possible the linage on your shutter motor just needs to be adjusted? You might try loosening the bolt half-way up the linkage, pulling the two pieces together (closer) then tightening the bolt. Also check the spring and see if it is in good shape.

I don't know how old your motor is but there should also be an oil hole at the top;maybe the "innards" just need a good lube.

Shoe

Hello Shoe
I did try adjusting the linkage. The motor has a lever with about 4 holes. The S hook (this louver uses chain and S hooks) was bent open when I moved closer to the shaft and still did not open. Since then I found a two stage thermostat and it’s doing great. The shutter opens approximately 6 degrees before the motor comes on.
My door is 8’ tall X 4’ wide so when I leave the door open the air just moves through the top of the opening and really does not help. I am at the conclusion that another vent on the other side of the door would solve the problem. The greenhouse is now running 12 degrees over ambient . We are expecting ambient temperatures of 85 degrees this week so I will most likely open the door and block off the top 4 feet with something.
Thanks for your input.
Oldude

Great! Glad you got it working like it is supposed to. And yes, putting in another vent sounds like a good idea, too.

Congrats, looks to me like you will really enjoy that greenhouse. This will surely open up a whole new area of growing for you!

Best,
Shoe

Shoe/Tigerlily
I added another 36” vent on the opposite side of the door and what a difference. The fan runs much less and the door does not slam shut when the fan is on. Tomatoes starting to turn red and the greenhouse is my new favorite place to be. No regrets and the November gas bill for the greenhouse was $40.
Life is great!
Oldude

Yay! Sure sounds like your work in progress is paying off.

Enjoy those tomatoes; they are just a distant memory here (for now!).

Shoe