Vertical Angle & Construction Clothes

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wrjdrk
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Vertical Angle & Construction Clothes

Post by wrjdrk » Sun Feb 23, 2014 4:50 pm

Hi all,

A couple of questions:

1.) The manual says to keep the form at right angles to the pole. I presume that means, only in the left-right dimension, not the up-down one, otherwise one would not be able to form the parabolic shape. My question is, how does one judge the angle between the form and the pole in the up-down/inside-outside plane? Does one just go by what fits the previous block best? In that case, fitting each next block in the "ramp" section becomes very critical, and in this area there always does seem to be a need for a bit of improvising, besides which, in that area the pole length has to be a compromise for a few blocks. Is it better instead to try to visualize the overall shape of the finished igloo?

The other thing is, in the first few rows, the form's built-in curvature in the vertical dimension appears to be just right, but on the higher rows, the curvature needs to be greater, so it is just not possible to fit both the inside and the outside of the form to the row underneath. Does one go by the inside, (or by the outside) after making sure that the previous row was made with a nice square top?

I ask because I recently built an eight-foot igloo, which came out basically okay, but it did not have the geometric perfection of the pictures in the manual, and it came out a few inches shorter than it was supposed to be. Also, looking at things from the inside, the block angles seemed kind of irregular.

2.) also, what are good clothes to wear to stay nice and dry while building and igloo? any other tips on this?

I want to note that when we built this igloo, we made the first two rows from snow collected nearby and packed straight into the form. The third row was made out of the snow we excavated to make the entrance, and the for next two, the outside person passed snow to the inside person through the entrance on a plastic sled. After that, the outside panel came off the mold and the outside person started passing snow to within the reach of the inside person with a shovel. This may have made a structural weakness, as the third row only was made of snow packed a second time.

Greetings to all,

Debbie

Banff Martin
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Re: Vertical Angle & Construction Clothes

Post by Banff Martin » Mon Feb 24, 2014 3:34 pm

Hello Debbie!

1. Correct, this refers to left-right, as the up/down is dictated to you by the existing walls. The angle is party influenced by the prior block & wall underneath, and partly by experience when you remove the form to start the next block; if the blocks don't line up well, the angle is off. This is typically corrected by having the left hand in the closest & left corner of the form while you pack it, pulling inwards with as much as a few pounds of force. After a few blocks you'll calibrate yourself to how much of a tug is needed. This tugging is maintained throughout the first 2/3 of packing the block; after that it isn't needed as much, though you can maintain the tug until you feel comfortable with the results.

The degree of tug decreases the larger the igloo; I found that no tug was needed on the 11' model.

The ramp section is an improv area where you aim to transition from one level to the next the best you can; your technique will vary! The flaws this area has are the reason it is to be away from the sunny & entrance areas. I advise just trying to set yourself up for the next level as best you can and accept that this section won't be ideal.

On the upper levels when the outside of the form seems to sag out, I let it do so. You can load snow & press it to engage the form & try to get it level with the inside but I don't spend much effort on this. So, the inside of the form is what I base the leveling on. I don't find much difference later if the plane is off slightly; the inside of the form on the wall seems to dictate how the block will be built anyway.

The block angles are mostly from the degree of tug when building the blocks, in my experience. Regarding the height, perhaps your fill level didn't quite match the fill level per block for that size of igloo? Hard to say.

2. Yes!
-The type of gloves is critical. You want a heavy mitt on the right hand and a heavy glove for the left. These need to be heavy enough that snow doesn't really melt on their outsides. If snow melts it will re-freeze and conduct cold through the gloves, making for very cold hands and a draining build. Your hands may sweat but it is better than the alternative. Be sure to wash these gloves afterwards as heavy gloves just don't air dry on their own well enough not to smell of mildew later.
-The packer needs a hood for near the end of the build, as snow will otherwise fall on their head & down their neck.
-Good knee pads. Without these the first two levels are pretty hard on my knees, mostly due to the cold but also the pressure. The more you spend, the less you'll mind these levels!
-Wear a water-wicking base layer and then a breathable soft shell (with hood). I'm a fan of Smartwool plus a pair of standard wool socks, so no amount of snow in my shoes/ankles or dampness makes me cold. Snowpants may be overkill, but you'll look like a professional. =)
-Don't forget sunscreen of course!

Yes, it is possible that the different types of snow could lead to structural weakness over time. It is preferable to build an igloo with the same type of snow so settling occurs evenly and the geometry is maintained. Density of snow varies; with freshly fallen snow being the lightest and most prone to sag, and old or pre-packed snow being the densest. While building with fresh 'snowball' material can make for a quick and forgiving build, it will compress more over time than one made entirely out of pre-compacted snow. If you know you'll have to build with varying types of snow, build the lower levels with the denser snow first.

I hope you've had a chance to camp overnight in your igloo?
If you're not having fun, you're not doing it right!

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Igloo Ed
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Re: Vertical Angle & Construction Clothes

Post by Igloo Ed » Sun Mar 02, 2014 7:43 pm

Indeed, Martin has it figured out, the pulling on the corner and all. Thank you, Martin.
My perspective: Line up the bottom of the inside panel to the block below as you set it down on the wall. Then, check to see if the form is at 90 degree to pole. If not, considered making it 90 as the block below may not have been built correctly.
After I have it in this position, I slide it onto the previously built block. If it doesn't fit, I use the form to chop into the block to achieve an overlap of the block and form.
The ramp area does require some fidgeting at times but I do hit an igloo once in a while where it does just go right through the ramp with perfect alignment.
I think it has to do with the very first 1/3 block and the form not being tipped enough. Changing the pole at exactly the middle of the second block ramp makes a big difference.
I'd have to agree with Marin, you may have been overfilling the form. That makes it come up to fast and it ends up being more of a cone shape on top. That is why the form didn't move/match up nicely to the wall when moving and positioning.

wrjdrk
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Re: Vertical Angle & Construction Clothes

Post by wrjdrk » Fri Apr 11, 2014 7:11 am

Hi Martin and Ed,

(Please pardon this late reply.) I did get to stay overnight in the 8' igloo I mentioned. The inside was arranged as the manual recommends for the 7' igloo since I was by myself. (I am a tall person and had previously found the 7' igloo too small for me without making a niche for my feet.)

A few days later, we had a warm spell with rain. Just as I had guessed, the top of the third layer was the structurally weakest area. The part above that retained its dome shape, while the lower wall tipped inward, so the igloo took on the shape of a broad-brimmed hat.

A week later, I built a new 8' igloo, paying extra-careful attention to the vertical angle on all layers, and using the same kind of snow throughout. On this one, after it was built, the first layer appeared to be tipped inwards slightly too much and the second tipped too little (too vertical). This igloo, though, lasted for weeks until warmer weather came. When it did start to sag, the tipping of the first layer became more pronounced, with the dome shaped retained above that, so the shape became that of a narrow-brimmed hat.

I am thinking that the second igloo's structural weakness may have been mainly in the base underneath and in the first layer. Thinking about it, each lower layer has to support all the weight above it, so the lower layers are where structural imperfections are likely to show up. I am thinking that next time, I will put more effort into making a really solid base before starting the igloo itself, and perhaps try to make the first one or two layers out of denser snow, even if that means digging down to reach underneath freshly fallen snow. Even if this sugary snow does not pack as easily, that is less of a problem with the early tiers, as they are more vertical and there is less of a risk of the block breaking and falling after the form is removed.

There is a tendency to want to get started fast, but it seems that the base is the most critical part structurally and this is where extra care and attention is called for.

You (Martin) wrote,
If you know you'll have to build with varying types of snow, build the lower levels with the denser snow first.
I agree. A couple of years ago I built an igloo with dense, sugary, snow for the lower layers and fresh snow for the upper ones. (This was a two-day build and it had snowed overnight.) That one lasted a long time. When warm weather came, it fell in on the upper dome first, while the lower walls remained up a little longer.

Ed wrote,
Line up the bottom of the inside panel to the block below as you set it down on the wall. Then, check to see if the form is at 90 degree to pole. If not, considered making it 90 as the block below may not have been built correctly.
Again, just to clarify, do you mean 90° in the horizontal direction only, or in the vertical one too?

Regarding overfilling the form, I was filling to about 1 1/2" from the top. Since the 8' igloo uses the same changes to the pole length as the 9' one, only with the pole shortened by 6", would that mean that the form is best filled less than for the 9' igloo? Keeping the proportions the same would suggest filling the form by 11% less, or about 1 1/2".

Looking forward to next winter and another igloo!

Debbie

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Igloo Ed
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Re: Vertical Angle & Construction Clothes

Post by Igloo Ed » Fri Apr 11, 2014 8:46 pm

Hi Debbie,
Yes, the 90 degree to pole thing would be the left/right. I refer to it "as seen from above" you will see 90 degree from pole to panel. If looking at the tool from the side, the angle is determined by aligning the bottom of the inner panel to the inside/top edge of the block below it.
I have a lot better results when I keep that bottom edge aligned. The slight pressure of constantly pulling on the top left corner of the form with my left hand helps keep that alignment. Without the pressure, the bottom right of the Inner Panel will blow in some. It seems trivial but it sure goes smooth if done correctly.
Not blowing in that lower/right corner also requires one other technique where I pack that corner with my finger tips. If I use my whole hand/palm it either blows the form in or the snow doesn't get packed enough and holes melt into the walls later when it warms up in the igloo.
It also seems like when the lower corner blows in, the top left ends up being further out and the next level above it doesn't fit right. The top left end of the block is out because I release the pulling pressure after the block is filled and packed a bit past the pole/pivot point and if the bottom is in, the top is out.
That's also where that important hard pack/push that blows the lower left corner of the Outer Panel out... That spreading of the form puts enough pressure that the inner panel won't blow in as easy and it also puts the entire form under some tension making it more ridged.
The pressure of the snow on the form also gives the snowflake pattern on the form surface some traction and the form won't move around so easily. Our first prototype had smooth surfaces and it was a real pain with it slipping around so easy.
There is a chart on the outside of the Outer Panel that tells how to assemble the poles for the different size igloos. It also tells how full to fill them. From experience only, 1 1/2 inch short on the nine footer and 2 inches short on the eight footer, all the rest are filled full.

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