Oct 1, 2013 at 8:35 am #1308245
I think I'd like to install a clear window on the vestibule fly of my Big Agnes, so I can see if the skies are clearing (when I'm all tucked up in my tent).
I have had tents with windows before, so I know they used some sort of flexible, clear material, but I don't know what that is, nor where to buy some — does anyone know?
Also, I realize that I'll be creating a weakness in the fly, but I intend to fully and carefully seam seal it — is there some other strong reason not to do this?
ThanksOct 1, 2013 at 9:37 am #2029892
marc DBPL Member
Profabrics in the UK stock clear tent window material, different grades. I would think that you would have more choice in the US though, you generally do.
I think the winter tents use material that will not crack in low temperatures. That may not be an issue for you though.Oct 1, 2013 at 9:42 am #2029894
I looked up what Profabrics had, looks like it's called Clear Window PVC. If you google "clear window pvc fabric" a lot of things come up.Oct 1, 2013 at 9:53 am #2029897
Dale WambaughBPL Member
@dwambaughLocale: Pacific Northwest
You might try a marine upholstery shop and see if they will sell you a small piece for your project.
I want a periscope :)Oct 1, 2013 at 9:55 am #2029898
OK, found some on eBay, called 20 gauge clear marine boat vinyl… Would that do, I wonder?Oct 1, 2013 at 10:21 am #2029907
The boat supply company I found on Google carried 20 and 30 gauge vinyls, so I assume both are pretty heavy duty. 30 would be the lighter of the two, so I might go for that. Dale's suggestion of finding a marine supply place might be good (if there is one near you).
(edit to add link)Oct 1, 2013 at 10:22 am #2029908
marc DBPL Member
I think putting in a window would not be much different than putting in a vent, in terms of creating weaknesses. Careful selection of the location, and perhaps reinforce the cut edge.
I think some of the North Face tents have windows, it may be worth checking pictures of them to see how they are done.Oct 1, 2013 at 11:02 am #2029924
We have a friend with an REI windowed tent; the window has come loose from the tent (not sewn in, apparently, just cemented). This is apparently a common problem with that tent model, as he found several owners online complaining of the same thing. He then asked me about ways to glue it back, which is why this thread caught my attention. I think it can be sewn, since that's what the boat upholsterers do; then I would just seam seal it.Oct 1, 2013 at 11:07 am #2029925
My cheapie Alps Mountaineering backpacking tent has a window, and it's sewn onto the fly, so there's no problem sewing it, as long as you seam seal carefully and copiously!
That's why I wanted one for my Big Agnes — after getting used to being able to see the sky/rain, I would miss having one so much…
I just wondered where they got the material and what it was — but folks have been very helpful, so now I know! (Don't know why I didn't think about marine supply — maybe I've been in the desert too long…)Oct 1, 2013 at 11:12 am #2029927
You're inspiring me to try and add a window in one of mine…or perhaps in a future MYOG tent. I recently sold a tent (SMD Refuge) which had fairly large triangular screened "windows" (actually vents) near the peak, with a horizontal overhang that allowed looking out both sides of the tent…I will miss that feature.
Let us know what material you end up choosing, and what your impressions of it are.Oct 1, 2013 at 11:15 am #2029929
Thanks folks — I think I'll order a piece of marine window material for this, and I'll try to remember to post a photo when it's finished!Oct 1, 2013 at 1:31 pm #2029972
Colin KrusorBPL Member
@ckrusorLocale: Northwest US
dk said: "The boat supply company I found on Google carried 20 and 30 gauge vinyls, so I assume both are pretty heavy duty. 30 would be the lighter of the two, so I might go for that."
The 30 gauge is the heavier of the two, and it's very heavy (30 mil). Plastic film gauges are the opposite of wire and sheet metal gauge. The larger the gauge value, the thicker the film. The 30 gauge PVC is 50% heavier than the 20 gauge.
To complicate things further, sellers and users of PVC film conventionally conflate gauge and mil. So, for PVC film, 30 gauge = 30 mil. This is very heavy film. Here is an example:
For other kinds of (non-PVC) plastic films, gauge usually equals 1/100 mil. So, if you bought some 100 gauge Kapton film, for example, or Tefzel or Mylar, you would find that the thickness was 0.001", or 1 mil (30 gauge Mylar is 0.3 mil or 0.0003", etc.). A piece of 30 gauge PVC film is one hundred times thicker than a piece of 30 gauge Mylar, in other words.
Someday the wisdom of the metric system will rescue us from this nonsense.Oct 1, 2013 at 1:36 pm #2029974
My bad – thanks for the correction! I was indeed going by wire gauges, assuming they worked the same.Oct 1, 2013 at 2:07 pm #2029986
Colin KrusorBPL Member
@ckrusorLocale: Northwest US
dk, it's easy to get confused. I can't keep them straight most of the time.
By my calculation, a one square foot piece of 30 gauge PVC film should weigh about 3.25oz. A piece of the same size of the 20 gauge PVC film should weigh about 2.2oz.
You might be content with this weight, Valerie, but if you'd prefer a lighter window material, there are other options. Optically clear urethanes, ETFE, polyester, and polycarbonate films are available that are much thinner than 20 mil and plenty strong. They each have pros and cons, and a sandwich of two materials (easy to do since many are available with clear acrylic adhesive) would probably give the best properties. A sandwich of 6mil urethane on 3mil polyester film, for example, would be plenty strong, more UV resistant than PVC, and one square foot of it would weigh 0.75oz.
Sorry for complicating things. Just thought you might find the information useful. I'm sure the PVC will work out fine if that's what you decide to use.Oct 1, 2013 at 2:13 pm #2029991
Wow, lots of technical knowledge out there! Impressive.
I think, for my purposes (small tent window, less than 1 square foot), I'll just go with 20 gauge marine vinyl. I get get a small piece on eBay for +/- $12 shipped, it's made to be used outdoors in all weathers, and it'll only add about 2 oz to the tent's total (not insignificant, but it's SO nice to be able to see outside!).
Many, many thanks to all who contributed guidance!Oct 1, 2013 at 2:48 pm #2030003
David ThomasBPL Member
@davidinkenaiLocale: North Woods. Far North.
With a density of about 125 pounds per cubic foot, I get 0.10 pounds (1.6 ounces) for 10 mil by one square foot and 0.20 (3.2 ounces) pounds for 20 mil, coming close to Colin's calc.
Since boat windows/canopies are using 20-30 mil, I'd be looking at 10 mil or thinner for a tent application.
Cheaper ($3.58 for 54"x36") from a fabric shop instead of a chandlery. (Stamping anchors on things always makes them cost more).
That vendor also has 20 and 40-mil clear vinyl. I'd suggest getting a yard of 10-mil and playing with it. Try some stitching patterns and then test your seams to destruction. Consider square windows, rectangular, circular, oval. Rutan's Spaceship 1 used small circular windows which gave a pretty continuous view up close due to the separation of our eyes.
The vinyl is rated for cracking to 0F, so good for 3-season use.
If that region of fabric takes much tension, you could stitch in a cross of thin nylon tape (1/2" width?) to transmit tension from one corner of the window to the opposite corner. Or go with the multiple small windows.
Mostly, we did a good job designing and building our house. I wish, though, that we had a window facing north visible from the master bed. We'd see the northern lights more often if we did.Oct 1, 2013 at 3:24 pm #2030014
You're right — 10 mil should be plenty thick enough for the purpose… and thanks for the sourcing info – I will likely order from there (cheaper than eBay for 10 mil).
I've been imagining an oval or a round window…just for the esthetics.Oct 1, 2013 at 5:46 pm #2030063
Dan YeruskiBPL Member
Ace Hardware has the clear PVC sold by the foot.Oct 2, 2013 at 5:29 am #2030174
Mark FowlerBPL Member
I have a suspicion that the clear pvc for boats may have a UV inhibitor in it and the regular fabric shop version doesn't. Worth checking before buying.Oct 2, 2013 at 9:08 am #2030217
Really good point about the UV — I'd better stick to marine quality plastic! Thanks for that…Oct 2, 2013 at 10:39 am #2030243
Dan YeruskiBPL Member
The pvc at Ace Hardware is used for windows. It more than likely has the UV inhibitors.Oct 2, 2013 at 3:39 pm #2030326
Brian MixBPL Member
@aggroLocale: Western slope, Sierra Nevada
I recently found a giant tent windowed rain fly in my camper. It's probably 10 years old and still very flexible and perfectly clear. The clear plastic sections are yours for shipping, if interested I'll measure the size of the windows. The rest of the fly I am using for a myog item.Oct 2, 2013 at 4:08 pm #2030332
That's very thoughtful and kind of you! Unfortunately for me, I ordered a small piece of marine UV material last night, so I won't take you up on your offer.
Thanks anyway! (And it's good to know that an old tent window, stored in the garage for many years, is still fully flexible and in good condition…
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