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Welcome! Ultralight backpacking is my passion, and keeping up on new technologies, gear, and techniques relevant to UL backpacking is what floats my boat. I'm always looking for the lightest, most functional gear to improve a lightweight or ultralight backpacking kit, and report my impressions and field testing results here. For hikers wanting to keep up on the latest and greatest ultralight backpacking gear, this is a good place to hang out. Also, there is a lot of information here (and on our informational website Southwest Ultralight Backpacking) on useful techniques and backcountry etiquette -- food for thought for hikers wanting to lighten their load and their impacts.

My goal for Ultralight Insights is to understand, test, and report on new technologies and gear of interest to lightweight and ultralight backpackers. It's a passion after all, so we just plain enjoy talking about it. I hope readers will add their own wisdom and comments, respond to my questions, ask their own questions, and correct me if I get something wrong. Happy hiking! Will

Wednesday, March 21, 2012

Make a Hooded Tyvek Rain Jacket and Chaps for Under $10


By Will Rietveld, Gossamer Gear Trail Ambassador

A high-end air permeable Gore-Tex or eVent waterproof-breathable jacket costs $350 or more, and it’s not ultralight; the lightest one is the Montane Spektr at 8 ounces. A polyurethane laminate rain jacket costs $150-$200 and is lightweight (down to about 6 ounces) and durable but not very breathable. Propore jackets are cheap but not very durable. In this article I will describe how to make a hooded Tyvek jacket plus chaps for under ten dollars, in a few minutes using a pair of scissors.

The finished Tyvek hooded rain jacket is extra long and weighs just 5.25 ounces. The chaps weigh 2.6 ounces. You may get some comments about the white color (like “where did you park your space ship?”), but it is actually quite functional because it stays cooler compared to a dark color.

Tyvek is a spunbonded olefin (http://en.wikipedia.org/wiki/Olefin_fiber) nonwoven fabric that is made up of millions of polyethylene fibers. “Disposable” Tyvek clothing”, made of type 1443R soft Tyvek is cheap, waterproof, somewhat breathable, lightweight, and highly resistant to tears and punctures. The fabric weight is about the same as silnylon (1.3 ounces per square yard).

You can use an available Tyvek lab coat as a rain jacket or windshirt, but it has snaps on the front closure and no hood, which make it less than ideal. So, the only way to get a hooded jacket with a front zipper is to purchase Tyvek coveralls and cut them off below the zipper.

The ideal Tyvek coveralls are DuPont “white disposable coveralls with hood”, style number TY127SWH. These are made of soft 1443R Tyvek without extra coatings, so it’s lighter weight and more breathable. Disposable ProShield Tyvek (and similar Tyvek from other companies) coveralls have a smooth coating on the outside, which makes it look like DriDucks fabric, and it weighs a little more. The challenge is purchasing a single coverall or two; most cleaning supply stores sell them by the case of 25. The easiest way to purchase a single coverall is from Home Depot, but they are the slightly heavier ones with a smooth outside coating.

Sizing is important; to get a jacket and chaps with long enough sleeves and legs, and enough room to layer over other clothing, you need to use coveralls that are two sizes larger than your normal size. I normally wear a size Large, so I get a 2XL Tyvek coverall. The larger size also provides extra length so the jacket and chaps overlap. If you only want to make a jacket you can go with your normal size or one size larger; note that the sleeves run a little short for a taller person.

The tailoring is so simple that anyone (including me!) can do it. Here’s the stepwise process:
  1. Lay the coveralls out flat on a table, front side up.
  2. Make a mark about 2 inches below the bottom of the zipper.
  3. Use a pin or other sharp object to puncture the coveralls all the way through to the backside.
  4. Carefully turn the coverall over and mark the exit point on the backside seam.
  5. Put the coveralls on and make a mark on one side about 4-5 inches below your waist.
  6. Take the coveralls off, fold them over, and mark the other side so the two sides are even.
  7. Draw a smooth concave curve from the center point to side marks on both sides of the coveralls (see photo below, four places total). This will give you a dropped front and tail for the jacket, and raised sides for the chaps.
  8. Use a sharp scissors to cut on the line all the way around. No hemming is needed since Tyvek does not unravel.
  9. To make the chaps, cut two pieces of lightweight flat braided cord 30 inches long, then sew the middle of each cord under the folded top edge of each leg of the chaps.

After making marks on the coverall for the bottom and sides as described above, draw a smooth line and cut on the line with scissors. This yields a tall jacket and a pair of chaps. My wife added tie cords at the top of the chaps to tie them to belt loops, and a couple of pleats on the backside to make them fit better. 

Note that since the front zipper does not separate at the bottom, the rain jacket needs to be put on as a pullover. To make the garments completely waterproof, coat the seams with Roo Glue or diluted silicone. If you wish, you can add a storm flap over the front zipper.

My Tyvek rain jacket made from the Home Depot Tyvek coveralls weighs 4.25 ounces, and the chaps weigh 2.6 ounces. A rain jacket made from the lightest soft Tyvek (style number TY127SWH) in size XL weighs 3.15 ounces. Although you get a pair of chaps from this project, my personal preference is to purchase a pair of Tyvek pants, which I will discuss in a future blog article. You can also wear very lightweight nylon rain pants, like the new Montbell Versalite Pant which weighs only 4 ounces.

You are probably wondering how waterproof and how breathable a Tyvek rainsuit is. I wore the jacket in the shower at home with 30 pounds of water pressure and it only leaked a little through the front zipper. As far as breathability, check out the following graph; I just happen to have that data from a previous project on waterproof-breathable jackets.

Comparative jacket breathability in terms of accumulated humidity inside the jacket during a sustained 2.25 mile steady uphill hike and reverse downhill hike. Jackets were completely zipped up throughout the hike. Note that the Tyvek jacket and DriDucks jacket perform about the same; they both reach 100% humidity inside after about 35 minutes and stay steamed up. The lightweight Marmot Essence Jacket (polyurethane laminate) performed slightly better, about the same as a traditional Gore-Tex jacket (Montbell Thunderhead Jacket). The more breathable eVent Montane Spektr Smock (lowest curve) was clearly more breathable than all of the other jackets.

Overall, a Tyvek rain jacket is very easy to make, very inexpensive, and very durable. Its breathability is about the same as DriDucks, and not that different from Gore-Tex, which is actually not very breathable. The white color actually makes a lot of sense since it will be cooler to wear in the summertime. Happy hiking!




11 comments:

  1. Question -- instead of chaps, why not tyvek kilt?
    I've never tried it, but it makes sense -- it's airy and moveable like a poncho, but not nearly as blousy, and at first blush, seems easier to construct. And possibly, it might have multi uses, like its older poncho cousin.

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    1. Great idea! I mentioned that in my blog on making a Tyvek groundsheet or bivy, but I have never made a rain skirt out of this Tyvek before. Its important to get type 1443R Tyvek, which is called "soft structure Tyvek". Its the type used in Tyvek clothing. My wife made a Tyvek rain skirt out of silnylon and she loves it. It's mid-calf length, which she says is about right. Also, she says it keeps her legs pretty warm. I plan to make one out of Tyvek to test out, and will report on it later on. Best, Will

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  2. This type of Tyvek is soft and quiet, so noise is not a problem. Will

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  3. Important Update: I just got back from a 6-day backpack with my friend Glen Van Peski, who brought his Tyvek hooded rain jacket. Glen added a storm flap over the zipper and sealed the seams with Roo Glue. The jacket performed well in wind and light showers, but it bombed when we hiked in rain/hail for an hour. His baselayer under the Tyvek jacket was soaked and he was plenty chilled. So, please heed this warning that a type 1443 Tyvek rain jacket is only good for wind and showers, not a serious rain. Its possible the Kimberly-Clark Tyvek suit (from Home Depot) may do better; it has a smooth outer surface and weighs slightly more. I will post an update when I get a chance to test it. Will.

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  5. I prefer good quality and durable rain jackets for my kids, ensuring that I remains secure all along.

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  6. I know this is an old post, but figured I would add my two cents. I used to work hazardous waste and wear tyvek suits everyday. Generally the white tyvek would soak through in the rain after an hour or so, they also tore on me all the time. The coated tyveks would hold up in the rain all day and were much more tear resistant, but they were also even less breathable and a little heavier.

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  7. Although this is a worthy project, I guess this is too much work and since my kids go with us on camps, I don't know if the jacket will hold up in increment weather. That being said, wouldn't it be simpler to buy inexpensive gear from trusted manufacturers? That's why i do trust and read quality reviews to help me decide if the purchase is worth it. Yet, when I think about it, being outdoors can be overwhelming especially when the weather is not cooperating at all. So, that being the case, it's off to various sites again to read more reviews. See this one first: http://backpackingmastery.com/top-picks/best-rain-jackets.html

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