[pct-l] down baffle designs...

[Paul Robison]

Holly...

Right !
the only real difference is,  most people make the baffle sidewalls out of a 
mesh or bug netting, to save weight.   making the entire center section out of a 
solid fabric provides durability (adds a couple ounces though!), and iwth the 
right fabrics provides and effective vapour barier

when you make your bag, obviously it wont have an EN rating,  but you can 
estimate warmth based on loft.   loft is the key to using insulation well
http://www.thru-hiker.com/projects/down_quilt.php
that link has a table for estimating warmth ...

...i went with 3.5 inches of loft,  which,  using the triangle baffles is REAL 
easy to design...
here is mine, it has 3.5 inches of loft:
http://www.whiteblaze.net/forum/showthread.php?t=65514

that is achieved by thinking of each baffle as a right triangle,   and the 
baffles spacing at 12 inches...
so you have length A and C with marks every  6 inches top and bottom  (6 inches 
mark top... 6 inches mark bottom, repeat)  so each side is a baffle 12 inches 
wide and 3.5 inches high... then you use a calculator to calulate how long your 
diagonal lines will be...  and mark the middle fabric sheet accordingly.


there is a slight problem in doing this though  you can end up with weird 
numbers (like marking your middle fabric every 6.738 inches).   so i started 
plugging in various numbers to see what came out nice and round...
i did 12 inch baffles ( two six inch langths) sewn into the center fabric every 
6.75 inches  (a nice round number i could mark) and that gives you 3.1 inches of 
inherent loft.  of course you get more actual loft cause the fabric isn't 
rigid,  it fluffls like the diagram in the link you sent me.

if you look on my whiteblaze post my bag has at least 3.5 inches of loft on all 
points with the dimensions above..   so pieces A and C are marked every 12 
inches  (but staggerred halfway apart),  and piece B is made up of 14 increments 
of 6.75 inches.

that gives you seven triangular baffles on each tide (top and bottom) on a 7 
foot long quilt.   two pieces of 84 inches long ( A and C)  and piece B needs to 
be 94.5 inches long.


see if you need it to be a bit warmer,  go for 12 inch baffles and 7 inch center 
pieces...  that will give you 3.61 inches of initial loft (this is what our two 
person quilt is).


let me know if i can clear any of this up.   if you're interested i can give a 
summary on how we do draft tubes etc as well.

~Paul









________________________________
From: Holly Eggleston <holly.eggleston at gmail.com>
To: Paul Robison <paulrobisonhome at yahoo.com>
Sent: Mon, December 6, 2010 6:27:06 PM
Subject: Re: [pct-l] Thru hikers for 2011...



>as a really simple design i used in my last quilt, that worked perfectly was 
>this:
>three strips of fabric   A B C ... fabric A and C are the same length, and 
>fabric B is slightly longer (i can talk numbers later).   length B weaves back 
>and forth, stitched alternating to A, C, A, C 
>
>hmm, hard to explain,
>
><-feet                  head ->
>------------------------------ A
>/ \ / \ / \ / \ / \ / \ / \ / \ / \ /   B
>------------------------------  C
>
>

Coolio. Looks like v baffles (yay intranets! 
http://www.downbags.co.uk/info/sleeping-bags/sleeping-bag-construction), but 
with vapor cloth. I like the CYA (literally) moisture strategy.

 

are you on whiteblaze?  i have a thread about it on there.
>
>

Cool. I just signed up as ilex, but wasn't able to find it search-wise. Do you 
ahve a link and/or what is your user name on there?
 
i wouldn't be hugely concerned about massive snow loads ... most we got was 2 
inches and everyone talked about how unseasonably cold 2010 was.  

>have you spent much time with you gear?  do you have a shake down trip planned?
>

Glad to hear it. The gear is undergoing a few trips, but is all pretty new as I 
did a round of updating to shave weight off, as I usually car camp / do shorter 
weekend backpacking (read: 10+ year old REI quarterdome, MSR whisperlight, Big 
Agnes Insulated Air Core, etc). I'm planning on getting a few weekend trips in 
January/Feb, doing the snow session with Ned in February. I dont have a long 
shakedown trip set up -- I figure that's going to be my meander for the first 
couple of weeks (pre-KO) in April and make any necessary SD runs.
 

i was supposed to spend the week after thanksgiving camping, but we got 8 inches 
of snwo the day i was supposed to leave and  it all got pushed back.  now it's 
far too cold.
>
>Echo and i are from British Columbia, but we're spending the holidays in fort 
>wayne indiana with my sister and her little boy,
>
>

Right on. I'm originally from Anchorage/Seattle, and spent a couple of years in 
Missoula, so I am very familiar with the Pacific NorthWet. The last couple of 
years (snow!) have been pretty whacky.

Upshot, by the time you get to Manning, you're practically back home!!  :>
 
anyway thanks for letting me ramble,  if you are interestedi n sewing your own 
ba i can give some rough dimensions that might help...
>
That would be awesome. Thanks!



>... goodluck planning and i'll see you out there,
>

You too. It's certainly an ongoing production. I need to start making LISTS.  

Holly
 
~Paul
>
>
>
>
>
>
________________________________

>
>
>From: Holly Eggleston <holly.eggleston at gmail.com>
>
>To: Paul Robison <paulrobisonhome at yahoo.com>
>Sent: Sun, December 5, 2010 8:27:29 PM
>
>Subject: Re: [pct-l] Thru hikers for 2011...
>
>
>
>
>On Sun, Dec 5, 2010 at 5:25 AM, Paul Robison <paulrobisonhome at yahoo.com> wrote:
>
>No i've been making quilts with my mom since i was 11,  so i went a little more 
>advanced than a ray jardine quilt.  but you should be able to sew your own quilt 
>and get something good to 20 degrees F and around 17 ounces.
>>
>>
Cool. I think I found the one you were referring to - somewhere between 
http://www.thru-hiker.com/projects/down_quilt.php and 
http://wintertrekking.com/index.php?topic=873.0 ? 


Alternatively, I'm also looking at the 
http://www.montbell.us/products/disp.php?cat_id=796&p_id=2321205 -  the whole 
clingy-but-stretchy thing has some appeal. $$$$ though.

 
i have a double baffled top quilt with 900 fill down and a vapour barrier 
between the baffle chambers.  it's 2lb's 2 ounces and is large enough for Echo 
and i to share.  has 21 ounces of 900F down in it.
>
>

Nice. Sounds like you have it down to a science!!  You inspired me to go 
researching baffle strategies.
 

i also hike with a neo air,  my wife and i have a regular and a small, and we 
press them together and sleep under our newest quilt (think Queen sized 
comforter)...
>
>the SL1 is a stellar tent weight wise... i saw them at REI and was impressed;  
>cramped but just what you need.  i section hiked 30 days of the PCT last year 
>and i never  once cowboy camped.  i share you creepy crawley aversion.  Candice 
>and i hiked last year in a Marmot mountaineering tent, but this year we're 
>giving the Nemo Meta 2p a try.  we've used it about 14 nights now and it's worth 
>the weight savings.  smaller, a little condensation,  but worth saving 4 lbs out 
>of our packs.
>
>

Cool. Yeah, I was just talking with my ex today (a camping gearhead, and who is 
amenable to letting me raid his gear stash) and he was talking about concerns 
with tent venting for snow/winter camping -- not entirely sure how that will 
work with the SL-1 -- the interior is well ventilated and there's a top zip vent 
in the vestibule cover, but not sure how that would hold up (or be propped open) 
in snow.

 
between mexico and KM i never had a problem finding a spot to set up a tent,  
though it meant stopping at 3 PM a few times... which was welcome anyways.  
obviously i've not done a full thru hike or anythign so maybe that'll be more of 
an issue than i expect.  there was one night we forced ourselves to push on and 
ended up camping on a ridge in the wind etc.  was the scariest night for me by 
far.  it snowed and howled all night long i didn't sleep a wink.  i think just 
looking at the maps and knowing when to call it a short day is all you really 
need.
>
>
>

I hear you there.  Now to bring lightweight hobbies to keep myself entertained 
on short days (backpacking guitar? musical apps on the iphone? crochet? knot 
tying?)
 
Goodluck i look forward to seeing you out there !
>

Thanks, you too! Where are you and Echo located? Will you be coming to the KO?
 
~Paul
>
>
>
________________________________
From: Holly Eggleston <verde at negentropy.net>
>To: Paul Robison <paulrobisonhome at yahoo.com>
>Sent: Sat, December 4, 2010 10:52:34 PM
>
>Subject: Re: [pct-l] Thru hikers for 2011...
>
>
>LOL. Yeah, I've considered it - I may give the Ray Jardine quilt a whirl - is 
>that what you did?  I also got the large neoair, which is extreeeemely 
>comfortable, and pretty light for what it is and gives plenty of flip room -- I 
>figure I'm spending 1/3 of my time sleeping, I'm willing to give a little to 
>make that more comfortable.
>
>Tent - I got the big agnes seedhouse SL1. (http://www.rei.com/product/734816)  I 
>wanted an enclosed tent due to the potential nighttime creepy crawly factor (and 
>mosquito escape).  It's pretty lightweight, and I like the mesh body for both 
>ventilation and view. Downsides, the mesh (even with fly on) can be drafty, so 
>it might mean some cold nights when windy. It's definitely a one person tent - I 
>could fit my pack under the vestibule, but not in the tent with me, but I figure 
>I'll just bring a bag with my clothes, and leave the rest in the pack. However, 
>the head part is wide enough that I can store some stuff near my head and it 
>doesnt feel too claustrophobic. Last but not least, the fly door is bad 
>positioning for when its raining, so I may rethink my tent choice by the time I 
>hit Washington. Or figure out some macgyver solution on the trail.
>
>Talking with frank miller, he said that a lot of folks cowboy camp unless it's 
>bad weather (due to exhaustion and trying to find decent footprint) , but see my 
>aversion to creepy crawlies, above.  
>
>
>Holly
>
>
>On Sat, Dec 4, 2010 at 7:28 PM, Paul Robison <paulrobisonhome at yahoo.com> wrote:
>
>oh i'd meant to say but hit send too soon,
>>
>>have you considered sewing your own bag?  best decision i ever made !
>>~Paul
>>
>>
>>
>>
>
>
>
>Holly,