View Full Version : 650fp vs 800+
I'm convinced that my 650 fill bags retain warmth better than the 800 fill bags. I am guessing because there are more "clusters' of down in the 650's. Can anyone else say they've had this thought come to mind?
No.
Seriously, though, this raises an initial question which is:
Could the difference be fewer feathers and larger down clusters for higher loft rating?
What other reasons are there for higher loft figures?
It stands to reason (and at least my experience) that higher loft ratings in quality gear is definitely warmer than similar gear with lower loft ratings (not to mention the lower total weight of down filling needed).
Basically trapped air is what keeps the heat in so I dont think it would matter.
The less air circulation inside the bag the better heat retention.
650 loft would have more down feathers per loft, so I guess with 850-900 down if it was barely filled to the same loft could have some clumped up thin spots and that could do it ??
Maybe construction techniques between the two ?? Letting some convection through on the colder one, or maybe its just over rated.
No.
Seriously, though, this raises an initial question which is:
Could the difference be fewer feathers and larger down clusters for higher loft rating?
What other reasons are there for higher loft figures?
It stands to reason (and at least my experience) that higher loft ratings in quality gear is definitely warmer than similar gear with lower loft ratings (not to mention the lower total weight of down filling needed).
Well loft is a relative thing too right? 5 inches of 650 could very well be more insulating that 5 inches of 800. I trust experience as you say you have. I'm still wary though.
http://en.wikipedia.org/wiki/Fill_power
http://www.comforthouse.com/refsafves.html
To sum it all up:
Fill power is a measure of the loft or "fluffiness" of a down (http://en.wikipedia.org/wiki/Down_feather) product that is loosely related to the insulating value of the down. The higher the fill power the more insulating air pockets the down has and the better insulating ability
Generally speaking, any bag of 650+ is going to be reasonably accurate in rating. (My favorite budget bag is considered by some to be less accurate than stated. Others say no different. YMMV).
Generally, higher quality down bags (Feathered Friends, Western Mountaineering and others) use higher fill power down (which traps air better than less quality down) and tend to be a lighter bag.
Better quality down means less down needed to do the same function. That's why a 20F bag from one company with lesser quality down tends to be heavier from the other brands using higher quality down. (among other reasons)
"Some comforters with higher fill powers may have less down than a lower fill power comforter. This is to keep the comforter from becoming too warm."
(for a down comforter..but close enough. :) )
So..will a bag with higher fill power be warmer? Not necessarily..but many budget bags (and synthetics) have less accurate ratings than higher quality bags with higher fill power.
OR..to REALLY sum this all up "Ya get what ya pay for". Even a dirt bagger like me suggests buying the best bag you can afford.
Well loft is a relative thing too right? 5 inches of 650 could very well be more insulating that 5 inches of 800. I trust experience as you say you have. I'm still wary though.
Well I dont think so.
It all has to do with the exterior and interior material, construction type too etc.
IE a V baffle bag will be warmer than a box baffle bag IMO because it will hold the down in place better with less clumped thin spots and just by its nature you should not have any thin areas at all.
If both bags have the same loft, both have the same shells, both have the same baffles and consturction, and the down is evenly distributed with no underfilled baffles they should be the same.
Seems to me that the older bags were overfilled soemwhat. They definately used heavier shell material.
Todays bags with everybody trying to save the last gram, they are made with micro thin nylon and even though they have the advertised loft the down is at a bare minimum to make that loft. Very skimpy.
I would rather carry 2 oz extra and have an extra 1700 ci of fill.
garlic08
10-28-2009, 10:54
After owning one 650 bag and one 800 plus bag, I must disagree. In my experience, there is no comparison. But with only two bags to compare, I'm no expert at it.
I'm with Garlic here. 800 is amazing.
My take on the differences as you step up in grades (and cost) is that the lower/cheaper down has bigger and bigger spines on it. The highest grades of down are all fluff, no spines. One of the reasons down degrades over time is that repeated compression can damage it. Cheaper down gets much more badly damaged by compression because the spines of the feathers get broken and can't spring back into shape when the pressure is taken off. Good down just fluffs right back up. Cheaper down, with those stiff spines leading the way, pokes itself right through fabric and migrates on out. Spineless down doesn't work its way out as readily.
It's not entirely wrong to look at construction techniques, though, because cheaper bags will cut costs all the way around, including using designs which require less fabric and less labor, as well as cheaper grades of down.
I went from a fairly cheap synthetic bag to 900fp down for both top and bottom insulation for my hammock. This stuff is divine! Warm all night long and I've taken it as low as 10 degrees with minimal supplementation.
BlackRock
10-28-2009, 14:09
Well loft is a relative thing too right? 5 inches of 650 could very well be more insulating that 5 inches of 800. I trust experience as you say you have. I'm still wary though.
I agree with Tammons on this. No, loft is not relative, it's an absolute measurement. I'll try to explain and answer below in my "way too long" post...
What is Loft?
Loft measures the volume that a single ounce of down can fill. You take an ounce of down, toss it into a container and measure how much of the container it fills. Theoretically 900 is the top of the range, so assuming you had 900fp down you could toss exactly one ounce into a 900 cubic inch container and fill it to the brim.
How to compare loft ratings.
You pick a volume to fill, 900 cubic inches, and fill it with 650 and 900 fill power down. You would need 1.4oz of 650fp down to fill your 900 cubic inch container and 1.0oz of 900fp. Same container and dimensions, same volume filled, but still only 650 and 900 for the respective loft ratings. The term "loft" is simply misused alot by manufacturers. But that's only the setup.
Which is warmer?
1 ounce of 900fp down or 1.4oz of 650 in the same container? To give it some dimension lets say it's a 4 inch thick baffle that's 15 inches square (15x15x4 = 900 cubic inches). The short answer is 1oz of 900fp.
But Why?
To answer that question you have to take a closer look at the actual down plumules. Tammons and Mags hit the nail on the head with trapped air. The tiny filaments found in fibers of the down trap air, that trapped air is what becomes the insulation layer. So the more air the down can trap the better it can insulate. Higher quality down has larger more dense plumules with more filaments. It's probably easier to see this difference so I took some pictures for everyone.
The plumule below is from my stock of 900fp down. What you are looking for in high quality down are large very dense plumes with lots of thick "hairs" or filaments on the down fibers.
http://farm3.static.flickr.com/2756/4053288272_64310c84a0.jpg
Now compare it to this next plume, taken from my 800+ stock. Overall it contains good looking plumes but a higher percentage are smaller and look more like the plume below. Both fill powers contain overlapping ranges of plumes, just think higher fill power means more of the bigger denser plumes found.
http://farm3.static.flickr.com/2783/4052544429_209fd0fbf6.jpg
You can obviously see that it's smaller and has fewer fibers of stringy down hairs. You can even see the difference between the actual filaments and how the top plume has thicker more full filaments. It simply won't trap as much or as big of air pockets as the top plume. It packs tighter and takes more of it to fill the same volume.
Now imagine that same baffle example.
You fill one with the 900fp plumes and the other with the lesser quality plumes. From the exterior you'd have identical looking baffles, if you weighed them one would be 1oz and the other 1.4oz but... If you could actually count the total number of filaments in each you'd actually find more filaments in the 900fp baffle. It would simply trap more air pockets and insulate better.
Now to toss in a few wrenches...
#1: Higher quality down only comes from mature geese. I.e. big dense plumes like the one shown above. The dividing line is generally 750fp (please note my terms "generally", "usually", "mostly", etc). Usually anything rated 750 and higher is handpicked from the geese while 750 and lower is eaten. So your higher quality down most likely comes from Canada or Europe whereas your immature lesser quality down comes from Asia (about 50% of the market).
#2: Feathers are made from Keratin which is what our own hair is made from. This Keratin strenghtens over time as it matures into a very strong thick plume. If you pick it too soon or get it from immature geese not only is it smaller and less dense but its also made up of more fragile fibers that will collapse over time causing the down to lose more loft sooner. So that 650fp bag is going to flatten out and get colder sooner than your 800fp bag.
#3: Really only seen with super high quality down (750-800+ vs 850-900) is something called clustering or cling. Fully formed clusters start to form "barbs" on each plume. Basically longer thicker filaments that you can see on the fiber above. What you start to see are individual plumes clinging to one another. Those "clumps" of down not only hold pockets of air in the filaments but the interlocking fibers create new larger pockets of trapped air yielding an even higher insulation rating.
Well... Thats about it for me, I'm spent :o I hope you find it interesting. I sure do. I didn't even get into the cleaning or conditioning of down, feather count, sustainability or the conditions geese may be raised in for their down.
Lot's to it, but I firmly believe along with Garlic08, Marta and Hooch who have all posted since I started writing this up that high quality down is worth it.
Enjoy,
Evan
www.blackrockgear.com (http://www.blackrockgear.com)
Or as I put it originally :
OR..to REALLY sum this all up "Ya get what ya pay for".
:p
I like one sentence summaries as I am not the brightest bulb in the box. ;)
Mags is such a helpful little fellow.
I think it may just be the case that the 650 bag I have is thicker and a bit more comfortable for me than the 800.
Mags is such a helpful little fellow.
http://www.whiteblaze.net/forum/showthread.php?t=54606&highlight=paved
The sense of humor is lacking in this one. ;)
Other things can work into it too.
How the bag is shaped, IE a montbell hugger is going to be warmer than a regular wide bag, IE less air and air movement around you body.
If it has a collar or if not and or how it is shaped around the neck and shoulder area, again a plus for the hugger without a collar vs a normal/wide bag without a collar.
If you move around a lot then you can pump cold air into a bag. That happens less with a collar or a more form fitting bag.
Also the hood is important. You probably lose more heat out of the back of your neck area than any place else. If you are a back sleeper and never move, and close down t he hood, no big deal. If you are a flip flopper or a side sleeper, then you will probably lose more around your neck.
Then there is the entire ground insulation issue, IE an Exped down or syn mat will make a bag feel a whole lot warmer. Those are toasty mats for sure.
The short answear to me is that all other things been equal , 800 is better than 600.
As usual a badly designed (or wrongly speceifyed ) product will still be so even if you use the best materials.
So if I made a sleeping bag with 500 fill or 900 fill I would still end up with a piece of crap except that one would be lighter.
Franco
Rocketman
10-28-2009, 17:23
There is some interesting work from the military on thermal insulations and density (which is not quite the same as "loft").
One of the reports or papers is below.
http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA481751
Phil Gibson of U.S. Army Soldier Systems Center, Natick, Massachusetts is one of the authors. The figures are interesting to look at and to attempt to seek answers on heat loss in practical sleeping bags.
There is a masters thesis on something like "the mechanics of down", but that isn't the correct title. It too has a discussion on loft and feather content as well as some discussion of the nature of down.
http://etd.gatech.edu/theses/available/etd-11202004-003552/unrestricted/wilde_timothy_p_200412_mast.pdf
Found it. You will probably find the computer modeling part less easy to read than the introductory materials.
I sent a copy of it to "Mr. Wiggy" of Wiggy sleeping bags telling him that there ought to be an equivalent paper on fibrous thermal insulations. He replied with his usual diatribe against down and worthless complicated mathematics.
There seems to be not much in the way of a giant amount of public data on the subject of the thermal and mechanical behavior of down.
So, lots of discussions end up with "in my experience".....
That has been my experience.
Rocketman
10-28-2009, 17:37
There is a fellow, Richard Nisley, who is a consultant on thermally insulated outdoor gear who writes occasional articles on www.backpackinglight.com.
Some of his articles are quite good. Others are.... well hard to understand.
As a consultant, there are probably limitations on what he can say, such as revealing much in the way of proprietary data that he gets from his customers.
There probably is a great deal more data and information on thermal insulations than you will find published in the literature or on the web.
So, we end up back where we were. Lots of talk, and slow progress in general understanding.
How much down can they actually get off one bird? Am I carrying around 5 or 6 birds worth of feathers while they are out there freezing somewhere?
There is some interesting work from the military on thermal insulations and density (which is not quite the same as "loft").
One of the reports or papers is below.
http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA481751
Phil Gibson of U.S. Army Soldier Systems Center, Natick, Massachusetts is one of the authors. The figures are interesting to look at and to attempt to seek answers on heat loss in practical sleeping bags.
There is a masters thesis on something like "the mechanics of down", but that isn't the correct title. It too has a discussion on loft and feather content as well as some discussion of the nature of down.
http://etd.gatech.edu/theses/available/etd-11202004-003552/unrestricted/wilde_timothy_p_200412_mast.pdf
Found it. You will probably find the computer modeling part less easy to read than the introductory materials.
I sent a copy of it to "Mr. Wiggy" of Wiggy sleeping bags telling him that there ought to be an equivalent paper on fibrous thermal insulations. He replied with his usual diatribe against down and worthless complicated mathematics.
There seems to be not much in the way of a giant amount of public data on the subject of the thermal and mechanical behavior of down.
So, lots of discussions end up with "in my experience".....
That has been my experience.
Nice.
10 characters
I wonder what BlackRock would think about this:
I think "brushed" nylon inner on a sleeping bag/sleeping quilt "feels" warmer. The hard finish nylon "stings" cold in colder weather.
In fact, I wish more sleeping bags/sleeping quilts had "brushed" nylon on the inside.
Do others here in the forum have the same experience?
Reid,
I was in Iceland. I was told the eider down is collected from the nest.
I don't know more about it.
BlackRock
10-29-2009, 13:59
Connie,
I'd have to agree. It does feel like the softer Taffeta or brush finishes on nylon or polyester fabrics is warmer. I'm not sure whether it is literally warmer or just feels that way.
Here is a good article that more or less talks about the same thing:
http://www.backpackinglight.com/cgi-bin/backpackinglight/comfort_moisture_transport_wool_synthetic_clothing .html
I think the softer finished synthetics might just wick the moisture away a bit different than the harder more sheer fabrics that may seem to hold it closer to the surface layer.
Eiderdown... Ooohhhhh! Me like. That stuff is the creme de la creme of down. It's from an endangered female duck in Iceland. What I've read is that they carefully harvest from either the nest or the female herself as the down is specifically from her breast feathers. They can harvest 1/2 an ounce per nest a year and apparently only get 9,000 pounds a year.
I first read about it because of the 1982 Russian team that did the Southwest face of Everest and wore full parkas made of Eiderdown.
That stuff is so expensive a pillow can cost $2500. If I made a hat out of that stuff it would probably cost about 800 bucks!:eek:
WOW :eek: and I thought my Icelandic sweater is deluxe.
Maybe I could get mature 800 900-fill down for a true 15 20-degree Farenheit UL topquilt?
What kind of "loft" height and money is that?
BlackRock
10-29-2009, 17:31
You can get some pretty nice down (800+) from Thru-hiker.com for $26 a bag (3oz).
For 15* you'd want approximately 2.5-3 inches of loft.
First determine the dimensions of your quilt and calculate the volume.
Example:
4ft x 6ft x 3inches = 10,368 cubic inches for a BIG topquilt.
Then divide by your loft rating (800fp) to get the ounces of down needed.
10,368/800 = 12.96oz of down required.
Add 10% overstuff 12.96*1.1 = 14.2oz down wanted.
Then determine the number of 3oz bags you need: 14.2/3 = 4.75 bags.
Five bags will cost you $130 bucks plus shipping.
I don't have my Singer Golden Touch-n-Sew.
Nevertheless, this is the kind of "data" I was looking for.
I had a Marmot Osprey sleeping quilt, many years ago, that was not warm.
The "loft" was 2.5-3 inches. I do not recall the fill-rating. I think it was sewn-thru.
The new designs are "driven" I believe by the hammock sleepers as "top quilts" and "bottom quilts".
I have been trying to evaluate the "facts" of the new sleeping quilts for a ground-sleeper given an appropriate sleeping pad is used.
The Neo and a CCF looks like it is neither too bulky, nor too much weight. I might be able to have a 15-degree sleeping quilt system with those combined.
The GoLite Ultra 20 looks good, if the temperature-rating were more generous. Reportedly, it is not.
The JRB Mount Washington with 2 oz overfill and pad converter looks like it may be what I am looking for. I am 5'6".
The MLD sleeping quilts are "sold out" and have only their 30-degree and 45-degree rated Spirit Quilts at this time.
The problem is, sleeping quilts have been practically always evaluated only by the hammock sleepers.
after reading this thread i've come to the conclusion that black rock is smart
I opened up the 650 bag. It's the same thing as what's in the 800 (bought from seven wonders) except it's smaller. Does that make any difference? How does montbell get the bags to stuff that small ??
It is really very simple...
Fill power is the area in cubic inches that one oz of down will fill. So one ounce of the 650 type will feel 650 cu inches and so on.
If the figures are correct , it may look the same to you but it isn't.
Franco
It is really very simple...
Fill power is the area in cubic inches that one oz of down will fill. So one ounce of the 650 type will feel 650 cu inches and so on.
If the figures are correct , it may look the same to you but it isn't.
Franco
I think you caught me. When I got to looking at it closer there is a difference. I'm letting it go now I think.
johnarthur39
11-11-2009, 11:34
When it comes to high quality down used by reputable manufacturers, I think people tend to obsess too much about fill ratings without looking at other factors such as construction techniques, shell material, total amount of fill, etc. There are many other factors that determine how well a sleeping bag or down garment will perform. It is also possible that manufacturers use different methods to measure the fill power of down. (e.g., what is 700 fill down to one manufacturer may not be 700 measured by another). My sense is that the difference between good quality 700 down and 800 down is fairly negligible in actual use (other than a slight difference in weight). Given two sleeping bags with comparable construction techniques, shell materials, same amount of accurately measured loft, and down fill measured using the same method; a bag with 700 fill down should be as warm as an 800 fill down. The 800 down will be slightly lighter and maybe a bit more durable. My guess is that most people would have a difficult time telling them apart if they didn't know which was which.
I agree with an earlier post that noted that with the trend towards weight reduction, manufacturers may use a higher rated down (if you believe the ratings) but use lighter shell materials and possibly a bit less fill. Warmth ratings are pretty subjective and vary across manufacturers.
BlackRock
11-11-2009, 13:18
When it comes to high quality down used by reputable manufacturers, I think people tend to obsess too much about fill ratings without looking at other factors such as construction techniques, shell material, total amount of fill, etc. There are many other factors that determine how well a sleeping bag or down garment will perform.
I would definitely agree. A higher fill rating can't make up for poor workmanship or a bad design. It doesn't matter how much 900 fill you have if it doesn't stay in place or isn't protected with a good outer shell. Then again coupling a top quality garment with 700 fill like the MontBell UL Jacket would not yeild the same quality garment as 850-900fp.
It is also possible that manufacturers use different methods to measure the fill power of down. (e.g., what is 700 fill down to one manufacturer may not be 700 measured by another). My sense is that the difference between good quality 700 down and 800 down is fairly negligible in actual use (other than a slight difference in weight).
Most manufacturers should be purchasing down that's already gone through independent testing, like from these guys (http://www.idfl.com/default.asp (http://www.idfl.com/default.asp)). I know some then condition and test it again for their own benefit but the testing methods are fairly standard. What isn't as standard is what sort of prep work or conditioning goes into the down before the tests. The difference between 700 and 800 is definitely not negligable. Even the difference between the 800+ I used to work with and the 900 that I buy now is noticable. Not only close up, but in it's actual characteristics inside and out of the product. Read my detailed post on page one about the differences with high quality down. There is more to it than you'd expect.
Having said that I would agree that down rating can be subjective. Western Mountaineering flip flops between having 850+ and 900 advertised in their bags while MontBell uses 800+ in their UL Jacket and 900 in their Ex Light Jacket. I've read where WM basically said they more or less purchase 900 but give it a rating of 850 just to guarantee you are getting at least 850 even though alot of the time it might rate very close to 900. My guess is that Montbell does the same. They probably get all the same down but use just the best batches for the Ex Light version of basically the same jacket.
In my own product I use 900fp and while it was independently tested I couldn't tell you whether or not you could reproduce the exact results or whether it would measure out to something less than that. What I can say is that the difference between the 800+ (usually rating around 830-860) and 900 is big and changed the product for the better. I can also say that between batches of the same 900 down that I get, some will be better than others. Not by much, but I notice the difference most likely because I stare at the stuff most all day :cool:
I would also agree that most people would have a hard time telling the difference between high quality down inside a sleeping bag. However, when you compare the top ranked bags side by side you'll see the difference between say the WM Highlight and the Marmot Helium, not only in build quality but in weight and loft. That right there is due to better down inside your WM bag. Still VERY close to one another but I'd trust my WM bag in colder temps over my Marmot Helium any day.
Where can you find the EN ratings for different bags?
johnarthur39
11-11-2009, 14:49
I have no doubt that someone who works with down on a regular basis can tell the difference between grades of down, particularly on direct inspection. My point is that in day-to-day use, given two equally constructed products, the apparent difference in practical use may be less than most people realize. It gets even harder to tell the difference when comparing products across different manufacturers. I have three Western Mountaineering bags of various ages, a down Sierra Designs bag, and various down sweaters and jackets collected over the years so I have some experience with down products. When I replaced my winter WM bag two years ago, I compared comparably rated WM and Montbell bags. My impression was that the WM bag had a greater amount of fill and higher loft than comparably rated Montbell bags. It wasn't that the Montbell bags were bad, I just got the impression that WM used a greater amount of down for a given temp rating. As I crawled around in the Montbell bags (at their store on Pearl St. in Boulder), I noticed a few thin spots that supported my impressions. I went with the WM bag. I have not doubt that the Montbell would have served me well. I just feel like I have a greater margin of error in the WM bag. It has more to do with the quantity of down in the WM rather than the fill rating of the down used.
Rocketman
11-11-2009, 16:39
Where can you find the EN ratings for different bags?
Europe..... the shops over there publish them regularly.
What you can do is to type in the manufacturer/name of the bag (in a google or other search) and then add the phrase EN13537 which stands for the European Normal (standard) that tells the bag was rated to these standards.
For example do a google search for "GoHeavy Morphine 20 EN 13537" which is looking for the bag called "Morphine 20" made by "GoHeavy" and you want to see the phrase EN13537 in there where they will probably tell you the temperature ratings.
There is also a phrase in French that someone described that accomplishes the same thing, but it is no longer in my notes.
With the EN type search, you will also pick up a few American shops. Most bags are now tested to EN standards because that is the only way to sell in the European market.
BlackRock
11-11-2009, 16:43
No worries John, I take nothing personally :) You've got some very good observations. I would agree that it's definitely hard to differentiate some of the products out there. I think you got it right when you said the WM bag seemed loftier with fewer thin spots. I'd add that I think it's not just the use of better down in larger quantities but it's also the focus on construction like you mentioned in your first post. If both bags had the same weight of fill but one had poor baffle design or thin spots due to bad down distribution it definitely wouldn't work as well.
The wonder though... Which is warmer, the 35* Montbell UL SS Down Hugger #4 with 8oz of fill or the WM Highlight which is also a 35* rated bag with 8oz of down. The WM weighs in at 16oz total while the MontBell is 21oz which is no doubt the difference between the fabric used, zipper, etc. Since they both contain 8oz of fill you'd expect them to be very simliar but my guess is the better down used in the WM is really the only thing that differentiates the bag's much at all.
Europe..... the shops over there publish them regularly.
What you can do is to type in the manufacturer/name of the bag (in a google or other search) and then add the phrase EN13537 which stands for the European Normal (standard) that tells the bag was rated to these standards.
For example do a google search for "GoHeavy Morphine 20 EN 13537" which is looking for the bag called "Morphine 20" made by "GoHeavy" and you want to see the phrase EN13537 in there where they will probably tell you the temperature ratings.
There is also a phrase in French that someone described that accomplishes the same thing, but it is no longer in my notes.
With the EN type search, you will also pick up a few American shops. Most bags are now tested to EN standards because that is the only way to sell in the European market.
I think we need a push for that in America too. Not that I distrust any of the companies but it gives credence to the claims. Is this an adjunct or subsidiary for lack of better terms that do this type of rating or is it still done by the companies themselves? Given also that I really don't know much about the EN testing methods.
Black Rock, what is it that you do for a living? Is it possible to MYOG bags that are as reliable as the big money bags? It's seems to me that the opportunity cost of a DIY bag is enormous, but not if it doesn't perform.
BlackRock
11-11-2009, 18:22
Reid - Right now I make the Black Rock Gear Down Hat (www.blackrockgear.com (http://www.blackrockgear.com/)) and when I'm not doing that I'm usually out climbing on a rock somewhere.
I think you can definitely make your own gear that is just as reliable and peforms as well as or better than what the big guys can make but it's not without its problems or effort. I think the hardest part is refining your item to a point where it starts to become a production quality piece of gear and to do that it can take time and alot of iterations.
For example, I probably made 20+ hats before my design became similar to what it is today. I experimented with different fabrics, patterns, threads, needles and stitches. It wasn't until around my 10th hat that I had anything you'd really want to wear on your head so there was no cost savings in that project.
Now it's not to say you couldn't sit down, carefully design a piece of gear and make a good item out of the gates. It's definitely possible and for that I'd simply recommend starting with alot of research and eventually using good quality fabric, thread and experimenting with your sewing machine and the types of stitches you'll be using. A good stitch goes along way.
There are alot of amazing new fabrics out like the sub 1oz DWR coated ripstop nylons or the UL silnylons for waterproof applications as well. Heck, you can even buy the #4YKK micro zippers for your projects like you find on some of the top end pieces just to finish out your UL piece of gear.
I'm not sure how much you'd save though since fabric and insulation will be expensive relative to what the big guys get it for in bulk. If you were to try and build a 0* bag you'd need about 30oz of down which would cost you about $300 bucks, then you may need upwards of 8-10 yards of fabric which would probably run around 100 or 140 bucks. With just that you are pushing the $400 mark and you still need thread, lycra's, zippers, pull strings, etc and most production bags only run $400 or so already.
It's not to say you couldn't make the design your own and justify the cost but it's alot of work for something that would be a first gen prototype piece of gear. I'm all for making your own stuff though so I say go for it! Check out Paul's site, Thru-hiker.com. He's got lots of good fabric, articles and even designs on making your own stuff. My guess is you've already seen it all, but if not, enjoy!
[quote=BlackRock;918339]
I'm not sure how much you'd save though since fabric and insulation will be expensive relative to what the big guys get it for in bulk. If you were to try and build a 0* bag you'd need about 30oz of down which would cost you about $300 bucks, then you may need upwards of 8-10 yards of fabric which would probably run around 100 or 140 bucks. With just that you are pushing the $400 mark and you still need thread, lycra's, zippers, pull strings, etc and most production bags only run $400 or so already.
[quote=BlackRock;918339]
That's a good point, very good. I was actually thinking of doing about a bag of that temp rating DIY but using a synthetic layer on the outside and having vertical baffles of down on the inside. Reasonable.....I don't know. I think it would be good for insulation but not really that sure if that'd be the case.