Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 32
  1. #21
    Senior Member TeeDee's Avatar
    Join Date
    Jan 2007
    Location
    Maryland
    Hammock
    DIY Bridge
    Tarp
    DIY 10'x11'
    Suspension
    Whoopie Slings
    Posts
    1,628
    Images
    300
    Quote Originally Posted by jbo_c View Post
    Exactly, the higher fill power gives you more, but much smaller air pockets = increased insulation efficiency. ....
    Where do you get the proof for the above statements? Your opinion or can you give a reference of someone who has actually done measurements and written reports on their measurements?

    Quote Originally Posted by jbo_c View Post
    ....
    I can't tell you that is in anybody's spec, but I'll hold my position that the main difference in quality is amount of feathers.

    Jbo
    Please provide reference of somebody who has actually done measurements or someone who processes down to produce down of varying fp.

    Quote Originally Posted by Youngblood View Post
    http://www.westcomb.com/content/FAQ/13

    "Fill power is a measure of the loft or “fluffiness” of a down 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. Fill power ranges from about 175 cm³/g (300 in³/oz) for feathers to around 900 cm³/g for the highest quality down. Higher fill powers are associated with a larger percentage of down clusters and a larger average down cluster size.

    Simply the higher the number the better and more expensive. The higher the number the higher it lofts and better it insulates.

    At Westcomb we source only the highest grade Canadian Hutterite Down that yields a fill power of 850+."
    Okay this is finally from someone who produces the down. Now they are making statements - do they have proof of their statements??

    1. How have they measured the number of air pockets?
    2. have they measured the insulating properties of equal volumes of down of various fp?
    3. Have they measured the percentage of down clusters and average cluster size?


    Just a few of the immediate questions that pop up.

    I would need to see their reports on what they have measured.

    It is easy for the PR people in a company to write descriptions. PR people tend to talk to the line people and get statements and then take those statements which are usually opinions and write them down as statements of fact. The really good companies also provide documentation for the claims made by the PR people.
    Those who sacrifice freedom for safety, have neither.

    Do not dig your grave with your teeth. (Unknown)

  2. #22
    Senior Member BillyBob58's Avatar
    Join Date
    Jan 2007
    Location
    Tupelo, MS
    Posts
    11,108
    Images
    489
    So what we need is a study to see if 4" ( or whatever ) loft supplied by 900 FP is of equal warmth to 4" from 800 or 600 FP. It will be lighter. Will it be as warm(quite possibly, but who knows)? Or possibly even warmer (unlikely I'm thinking).

  3. #23
    Senior Member TeeDee's Avatar
    Join Date
    Jan 2007
    Location
    Maryland
    Hammock
    DIY Bridge
    Tarp
    DIY 10'x11'
    Suspension
    Whoopie Slings
    Posts
    1,628
    Images
    300
    Quote Originally Posted by Joe Cross View Post
    Here's a chart I found on BPL that may be of some help.
    Great - a chart that means someone has done some measurements. Thank You.

    Since I am no longer a paying member of BPL (long political rant here that is unnecessary ), can you also provide any documentation that accompanies the chart.

    I am having a hard time understanding the quantities column - it gives a weight, but says nothing about the volume or loft occupied by the down. For example, 200 g: is that in a container with 1" of loft, 2" of loft, .... ?? Unknown. Does the loft vary with fp or is the down constrained into the same container? Is the container rigid so that all fp has identical loft or is the container fabric so that the loft will vary with fp?

    Ideally, we would want 200 g of 700 fp and 200 g of 800 fp in different containers each of a size computed for the weight of the fp.

    Hopefully there is documentation with the chart that explains how they made their measurements. Were the measurements made for equal volumes or equal weights? I am betting equal weights since the chart is built around equal weights for the 2 fp. Unfortunately equal weights with identical volumes would seem to degrade the ratings for some fp values and favor others. DIYers would probably be more interested in equal volumes since they tend to compute the weight of down needed for the volume of their project. Manufacturers on the other hand are just the opposite, make the shell and inject the same measured weight for all fp values - same procedure to follow, means lower cost. The latter seems to be the easiest way and the way all of the comparisons referenced to date were done which makes sense since they would probably be paid for by the manufacturers.

    Some tentative conclusions can be drawn from the chart.

    For a typical top quilt, with say 15 oz (425g) of down, the chart seems to indicate that the temperature rating would go down (get better) by about 5 degrees F in going from 700 fp to 800 fp. Is this trend linear with fp, e.g., would there then be another 5 degrees in going from 800 fp to 900 fp? If the relationship is linear in this manner, buying 900 fp instead of 700 fp would probably be a worthwhile investment. If however, the relationship is not linear, the investment may be better or worse depending on the trend of the curve. If they had also included 600 fp and better yet 650 fp also, then the relationship could be better extrapolated. For the limited fp measured, I would need to compare the cost of 700 fp to 800 fp to see if the 5 degree improvement was really worthwhile for the volume needed to fill. For example, comparing 15 oz of 700 fp to the 13.1 oz of 800 fp needed to fill the same volume, I would need approximately 2 oz less of down. If down is costing approximately $10/oz, then the 800 fp would cost about $20 less for equal price for 700 fp and 800 fp. Probably unrealistic.. The next question left unanswered for the DIYer, is would the 13 oz of 800 fp provide the same or better temperature rating as the 15 oz of 700 fp?? Interpolating the chart seems to indicate it might be a little less.
    Those who sacrifice freedom for safety, have neither.

    Do not dig your grave with your teeth. (Unknown)

  4. #24
    Senior Member TeeDee's Avatar
    Join Date
    Jan 2007
    Location
    Maryland
    Hammock
    DIY Bridge
    Tarp
    DIY 10'x11'
    Suspension
    Whoopie Slings
    Posts
    1,628
    Images
    300
    Quote Originally Posted by BillyBob58 View Post
    So what we need is a study to see if 4" ( or whatever ) loft supplied by 900 FP is of equal warmth to 4" from 800 or 600 FP. It will be lighter. Will it be as warm(quite possibly, but who knows)? Or possibly even warmer (unlikely I'm thinking).
    Yep - that's what is needed for a DIYer to really compare the worth of 900 fp over 800 fp or 700 fp. Then it would be possible to see if the higher cost of the higher fp is really offset by the use of less down to get equal performance and less weight. If the performance is less, equal or better, then by how much? It's one thing to pay for the higher fp to get less weight, but if the higher fp needs more loft for equal insulation value, then the weight savings is diminished and the cost is even higher. It might very well be that the insulation value is nearly equal, but the chart provided by Joe Cross doesn't seem to bear that out. As I interpolate the chart, it appears that getting equal loft with 700 fp and 800 fp may not get you equal performance - less weight, but not equal temperature rating.
    Those who sacrifice freedom for safety, have neither.

    Do not dig your grave with your teeth. (Unknown)

  5. #25

    Join Date
    Aug 2008
    Location
    wherever the wind blows
    Hammock
    DIY gathered end
    Tarp
    Hammock Gear Cuben
    Insulation
    100% Hammock Gear
    Suspension
    Whoopie Sling
    Posts
    1,549
    Images
    26
    I enjoy reading these threads (when I get the chance). I do not always have time to enter the discussion as deeply as I would like but I will comment briefly on my experiences with the suppliers I have used in the past.

    3 of the 5 suppliers I have used in the past rated their down as a ratio and not by fill power. It also appears to be the way fill power is discussed over at the IDFL. There is a lot of literature over there for those inclined to wade though it. Anyway, as I was saying, the suppliers I have dealt with generally refer to the down as a 85/15 or 90/10 or 95/5. These numbers are the ratio of goose down clusters to the number of feathers. Also, since there are always going to be SOME feathers even in the highest quality of down, there is a limit in the size they are allowed to be. This information is also over there at the IDFL site. You might have to register to read some of the articles but it is free to do so.

    So, generally speaking, higher fill power down DOES have a higher ratio of goose down clusters to feathers. Since the higher fill power down has less feathers...it is able to perform better in the loft test. There are MANY variables that come into play when the loft test is performed. Things from relative humidity to how often the equipment gets cleaned can be a factor. Many suppliers will not even sell goose down that is rated to 900 because at those ratings, the testing to certify it can be cost prohibitive. Samples frequently have different results (not by much) when retested even during the same day. For goose down to receive a specific rating, it has to meet or exceed that number during testing. 900 is so close to perfect that consistently getting over that bar can be a challenge...and costs money. Whether that money is worth it is for the consumer to decide. That is why these discussions are so great...and important.

    ~Stormcrow
    Owner/Founder at Hammockgear.com - Hammock Camping Outfitters
    Home of the Burrow, the Incubator, and the Phoenix

  6. #26
    Senior Member
    Join Date
    Dec 2007
    Location
    Doraville, GA
    Posts
    946
    Images
    23
    Quote Originally Posted by stormcrow View Post
    Anyway, as I was saying, the suppliers I have dealt with generally refer to the down as a 85/15 or 90/10 or 95/5. These numbers are the ratio of goose down clusters to the number of feathers. Also, since there are always going to be SOME feathers even in the highest quality of down, there is a limit in the size they are allowed to be.
    Do you recall what fp goes with the 85/15, 90/10, and 95/5? Seems like I have seen some type of correlation before.
    Youngblood AT2000

  7. #27

    Join Date
    Aug 2008
    Location
    wherever the wind blows
    Hammock
    DIY gathered end
    Tarp
    Hammock Gear Cuben
    Insulation
    100% Hammock Gear
    Suspension
    Whoopie Sling
    Posts
    1,549
    Images
    26
    Quote Originally Posted by Youngblood View Post
    Do you recall what fp goes with the 85/15, 90/10, and 95/5? Seems like I have seen some type of correlation before.
    The lab report on one of the batches I received had the following data:

    Down Cluster: 94.4%
    Down Fiber: 1.3%
    Feather Fiber: 1.2%
    Water Fowl Feather: 3.0%
    Broken Damaged Feathes: 0.1%

    This particular batch was rated 905 fill power.

    I think most times I have seen it this way. The 95/5 quality is the best I personally have been able to get and that is what tests out to 900 fill power. The 800 fill power is what I used to get from Canada and that was closer to the 800+ fill power. I have never bothered with the 85/15 but would guess that to be the 650-750 fill power range...just a guess though.

    ~sc
    Owner/Founder at Hammockgear.com - Hammock Camping Outfitters
    Home of the Burrow, the Incubator, and the Phoenix

  8. #28
    Senior Member tomsawyer222's Avatar
    Join Date
    Jan 2008
    Location
    ladson SC
    Hammock
    Custom dragon
    Tarp
    Custom made cuben
    Insulation
    custom peapod
    Suspension
    Whoopie sling
    Posts
    255
    Images
    12
    Once we figure out how much more insulative the 900 fill is then the 800 the real question is... is it worth the price? Generally speaking you can get 800 fill power for about 6.50 to 7 dollars an ounce maybe sometimes 8 but 900 fill is 10 dollars and ounce almost everywhere. So over a quilt that requires 15- 20 ounces of fill of 800 you will not really save that much weight if you use the 900 and dont overstuff. If you still use the same weight and of down and just take the increase in warmth it gives at about 5 degrees more then was 5 degrees worth the extra 70 dollars for 20 ounces of down?

  9. #29
    Senior Member TeeDee's Avatar
    Join Date
    Jan 2007
    Location
    Maryland
    Hammock
    DIY Bridge
    Tarp
    DIY 10'x11'
    Suspension
    Whoopie Slings
    Posts
    1,628
    Images
    300
    Quote Originally Posted by stormcrow View Post
    I enjoy reading these threads (when I get the chance). I do not always have time to enter the discussion as deeply as I would like but I will comment briefly on my experiences with the suppliers I have used in the past.

    3 of the 5 suppliers I have used in the past rated their down as a ratio and not by fill power. It also appears to be the way fill power is discussed over at the IDFL. There is a lot of literature over there for those inclined to wade though it. Anyway, as I was saying, the suppliers I have dealt with generally refer to the down as a 85/15 or 90/10 or 95/5. These numbers are the ratio of goose down clusters to the number of feathers. Also, since there are always going to be SOME feathers even in the highest quality of down, there is a limit in the size they are allowed to be. This information is also over there at the IDFL site. You might have to register to read some of the articles but it is free to do so.

    So, generally speaking, higher fill power down DOES have a higher ratio of goose down clusters to feathers. Since the higher fill power down has less feathers...it is able to perform better in the loft test. There are MANY variables that come into play when the loft test is performed. Things from relative humidity to how often the equipment gets cleaned can be a factor. Many suppliers will not even sell goose down that is rated to 900 because at those ratings, the testing to certify it can be cost prohibitive. Samples frequently have different results (not by much) when retested even during the same day. For goose down to receive a specific rating, it has to meet or exceed that number during testing. 900 is so close to perfect that consistently getting over that bar can be a challenge...and costs money. Whether that money is worth it is for the consumer to decide. That is why these discussions are so great...and important.

    ~Stormcrow
    Thank you for this information. That the pretty much backs up youngblood.

    I still have the same problem though. Down (& feather mix ) is always rated at equal weights and varying volume. That makes sense since it is not possible to rate at equal volumes until a fp figure has been determined.

    To restate the obvious and the reason I started this thread:

    The problem is for a DIY project it is usually customary (for every post by HF members I have read about DIY down quilts) to first determine the size of the desired quilt, Length x width x loft/thickness, compute the volume of the desired quilt and then use the fp value to compute the needed amount/weight of the down to fill the quilt. The DIYer will at this point compute the needed down for 2 or more fp values (unless the DIYer already has down of a given fp) and compare the amounts needed to determine the cost and thus determine which fp down to buy based on various factors, cost and weight usually being the 2 most obvious.

    So a DIY project is not determined by equal weights and varying volumes of down at various fp values, but by equal volumes and varying weights of down at various fp values.

    I would still like to see data on temperature rating by fp for a constant volume and varying weights. All of the data I have to date is for a constant weight which is of very limited use for a DIYer deciding on the relative benefits of cost/weight/temp rating.

    I also acknowledge that I will probably never see such test results.

    The limited data that was posted on the BPL chart comparing 700 fp and 800 fp at various equal weights would seem to indicate that the temp rating is not going to be the same for different fp values. I say seem to indicate this since the chart doesn't have any indication of whether the 2 fp samples of equal weight were tested using the same container size or if the 2 fp samples of equal weight were tested in containers which allowed the down to expand to it full lofted volume.

    If the container was of the same size, then the higher fp down was compressed. The opinion of the BPL expert says that compressing the down of the greater fp value has no influence on it's temp rating. But if loft measurements are of any value at all, it would seem that testing the 800 fp down at it's full loft, that the 800 fp sample of equal weight and greater loft would give a lower temp rating which is exactly what the data in the chart show. But how was the lower temp rating achieved???

    I have not been able to reconcile this as yet.
    Those who sacrifice freedom for safety, have neither.

    Do not dig your grave with your teeth. (Unknown)

  10. #30
    Senior Member
    Join Date
    Dec 2007
    Location
    Doraville, GA
    Posts
    946
    Images
    23
    Quote Originally Posted by TeeDee View Post
    The limited data that was posted on the BPL chart comparing 700 fp and 800 fp at various equal weights would seem to indicate that the temp rating is not going to be the same for different fp values. I say seem to indicate this since the chart doesn't have any indication of whether the 2 fp samples of equal weight were tested using the same container size or if the 2 fp samples of equal weight were tested in containers which allowed the down to expand to it full lofted volume.

    If the container was of the same size, then the higher fp down was compressed. The opinion of the BPL expert says that compressing the down of the greater fp value has no influence on it's temp rating. But if loft measurements are of any value at all, it would seem that testing the 800 fp down at it's full loft, that the 800 fp sample of equal weight and greater loft would give a lower temp rating which is exactly what the data in the chart show. But how was the lower temp rating achieved???

    I have not been able to reconcile this as yet.
    TeeDee... I can sympathize with things not making sense when they should. There is misinformation out there and some of the data you find is likely just wrong because of how it is acquired, if nothing else.

    I think the calculations used for the volume of down fill needed are... well, I'm searching for the right word and can't think of it, maybe naive is a good choice? There is a reason we use baffles or otherwise compartmentalise quilts and that enters into what is going on. They certainly influence the volume of down needed and how well the quilt will perform with a specific volume of down. From having personal experience with breathable down sleeping bags and quilts, and inflatable down air mats, I suspect whether the down is contained in a breathable container or an air-tight, inflated container are also big factors.

    Sidestepping how to compute how much down is actually needed and ignoring inflated air mats, I suppose we could classify the volume of down fill in a breathable container like we use for quilts into a number of categories and then think about what defining characteristics they might have.

    One category might be understuffed such that while the quilt appears fully lofted, a closer exam reveals gaps in the distribution of the down insulation. Another category might be where it is fully lofted and with a uniform distribution of down insulation. Overstuffed might be fully lofted with uniform distribution of down and some amount of puffiness shown between baffles. Severely overstuffed might be so overstuffed that it supports you like a mattress when you lay on it, you can't hardly compress into a stuff sack, and you start thinking it might be best to try rolling it up to put it away.

    I don't really know what the categories might be, but I think this might be one way to approach what you are trying to get at. I've seen quilts or sleeping bags with at least the first three categories and have some understanding of some of the different characteristics they have.
    Youngblood AT2000

  • + New Posts
  • Page 3 of 4 FirstFirst 1234 LastLast

    Similar Threads

    1. Black Wolf Returns ...
      By Black Wolf in forum General Hammock Talk
      Replies: 15
      Last Post: 10-01-2014, 11:15
    2. Warbonnet returns?
      By Red Cinema in forum Warbonnet Hammocks
      Replies: 8
      Last Post: 10-28-2013, 18:32
    3. Coyote Returns
      By pgibson in forum Arrowhead Equipment (Home of Kick Ass Quilts)
      Replies: 0
      Last Post: 04-27-2011, 09:36
    4. Too Much Loft; Diminishing Returns?
      By Trooper in forum Under Quilts
      Replies: 15
      Last Post: 01-17-2011, 20:48

    Tags for this Thread

    Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •