Determining unknown down rating??

[Ryan “Rudy” Oury]

Anyone know if its possible to figure out the rating of an uknown collection of down? I’ve got a 10-12 yr old down REI sleeping bag that I haven’t used in probably 9 years. I’m considering if it would be worth opening it up, and salvaging the down for some clothing, but would want to know the rating first. I’m gonna contact REI to see if they can look back in their specs too, but not too confident I’ll hear back.

[Jerry Adams]

You could put it in a container with known cross section area, measure how deep it is, calculate volume, and weigh it, divide

For their official test they’re pretty specific about the details, but you could estimate

Maybe wash and dry the down first.  Find a thread where the specifics are detailed – soap not detergent, rinse a bunch of times, dry maybe with a tennis ball or whatever to fluff it.

It’s probably about 700 FP – probably degraded with time but if you washed it it might be a little better

[James Marco]

10 years ago? Try to google the model. Often you can pull up an old report.
A good overall guide would be: Nomal: 550-650, Good: 650-750, Best: 750-850
There were a very few 850+ bags ten years ago. My bags from that time were all 750-800.

For clothing, fp is less important that many people think. Often you will find a down sweater at 12oz only to discover it only has 4-5oz of down. Or, about 1/3 of the total weight. Adding an extra 1/2-3/4oz of down to make up the difference really is not that critical, unless you are looking at SUL weights. Remember, fill power means volume. The difference for 4oz of fill at 800, means 3200ci, ~4.6oz of 700fp would perform as well. Even with 600fp, the weight of fill would only be around 5.3oz.

[Ben H.]

I’ve no experience, but every report I’ve ever read of someone trying to do this, they say it is not worthwhile.

I agree with the above comment that fill powers have gone up in the last ten years.  Unless you bought a top of the line bag from REI, I would guess it was around 650 FP ten years ago and may have degraded in the intervening time.

Also agree in clothes, fill power is not that critical.

[Ryan “Rudy” Oury]

Thanks for the responses all. REI actually got back to me really quickly. They said it is 600 fp down.

So follow-up question then… if the bag weighs 60 oz, what do you think is a rough guess at the actual amount of down in it? The fabric isn’t thick, but its definitely not UL so I’m sure its contributing a fair bit. I suppose I could try to do some rough calculations of how much fabric & zipper are on the bag? Maybe I’ll reach out to REI again and see if they can tell me what kind of fabric was used.

Ben – I hear you and have a feeling that it will probably be more trouble than its worth trying to salvage the down… but we’ll see :)

[Ryan “Rudy” Oury]

Well, guess I should have just looked before asking the last question… the “no one is allowed to remove this tag except the consumer” tag actually states 30 oz of down material was used. So that mystery is solved.

But I fluffed the bag up and got rough measurements of its volume, and based on those numbers, the down is currently only 350-400 FP. Looks like its time to wash it!

[Fabian S]

Hey,

in Germany, we have a formula we use to figure out the approx. temp rating of your sleeping bag:

TLim = 17,5 – ( 3,5 * Height / 2 )

Fabian.

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