UQ Overstuffing

[Just Bill]

To me, the overstuff isn't to get the quilt to a lower temp, but rather to keep from cold spots where the down didn't loft into correctly. I've experienced this a couple times.
A quick setup in the dark didn't leave enough time for the down to loft up and caused me cold spots only remedied by hopping out and smacking the quilt around to move the down into the unfilled voids.

That's kinda the deal anyway with down. One reason I prefer synthetics for fast/light trips is that I don't need to wait 1/2 hour before crawling in.

Overstuff won't really help that much, you still need to wait for the down to loft on it's own or with some good shakes and gentle pats to help it along.

Assuming all things are equal- if your bag wasn't fully filled to begin with (a mistake I have made in construction) then you need to solve that first. I do agree- a little extra is often worth it in this regard- but closer to 5-10% seems the better number. If you are buying a bag- the vendor has figured this out for you (and gone a little extra too) which is why most of us agree that many vendors have underrated their gear a bit.

That said- I may use 35% for MYOG to make it easy- but I know that most of that fluff is to fully fill the shell and cover my imprecise math. I think that is the case on most down products- you make a shell- take a guess- and adjust your OS variable until you are happy with it. Doing the math I see that the baffles deform much more than simple area x loft implies. So most of that OS% is simply fill in my experience.

[CC_Cinci]

Doing the math I see that the baffles deform much more than simple area x loft implies. So most of that OS% is simply fill in my experience.

I remember reading your explanation for this... Are you sure the actual fabric of the shell is stretching to create more area/volume vs the distance between baffles becoming shorter to explain the change in shape while keeping a fixed area/volume? It seems like you would really have to add a lot of extra down to get the shell material to stretch.

[pinballwizard]

First of all, WOW.... You all just scared the bejesus out of me if I thought I could make my own quilt by just sewing a pattern and stuffing some down in it. Apparently a need a degree in thermodynamics and physics to make a quilt.
So good news that point number two is I just purchased my first quilt, and it's a 0 degree incubator with one ounce overfill. My question from this brain trust of fill power, powerhouses, is one ounce of overfill to a zero degree UQ even going to do anything, or did I kinda just add a drop of waterfowl into an ocean of down?

I apologize if this was already well covered. A bit of the thread was too in depth and elaborate that I may not have taken it ALL in.

[Thumbs]

I remember reading your explanation for this... Are you sure the actual fabric of the shell is stretching to create more area/volume vs the distance between baffles becoming shorter to explain the change in shape while keeping a fixed area/volume? It seems like you would really have to add a lot of extra down to get the shell material to stretch.

Not stretching, but expanding from the nice calculated rectangular tube, to a more rounded one.

[CC_Cinci]

Not stretching, but expanding from the nice calculated rectangular tube, to a more rounded one.

Solid, stupid of me to have assumed a rectangle had the same area as a circle with the same circumference (I've never been all that great at geometry)!

Just Bill,
Very nice calculations. This helps explain why my 40%+ overstuffed TQ doesn't seem to be bursting at the seams.

[Just Bill]

First of all, WOW.... You all just scared the bejesus out of me if I thought I could make my own quilt by just sewing a pattern and stuffing some down in it. Apparently a need a degree in thermodynamics and physics to make a quilt.
So good news that point number two is I just purchased my first quilt, and it's a 0 degree incubator with one ounce overfill. My question from this brain trust of fill power, powerhouses, is one ounce of overfill to a zero degree UQ even going to do anything, or did I kinda just add a drop of waterfowl into an ocean of down?

I apologize if this was already well covered. A bit of the thread was too in depth and elaborate that I may not have taken it ALL in.

No good answer for you...
two things you could ask your vendor-
Easy one- how many ounces of fill go into it normally (16 ounce roughly)? One ounce in 16 ounces is only 6.25% over design- not a bad amount to give you a little help with wear and real world lofting. Not to mention cheap/light enough peace of mind.
Hard one- how they made/designed it.

[Just Bill]

Not stretching, but expanding from the nice calculated rectangular tube, to a more rounded one.

Exactly- I like the word deform- but same deal.
Perimeter stays the same Cinci- but as the shape changes- even a little- the interior volume increases as shown.

Huge deal for MYOG.
The good news from the BPL discussions- it is wasted weight/money to a certain extent- but density increase does provide some measure of additional warmth. So at least we can say (or at least I agree with)- that if you err on the side of caution and use too much fill you won't see a decrease in rating.

For a regular consumer- just buy a good product from a knowledgeable vendor who can advise you. I think the OS stuff is good to know for MYOG, but for a consumer it's not important at all.
If you are buying a bag to last "forever" you can add a little overstuff- it won't hurt anything but the scale or wallet- and even then those impacts are relatively minimal. Of course you might be better off in 10-15 years simply recovering the down and putting it in a new shell as that is likely to be a bit beat up by then. Or if not, finding a vendor to restuff it for you.

[ckmaui]

being a pro photographer most my life both underwater for 15 years and above for last 15 I see things like this but on the photography side usually about sensor size or lens apertures or other things kinda laughing that it also happens here but laughing in a good way

in reality buy top gear and its not the gear its the photographer after that point

I kinda figure buying from a great quilt company I chose HG who has a great rep and there 0 should be fine but of course threads like this make me second guess everything and get all paranoid ahahahhahahaa but that is my issue

interesting read for sure


and
thanks Boston for responding to my question

[Boston]

No problem. I figure after causing your confusion, I can help eliminate it too, hopefully.

I don't know of any vendor on here that put's out a bad product. So fret not, whatever choice you made will probably work out for you.

[ckmaui]

so decided to go with 2 oz overfill after reading again and understanding more also after the manufacture response for sure was not about the warmth like I had thought but about maintaining the distribution and air space better


asked HG about it and this was the response

Down plus the loft of the down is how we determine the degree rating for quilts. 1 or 2 ounces of down over an entire quilt will not change the temperature rating very much, but it will make it "more fluffy" which will help those cold pockets where down has shifted. If you are worried that may happen, then I would add a couple ounces to your quilts. Each ounce of down is an additional $9.00. You can make a custom order ticket off the website and reference your order# and we will get it done I hope that clears up your questions on that issue.

so thanks again
going to come back read this in a week or so again sure more will sink in

so for sure learned its not as much for warmth as it is maybe keeping that loft and the distribution more even of course providing more uniform warmth

No problem. I figure after causing your confusion, I can help eliminate it too, hopefully.

I don't know of any vendor on here that put's out a bad product. So fret not, whatever choice you made will probably work out for you.