Loft & Down Chart for Top Quilts?

**packman9000** · 12-11-2020, 10:21

I apologise in advance if this has been asked already - I've been through the stickies and I've tried searching but haven't turned up anything other than Shug's chart for loft height to temp.

I'm exploring MYO top quilt, but having real trouble finding anything about down weight for filling the baffles. Is there a resource that I'm missing for how I'd match up loft with temp with the amount of down needed? This thread was very helpful but doesn't specifically answer how many roughly ounces are needed. I know other factors are involved like the width of the baffles and so on, but I'm looking for a general starting point.

Thank you so much! I've been all over trying to find it.

**FLTurtle** · 12-11-2020, 10:26

https://www.hammockforums.net/forum/...ead.php/157408

**packman9000** · 12-11-2020, 10:27

Yep, I saw that, but it doesn't specifically answer my question.

I edited my OP to note that thread.

**Cruiser51** · 12-11-2020, 10:42

Dialout ... this link is the thread where the Catsplat calculator was introduced, it's a long thread, but near the end there is a link for the latest version of the calculator. https://hammockforums.net/forum/show...light=Catsplat

This isn't exactly a chart, but it does help you design parameters for TQs and UQs, and gives you the temp performance for whatever you design, of course there are a few caveats using it, but it is about the best start you can get IMO.
Although the thread is a good read (and I sugget you take a good look), the latest calculator is here https://hammockforums.net/forum/show...light=Catsplat

Brian

**FLTurtle** · 12-11-2020, 10:46

Ahh, the weight, not that height...my bad.

Ok, so fill power means how many cubic inches will 1 oz of down fill. So, if each baffle is 2" high, 4" wide" and 76" long...you have 608 cubic inches.

If you're using 850 fp down, you need: 608/850 = 0.71 oz per baffle.

**packman9000** · 12-11-2020, 10:56

That's the type of info! There's no such thing as too much information when you're MYOG. Time invested up front is money saved later.

I understand the whole loft height-temp thing, and I know the amount of down correlates to maintaining the height, but I couldn't for the life of me find info about how much to use as a starting point or even proper terms to search for. And of course the quality or type of down comes into play but that's a different story. Thanks @flturtle for the quick and easy way to rough it out ��

This is a great starting point for planning my quilt; I was starting to feel maybe I'm dumb and missing some super obvious thing. Thank you both so, so much!

**Cruiser51** · 12-11-2020, 10:57

Turtle ... that is the simple version of the calculation, but it assumes 2 things that likely aren't going to hold true 1) the down is actually going to be 850 in the field and 2) the shape will also hold true once it is sewed up.

Some factor to compensate for those items are needed, in the calculator it is done with the term "over stuff" .... if this isn't incorporated somewhere, the quilt will definitely not meet design expectations (think not filled sufficiently). Not big fan of the term "over stuff" because it doesn't really capture the purpose of the term/factor which i believe is to do the major compensation for those 2 above factors (typically it is 30-40%)

Brian

**packman9000** · 12-11-2020, 11:28

Ahhh...see I didn't know that, I assumed overstuff was like 99% in relation to how well it would hold shape, with marginal bearing on thermal efficiency and not at all necessary to actual R value.

Is there an easy way to rough in how much down, including the erroneously named overstuff? I would've given my specs and ask for an estimate, but that doesn't help for any future projects so I am keen to learn it for myself. Thanks Brian

**FLTurtle** · 12-11-2020, 11:42

Yeah, I figure the exact measurement would be the starting point. When they say "20% overstuff" that would be 0.71 x 1.2 = 0.852 oz per baffle.

**Cruiser51** · 12-11-2020, 19:52

Dialout ... mine is only one opinion, I will decide on the temp rating I want and input stuff from there.

The general rules I use are that the chamber width isn't more than twice the height, otherwise I find the chambers can be a little "squishy" ... so for a 2" high baffle, I wouldn't exceed a width of 4" and likely I would stay under with what ever works out with an even number of chambers for the quilt width. I have also decided that a value of 30-40% "overstuff" works well (for me), that slides from 40% at thinner quilts to 30% for thicker quilts.

For the top quilt you also have to decide on the shape, rectangular or tapered ... or a combo of both.
The link I posted is for UQs and not completely transferable, if you are interested a top quilt calculator, send me a message with your email and I will send a copy of an Excel sheet I made to do top quilts.

Brian