I want to replace the down in a sleeping bag with synthetic material. Where are some sources of synthetic insulation materials for sleeping bags? Thank you.

Just about any textile store has polyester insulation material. Used for stuffing quilts, pillows etc. Try there.

It's can be Batting.

https://www.fabricdepot.com/bl...ial-guide-to-batting

Sounds easier to just buy another bag.

Grizz

Id buy another bag, Why would you do that, down is about the best bag insulation I know of when used with a light canvas cover..

You could buy a bed comforter, fold it in half, and sew the bottom and side. It can be one selected for size based on a single bed or all the way up to a king size. The comforters get real price cuts in the spring.

Can't help but wonder...WHY? I recently bought a bag from Bass Pro. Light canvas cover. rated to 20 degrees, about $100.00...Made in China! Surprise surprise

Have to admit, pretty darn good bag, heavy, not for backpacking. I don't think you could re fill for that money

If it’s anything approaching a decent bag it probably has baffles sewn in it to prevent down migration. Meaning you’ll never be able to fill those baffles unless you cut them open.

Way too many great bags for good prices out there. I’ve used LL Bean down bags for almost 30 years now, they have synthetic bags too.

I have a over size Eddie BAuer and a woods that Ive had and used hard for maybe 60 or 70 year, still good in there canvas cover I design with pockets for every thing imageable. Not for backpacking but great in a tent in the high country base camp..or on a branding. my now 65 year old son and his buddy went camping about 55 years ago and left some gear and and Bauer sleeping bag, the best quality on a railroad track ,train came by cut it in half..Any way sent it to Bauer to sew up, they sent me a new one which I still have, and saved a childs life!

Had another incident with a hunter who just graduated guide school made the mistake of tieing his down sleeping bag behind his saddle as he forgot to pack it on the pack horse..about an hour or so later it came untied on one end flopped down on one side and his mule started bucking and stuckk a foot through the bage bucked the little buckaroo off an headed back down the trail down floating a trail behind him..the kid said damn Mr.Atkinson you don't see a sight like that very often. Nope and you wont see a guide sleeping in the kitchen tent in his clothes!! His company woudn't even reply last I heard//