feedbag/question on using foam for lining

[toothjockey]

Finished my round of bicycle stem bag/feedbags.
https://imgur.com/a/9jkSM
I used the instructions from this article, http://www.bikepacking.com/gear/make-your-own-stem-bag/
Shell:Cordura 1000D
Liner: 1.6 oz HyperD diamond ripstop nylon
Top: 1.9 oz Ripstop Nylon top, from ripstopbytheroll. I added some foam (Foamies from Walmart) to add some rigidity.

How do you all add foam for your projects? I sewed it to the fabric, but it is bunching up. Any suggestions for using foam for a liner between layers of fabric?

[Adam Alphabet]

Nice Job! Looks great.
While I've not made a padded feedbag I've used foam in all sorts of other projects. I use half inch seam allowances for everything. I usually cut the foam, inner liner material and outer material all to the same size for the piece I'm making. I sandwich the foam between the outer layer and the inner liner layer and sew all the pieces together. When you sew it together the needle holes perforate the foam and you can usually tear the excess (at the seam allowance) out. If it's nigher density foam you made need to trim tight with little scissors. This way you're left with inner and outer material seam allowance and eliminate the thickness of the foam for when you add your collar and bottom, or whatever else you're making. The trimming is a bit of extra work but I've not had and foam migrate on any projects as it's been sewn in place.

Hope that makes sense.
Good luck!

[toothjockey]

Thanks for the advice. I'm almost finished with round two, using your suggestion. It has made the foam easier to work with, but i have to use grosgrain to cover the seam allowances now that they aren't hidden between the two layers of fabric. I also put in a mesh pocket which I'm excited about. I think the next version will be a blend of the two ideas... Will post photos of this one when complete.

[Adam Alphabet]

Thanks for the advice. I'm almost finished with round two, using your suggestion. It has made the foam easier to work with, but i have to use grosgrain to cover the seam allowances now that they aren't hidden between the two layers of fabric. I also put in a mesh pocket which I'm excited about. I think the next version will be a blend of the two ideas... Will post photos of this one when complete.

Nice! I always trim the allowances after I've got a bag all stitched together. I think that's common practice? I taught myself so kinda do things my own way haha. Pumped to see the finished product.

[bumbler]

Seems to me it'd be important to use closed-cell (rather than open-cell) foam, so that it doesn't soak up & hold water if/when it gets wet.

That said, I've used Reflectix for padding before - lightweight, doesn't absorb water, and holds its shape pretty well.

[dream4est]

What I would do with a home machine to make it look professional is buy the Sailrite binder attachment and bind grosgrain on the 4 layers of material and the 2 layers of foam. Problem is a lot of home machines cant do that its too thick to sew through correctly. They can handle one layer of foam and freak out on two. The solution is probably what you have already figured out. All of the shape to a Revelate gas tank or feedbag comes from binding the 6 layers inside out. Its hard to get around this basic principle I have two industrial machines that i setup to handle binding one never does anything but that. I have never had a home machine do the 6 layer move well i just cut out the foam too but that kills stability IMO.

edit- one trick you could do with a feedbag is to add a liner layer sewn at the top opening only it would cover the seams etc. You would sew it last inside the cuff all right side. no one would ever see the interior and the liner would be easily popped out and washed.

[vermont]

Dream4rest... I knew the binder attachments existed but did not know where or even what they were called.  I am kinda dorky excited to finally find out where to get them.  Thanks...
Toothjockey.  If I understand your question correct, you could try to "quilt" it in the fabric, especially if its the inside layer.  Just use the longest stitch you can so it puts in less holes.

[dream4est]

If one was crafty and smooth you could glue the bias tape or grosgrain on lightly with seam sealant or quilters spray and after drying sew the whole shebang together. That may work for home machines better than trying to learn binding which is the hardest part of bike bag sewing IMO. Even faux bar tacks are not hard to master compared to binding that looks correct. One could simply cut strips of light material sew the edges down and glue that homemade bias tape on too (remember to cut on the 45 bias and sew the pieces together on a 45 bias as well). After final seam, it would look double stitched and neat if one was on their game.

[toothjockey]

Round two. https://m.imgur.com/cJlbyXu,FPw9K4S I sewed the foam between the shell and liner, pulled off the seam allowance of foam and sewed this together. Added a mesh pocket for snackies! This method pushed my sewing machine to the limit. I think the next one will be a combination of these two methods. I'm sure this cheap open cell foam isn't the best idea, but it's cheap and easily available...

[vermont]

That stuff you are using is either closed cell or pretty close.  I've used it before and its still holding up many years later.

[bakerjw]

I go a lot simpler with my feedbags. My next rendition might have some foam stiffeners in them, but this has worked well so far.