Making DIY Dry Bags



Raffle Dry Bag & Scrap Material

(Some of this is because I know Chip is trying to puzzle out DIY dry bags. Most of it is because, ya know, I tend to blather on a length, especially about simple shop projects)

I made the usual template before marking and cutting the fabric for Waterdog’s raffle prize dry bag, requested at 14” diameter x 22” tall when fully open, marking and cutting out a visgueen template. First a simple full size rectangle, then cutting out the requisite top flaps and notches.

P3300007 by Mike McCrea, on Flickr

With a template for those dimensions cut from 58” wide heat sealable fabric I had a “scrap” piece 24” x 16” left over, and after cutting out the short side of the dry bag top flaps had another long narrow piece, 2 ½” x 21”. I have ideas for those pieces.

P3290004 by Mike McCrea, on Flickr

Waterdog’s dry bag with cut out fabric in progress, 1” “flap” with interior hem notch ironed over on the inside. That little flap gets ironed down with the fabric fully open, before ironing the bottom and side of the bag.

P3290001 by Mike McCrea, on Flickr

The material is then folded over at the centerline and ironed together on the bottom and side edges. I dog ear ironed triangles on the bottom corner for future grommet installation and rounded off the tips.

P3290003 by Mike McCrea, on Flickr

Time for the webbing and peculiar long side flap. Note the 1” square corner notch, cut out so the flap will iron down inside the bag without overlapping the 1” heat sealed side hem. I cut a little 1/8” slice from the other corner, so it is easier to fold inside and iron.

P3290002 by Mike McCrea, on Flickr

For no-sew* immovable webbing I add a streak of E-8000 adhesive sealant to one side of the webbing and to the folded over side of the long flap, so there is adhesive on both sides of the webbing. Lay the webbing in place adhesive-side down, fold over the also-adhesived flap (smeared along a marked placement 1” length stripe), stick a board on top and clamp that down. Couple hours at least, but left clamped tight over night works better with E-6000.

P3290005 by Mike McCrea, on Flickr

The E-6000 adhesive sealant ($3 at any Walmart) is kind of unnecessary if you sew the webbing in place at the ends, although it does help stiffen the webbing, making it easier to flat foldover and roll down. I threw a couple crude stitches through the webbing just for funsies. It is nylon webbing and easy to pass needle through.

A brief comedic pause; I told a friend this tale and his response was “Oh, I know you’ll never admit that to anyone else”. I love to prove Doug wrong.

I do not like sewing, and I suck at it. Just threading the needle is a challenge. I sewed the side release buckles on one bag, took a call, went back to the shop and began sewing the buckles on another bag. Only punctured my fingers thrice so far and only bled once. When I finished sewing the webbing together on that side I looked down and what to my wondering eyes should appear - the half of the release buckle I meant ladder lock weave the webbing through before sewing the ends together, still resting untouched and unattached on the bench. “Gee wilikers” I said, or something less family friendly.

Two hints with that glued webbing methodology beyond idiotic mistakes; do a test fold and mark where the length of webbing will be placed inside the long flap fold; pre-glued webbing glue side down, then pre-glued flap folded over and clamped. That webbing is inset further in the flap than you might think; do a test fold and placement mark.

And, whether you glue or sew the webbing in place, always, always cut the webbing a few inches longer on each side than you think you need. The webbing running back and forth through the ladder locks uses up more length than you might estimate. The ladder lock itself takes up some length. 12” wider than the bag width at a minimum, 6” of free webbing outside is usually about right. I’d rather cut an inch or two of excess webbing off later than, oops, come up too short.

While that webbing adhesive is setting up it’s an ideal time for a beer, and some thought about what to do with the scraps.

I used red fabric for Waterdog’s bag. Red is easier to see if floating downriver after an oops than darker colors. Yellow or orange would be even better, but leftover red scrap, even skinny strips, have other uses.

Those long skinny scraps simply get folded in half and ironed over, with a grommet seated through one en,d and become canoe overhang red flags. Easy peezey no template needed. Little piece of corner rounded High Intensity reflective tape on each side and length of Lawson Glowire cord and that flag is very visible, even when walking around the truck at night. Maybe, clonk, especially when walking around the back of the truck at night.

P3310027 by Mike McCrea, on Flickr

The 24 x 16 piece is kinda small for a dry bag when folded and ironed over. It might make a slender envelope-flat dry bag for extra maps, journal & pen, or book and glasses.

I made a (got-lazy freehand) template for that big scrap piece, cut out the fabric and ironed it up to see what condition my condition was in. NOTE: My condition was uneven; Freehand meant I didn’t bother to use a square. Yeah, don’t do that, take the extra 10 seconds to square up all of the folded together edges

FWIW if you have slightly uneven edges along the ironed hems it is easy to trim them using a razor blade along a straight edge. No one will ever know you were not even, or level on the level.

That brief musical interlude concluded the morning’s dry bag efforts. I love John Prine, he has a voice even I can sing along with.


Last of the ironing, buckles, grommets, E-6000 and etc.

The inside of the long flap with glued webbing, having set up clamped overnight, still need to be ironed down. That hem is a little tricky, since the ironing is done inside the bag. I drop the fabric enveloped webbing area over the side of the ironing cardboard, so I have a flat surface to iron. It helps to stick something inside the bag to prop it open while ironing.

With that final ironed flap done the webbing ends slip through the side release buckles. Again, I cut that webbing with 6” hanging out each side and it was just enough, I trimmed off zero excess webbing.

P3300019 by Mike McCrea, on Flickr

The scrap envelope bag is a bit on the winky side, at least compared to my customary book bag. I have a well used (every trip) Sotar/Paddler envelope bag that easily accommodates a journal, 600 page book, reading glasses, flashlight and etc. 12” x 15” interior when rolled closed, but would need at least an 18” x 32” rectangle of heat sealable fabric.

P3300012 by Mike McCrea, on Flickr

P3300014 by Mike McCrea, on Flickr

Those “book” bags are handy for lots of flattish things. The old Sotar bag has been so useful that I’ll make one that size next time I have a big enough scrap piece.

The scrap material “book bag” is only 10”x 9” interior when rolled closed. Big enough for a Steno pad, pen, reading glasses, paperback and flashlight.

P3300015 by Mike McCrea, on Flickr

P3300018 by Mike McCrea, on Flickr

Waterdog’s 14” diameter x 22” long when open bag came out according to spec, although 1” short due to a template foldover miscalculation. Close enough I hope.

I need a grommet on each of the overhang flags, and wanted grommets on the dog eared corners of the larger bag. Usual practice, melt a right sized sealed hole with a hot nail head.

P3300021 by Mike McCrea, on Flickr

And tap the grommets in place. I am (without evidence) leery of sharp brass grommet edges stress pressed against the fabric and slicing through. A little bead of E-6000 softens that transition around the grommet edge. Seems to help the High Intensity reflective tape adhere when it is flapping around at 70mph too.

The dog eared corners with grommets help shape the bottom of a dry bag and provide tie down points.

P3310026 by Mike McCrea, on Flickr

Next up, figuring Chip (and others) may still be confused about that notched and flapped cut out shape, making a template.


Making DIY dry bag templates

I know Chip and others are puzzling out or thinking about making dry bags. This is harder to clearly explain than actually do, and will make a lot more sense when you iron up the first bag.

Working with my best shop partner we made our first dry bags using Chuck Holst’s on-line instructions and diagrams.

Chuck is a lot less wordy than I, but even so Joel and I read and reread some sentences in that description out loud to each other and were still puzzled before we thought we had it figured out. I just reread Chuck’s description and realized that, from the very first bag, we made our’s differently.

Chuck describes using two separate pieces of heat sealable fabric and ironing together the bottom and both sides. I have yet to make a dry bag that way, and instead cut a piece of fabric double wide and simply fold it in half, needing to heat seal only the bottom and one side. Don’t know if we screwed that up or thought of it ourselves, but I know the folded side can’t leak or separate.

Either method will work; the template halves may be easier to make with two separate pieces, the fold over method saves a couple inches of fabric and eliminates heat sealing one edge.

In making templates I eventually got smart (only after making dozens of paper templates, some from gift wrapping paper), cut some yardage of visqueen plastic to the heat sealable fabrics 58” width, and rolled it tightly on a piece of PVC pipe to take out the wrinkles. The heat sealable fabric, which also came folded, is likewise rolled on a piece of pipe; fold wrinkles on either fabric or template make for uneven edges, even with a T square.

If you are planning more than one bag having the template material cut to fabric width can save from making unnecessary scraps, “Oh look, if I lay out the templates in this orientation I don’t have as much waste”

The usual template cuts are actually pretty simple for cylindrical or flat bags, and once you’ve made a few of those the template shapes for tapered bags or instrument bags become more obvious.

Start by measure the length and width needed for the bag. At minimum add 4 inches to the length; an extra 3” at the top become the long flap folded over the webbing, plus an inch for an ironed over hem at the bottom.

Double the width of the bag dimension, and add two inches. The fabric will be folded over heat-sealable-side-to-heat-sealable side, so only the bottom and one side of the folded together material needs to be ironed together. The extra 2 inches are for the interior unusable 1” heat sealed hems on one side.

Those 2 inches of interior dimension hem matter when making a just right sized bag for a Therma-rest pad. Or a little larger than “just right”; a bit of slack helps slide the pad in and out and you can purge a little air when rolling closed.

FWIW when using a custom dry bag for a Therma-rest I tighten a strap or two around it when purged and rolled closed, on the off chance that it might somehow self-inflate inside the dry bag and become a PITA to remove. And put it in the bag valve up, just in case.

For a big folding camp chair bag add an extra 5 or 6 inches, so the chair slips into the dry bag more easily where protruding arms or cup holders usually snag. An extra 5” is only 1 ½” of extra circumference girth; how snug is too snug is up to you.

With that basic rectangle of template cut out Sharpie a line up the vertical center of the bag, that is the fold over line, and becomes the divider between the long and short flaps.

To make the short side flap measure and mark a line 3” down from one edge to the center line and cut out that skinny rectangle of fabric. Make 1” slice further down along the Sharpied center line and the short flap fold over is done.

To make the long side flap cut a 1” square notch from the far corner (not the corner near the centerline). When ironed inside the bag that 1” notch will heat seal without overlapping the already ironed 1” side “hem”. The heat sealable fabric only sticks when ironed shiny heat sealable side to heat sealable side.

Kinda like this

P3300007 by Mike McCrea, on Flickr

With the template made it is a good idea to do a test fold and make sure all the edges line up and the flaps & notch have been properly cut. Finding a mistake after you have cut the fabric sucks.

To cut the actual fabric square up the edge of the material first, rarely does the fabric come with a straight cut edge.

Lay the proofed template on the heat sealable fabric and tape it down in a few places so it doesn’t move. Take a straight edge and sharpie the outline, and the 1 inch center slice for the short flap foldover.

I have done better cutting the fabric using (good, sharp) scissors, despite my scissor work remaining at grade school level. Using a razor blade against a straight edge I tended to wobblewaver more. YMMV.

Making the template is as much work as ironing the bag, and you never know when you might want to make another one of similar size/shape. On the not so smart side of making and saving templates for possible future use note that I (still) stupidly Sharpie the bag size and specifics in the middle of the template. Rolled up and stored on a long shelf with a couple dozen other templates that unseen ID does me no good.

At some point I need to unroll all of those dry bag templates and Sharpie the dimensions on the outer edge of the rolled material. Or ask Dan Cooke at CCS how he identifies his templates; I believe Dan has clear Mylar templates for dozens and dozens of canoe spray covers, tandem and solo, in various designs. I bet he isn’t unrolling template after template, muttering “Nope, not that one” and “Nope, not this one either”

For template storage I get why he uses stiff-when-rolled clear mylar. And not visqueen.

Or gift wrap. I really need to remake those newspaper and gift wrap templates, they are crushed and flattened and tattered.
Oct 22, 2014
Reaction score
Thanks for the instructions, Mike. I managed to make a bag. It came out well enough, but a little shorter than I wanted. I failed to realize that I needed to add to the desired length half the diameter of the bag. When the bag is inflated from the flat envelope shape to a roughly round shape, some of the length of the bag becomes the bottom, and the overall length is accordingly shortened.

I used an old iron that was probably somebody's throw-away before I converted it to waxing skis in the 70's. It's old. Fabric-jacketed electric cord old. The iron's more recent use has been on iron-on, oak veneer. It's always the cotton setting they want, both for veneer and now, I read, dry-bag material. Well, how hot is that? According to an internet source, 193F is the ideal temperature for ironing cotton.

So, I set my aged iron to cotton and held my Martha Stewart thermometer on the bottom. The old iron goes right up to 399 before Martha's display just reads HH, which must be Martha-speak for hot as heck. My, that seemed way hot. To the laundry room I went, where I set the household's present, somewhat-modern iron on cotton. Martha says that one goes to 280-325F, and I assume there is a thermostat turning the heat coils on/off to keep the iron a bit under and over 300.

I dialed the old iron back until I got the iron to somewhere near 300 (mid "silk"). That setting worked well, but thirty seconds seemed a long time. I had a few scraps after the first bag, so I did a timing test. The piece I ironed for ten seconds I was able to pull apart, with moderate difficulty, and I could see that the glue melt was incomplete. There was no difference between the 20- and the 30-second ironed scraps. In both cases, I couldn't budge the seam by hand pulling and resorted to using pliers. In both cases, the material ripped before the ironed seam gave way. So, I tried a 15-second melt, with much the same result, the material ripped, but the seam had given a tiny bit.

I've written Seattle Fabrics to inquire about the ideal ironing temperature. No response, and I'm thinking they may be a locked-down, non-essential business.

I think if you are contemplating using this material it is worth knowing the proper ironing temp and time. I know between the two irons in my household, relying on the "cotton" setting produces different temperatures on the bottom of the iron, so specifying "cotton" isn't very exact and I'm hoping there is a better answer.

It is possible that Mike's iron needs 30 seconds to fuse the heat-seal, but with a 300F iron, 15-20 seems plenty.

I'm impressed by how strong the bond is once the material is heat sealed.


I managed to make a bag. It came out well enough, but a little shorter than I wanted. I failed to realize that I needed to add to the desired length half the diameter of the bag. When the bag is inflated from the flat envelope shape to a roughly round shape, some of the length of the bag becomes the bottom, and the overall length is accordingly shortened.

Chip, glad to hear you made your first bag, and hope it encourages other folks to give it a try. Once you have made the first bag the subsequent versions get easier, and better. Let’s see some photos of your work when you are finished.

Good point about sizing the bags. I usually add a couple extra inches, beyond the inch that gets ironed over on the bottom and the four or five inches for the top flaps and fold over closure.

With the ALPS chair bags I was going to have such a small amount of heat sealable fabric left over that I just cut it full 58” fabric width, figuring I could always roll it down a couple extra times. I found that extra length handy to store my little day hammock, so all of my leisure layabout furniture was in the same bag. I stick a pair of socks in their as well, so when the chair comes out and I have a sit to change from water shoes to camp shoes I have a dry pair of socks at the ready instead of digging in the clothes bag.

The piece I ironed for ten seconds I was able to pull apart, with moderate difficulty, and I could see that the glue melt was incomplete. There was no difference between the 20- and the 30-second ironed scraps. In both cases, I couldn't budge the seam by hand pulling and resorted to using pliers. In both cases, the material ripped before the ironed seam gave way. So, I tried a 15-second melt, with much the same result, the material ripped, but the seam had given a tiny bit.

It is possible that Mike's iron needs 30 seconds to fuse the heat-seal, but with a 300F iron, 15-20 seems plenty. I'm impressed by how strong the bond is once the material is heat sealed.

I had read the recommendation to use the hottest “linen” setting on the household iron, and before making the first bag ironed some test strips from 10 seconds to 60 seconds. 30 seconds proved impossible to pull apart by hand and I shoot for approximately that iron time.

I’m sure you discovered that the requisite 20 or 30 seconds is longer in practice that you might think while pressing the hot iron. I have to watch the second hand on the shop clock or I will move along too quickly.

If you want to check for straight heat sealed seams just stick your hand inside the bag and see if any of the seam can be parted. If there are areas with some little bit wasn’t evenly seamed against the ironing fence just sharpie a dot on the suspect area of hem outside the bag and iron that area again.
Jul 6, 2021
Reaction score
The Hereford Zone along the Mason-Dixon Line
I found a SD card from 2011 that has photos of the first DIY dry bags we made, those photos originally “saved” on Community Webshots, with a thread on the Solo Tripping site. Lots of other fun stuff on that card too.

We made a bunch of custom dry bags that session, including DIY dry bags for camp chairs, sleeping pads, a banjo and a guitar. We cogitated together on the peculiar design requirements, kinda bassakwardly “practicing” the technique on more complex \_/ instrument bags first, then making the simpler cylindrical stuff. Joel did most of the work, slaving over a hot iron.

DSCF2078 by Mike McCrea, on Flickr

That was as it should be, some of the trickier bags were for Joel’s various instruments.

DSCF2080 by Mike McCrea, on Flickr

DSCF2079 by Mike McCrea, on Flickr

DSCF2108 by Mike McCrea, on Flickr

In a testimonial to the durability of that heat sealable material those DIY instrument dry bags are often strapped to the back deck of a sea kayak under the Florida sun, still going strong after 10 years.

Our first (of many) cylindrical dry bags were made that session as well; a chair bag and a handful of sleeping pad bags. We even learned to dog-ear iron down the bottom corners and install tie down grommets.

DSCF2185 by Mike McCrea, on Flickr

The grommets in the side release buckle webbing are semi-superflous, but we were trying new things.

And a stand-alone custom dry bag for the quarter-keg sized Wiggy’s 0F bag. Even in a compression stuff bag that non-mummy synthetic thing is huge. And so toasty.

DSCF2195 by Mike McCrea, on Flickr

(Shop rags stuffed in just to see if there was still room for a sheet or small camp pillow)

Some pluses to making DIY dry bags; once you’ve learned how on the first one subsequent bags get easier and easier, saving the templates and making more of the same size is easier still, and it is a winter “shop” project that, if necessary, can done in the living room without lofting sawdust everywhere or spattering epoxy on the couch cushions.

And they make great gifts.