Do you seam seal?

[flanagaj]

I have just made my first frame bag, and whilst I am pleased with the results I am conscious that the sewing process will have punched thousands of holes through the pu coated backer of the fabric.  Do people on here apply a seam sealer to the joints?

I did purchase some seam sealer tape, but when I tried applying it, I didn't have much luck and it ended up melting the pu coated backer.  So I stopped trying.

I was hoping I could maybe get a liquid based product that I brush on the seams and it dries?

[Adam Alphabet]

Some do, some don't.. I don't, but for a kit I'm going to make later this year I will, experimenting with some ideas.
I've used this in the past, easy enough to work with...
https://www.mcnett.com/gearaid/silnet#10440

[Inkerpok]

I've built a bunch of stuff this winter and seam sealed it with the homebrew silicone/naphtha method. Just did my first trip with some rain and I'm glad to report that everything stayed dry! I started out using a mix of about 3:1 (spirits:sil) but was getting a little leaking when I tested in the sink so I am closer to 1.5:1 now.

[wunnspeed]

I don't seam seal and I'll tell you why. In spite of XPac and Cordura being quite water resistant at the beginning, it doesn't take long for the dirt and oils to start building up on and in the fabric and that will be what pulls water into your bags at that point. So, seam sealing, to me, is kind of a Sysiphis-like endevor. However, others do it and claim to be fully-waterproof which I can't quite believe. For me and for what I tell my customers, if you want or need anything to remain dry, use a freezer Zip-Lock or dry bag. Then, you don't have to worry about it at all.

[Inkerpok]

Well wunnspeed appears to be right. I built my stuff out of vx21, and like I said above, I seam sealed. In 4 hours of drizzle a couple of weeks ago everything remained dry. But I went out this weekend for 2 full days of riding in the rain. And it did rain ALL day, including some hours of pouring down. Both days my bags soaked through (I was able to stay indoors and dry everything overnight). And the material wasn't particularly dirty or oily, in fact they are pretty new still and as clean as they will ever be.
   I am a little disappointed since I thought vx21 was more waterproof than that, but at the same time I wouldn't build with heavier material if I had to do it over again.
   Fortunately all of my "need to be dry" items were in homemade cuben fiber dry bags and they performed flawlessly, so it's all good. I will probably continue to do some seam sealing because I think it helps with splash from stream crossings and drizzle riding, but... Yeah... Put everything in dry bags that you need to keep dry

[wunnspeed]

Hey Inkerpok.... cool that you got your bags done and that they work well. Sorry that I was right but I'd rather give you and my customers the truth rather than get their hopes up and end up with wet equipment or clothing. Cuben works quite well be I've found that even that will soak through at some point. Water is just EVIL! :-)

[Bob Loblaw]

wunnspeed,

I make my bags with a VX21 outer layer and a yellow silnylon inner layer for visibility. Would having that second waterproof layer make it worthwhile to seam seal or would I still be wasting my time?

[Smo]

I find that the most difficult places to seam seal Xpac are corners.  Also, where velcro attachments come in is another place that is hard to seal.  I've had the best results with copious amounts of seam grip after binding the edges with another strip of Xpac.

It's possible to seam seal a frame bag well (adding a storm flap to the zipper as well), but I don't think it's worth it for most riders.  I have some backpacks that I've seam-sealed and have done really well in the rain, but I don't tend to bikepack when its wet (I'd rather hike) so I haven't seam sealed any of my personal bikepacking gear except my handlebar roll.

[wunnspeed]

Hi Bob... My worry about having a second waterproof layer is when (not if) the water seeps inbetween the layers. Who knows what that latent moisture will do to your bags? My personal preference is to not line my bags but I kind of understand why people do (looks cleaners and some added abrasion resistance). What you lose is that you add at least 50% more weight and the possibility of water seeping in between the layers. Since all the XPac I've used is light colored on the inside, I've never had an issue finding anything.

For what it's worth... and I may have already mentioned it but I don't seam seal my personal bags either, just my tent.

[falkenjaeger]

Maybe my question is a little off the original topic. But what would be your recommendation to coat the bags (from the outside of course) if the original coating has somewhat lost its effectiveness after heavy abuse on the bike? The material (Cordura) kinda gets soaked even in light rain. Thanks!

[brankulo]

i wander if guys like revelate or bedrock seam seal their products. i have done it once and it takes quite a bit of time.

[Smo]

Maybe my question is a little off the original topic. But what would be your recommendation to coat the bags (from the outside of course) if the original coating has somewhat lost its effectiveness after heavy abuse on the bike? The material (Cordura) kinda gets soaked even in light rain. Thanks!

Well, first I would actually turn the bag inside out so you can coat the inside, the coating will wear off slower that way.  But honestly I wouldn't recommend trying to make Cordura waterproof, it's just not made for it.  By the time you coat the whole bag you might as well make a new one out of Xpac instead.