Need some advice about a bag mod, Please

[GraysonK]

Hi all,
I wasn't sure where to put this so I hope this is alright.  If it's the wrong place, please move it. 
I want to make a few changes to one of my timbuk2 bags.  but first, I suck at sewing but I can learn and second I'm not entirely sure I need to sew one of these.
First mod/addition:
I found some old patches that I'd love to put on my bag but there's a couple of problems.  I'm not so much worried about voiding the warranty as I am messing with the water proof feature.  The bags are ballistic nylon (the colored part) with a water proof liner on the inside (it feels like plastic and I forget what it's called right at the moment).  So basically, the flap where I'd like to put the patches are two layers.  I'd like to be able to stitch the patches on without puncturing the liner...any idea how to do that?  The other option would be to put an iron on backing onto the patches and ironing them on but I'm wary of doing that because I don't want to melt the ballistic nylon.  Any ideas on how that might work without totally ruining the bag? 
Or should I just use glue?
Second and this one I think is kind of cool:
I'd like to add either an elastic strap inside the bag on the side to hold a water bottle upright in the bag.  Again, we have the sewing issue but this time I'd have to puncture the water proof lining because that's what on the inside I think.  But not necessarily the ballistic which is fairly water resistant in it's own right.  My other idea that I just now thought of was this...is there a water bottle pouch out there that has velcro backing on it so that I could just add some adhesive velcro to the side of the bag and just set it down in there and attach it to the side with the velcro and then just put the bottle in it like that.  Did that make any sense at all?  I've tried to search for something like that but I don't really know what to search for.  I just want to keep my water bottle upright when the bag is not totally full so I can access it a little easier.  And I wanna play a little bit.   
Thanks for reading. 

[Zack]

I would use hot glue and just hot glue the velcro to the bag and to the patches.  Don't know about the elastic strap, but it should only take a few stitches and it doesn't matter what they look like since no one will really see it.  I wouldn't worry about the waterproof lining too much.

[Magnus]

its not that hard to sew a patch on without puncturing the lining, you just have to pinch up the part you are sewing away from it and since it is just a patch running stitch should be strong enough.  As for puncturing the water proofing, that could be a problem, although if you wax the thread you use with beeswax it should mitigate that.

If you want to cheat and use glue, I would recommend a product called "Shoe Goo", as its name suggests it is designed for use on shoes, however it is a great adhesive for leather, fabric and plastic that dries flexible

[GraysonK]

Thanks guys, I appreciate the replies.   

[Anthony]

I'd go with glue also.  Instead of globbing it onto the patch, kind of "paint" it on with something flat like the backboard of a notebook.

[Grant Lamontagne]

Whatever you do or don't do, I'd suggest giving it a good once over with a silicone sealant spray, like the kind used on jackets, shoes or automotive upholstery, so that any punctures you may make have a good chance at being sealed up again.  Even if you don't stitch anything up, it still helps to add a layer of waterproofing on top of the waterproofing!

Plus, the cans are pretty cheap ($5-10), available almost anywhere, and can also be used on just about any fabrics, so it's handy to have around anyway.

Def

[GraysonK]

Thanks guys!  I have some kind of sealant, but can't for life of me find it or remember what it was.  But it did work rather well.  One of the info sites I did find recommended using a thread with wax on it in order to seal the holes made by the needle.  That seemed interesting, but I like Def's method much better. 
As for sewing I have a few bags that I could practice on that are kind of double layered fabric so I'll try to experiment a little.  I'd really like to do the sewing since I've never really be good at it and would like to learn.  Plus I think it's cool to be able to mod bags and such since I don't have the equipment or the space for modding knives.  LOL!
Thanks guys! 

[nuphoria]

I'd agree with the glue and the careful stitching as already mentioned above.

Sorry, nothing else intelligent to add for you today! However, I do want to see what patches your adding 

[GraysonK]

Thanks all...I know it's cheating but I think I'm going to go with the glue option.  I have a hot glue gun is that preferrable or is the Shoe Goo option better? 

[Magnus]

Thanks all...I know it's cheating but I think I'm going to go with the glue option.  I have a hot glue gun is that preferrable or is the Shoe Goo option better? 

I would stay away from hot glue, it gives you very little time to position it, could melt the bag, and isn't all that flexible when set.  I have never found it all that strong either.

shoe goo is great stuff, just make sure read the warnings about using it in a well ventilated area.

[nuphoria]

I use Evostick which is probably similar - you get off your bloody truck if you don't ventilate the room, so it depends what outcome you'd like from it I guess

[glorn]

I use Shoe Goo quite often and have for years. I will vouch for it being very good stuff.

In regard to patches, I use Shoe Goo to glue the velcro to the back of the patches I use on the Fatboy. Strong stuff, and good for that sort of thing.

But, I would advise you to just stitch your patches on the Timbuk and go right through the liner. Just do a neat job and use good thread. You won't see water come through the stitches, at least I never did. My old Timbuk saw many years of heavy rain.. day after day.. on the bike and off, and I had pins and patches both that penetrated through the two layers. So did many of my messenger pals, and nobody complained of water coming through.

If it worries you that much, after you stitch it on, I suppose you could seal over the patch stitching on the inside with duct tape or some kind of sealant. I like the wax idea too.

I even had my old bag develop so much wear that the liner split in places, and I still never had wet cargo. I've seen bikers with the liner on all brands of well used bags fixed with duct tape, and they were working.. so it must have been fine or else they'd have had wet packages.

If I could survive three winters and three springs on the bike 5 days a week with pin holes and stitching in mine, I suspect you'll be just fine. 

[GraysonK]

I use Shoe Goo quite often and have for years. I will vouch for it being very good stuff.

In regard to patches, I use Shoe Goo to glue the velcro to the back of the patches I use on the Fatboy. Strong stuff, and good for that sort of thing.

But, I would advise you to just stitch your patches on the Timbuk and go right through the liner. Just do a neat job and use good thread. You won't see water come through the stitches, at least I never did. My old Timbuk saw many years of heavy rain.. day after day.. on the bike and off, and I had pins and patches both that penetrated through the two layers. So did many of my messenger pals, and nobody complained of water coming through.

If it worries you that much, after you stitch it on, I suppose you could seal over the patch stitching on the inside with duct tape or some kind of sealant. I like the wax idea too.

I even had my old bag develop so much wear that the liner split in places, and I still never had wet cargo. I've seen bikers with the liner on all brands of well used bags fixed with duct tape, and they were working.. so it must have been fine or else they'd have had wet packages.

If I could survive three winters and three springs on the bike 5 days a week with pin holes and stitching in mine, I suspect you'll be just fine. 

Thanks Glorn!  I was hoping maybe someone had experience with either these bags or something similar to answer the "will sewing make the bag leak" issue I was afraid of.  Ok, so I think I'm gonna sew it.  Gotta ask mom for some stuff while I'm home for the holiday.  Thanks again to everyone.  I'm gonna practice on a different bag and if I screw it up I'll glue it.    Either way, I'll post pics.  Thanks again!
Gray