adding a bottle cage...
 

or rack or whatever the term is!

My bike is built around a 1983 Schwinn Voyageur steel frame. It only has the one bottle cage, attached with eyelets or braze-ons or whatever you call THOSE things (can you tell I'm new, here? :o ). I would like to add an additional bottle holder, but don't know the best way to do that. I could maybe find a frame builder that would be willing to drill the frame, but would that weaken it?? I'm planning to do a very long distance tour and need all the bike strength I can obtain. I could also get one of those kits that uses a triton-class zip tie to hold a nut fixture in place and do it that way. Do those last? How aggravating would something like that be? I'll get plenty of aggravation from traffic, I expect, and don't need any extra, if I can avoid it

So, what's the current wisdom?

Thanks in advance!

clamps are tried and true

Couple of easy fixes. Try two fish, they make bottle holders for all kind of bike issues. I assume your bottle holder is on the seat tube? Have your LBS drill some holes in the downtube and install some rivnuts. Your bike is made of strong steel, no worries. My fix that I used, wrap some innertube around the downtube, place the bottle holder against it, use 3 big zip ties to attach and then use pliers to tighten, easy. Or use a hose clamp.

You can get a bottle cage that attaches with hose clamps, and/or there are bottle holders that attach to the seat rails.

I have a double bottle holder from Profile that mounts on the seat rails that I bought in case I want to carry more than the two bottles on the frame.

thanks for the info! My bottle cage is actually on my down tube, but I want to add another one on the seat post. Looking more closely at my bike, I've realized that I DO actually have a second set of braze-ons, on the downtube, but on the BOTTOM of the tube (in my naivety I didn't even think to look there). I could use that one as well, but it seems mighty exposed to road hazards, etc.

That's a typical place for touring water bottle cages. You don't necessarily drink from that bottle and you just transfer the contents to the other bottle or you rinse off the valve. The seattube, by the way, was usually kept clear so that you could mount a frame pump there. Today's minipumps (Topeak Road Morph is the best one) fit next to the water bottle cage or under the top tube.

I like the Elite VIP water bottle clamp for an extra cage. Works well and looks a lot better than many of the alternatives.

I've seen that kit and it's the one I'm thinking I'll use. My mini pump fits next to my down tube water bottle.

CamelBak HAWG or MULE = 4-5 waterbottles.

Actually... HAWG = 8-10 waterbottles if you don't want to carry much else in the pack.

Here are two links with a zillion ideas:
Methods for Attaching Water Bottle Cages without screws and bosses | Bicycle Touring for the Long Haul
Adding Water Bottle Cages to Bicycles without Braze
I don't know if it's mentioned at the above but I have also seen mounts that replace the top cap on threadless headsets.

I've got a mule, but I've also got a really, really lousy back - so depending on how that works out, I need to be able to have bottle options, as well. Plus if I do a cross country in 2016, I might need all the water I can get my hands on. :) But absolutely, camelbak is a great option!