Internal frame is pretty much standard now. I’d also choose an internal frame because, as you said, it shields the framing from the elements/keeps everything together. Also, lots of internal frame packs will have straps across the back/compression straps that you can attach things to.
TBH, assuming your son is fairly young you probably don’t need that good of a backpack. He’s probably not carrying very heavy loads that would put a lot of stress on him, and he’ll probably outgrow it pretty quickly.
For a child? Doing relatively casual weekend camping in the summer? external frame.
An internal frame pack actually has to fit. that means a new pack whenever the child grows appreciably in their back, or purchasing a pack with an adjustable torso length. As a short-torsoed adult , I’ve experienced that ill fitting internal frame packs can produce a lot of back pain.
the benefits of internal frame packs are not realized unless the hiking is actually somewhat rigorous, as explained in this Backpacker article.
An REI article on considerations when choosing a backpack:
The external frame packs are a lot more convenient to load and unload than internal ones that are, let’s face it, basically glorified duffel bags. However, in terms of ergonomics and where they carry the weight the internal frame packs are vastly superior for hiking with heavy loads over long distances, hence the almost total extinction of the internal frame ones. For the average Boy Scout hike though, external is just fine though. If he does get more into ambitious backpacking, an internal frame pack will likely be in his future, but it may still be nice to have the old external one for shorter trips.
One drawback of external frames is their tendency to catch on low branches when you’re hiking a narrow trail or on the thwarts of a canoe. I know the frustration of trying to lift a pack from a canoe when the frame catches on a thwart or a paddle or anything else, especially when you’re tired and standing precariously on slippery rocks. For canoeing, internal frames are the way to go.
Internal frame packs are more than just “glorified duffle bags”; a properly designed and fit internal frame pack will allow for carrying heavier loads over uneven mountainous terrain far more comfortably than an external frame pack. Where ex-frames shine is their ability to support very heavy or bulky loads over relatively level ground that would be awkward or just not fit in an i-frame, e.g. a very large water jug or bladder, large food containers, a generator, et cetera, for which a cargo hauler frame is necessary. As Esox Lucius notes, ex-frames also are not compressible and tend to snag on every damned thing, so they’re really best suited to desert and prairie hiking, not forest or mountain trekking, nor for general backpacking travel. For general use, a well-fit top-loadin internal frame is vastly superior to an external frame pack, and there are many makes on the market which are adjustable to accommodate changing torso heigh (e.g. Osprey, Kelty).
If there’s an REI near you, ask them when their next used gear sale is. They usually have lots of used but still perfectly serviceable backpacks for cheap. Packs that retail for $200 to $300 can be had for $30-$50 at those sales.
Edit: And many internal frame packs will have gear attachment loops on the outside. You could, for example, strap your tent to the outside bottom, trekking poles to the left, and a sleeping pad to the right – all without compromising internal carrying capacity.
I’ve used both and I have both. They both work well and they both have their advantages and drawbacks.
A large factor would be what is the weight the child will carry and what is the child’s weight and fitness.
External is best for heavy loads (over 30 lbs for a average male adult), but once the carry weight starts coming down then internal becomes more comfortable partly because they weight less further reducing weight (pack weights of under 20 lbs), From 20-30 not much difference and this is a common backpacking weight range. and going further frame-less packs can be about 1 lb total and can be used for ultralight hiking (usually under 10 lbs total carried), but frameless vs internal compete in the 10-20 lb range. Much of this is subjective and people may have preferences and body types that work differently.
Outside of trail workers there is very little need or reason to strap on things externally that are not already accounted for with internal frames (exception crampons and perhaps bear canisters).
A rare thread – everybody gives good advice. :0 And the advice is: it depends. There are packs for all kinds of specific uses. I will say that you really don’t want to put a 70 liter pack that weighs seven pounds on a Boy Scout for a weekend trip – at least, not if you like your kid even a little bit.
There is only one pack I would recommend to just about anybody for just about any kind of trip. Jam 50L Pack. It’s been popular with Appalachain Trail thru-hikers for a long time yet it’s small enough and light enough (less than two pounds) to be good for day hikes or shopping trips. It is very versatile and compares well to packs costing over twice as much.
Backpacks are not waterproof; too many seams. You use a pack liner to keep things dry. Pack liner is a fancy phrase for “plastic trash bag”. For extended trips, double up on the trash bag or use a trash compactor bag made of thicker plastic.
Well, sometimes you might want to do that for accessibility and weight distribution reasons. Tents, for example – it sucks having to dig everything out of your backpack to get to your tent, especially if it’s getting dark or rainy. Not every backpack has sufficiently big front or side pockets that let you easily get at something in the middle. Having the tent strapped to the outside means you undo two buckles and you’re ready to go, while the rest of your gear can sit safely under a tree or a rain cover. And with heavier or bigger tents, sometimes they won’t fit horizontally inside the backpack, which means you’ll have to pack it to one side or the other. If you don’t happen to have something cylindrical and heavy on the other side, it can screw up your weight distribution. Hanging it outside also lets you keep the weight low to your hips.
I mean in the end it’s all subjective, as you said, but I’ve found those external buckles to be very handy and wouldn’t be so quick to dismiss them outright. Admittedly I tend to overpack a bit compared to most people (I was a trailworker…), but even on fun weekend backpacking trips, those straps are handy.
The keep the bag clean(er), wick away moisture, prevent damage to the inner shell, and add about 5 °C/9 °F to the ostensible rating of the bag. They’re a good investment if you have an expensive bag or camp in inclement weather; for casual fair weather camping, a sheet or light blanket does almost as well.