One of the problems with making bows is that it pretty quickly becomes an expensive hobby just making them for oneself, unless one is willing to give them away, or sell them. With that there are liabilities, and a far wider range of possible uses/abuses than any one person might develop. So it becomes worth while to use the industry standard product because it should work out ok, and if it doesn't there is the fact that it is the standard and that it was used in the recommended way. Peace of mind if nothing else. If one has, however, been using epoxies in structural applications for 40 years, one will know when one can or cannot make substitutions, though the above still applies.
"I've made a good number of bows over the years. I have never had a riser failure. Had some limb issues, one was a totally bone-headed mistake on my part, the other couple were delams. You learn and move on."
I have a friend who is a very legitimate shooter of heavy weight bows. He has had riser failures from several of the best respected makers out there. The only thing he does that may not be typical is he shoots heavy weights and doesn't unstring the bows when he is done, which is actually a recommended stringing practice of one of the makers whose product failed. So I don't think one should be complacent about risers if there is a wide range of uses on the table.
"The overriding reason for the question was as I was looking at some other bow building forums, I did notice that some were gluing up parts of the bows with smooth-on at room temperature. These were mostly take-down bows. I kind of got the idea that they were leaving risers glued up at room temperature only. Then they would bake the limb components."
I read an interview with a well known builder, and he emphasized this as one of his practices for some reason. Certainly the extreme heat of a post cure is not something one would normally want to subject a complex wood composite precision structure to. Doubtless in an internet world this interview has been seen by many. Best practices would call for an analysis of the tensile strength of SO in this application vs other epoxies. I think SO has a unique track record for limbs, but when it comes to products like a riser, I would be less convinced. There are simple test protocols for structural epoxies and many competing products particularly in the home aircraft industry that are even certified. No epoxies should just be substituted based on guesses, but the testing is relatively simple.
A one word guideline is "hard". We want the hardest glues possible. People often embrace glues that are soft because "bows are meant to bend". That is certainly not true of risers, and untrue as a guideline with limbs. If the structure was once bonded and later failed, creep in the glue line is one very likely culprit. Post curing will harden glues. Epoxy also continues to harden in some cases for a long time. Extremely thorough mixing is essential. The quality and composition of the glue is another factor.
"I guess I was under the assumption that one needed to cook the SO 1: to cure it and 2: because curing it at some kind of elevated temperature would prevent it from de-lamming if left in hot enviroment. I understand any bow left strung in a hot vehicle will blow, but I guess I was wondering if glues, left uncured, would soften and fail even with a bow at rest."
There is a thing called the glass transition temp. that you can google, and it essentially comes down to what you have said. Post cured composites exhibit higher mechanical properties, and greater resistance to heat.
I think another thing that may be worth considering is this one famous bowyer's experience vs. the manufacturers of millions of wooden riser bows over the last century. What are we doing today that is allowing us to have failures where we previously didn't?
"Never heard of the G2 and appreciate the comments on the west systems epoxy. I live in a small community in the high desert where marine grade adhesives aren't readily available. I have to order anything better quality than gorilla glue or titebond...lol."
Probably a better bonding environment than beside a lake. I would not encourage oddball departures from standard procedures or glues. To some extent that may be what is happening with SO also, it seems more common than not that people are not following the manufacturer's procedures. So that is a change that people are taking onto their backs. If one is going to do that one might as well do some testing also of other room temp glues. However, none of the room temp glues are going to solve the car trunk problem, as far as I know.
It is great that we have this freedom to freeboot it here in NA, but in some other countries one would not even be allowed to set up a woodworking business without extensive certifications. So we have the freedom here, but some reasonable degree of professionalism isn't a bad idea.