Originally Posted by
Chombi
Used both contact cement and 3M77 glue on all sorts of things through the years. Not specifically on saddles, but leather and fabric item like leather motorcycling boots, backpacks, bags, suitcases.....
My experience had been that 3M77 spray is mostly like "Spray Mount" on steroids. Used it for many years at school, then at work, building architectural models and at home for light duty bonding for items that stay inside the house, and yes, I have had the stuff fail its bond when exposed to heat, while contact cement is permanent glue, by definition.
If you look at the bottoms of many, if not most plastic based, padded saddles you will usually see evidence of manufacturers using some type of contact cement, which presents itself as brownish, hardened material at the edge where the saddle cover material meets the saddles, plastic base, especially at the nose and tail areas.....
So, at least these most critical high stress areas, contact cement would be the best to use. As already noted, use the 3M77 only at the top, foam padding/cover interface, but not at the bottom edges at the nose tail and sides, under the saddle.
...what sort of failure ? What sort of heat ? If it genuinely does not work, I would like to know. When I look at the saddle covering failures, I see only a failed adhesive bond, most likely due to aging. How can i tell what this is, exactly ? Brownish hardened material seems to cover a lot of ground with regard to aged adhesives. While nothing is forever, 3M advertises
#77 as a permanent adhesive. I take them at their word.
Certainly they offer a number of adhesives. Something called Hi-Strength 90 is offered, but a little harder to find. A slightly less strong adhesive allows for the occasional adjustment immediately after mating, which turns out to be important when doing this repair.
Again, not to make too much of this, but my suspicion is that maybe you think that more is required in this particular usage in terms of strength than my own experience has led me to believe. If the issue is one of ease of application and use, I simply find that with proper care and masking, it is easier for me to apply and even coat of this contact cement to the irregular surfaces along the edge and underside that have come loose. I rarely remove the entire covering and start from scratch, because it seems like unnecessary work to me. And also once again, I've been using this stuff for at least six or eight years without any failures of the mating of the surfaces between cover and saddle.......you do need to make certain that the old adhesive is removed if it is too thick on the surfaces to be joined, but other than that, I don't see the problem here ?