Starlight is spot-on with all of his comments. I would only add the following extra detail.
6.38mm lam ... 10.38 lam
Like Starlight, I'm confused here: Maybe you are talking about 6.38 mm laminated glass, and 10.38mm laminated glass? Those are not standard metric thickness, but they are not imperial either... 6.35mm is 1/4", so that sort of makes makes sense. 10.38 is sort-of-kind-of close to 7/16".
Source of the postI'd still have both door frames connected to the same single wall. Is it possible, or even worth the trouble, to attempt to decouple the second sliding door ...
As Starlight pointed out, there are differences in approach. For highest possible isolation, there is no doubt that full decoupling is necessary, and there are framing techniques for dealing with the structural issues. If you don't need maximum isolation, then you can have coupled frames, as long as you understand that your isolation won't be as good as it could have been. However, it will still be better than nothing! That's the deal here: If you need an increase in isolation, then two leaves will usually be better than one, so you will get an improvement. And if you need max isolation, then fully decoupling the framing will get you an additional improvement.
Using rubber all around your frames will not completely decouple, but will certain do something to help.... provided that it is the right rubber!
Obviously needs to be high density rubber, but it should still stop vibration passing from one door system from the other, no?
Once again, Starlight is totally correct. High density rubber would not be the right choice. In fact, you should choose the type of rubber that does the job correctly. That will be a softer rubber, such as the ones Starlight mentioned, but even then you should do the math to find out how thick to make it, and the exact "softness" you need. When it is all installed, the rubber should be compressed between about 15% and 25%. depending on the rubber. 20% is a good ball-park estimate, but you do need to check the manufacturer's specs to find out the optimum compression (more correctly called "deflection", since you can't actually compress rubber...). Then you need to figure out how heavy the window is, and use that to decide what rating of rubber you would need that would deflect by the right amount when it has the weight of your window on it. That's the general principle. It's not hard to figure out, by you do need to be careful: If you calculate wrong, then the rubber will either be squashed too much, so it won't decouple, or it won't deflect enough, and it won't decouple.
Also, you need to use rubber sleeves and washers around the screws/bolts/nails that you use to hold the window in place, such that they do not touch the window frame itself: There can be no hard contact between the window frame and the surround that is attached to: that would just "short circuit" the rubber entirely.
Is silicone the way to attach the rubber to the wooden frames around the "decoupled" sliding door?
Depends on the rubber! Some adhesives will attack and damage some types of rubber, other adhesives just won't stick at all. Check with the manufacturer of the rubber, to find out which adhesives you can and cannot use. But you probably won't actually need adhesives, if the mounting surfaces are clean, smooth, and flat. The rubber itself should be fine, since it will be held in place with the fasteners that you use (screws, bolts, or nails). Sorbothane in particular is sort of slightly "sticky" to the touch, and seals well to most surfaces.
- Stuart -