But still as the OP asked, why in the world would you have a wing cover with a zipper IF the darned thing can't be serviced by the end user? If it was meant to be serviced by the manufacturer why not have a sewed seam in the cover material? Or just make the wings more like rec BC's so no one will be tempted to fix them their selves period? As a prime example my Apeks wing doesn't have a user serviceable bladder but yet it has a zippered cover.
On a side note my DSS SS backplate is a tank!!!! The thing will out live me and future generations to boot. B.
Getting the bladder into the wing shell and sewing it shut is not a simple proposition. It *might* seem simple, but keep in mind that all the seams on a well made wing are first sewn with the material "finish" side in. Then the wing is turned finish side out and the seams are top stitched. It's a bit like making a pillow, somewhere, somehow you have to get the stuffing in and close the pillow.
The DSS wings that are sewn shut, i.e. without a zipper, are a pretty good trick to produce.
And they require a very skilled operator who can avoid sewing through the bladder for the final step.
Zippers can make assembly of the wing easier, particularly with a full circle wing.
You do of course realize that you are making the very points I've been making for years concerning the utility of zippers in wings.
The fact remains that most users don't want to replace the bladder themselves, they lack the tools and expertise. Same for most dive shops. That means even the wings we produce with zippers are usually returned **by choice** to have us service them.
It's pretty hard for a dive shop, who may only work on wings very occasionally, to have the small parts, and the skills to do a bladder replacement and actually turn a profit.
Our staff OTOH, can do the job pretty quickly, has access to grommets and seals etc. if needed, and the customer gets a factory assembled and tested wing.
Are their divers that are qualified to do the job themselves? No doubt, but it's next to impossible for a manufacturer to be able to identify who is and who is not.
Are there divers (and dive shops!) that really shouldn't attempt a wing repair? Yup. Several hours of phone support and 2 dozen emails later, plus a returned brand new freshly ruined bladder is something one need not repeat too often before bladder sales become very limited.
Tobin