Check out this guide from NRS, I think it should be able to help you. I am unsure of what drysuit you have but the company who made it may have instructions specific to your drysuit.

https://www.nrs.com/repair/gasket_replacement.asp

Video of Gasket being replaced:

https://youtu.be/Et6k1f0WVyM

Jerry,

The NRS instructions look pretty good.  I have a couple of comments:

The form should be at least 2” thick.  If you don’t have 2” thick mincell or ethafoam, you can use pink building insulating foam.  Wrap a couple of layers of plastic wrap tightly around the form  and hold the wrap in place with tape.

Push the form into place from inside the suit.  It should be a snug fit.  If the form is loose, the gasket might not seal well.

Most definitely, do not use a tapered, cone-shaped form.  As soon as you put the aquaseal on the gasket, it will start slipping off a  tapered form.  In fact, in my experience, the gasket will start slipping off a disk-shaped form with straight sides too.  I don’t think a rubber band will hold the gasket in place unless it’s a really strong one.  I cut some strips of duct tape and use them to hold the gasket in place.  When you remove the duct tape, there will be some residue from the duct tape that will stick to any aquaseal that oozes out past the edge of the gasket.  A bit unsightly but won’t affect the repair.  Try to wipe off any excess aquaseal before using the duct tape.

After finishing, watch the gasket carefully for a while to make sure it isn’t slipping.  There is nothing more annoying than to go away and come back to find the gasket has slipped off the form.

Overcuffs are a pain in the neck when replacing gaskets.  Peel them back as far as they will go and hold in place with painter’s tape so they don’t get in the way.

Diluting the aquaseal with Cotol will make it thinner and easier to apply.  If you use Cotol, be aware that the Cotol will evaporate pretty quickly and the aquaseal will start getting thick again.  You have about 10-15 minutes working time before this happens so don’t mix the Cotol until right when you are ready to apply the aquaseal.  If the aquaseal gets too thick before you are done, you can add a few more drops of Cotol to thin it out again.  You don’t have to use a lot of aquaseal.  A thin layer will do the job, and less will ooze out the back edge of the gasket.

Wrist gaskets are the easiest to replace because they’re the smallest.  Ankle gaskets are about the same.  Neck gaskets are very difficult.  Some dry suits and tops don’t have neck openings that will take a disk shaped form very well.

Good luck.  SYOTR.

Chris, thanks for the great tips and advice!!  I’ll have to remember the painters’s tape!!   When I did my neck gasket, I used a stock pot as the form.  We used zip ties to keep the gasket from slipping (Jon’s idea, not mine), it seemed to work well.  Since the rest of the suit leaks massively, I can’t really speak to the watertightness of the neck gasket, but it looked nice when I finished it.

Good luck, Jerry!

Sarah