Drysuit Neck Gasket Replacement

It finally happened -- I ripped the neck gasket on my Kokatat drysuit (out at Rum Island). This article describes the procedure I used to replace it. You may be better off using the NRSNRS: Gasket Repair Instructions or KokatatArticles: Neck Gasket Repairs With and Without Kokatat's Gasket Repair Kit instructions, but the following worked well for me.

The NRSNRS: Gasket Repair Instructions and KokatatArticles: Neck Gasket Repairs With and Without Kokatat's Gasket Repair Kit instructions contain important information about replacing gaskets that I don't repeat here, and some warnings and cautions as well.

Items needed...

Mountain Equipment Co-opKokatat Latex Neck Gasket (Unisex)
Product Number: 1906-320 (Victoria) usually has Kokatat neck gaskets in stock for about $29. If not, they can be ordered from their web site.

To replace a neck gasket, a round form must be placed inside the neck area so that the gasket can be glued to the neck. This type of drysuit (Kokatat Gortex GMER) has a neck collar that is smaller than the neck which makes it difficult to insert and remove a form.

To solve this problem I made an adjustable form from a plastic bucket. I used one from Home Depot that measured about 10" in diameter, 13" tall, and had a slight taper to it. The thickness of the bucket wall was a little over 2 millimetres. I think it would be better to use a bucket that wasn't tapered, but I thought this one would work OK.

Note that for all of the instructions below, the neck collar on the drysuit was folded down out of the way (below the bottom of the gasket).

If the old gasket is in reasonable condition, cut it off (with scissors) just above the fabric. You will be gluing the new one to the strip of gasket that remains.

With the saw, cut two sections from the bucket, both 3.5" tall. Using two sections will make the form stiffer.

To start, both sections will be the full circumference of the bucket. File and/or sand (course grit) all corners and edges of the first section so it won't damage the drysuit or the new gasket. I'll refer to this as the "outside" section.

At one end of the outside section, drill 2 holes (#1 and #2 in Photo 1). Collapse the section to a smaller diameter, put it inside the neck, and expand it until it's tight. Mark the location of bolt holes #3 and #4 on the other side of the section and then remove it.

Cut the length of the second (inside) section and mark where to insert it (Photo 1), making sure that it won't interfere with the ends of the outside section when bolted together. Again, file and/or sand all corners and edges. Do a quick, light sanding (course grit) of the areas of the two sections that will be glued together.

Glue the two sections together with contact cement. Put the form back inside the neck, expand it until it's tight, and confirm the location of bolt holes #3 and #4. Remove the form and drill both of these holes.

Photo 1

Countersink bolt holes #1 and #2 on the outside (Photo 2) so the bolt heads won't damage the suit or the gasket.

With the course sandpaper, sand the outside of the form (in the direction of the diameter) to help prevent the gasket and drysuit from slipping. Put a layer of tape on the form as shown to prevent the gasket from becoming glued to the form.

Note that my drysuit and gasket are both size: Large. With the bolts in, the outside diameter of the top (widest) end of the form is about 8-3/4". [Edit: I've now also replaced a small gasket on a men's small drysuit. I used the same form and it worked fine. I just had to drill new holes to make it smaller.]

Photo 2

If your (bucket) form is tapered, keep the wider end at the top (Photo 2). This will help prevent the new gasket from creeping up while you're waiting for the glue to dry.

To put the form in the drysuit, take out the bolts, collapse the form to a smaller diameter, put it inside the neck, expand it until it's tight (and the bolt holes line up), insert the bolts, put the nuts on and tighten them. You should be able to insert one bolt above the neck and the other below the neck without much difficulty. Position the bottom of the form about one third of an inch below the bottom edge of the old gasket.

Consider putting acorn nuts on the ends of the bolts to prevent damage to the new gasket.

The result should look something like Photo 3 (the green tape is missing). Note the strip of old gasket still attached to the suit.

Photo 3

Put the new gasket on the form for a trial fit. As you can see in Photo 4, the new gasket will likely be tight at the top of the form, but there will be many "hills and valleys" around the bottom edge. This shouldn't interfere with the gluing.

Photo 4

To prepare for gluing, remove the gasket and lightly buff (with 220 grit sandpaper) the strip of old gasket and the section of new gasket that will be glued to it. Clean both with alcohol.

Place the new gasket back on the form and carefully line up the bottom edge with the old one. At this point, I would recommend not moving the drysuit or form until the gluing is complete. Otherwise you risk shifting the form and the new gasket may end up misaligned.

Fold the bottom edge of the new gasket up until the strip of old gasket is fully revealed. Apply contact cement to the old gasket and to the folded up portion of the new gasket, being careful not to drip any contact cement on the drysuit.

Even with good lighting it can be difficult to get 100% coverage on the areas where you are applying the contact cement. I checked the coverage with a flashlight and found small areas I missed, especially near the edges.

I find the disposable foam paint brushes (Photo 5) to be very good for applying contact cement. They soak up a bit of cement and have a sharp edge that makes detailed application easier.

Once the contact cement is dry, carefully fold the edge of the new gasket back down. Work your way around the gasket, pressing the layers tight together. Watch that the ends of the bolts on the inside of the form don't damage the gasket!

Take the bolts out of the form, collapse it to a smaller diameter, and slip it out the bottom of the neck. Don't try to take it out the top.

Photo 5

To get a good fit on my neck, I always trim a new gasket. It's scary, but works well once you've done it a few times. There is a good articleBoaterTalk FAQ
Trimming Gaskets
by Richard L. Hartman that explains how to trim gaskets, as well as the pros and cons of trimming versus stretching.

To trim gaskets I use an X-Acto knife with a NEW pointed blade (Photo 5). The articleBoaterTalk FAQ
Trimming Gaskets
by Richard L. Hartman recommends using a stainless steel saucepan as a form. I find that a steel pan dulls the blade quickly and when cutting, the tip of the blade sometimes "sticks".

Instead, I use a flower pot (Photo 6). This one is made of thick plastic and is not tapered. I bought one that is just a bit bigger than the gasket opening. It works well and the blade doesn't stick while cutting. Even if you know you'll be cutting more, I recommend cutting one ring off at a time (cutting between the ribs). It's good practice for the final cut!

Note: As discussed in the article,BoaterTalk FAQ
Trimming Gaskets
by Richard L. Hartman the gasket should be inside out when cutting it, so you can see the ribs and cut between them. (Photo 6 does not show the gasket inside out.)

Photo 6

If you trim off one or more rings and find that the gasket is still a bit tight, consider putting a slightly larger flower pot in the neck opening and leave it over night, just to stretch it the last little bit.

Last Revised: June 10, 2008. Home