Cutting out Fiberglass Seat???

You may have seen my other post about my broken NDK seat. I have fixed it with epoxy resin and glass cloth…and a little devcon plastic welder.

We’ll see if it holds.

I am still considering putting in a new seat though as I am not 100% confident in this one now.

If I decide to cut this seat out and put in a new one, what is the best tool to use to cut the seat out and then to grind down the edges?

I probably will have to go out and buy something for this…would a Dremel tool have some sort of an attachment for this?

Can I get some sort of attachment for my drill that will allow me to cut it out?



Dremel tool
They rock for cutting fiberglass. They come with borsic cutter wheels (At least the kit I bought did), which will walk thru glass like it’s butter. Use a light touch, and resist the temptation to cut fast, and it’ll be a breeze.

Broken seats are very common in NDK’s. I know about a half dozen Explorer owners who have had the same thing happen. Most removed the seat altogether, and replaced them with foam seats. The foam is much more comfy, too.


wary of spinning blades
especially without guards. I don’t doubt there are skilled people able to make a Greek statue with a chain saw or cutting blade on a drill but why not take the safer way out? Try a sable saw or hand held hack saw blade. Wear a mask. Try a rough file, 80-100-180 grit sandpaper.

The Dremel cutting disks do, indeed, have a tendency to fly apart if they’re not held exactly perpendicular to the material being cut. So, a mask really is a good idea or, at the very least, eye protection.

Dremel Is The Word…
for glass work. Go slow to go fast. Edge down with the cutting wheel on the scribed line. Edge back up to let the debris clear. Move a tad bit down the line and edge down again with the cutting wheel. If you try to use the cutting wheel like a circular or jig saw with constant pressure, you will have a lot of broken cutting wheels.

Also wear inhalation protection and safety glasses. The cutting wheel throws of a fine cloud of epoxy and glass. Stuff you would not want in your lungs…


from the school of DIY and hard knocks.

high speed dremel on small disc, it was the cutting blade on a drill that worried me.

Dremel cut-off wheels
come in two different grades of thickness.

The heavy duty ones are almost twice as thick as the standard ones, and will last MUCH longer!

Having went through 100’s of them in my former part-time business (contract building R/C model planes for a large hobby shop), here are some tips for happy use:

  1. NEVER turn the Dremel tool while cutting so that it would cause the cutoff wheel to bend in the cut. That will cause the wheel to shatter almost instantly.
  2. Do not bump the wheel against a hard surface while operating for the same reason.
  3. Operate the Dremel at it’s highest speed when using the cutoff wheel, and use LIGHT pressure. Let the wheel do the cutting!
  4. Make sure the retaining screw is snugged up. If it gets loose, the wheel will “wobble” out the mounting hole, and ruin it.

    Watch for overtightening the screw, also, as you can crack the wheel this way.
  5. Robart makes a 90 degree angle drive for the Dremel which helps getting the wheel in places where the body of the Dremel would be in the way.

    As others have said, ALWAYS wear safety glasses or a face shield when using this tool. A shattered wheel makes excellent high-speed shrapnel!

    Depending on what you’re cutting, at least a dust mask is a good idea, also.

    For jobs that are a bit too heavy for even the heavy duty Dremel wheels, you can get an inexpensive angle grinder for which you can get cutoff wheels that will make child’s play of large bolts, angle iron, or what have you.

Replacing seat

– Last Updated: Apr-02-07 10:21 AM EST –

Cutting out a seat is easy, putting in a new one is tough. It would be a bit of a chore to replace the seat with another glass one and re-attach it with struts like when the boat was new. Is that your intention? It can be done but requires multiple layers of glass cloth. Grinding away the struts on a taper and building up layers of glass - that type of thing.

I would just over glass up your existing repair if it fails before contemplating a new seat unless it's uncomfortable for you. I know people who have cut out glass seats but usually replace them with some kind of closed cell foam seat they like and just glue in place.

I have cut 3
seats out of NDK boats with a hacksaw blade. You can get a handle device at a good hardware or auto parts store that will cover most of the blade and leave 2 or 3" out to cut with.I leave 3" or so of the side hanging down (ears) to provide a place to attach back band and seat to. This requires two cuts forming an “L”. Just smooth with some 120 grit wet or dry sand paper or a small file.

have you seen this page??? Derrick ripped his out and put in foam…


I used a dremel on this one. much better job. :slight_smile:

fibergalss protection
In addition to the eye protection and maybe a mask mentioned by others, you should wear a long sleeve shirt. Those little glass fibers are not particularly dangerous to your arms, but they do itch like crazy

I have pics of the process on Webshots

While I prefer to use a Fein Multimaster for this type of work, it’s an expensive tool that’s really not necessary. In fact, you don’t need anything more elaborate than a hacksaw blade with one end wrapped in duct tape.

If you’re going to use a Dremel tool or something similar, make sure you get their REINFORCED cutting wheels. They’re easy to spot, as they’re pretty thick (~1mm) and you can see the fibers in them. The thin composite wheels have a tendency to shatter dangerously in use. Regardless, safety glasses are a MUST for this type of work.