Nylon over wood veneer - How to do it without bubbles
Posted: Thu Jan 13, 2022 2:12 pm
After some really frustrating failures, I've found this method to work very well. I have used both Entropy One and System3 (#2 hardener) original epoxies for this part of the process and both have worked equally well.
1. Press ski with a very thin skim coat of epoxy on top. You'll likely have to sand a few spots where extra epoxy leaks through on top and some small air voids form, but this is usually minimal and cleans up in a few minutes. I flash the skis on the band saw so they are very close to the their final shape at this point. This will give you a flat top surface to work on, rather that sloping edges where you can't judge the edge of the ski exactly.
2. Take your nylon trimmed to size and place in the press at medium temp (130-150) for 5-10 minutes so it has the same shape as the ski. Don't go too hot or it forms lots of small warps. This pressing step is critical to keep it from wanting to lift off the ski at the tips and tail once you stick it down. You'll be fighting it constantly until the epoxy cures enough to hold it down. The nylon will want to return to its original shape (usually rolled up in the opposite curvature of the ski). Since you are curing at room temp, this can often be for over an hour.
3. Put some sort of mold release on the bottom of the ski, such as carnauba wax. The epoxy will run over the edges and onto your base. You can sand it off later, but this takes a lot of time. This wax shouldn't be taken up into the base since you aren't heating it, you haven't sanded it yet, and it can be rubbed off later.
4. Lay down a thick coat of epoxy on the veneer, smoothing it out as best you can, but you want it to be a consistent thickness, around 1mm thick (pro tip: mix your epoxy fairly slowly to avoid introducing extra air. Don't use a mixing paddle on a drill, as this whips a lot of air into the epoxy).
5. Lay the nylon on top and use a smooth roller to work the bubbles out from the middle to the edges. All the bubbles will just push right out. I have a 4 inch wide Speedball roller used for ink printing and available at most art supply stores that is perfect for this part.
6. Stay close and watch it. The nylon is rarely without some warpage here and there and this will cause it to want to lift and pull air underneath in a few places. Keep rolling out the stubborn areas until they hold. Occasionally, I use some small weights to keep it flat down in selected areas that just keep lifting. In the attached picture you'll see the box the epoxy came in resting in one place that just kept lifting a little.
7. Check it every 10 minutes during the initial cure time as little bubbles like to sneak in. You can use gentle pressure to force them out.
8. Leave it to fully cure before trying to trim away the extra nylon. If you get antsy, you can pop it up and ruin the whole thing. I cut the nylon off with a fresh blade from the top in a short sawing motion. Go slow. It can still lift off if you are pulling it up or flexing it down hard enough (ask me how I know). Then do you final edge shaping and side bevel and it won't lift.
This process has worked well for me. I attached a couple pics of my most recent pair. If you have any other tricks or an easier way, let us all know.
1. Press ski with a very thin skim coat of epoxy on top. You'll likely have to sand a few spots where extra epoxy leaks through on top and some small air voids form, but this is usually minimal and cleans up in a few minutes. I flash the skis on the band saw so they are very close to the their final shape at this point. This will give you a flat top surface to work on, rather that sloping edges where you can't judge the edge of the ski exactly.
2. Take your nylon trimmed to size and place in the press at medium temp (130-150) for 5-10 minutes so it has the same shape as the ski. Don't go too hot or it forms lots of small warps. This pressing step is critical to keep it from wanting to lift off the ski at the tips and tail once you stick it down. You'll be fighting it constantly until the epoxy cures enough to hold it down. The nylon will want to return to its original shape (usually rolled up in the opposite curvature of the ski). Since you are curing at room temp, this can often be for over an hour.
3. Put some sort of mold release on the bottom of the ski, such as carnauba wax. The epoxy will run over the edges and onto your base. You can sand it off later, but this takes a lot of time. This wax shouldn't be taken up into the base since you aren't heating it, you haven't sanded it yet, and it can be rubbed off later.
4. Lay down a thick coat of epoxy on the veneer, smoothing it out as best you can, but you want it to be a consistent thickness, around 1mm thick (pro tip: mix your epoxy fairly slowly to avoid introducing extra air. Don't use a mixing paddle on a drill, as this whips a lot of air into the epoxy).
5. Lay the nylon on top and use a smooth roller to work the bubbles out from the middle to the edges. All the bubbles will just push right out. I have a 4 inch wide Speedball roller used for ink printing and available at most art supply stores that is perfect for this part.
6. Stay close and watch it. The nylon is rarely without some warpage here and there and this will cause it to want to lift and pull air underneath in a few places. Keep rolling out the stubborn areas until they hold. Occasionally, I use some small weights to keep it flat down in selected areas that just keep lifting. In the attached picture you'll see the box the epoxy came in resting in one place that just kept lifting a little.
7. Check it every 10 minutes during the initial cure time as little bubbles like to sneak in. You can use gentle pressure to force them out.
8. Leave it to fully cure before trying to trim away the extra nylon. If you get antsy, you can pop it up and ruin the whole thing. I cut the nylon off with a fresh blade from the top in a short sawing motion. Go slow. It can still lift off if you are pulling it up or flexing it down hard enough (ask me how I know). Then do you final edge shaping and side bevel and it won't lift.
This process has worked well for me. I attached a couple pics of my most recent pair. If you have any other tricks or an easier way, let us all know.