I’m about to get a 3mm sheet of black Komatex to use as stringer material. I was thinking of placing the Komatex between my masonite rocker template and my EPS block so that when I hotwire the rocker it would cut the Komatex at the same time as the EPS. Then I can remove the masonite template and Gorilla glue the stringer. I guess I could glue it to the side of the EPS before cutting, then just glue the other half of the EPS on. Can this be done? Is it just better to glue the Komatex in between the EPS after hotwiring and then shape the stringer down to match the foam? Also, do you sand the Komatex before glueing or is the bond strong enough without sanding first?
Komatex is PVC foam right? If you heat/burn PVC you get poisonous fumes coming off, so prob not a good idea to hotwire it. I think it would make a nasty mess when it melted anyway. It cuts quite easy with a craft knife anyway, and then just plane down the excess once its all glued up.
beside nasty fume stuff the Komatex would cut a lot slower than the EPS. And that is slow enough. Template out the stringer and clamp the sheet to a table. Then use a sabre saw. Sand down the top and bottom to even out your cut.
It’s glues up fine without sanding the sides. Slightly wet out one side of either material. I’m doing perimeter stringers so I had to do one side per. For a center stringer glue up both halves at once. Blue tape or blue tape and clamps to hold. It’s easier if you do the stringer before cutting out the outline. The Komatex planes and surforms very nicely.
Are you doing perimeter stringers with the Komatex? If so, how are you doing that? Is the Komatex curved along the outline?
I don’t think you can Hot wire Komatex without snapping the hot wire.
Shipman and I glued up our Komatex stringers with Gorilla glue. The EPS is so pourus the glue worked it’s way out about one inch out on each side of the stringer. Not too ugly but not perfect like Clark foam glue ups.
I painted one blank white just to hide the glue.
Next time we will find another way to glue up our stringers!
use a lot less gg glue next time around…
or try Roo or Titeb
place your masonite HW template right on the koma and trace/score it with a sharp utility knife. once its scored, just bend/snap it off and you got your stringer…easy
Strange, maybe our eps is different, I never see glue suck, I have glued up with white wood glue (similar to US elmers), polyurethane glue and epoxy. If your foam is sucking that much glue you might try sealing the bond layer with epoxy/microballoons first but that seems counter intuitive to a strong bond.
Yes, the stringer on both sides curves with the outline of the shaped board.
From the block of foam I hotwired the profile, cut out the template outline and squared the rails. Planed and block sanded to close to the finished dims. I marked a line 1.5" in from the rail on both sides. Using a Japaneese hand saw I cut the rail band off. The Komatex I templated using the rocker profile and cut it out using a sabre saw. One side at a time I glued it up using Gorilla Glue. Slightly wetted the non glue side with water. Blue tape, long clamps and 24 hours later I repeated the process. Shaped the band down using the planer and a surfoam to match the shaped top and bottom. Spackled the last couple of days. Sand the spackle coat tonight and glassing Saturday and Sunday. I’m letting my 16 year son do the art work tonight, I’m scared!
way to much glue boyzzzzzzzzzzzzzzz
Got any photos of that wild stringer project ???
