EPS sandwich

General Discussion
1

hello to all,

After last years disaster (not shown to swaylocks) this year I decided to try with a balsa sandwich. I will try to show all the steps I’ve done and all the problems I’ve found.

Maybe I will not show new things to the swaylocks addicts but hope my comments will help any sandwich beginner…

  1. hotwire cutting: Be sure you have enough tension on the wire, when it gets hot it also becomes longer, also the rocker templates should be very sanded. Take your time and do it with somebodys help.

  2. The deck is cut: consider the sandwich thickness in the rocker profiles, it’s easier to hotwire cut than sand the EPS.

  3. drawing the outline: you’ve also to take care with the rails thickness in the outline template.

PS: maybe this is the first balsa sandwich made in spain?



2

  1. To cut the outline I use an electric handsaw with an iron blade: this blade is slower and less destructiva than wood blades. After utting with the handsaw I sand the outline with all the accuracy I can.

  2. do the bottom sandwich layout, I used masking tape to maintain the woods toghether.

  3. Put the wood in the roker bed.

Next steps don’t have picture

  • Cut the inlay fiberglas do it about 5mm smaller than the outline

  • check the vacuum pump.

  • Mix an epoxy batch, about 150mm will be enough.

  • put the board with the fiberglas and epoxy in the rockerbed and over de balsa.

  • close the bag and start cheking for holes.

676×507 82.9 KB

676×507 81.3 KB

676×507 81.3 KB

3

a little more…

  1. If you’ve done all the steps before correctly you only have to wait (mrs Putxi loves this moment). I didn’t do the vacuum in the terrace, I only did the mixing and get into the house with the rocker bed and the board. The vacuum bag never goes outside the house to avoid hole risk, always use the vacuum bag in a clean area.

  2. when the resin is hard you can remove the vacuum bag. Check the curved lines in the rocker bed, thi is the consequence of a lack of tension in the Hotwire cutter.

  3. Also the masking tape can be removed. If you have too much resin it can flow between the woods, to save money I used non transparent epoxy in this step and this flow of resin will be a problem in the future (check the dark areas).

676×507 77.9 KB

676×507 74.8 KB

676×507 64.8 KB

4

Looking good. That is a nice size EPS block. I guess the wife is going to have to get used to surfboards on the coffe table.

5

Thanks Putxi. Keep us updated. I’d like to see how you do the rails. Nice outline .

Just curious- what did you use for breather cloth? Also, what is that purple stuff seeping out from under the edges?

6

Hi Putxi. Greetings from the Basque Country! :wink: Any advance in the project or is in “stand-by”?

What method did you use to set the rails?

…

Just get a old freezer pump and i am anxious to start my sandwich project.

sUgOi

7

looking very good!

My tip: I bag on the bottom skin before cutting and truing up the outline.