Hotwire deck roll

Florian_R · January 21, 2011, 9:24pm

Hi everyone,

today I had an idea how to hotwire the EPS for my next surfboard. I have no planer and no planing skills, therefore I prefer to use templates as much as possible. To try out my idea, I hotwired a scaled model (1:4) of a surfboard, a 6’ surfboard shrinks to around 18" inch. But let the pics tell the story:

small block of xps with the outline template of the scaled surfboard model:

I added a template for the deck roll at the nose and the tail side of the block:

Hotwired the deck:

added the rocker template. This isn’t going to be the bottom contour curve, as it would be to flat. A little rocker has to be added by bending the eps while attaching the wooden skins later.

Hotwired bottom and cut outline:

As mentioned, during lamination or vacuum-bagging the skins on the eps would need some additional rocker, otherwise the deck contour would be straight, which would at least look a bit strange.

After a minimum of shaping the core should be finished for vacuum-bagging the skins on.

Well, what do you guys think?

hans · January 22, 2011, 12:52pm

As far as I can see it from the pics, this is XPS, not EPS.

Its a nice new approach if you don’t want to use the planer. But the planer is the fun part! I’m interested in the end result.

Florian_R · January 22, 2011, 7:47pm

Hey hans, your right, that’s xps. For a real surfboard I’d rather use eps because I read at sways that pre-bending xps is not a good idea. Reportedly XPS tends to snap if pre-bent, can anyone confirm that? For the model i choosed xps because i had some scrap pieces left.

karl · January 22, 2011, 8:45pm

The other way to hotwire deck roll is to use masking tape to set out the rail bands and hot wire along the tape, then just sand to blend.

hans · January 22, 2011, 8:49pm

So you want to hotwire the deck like that with a real size surfboard? You’ll need a 2m wire! That won’t be easy, and the shape won’t be good because the wire always lags behind.

Florian_R · January 22, 2011, 9:10pm

Well hans, that already came to my mind as well, but I thought about hotwiring 3 or 4 pieces and gluing them together for the real size surfboard. I like to buy my eps in the hardware store, where you get only 50cm x 100cm pieces anyway. but its cheap, 4€ (=5$) a piece.

Florian_R · January 22, 2011, 9:10pm

Hey Karl, that’s also a good idea. How do you prevent the hotwire from burning through the tape or sticking to the tape?

grasshopper · January 22, 2011, 9:21pm

it is better to get your rocker close to what you will want it to be before bagging. there are much better ways get a deck crown. one of them mentioned already with the tape to guide your railbands.

another method is to hotwire your desired profile, then lower your hotwire guides and place a wood or metal spacer on the deck and pull the wire along the shifted guides. the spacer will keep the wire from going in at the apex and the wire will be bent down to the guides, giving you a crowned deck. this is just a starting point, as you are not going to want the same deck roll along the whole length of the board.

eps is pretty easy to shape - you could do the deck crown with a sureform and/or coarse sanding blocks and some elbow grease if you dont want to use a planer.

karl · January 22, 2011, 9:33pm

The hotwore doesn’t burn the tape. But the edges of the tape sink in a little, so I put the tape a little outside the line I want to cut. For shortboards I can use a hotwire bow that’s only about 10 inches wide - easy to control

K