Whitelion Windsurfing

Tim Hemer

Tim Hemer

Making a board in winter can be a frustrating exercise with many epoxies requiring minimum temperatures of around 20 degrees Celsius to cure correctly. Up until recently I have only built boards in the summer months as I didn't want to risk burning the shed down with any of the usual methods such as heat lamps or domestic fan heaters. The other problems with lights are a huge delta-T over the surface of the board and most of the heat generated is lost. Of course you can enclose the board with the lights but then have an even greater risk of overheating near the lights and a possible fire! I also began to laminate on a table and found it was hard to get a large enough workspace to laminate the cloth in one flat section. The solution was a Hot Box!

The Hot Box allows you to:

gently warm your laminating resin
warm the board to be laminated
warm the cloth to be laminated
cut cloth without repositioning
maintain resin temperature during laminating
maintain precise curing temperature of the laminate
store blank foam when not in use

Heating is provided by 2 x 400W fan forced block heaters with a digital temperature controller with temperature ramping. These allow gentle heating of the air with continual circulation; it really is a big fan forced oven.

There is a slot near the edge of the door to clear a vacuum tube and I have added wheels to stand up the box when not in use. I recommend you have someone help you lift it onto its wheels though as it can be dangerous if you slip and flatten yourself!

I tied to save a few $ on insulation and use sisalation as the coldest nights in the shed would be about 5 degrees celsius. Also the plywood insulates fairly well on its own. If you were wanting to minimise operating costs or work in consistently low temperatures I would insulate all of the inner surfaces except the top and bottom. On the bottom I would place the insulation underneath to maintain the hard wearing floor. On the top I would place insulation on top once the board is inside as you need the lid to conduct heat for laminating and pre warming the cloth.

So far I have utilised the Hot Box to make 2 boards and have had no problems running it all night.

I will do a drawing if there is any interest in the comments!

Tim Hemer

Here is a quick video of a 1/10 scale model I machined of the HD Slalom 83. The objective was to view both the hull and deck concaves and to check all of the other contours looked ok before I sent the template files off for laser cutting. The plan is to cut the full sized board when I have finished my large scale CNC router.

Normally the hull would be machined before the deck since it is more critical for performance than the deck. Also you can vac dag the hull before machining the deck for added dimensional stability, and machine trim the hull sandwich and rail tuck below the wide point of the rail.

In the video the deck was machined first as it was easier in this case, but, unfortunately I squeezed the polyester bog supports out wider than the tape on the foam and a few small strips of the deck got eaten.

Hopefully I can post about modelling the board in SolidWorks and what works for me.

Tim Hemer

I have finally finished my latest build - the Slalom 83 (formally Creeper 83, I am reserving creeper for the speed boards ;)

The final specs are:
Width: 83cm
Length: 247cm
Volume: 150L
Weight: 8.5Kg

I went in a new direction with this design and incorporated a double vee flowing into a tri-panel vee in the tail. The intention is that it will plane early but not become flighty at speed or with smaller sails. I tried the board out yesterday at the top of its range and couldn't find fault. The shoulders never caught in the chop or dragged in the troughs and wheelies were predictable and easily controlled.

Gybing was fascinating as there was so much variety on offer. I could bury the full rail for a drawn our slalom style turn or snap it around quickly off the back foot. Alternatively, I could use a combination of the two which worked well in the lulls - Fast entry with a sharp tail turn after the rig flip to enter the new tack squarer to the wind. Also since the board planes so early and the straps are free from the flow I was going a slow as 8 knots on the exit and remained on the plane.

The board is made solid and there is a bit of extra weight in twin delta stringers, this board is made to last and take the punishment of the chop and my local.

Needless to say, I can't wait for my next session closer to the middle of the boards sail range.

Tim Hemer

Time for the final clear coat, sanding and non-skid. I will keep a matt finish which shows the weave when wet - just like the finish on fins. My non-skid was late night inspirado and I already don't like the waistcoat looking front - this will change down the track. Also had a bit of trouble with the non-skid fisheyeing over to 1200 finish underneath - another experience for the memory bank. This will be the last clear finished board I do, opaque sanding coats are so much quicker to finish.

Clear coat, none under the pads to save weight.

Clear coat tail.

Wet and dry of the clear coat.

Wet and dry finished.

Pads and non-skid finished.

Hull sanded.

Nose clear coat.

Finished tail.

Ready to Rock.

Tim Hemer

Deck is bagged(200g Twill carbon, 130g plain glass + patches) and initial sanding is almost finished. Next up is to fill a few low spots I should have filled before glassing but couldn't be stuffed, then a finishing coat for polishing.

I glassed(2 x 130g plain glass + patches) the hull old school(not bagged) and everything was sweet until some gassing of the dcell combined with some crimped glass to form a few bubbles. Yet more repair work. The newer surfboard glass(130g) seems to use smaller glass bundles(and have larger openings in the weave) which leaves more resin on the layup table. I think the layup might have been on the dry side as a result which doesn't help. I probably should have glassed the hull on the board then feathering the 2 layers around the rail would have been easier.

There are a few tricks I tried for the hidden (under carbon) inserts which worked well.