The Jig: Your 4WFS installation jig consists of three parts:
A thin base plate with 2mm non-slip material on the underside (Fig1)
A 10mm plate with a circular hole (Fig2)
A 24.5 mm thicker plate showing a larger circular hole with a narrow “lollipop” extension (Fig3)
A router bit with a top bearing (1/4” shank + 1/2” wide top-bearing and 1/2” wide cutter with a cutting length of 1”) should be used with the router.
Set router depth to 33mm
Once the board has been shaped and immediately preceeding lamination, blow all excess foam and dust from the area where the fins are to be installed. Use your compressor if necessary. This will ensure that the rubberized jig surface will have adequate grip during the whole routering procedure.
Left, right and centre is referred to “on the jig” when viewing the board with the bottom deck facing upwards and from tail to nose. Also note that the actual left and right fin will always rest on the outside of the shapers vertical line once installed.
Mark your usual shapers dot on the shaped blank and join the 2 dots with a thin pencil line 5” apart (Fig 4)
Place the second ‘circular hole’ jig plate (Fig2) on top of the non-slip base plate (Fig1), making sure the 2nd plate slots firmly into the grooves of the base plate.
Align the combined plates (1) and (2) over the shapers dot on the blank (Fig5), ensuring that the dot can be seen through the relevant hole on the 2nd jig plate. For centre fins use the “C” marked hole, right fins use the “R” marked hole and left fins use the “L” marked hole.
Align the jig such that the vertical line on the blank aligns with the vertical line on the jig. You can also insert a long allen key into the left, right or centre locating holes and align up the shapers dot with the shaft that touches the blank.
Place the router over the hole and gently router out the foam, starting from the centre and “worming” your way outwards. You can keep one hand on the base plate for extra stability if required.
Whilst keeping the base plate in position, replace the 2nd jig plate with the third thicker “lollipop” jig plate (Fig3 + Fig6) and router out accordingly (Fig 7). Blow out all the holes after routering is complete.
If you want, you can check the accuracy of the routered holes by temporarily placing the 4WFS boxes into them, making sure they sit flush with the blank’s surface. Remove the boxes once this check is done.
Mix up 30ml of a laminating resin paste (no wax), consisting of 30ml laminating resin (preferably Epoxy**) and adding Qcell / Glass Bubbles / Micro-Balloon, together with 3-5% of catalyst. This ensures a fairly hot mixture to set them off fast (as there’s only 0.5mm gap around the box once you cut the hole).
You’ll only use about 20ml for a full thruster set. The resin mixture should be consistency of a paste, not “runny”, in between say honey and peanut butter. (* see footnote)
Using a narrow brush paste the resin mixture into the holes and side-ledges, making sure that all the foam surfaces are primed with the paste and touch the underside of the box. Wipe off any excess paste off the blank.
Insert a set of plastic fins into the assembled disc+ box and place the boxes into the holes and push down gently until the fins are perfectly aligned to the shapers line and the box is flush with the boards surface with only the top ridge protruding above the surface. If using NON-ZERO degree side discs, make sure that the “+” sign is facing the rail.
Ensure that the boxes are now flush with the blanks surface with only the higher sandoff ridge protruding above the surface (this is where the glass laminate will lap against)
You can slightly modify splay by 0.5 degree at this stage as well but make sure that you don’t lift any side of the box above the surface of the blank. Remember that the fins can easily be adjusted later using the interchangeable 4WFS interdiscs.
Allow the resin to cure and then gently remove the fins by applying downward pressure on the box whilst levering the fins out. (Fig 8)
Screw down the 2 grubs screws on each disc until below the surface of the disc.
Using a high-temp 48mm masking tape apply over the discs to just overlap onto the box.
Rub the masking tape over the discs’ surface and especially over the sand-off lip area to ensure it is sealed off completely. Use a sharp Stanley blade and cut the masking tape at the base of the sand-off lip. [Fig.9] This makes sure that no resin enters the disc area during board lamination.
Laminate the board in the usual way. Apply extra 4 oz patches over each fin box area.
Sand down the board in the usual way. The masking tape stickers will pop off naturally to reveal the interdiscs. No more sanding is required at this stage around the box.
Your installation is now fully complete!
* For Australian shapers you can obtain a ready made paste from Fibreglass International (FGI) under product code F61428/1136 “Flexible Laminated Casting Base”. Catalyst must still be added at time of use. ** If using epoxy to laminate the board or otherwise FGI, or failing which vinylester or failing which polyester.
4WFS strongly recommends installers to read through the installation procedures, view our installation CD and/or observe a test install which can be arranged through your local 4WFS representative. Neither “Four Way Fin System” nor “Air-Core Technology” accept any responsibility for faulty installations and for any injury, loss or damage to you or others occuring during the installation process. Saftey gear should be worn at all times. The system and equipment is used entirely at your own risk.