Glassing the top, then bottom?

Is there any reason not to laminate the deck of the board first, and then the bottom of the board second?

The reason why I ask is because I’m installing lokbox fin boxes (in the bottom of my board, of course), and I need to get some cabosil before I continue the installation. I figured why not glass the deck of the board so I’m not wasting time waiting for the cabosil before I glass the bottom?

Hi! Sometimes the answer is right in the tip of the tongue, but out of the view of your eyes. When you laminate the bottom first and then the deck, the overlaping of the last one preserves the bottom of being oversanded on the edges. If you do the opposite way, besides increasing sanding work on the deck rails, you will have a hard time trying to even the overlaping in the bottom. In addition, it can appear a line of small bubbles all over the deck cloth borders in the bottom of the board. Good luck, and keep waiting for the cabosil and then do it in the right way.

I think you can lam the lokboxes in with straight lam resin.

I know that is what Futures recommends.

Drew

Doesn’t TR have any q-cell/cabosil? Why do you need that stuff anyway? Just rout the boxes tight and do it the way Drew said. And make sure you put an extra patch over each one.

P.S.: JLW, are you working the Big Sea Day comp on saturday?

Jim definitely reccomends no cabosil, only straight lam resin… much mcuh stronger… here’s all the lokbox info I collected recently, HTH

Jeff


We try to get people to get our install equipment simply because it does a really clean job. A perfect tight cut which we feel is vital to the integrity of our box. Especially with the large based keels. A sloppy cut could lead to a box failure which bums everyone out. But at the same time we understand the costs, and that some people might just want to try out a set. My suggestion would be to use either some 1/4 inch lexan or other type of hard plastic or even paneling, and flip the box upside down and trace out it’s outline. This cut the (ellipse) should be 3/16ths deep, and sometimes a tad deeper for deep concaves. You may want to rig up some kind of depth gauge also. Once you have that cut using a dremel or small router, just take the box, line it up with the screw towards the stringer(towards left on rear thruster fins) over the hole and press it down into the foam. This will leave an impression of the cavity portion of the box(deeper part) into the foam. The depth you need to cut from there is 1/2 inch. If you do it clean, it will install nice. Be sure to have the cavity opening taped off or use the lokbox sticker which comes with the boxes from the supplier. Install with approx. 2/3 ounce straight lam resin, spread around hole wetting all bare foam, and press box in using slow even pressure. Angle is built into the fins so be sure to push each box in evenly. If you tilt one out or in, try to tilt the other the same. Note:(Install dummy fins come with jig) Now just spread a light even layer of resin over the face of the box, without leaving any thick globs anywhere. Squeegee off any excess resin around the box. Let harden. Now cut glass patches minimum 1 1/2 inch larger than box all the way around(slightly larger for fish boards) and apply over the box with second coat of straight lam resin.

(2 layers of 4 ounce or one 6 ounce and one 4 ounce recommended for fishes) saturate and squeegee the patch flat removing any excess resin. Hot coat.


if your doing it on the foam, you must first add a new dot where you actually place the box. On fish, the boxes get adjusted forward to compensate for the width of the long bases on the keels. A good standard measurement would be 1 inch. From your rear dot, move forward one inch and place a new dot. If you have the boxes, you will notice hash marks on the face for adjusting the fins. The second mark from the end of the box is the shapers posititon. This mark must be centered over your forward dot, then offset outwards 1/16th of an inch just like with fcs. So from your rear mark, just move up 1 inch, and out 1/16th. Also place a new dot next to your front dots that’s out 1/16th as well. Flip the box upside down, then measure 1/2inch from the end and put a small pencil dot on the bottom of the box. This will help you find your new mark. The dot on the bottom of the box should be 1 inch forward from your original mark, and out 1 1/16th. Once you’ve got it in place, draw a line around the perimeter of the box, and you now have a line to go by with the router. 3 /16ths depth for first cut, another half inch deeper for the cavity(deeper) cut. Using straight lam resin (2/3rds ounce per hole) spread a liberal coat all around the inside of the hole. Press the boxes in with slow even pressure and set angles (6 degrees). Let gell. Don’t forget to squeegee off all excess resin from around the boxes. With no dummy fins you will already have the pre-cut stickers applied to the boxes. So setting the angles will be more like (put 'em in as flush as possible with your fingers). When laminating, cut oval patches minimum 1 1/2 inches larger than the box all the way around and place over boxes. Now pull out your full length layer of glass for the bottom. Laminate board and hotcoat both sides. Sand. Your done.


you’ll notice the raised “rim” around the cavity where the fin fits. We call this the resin rim. This prevents resin from getting in the box when you glass over it. Try to rout the holes only deep enough so the box fits in flush. Use the box itself to “dry fit” and check for proper rout depth. When you install the boxes, you use straight lam resin (2/3 rds ounce per box) and spread it around the hole real good. Press the box in with slow even pressure. Paint a light film (don’t leave any big globs) of resin over the face of the box, and use a squeegee to remove any excess resin from around the box. Let gell. Apply pre-cut stickers(what you called cardboard thingys) straight onto the resin rim. Cut oval patches (6 ounce for strength or 4 ounce if you want it light) and resin them over the boxes. Chase out all bubbles from around the resin rim area (note: cutting a small slit 1 and 1/2 inches in length right up the middle of the patch helps you get rid of the bubbles). Now squeegee all excess resin out of the patch around the box. Hotcoat. When you sand the boxes, they will open automatically with NO RAZOR BLADING NECESSARY!

As resin hardens it shrinks and will pull the rocker in the direction of the lam. This is much more accentuated with the first lam layer. Most people prefer a slight flattening of the rocker so they do the bottom first, also the shape of the rocker tends to resist being changed a little better on the bottom/convex side.

Quote:

Doesn’t TR have any q-cell/cabosil? Why do you need that stuff anyway? Just rout the boxes tight and do it the way Drew said. And make sure you put an extra patch over each one.

P.S.: JLW, are you working the Big Sea Day comp on saturday?

Nevermind, turns out I don’t need cabosil.

Unfortunately when I installed the boxes, they were flush in the routed hole. After the installation with laminating resin, they seemed to be slightly raised (like 1/16", maybe 1/8" tops). I think the reason for this had something to do with the resin curing quickly, causing the resin to expand, thus causing the box to rise higher.

I don’t think it’ll make too much of a difference, though.

You can always just sand down the elevated edges, Josh. I’m gonna make you work for this gallon of resin! Hah, just kidding.

In reply to the P.S.: No, but I’m doing the longboard and shortboard divisions. Hopefully I get to the finals in longboarding.

Howzit JLW, Actually resin shrinks not expand, I think the shrinkage is about 6% with poly and less with epoxy. Did you put any fiberglass in the bottom of the hole? I don’t remember ever having a box rise up, but I have had a glasser friend tell me that he’s had leash plugs rise if he kicked the resin to fast. Hope it’s OK and you don’t have any problems later on.Aloha,Kokua