Hi, i just got done glassing my longboard, i need to install the fin box. i did searches all over and i couldnt find the info regarding my questions. ok, so the little tabs on the fin box are so that it can rest on the board and you can make sure it is level with the surface of the board, correct? after the resin has set, your supposed to grind down the part of the fin box above the tabs, correct? if so, what do you use to do this. also, why is this ‘excess’ part of the fin box even there. i’m guessing it is a barrier to keep resin from flowing into the box, am i right?
Yes, yes , Disk Sander, yes. There are several different ways guys put there boxes in. You might want to read this thread first:
http://www.swaylocks.com/forum/gforum.cgi?post=108827;search_string=fin%20box%20resin;#108827
thank ya, ok i dont have any cabosil or any of that stuff ive been reading about. i am using epoxy and i have some that dries in 10 minutes (4/1) and i have the surfsource 30 minute (2/1) ive heard about mass heating but don’t really understand what it is. do i use the 4/1 or the 2/1 for setting the box. thanks. daniel
Daniel- I am not familiar with the 4/1. I use Resin Research 2/1 and do my boxes in two pours (1 to set and the 2nd to fill).
If you are concerned about heating, you should install the box using several resin batches: (1) Mix 1/2 oz batch, add tiny cut-up pieces of scrap cloth and let cloth saturate. (2) Spread the epoxy/cloth mix along the bottom and sides of the hole. (3) Set box in and align, let cure fully. (4) Mix another 1/2 oz batch and color with opaque pigment. (5) Pour this around the box perimeter, pushing it in the gap between the box and hole with a hard squeegee. (6) Repeat #4 until flush with the bottom glassing. (7) Use a rotary sander with 60 grit, take the box down to 1/16" higher than the surrounding glass, change to 80 or 100 and get it flush. (8) Mask the box slot with a piece of tape and laminate cloth over it, cut the cloth, hotcoat, and finish like the rest of the board.
Several things you need to know: Level the tail of board so that the epoxy evenly flows. Do not route the slot so deep that there’s clearance under the box as it rests on the tabs; it’s OK to have 1/16" but no more. Always scratch up the sides and bottom of the box with 40-60 grit and wipe with acetone, put in a 8" or bigger fin. Align the box using the fin and a T-bevel tool, don’t rely on eyeballing it unless you have leveled stands and alignment lines on the wall. Once you’re aligned, put tape across the top of the fin rail-to-rail to hold it and re-check the aligment.
Hey glassbreaker,
The reason you want to pour the mixed epoxy in small batches is to reduce the “mass heating” (exotherm) that could potentially get so hot it could melt a hole in your board.
Epoxies consist of a ‘base’ and a ‘curing’ agent. A chemical reaction occurs between the two parts generating heat exotherm and hardening the mixture into an inert, hard ‘plastic’.
More epoxy mass = more exotherm.
~Brian