Manual installation of Bahne boxes

Hi Guys,

I am installing Bahne boxes without a router and not sure if i am on the correct track. heres what I am doing:

  1.  I mark the place where the boxes will go
  2. Using a cutter, I cut the class and prying it out,
  3. Using a long nose plier, i grab the wood and twist it so that it will pry out.

I am only using regular 3-ply plywood for the stringer and chiseling it out is very hard for me. 

Also, after glassing, we drew in the paint job, i didn’t have a chance to hot coat it anymore. this board was done with epoxy and the paint is an acrylic-epoxy type. Can i do a gloss coat on this directly using polyester resin?

Any advice for me?

Thanks!


WHATEVER YOU DO DO NOT EVER EVER EVER USE POLYESTER ON AN EPOXY BOARD

I’ve installed a single fin box like that before. Although I cleaned up the area so it was much cleaner looking, picked out the loose chunks and sanded everything nice and flat. The box is fine, surfed the board five times or so since. It went in with some 6oz glass too. 

Not sure about poly gloss over epoxy. Obviously, don’t put it anywhere it will touch eps foam. 

I posted a detailed step-by-step explanation quite a few years back but I’ll be damned if I can find it now… currently funky ‘search’ function lists everything by “Anonymous.”  Also… why are some many posts being repeated right now? 

Anyways - measure your box and get the dimensions centered where you want your box.  Maybe just take the box and mark around it.  This would be a good time to check the depth of the box and the thickness of your tail. Take a little drill bit and drill a hole in each corner.  Get yourself one of those nifty stainless steel rulers and position it so it is right on those corners you drilled.  Tape the ruler down so it is on the outside of the box outline.  This way, if your blade strays off course you won’t be slicing in to the bottom of your board outside the line.  TAPE THE RULER DOWN SECURELY.  With a box cutter, sharp knife, or even single edged razor blade make multiple light cuts - starting at each corner and cutting towards the center.  Don’t try to cut all the way from corner to corner or you’ll likely cut past one of the corner holes and fuck things up.  

OK - got one side cut through the glass? (It may take a lot of light cuts)  Move the ruler to the other side and do the same thing.  Remember… tape down the ruler on the outside of the box area, cut from each corner towards the middle of the line, then from the opposite corner to the middle.  Now do the cross cuts at the ends.  Be careful as you don’t have a lot of distance and those knives can go fast.  Once you’ve done all sides, dig the blade under a corner of the glass and peel up the rectangular piece you’ve cut.  

Now you’re looking at a nice clean rectangular section of the board with no glass, right?  Time to get out a sharp wood chisel and start chiseling out foam and stringer.  Try to punch directly down at the ends and then carve towards the ends from the middle.  just take it slow and cut a little at a time.  Keep punching out the ends where the stringer needs to be removed.  KEEP AN EYE ON YOUR THICKNESS AS YOU GO.

You don’t want to go through your deck glass, OK?

Once you’ve chiseled out a relatively even depth, test fit your box.  If all is well, mask off the outside of your hole, LEVEL THE TAIL of your board,  remove any bridges across the top of the box, insert your favorite fin, mask everything off - the top of the box and the fin.  Install that sucker with some medium catalyzed resin and a layer or two of glass inside the hole.  Use the fin to make sure the box is vertically aligned - tape it from tip to rail on both sides to keep it vertical.  Check it from the nose and the tail.

Once that resin kicks off, get out your grinder and remove all excess gunk. Scuff a football shaped area around the box and ‘Cap’ the box with a layer of glass that extends around the box.  I’ve heard that you can get by without masking the top of the box slot but I do anyway.  Once the cap is cured, feather it out.

Finish the board as usual.  Believe me this works - I’ve done lots of boards this way before I got a router.  The sharp corners of my box installations were practically my trademark.

And yes - make sure you know what kind of foam it is.  Like the guy above said, epoxy is OK for urethane and EPS foams but polyester is only for urethane foam.

 

Be careful using the knife/razor to cut the glass.  As John said they can go fast.  Keep both hands on the tool and lessen the chances of cutting yourself.  At the very least keep one hand on the tool and the other in front of the blade.

“Be careful using the knife/razor to cut the glass”

Agreed but I’d have to say that taking a router to the bottom of a new board always give me high anxiety.  A sharp blade and light cuts minimizes risk of slips.

That’s interesting… maybe you can define “epoxy board?”  I’ve applied polyester gloss resin over rough sanded epoxy fill coats without any trouble at all.  

I’ve also used epoxy resin on urethane blanks.  I was once told by a widely respected surf shop owner that it can’t be done… “epoxy resin can only be used on EPS foam” or some such rubbish.  Polyester should work OK for ding repairs on a urethane cored board (even when foam is exposed) if properly prepped. 

I hear the term “epoxy board” quite often but I don’t think it goes far enough in describing a board.  I want to know what kind of foam is inside as well… at a minimum.

I cannot remember when or where.  But I read PE resin does not work well over cured Epoxy but epoxy over cured PE works better.  I think it was on a boat builder/repair forum.  I have no idea about the validity of this because I have never tried it.

That is not a “Bahne Box”…

For your install do what JohnMellor says. In California it matters. The fin box posted by Cha10822402 is not a Bahne Box. I’m not sure who owns what… or where the true story comes from…IF you live in California and you ask for a Bahne Box you will not get what Cha.posted…No… You will get a top quality fin box. And if you look inside the box you will see these words…Fins Unlimited TM  10.5 Channel  Encinitas, Ca  USA…

That box looks like the ones I’ve seen on Asian popouts. Can’t see why anyone wouldn’t use a router for boxes. Not exactly a heavy duty task and a small trim router would suffice. Harbor Freight sells one for 30 bucks. Worth the investment, IMO

http://www.harborfreight.com/power-tools/routers/14-in-24-amp-trim-router-61626.html

 

[quote=“$1”]
 Can’t see why anyone wouldn’t use a router for boxes. Not exactly a heavy duty task and a small trim router would suffice.

        Yep.