Sanding Fin and Leash Plugs

Ok, so I've done a few boads now, shaped and glassed and most things seem to be coming along nicely!!!

One issue I seem to have repeatedly is sanding down fin and leash plugs.

In some instances I sand too much exposing (not completely) cloth, or the fin plugs ending up not completely flat. I've tended to use the edge of a 7" hard sanding pad with 60 or 80 grit paper on a variable speed sander to take down the plugs. This seems to be the quickest and easiest way to tackle it (angleing the pad slightly so the edge of the pad is doing the work)...however I am a little disappointed in the final result.

I am about to sand a board (next couple of days), fin and leash plugs on my first 'sold' board (to a buddy at work!) and I would like to get an idea if there are some tips I could consider to assist witth a better finish...not that my current finish is that bad, would just like to get an idea of how you guys tackle this step!!!

Let me know!!

Cheers M

OK first get some magnifying glasses, and use a smaller less powerful tool.  Don’t go down on the grit (hard disc) too far 50 or 60, work well, and don’t build up too much heat by friction. 

even a hard power pad is too soft to take down plugs unless you are really good. it will do as you say - leave the plugs proud but sand into the weave.  use a 36 or 50 grit hard disk and like ghetto said, dont take off everything with that. (be careful and go slow - you can do a lot of damage quickly with this if you dont hold it at right angle with right amount of pressure)  then hit it the general area with 100 grit on a hard pad, still leaving a little material to be taken away by a progression of finer grits. and let the general sanding finish it out.  dont keep going at a trouble spot - work the whole area so it will blend in.  these are trouble areas - look at most sanded finish boards and there will be some weave showing if you look closely enough. there are some prep tricks to get a flat weave free finish that involve grinding/basting before the final sand coat. 

I baste the laps and other trouble spots like leash cup location with sanding resin prior to hotcoat to help prevent sand thru. I also tape the area surrounding the leash cup when I “grind” it flush.   I’ve learned the hard way several times.

Get a smaller grinder and a nice hard disc that is flat. Paste trouble areas, and tape around plugs, if you have to.  Practice, Pro’s trigger there machines, and understand and adjust to the intial torque that pulls the disc down on edge. Trigger, then release and slowly burnish the area away.  When the machine gets really spinning the friction softens the material so it goes away quicker, and when you understand this you can use it to speed things up.  But for now try not to heat up the area, Keep the RPM’s low, and proceed slowly.

You can do the whole thing by hand with 60 grit paper and a wood sanding block. I use a small angle grinder. Runs off of compressed air. You can set up your electric hand drill to grind fin systems and leash plugs. I f'ked up alot of stuff with the big power sander. You can do a lot of good stuff with a Dremel tool too....... the end of the've got to work smarter not harder




...And....think about GhettoRat's posts a few times....

sanding makes heat. Too much heat can cause big problems...Big me.....dull sanding discs create more heat than sharp discs.

That angle grinder is an invaluable ally.  You can do a whole lot of neat things with it. 

backyarder warning.

to bring plugs & boxes flush, I use 50 grit on a 4.5" grinder then well worn 100 grit on milwaukee w/med 6" power pad

4 minutes plug install, the popping noise at the begining is rain hitting the roof of my shed

not shown: I scruffed up the plug with 60 grit before dropping it in the hole



I set my leash plugs deeply to minimize grinding. I don’t have an angle grinder, so I use a DeWalt orbital with 40 grit to take down the bulk of the material, then finish it off by hand with a small hard block and 60 or 80 grit till I get down to the surface of the hotcoat. Then sand as normal.

For the my last couple boards, I’ve been using my version of this to cut down boxes and leash plugs:

I have to thank Greenlight for the idea, but since money is always something that there should be more of I just made one out of 3/4 ply and glued some sandpaper to the bottom to prevent slipping. You just make sure your router is set properly, just a tiny fraction above the bottom of the jig, and you can pretty much get the box/plug flush with the surface of the board, then sand as you normally would.


I’ve used that jig too… works well to grind down the top of the Probox boxes, which it was designed to do. I have a separate router bit I use just for that purpose in order to keep my hole routing bits sharper longer. Also… make sure your router does not slip. You can very quickly damage a box if your router depth changes as you’re working. So… lock in your depth adjustment tightly, go slow using a dedicated bit, and you can be done in minutes.