Sanding Freelap between bottom and top deck

What I didn’t show you you. Small fiberglass patches to nose and tails placed on and sanded to make for a perfectly sealed board when top lamination is glassed on. No chance of any gap at nose or tail when sanding the deck lap.

I would pound or sand the cork below deck level and grind up some wood you are using for board build and make a epoxy wood slurry to fill in recessed hole over cork.

You are doing a commendable job on your hollow board build. I personally don’t think I could get it to the glassing stage. Can’t wait to see the finished product. Only mean any of my suggestions as constructive criticism, on a very technical build. in my opinion that I could not personally pull off.

First up thanks for all the constructive comments.

BB30 - when you say I need to sand further, is this for aesthetic or strength purposes? The photo has particularly badly picked up the sanded resin on the board, it feels smooth to the touch. Are you sanding the entire rail and bottom area to key the surface for the deck lamination to grip to?

The board is never going to look like the one you have posted in your picture, my initial starting construction method was flawed and has resulted in a lot of error built in to the shape of the board. I’d never construct a board using this method again, I didn’t really have an understanding of working with wood when I begun this and thought I’d be able to do certain things in shaping which were not realistic. This is fine, it’s been a learning curve and for the next one I’d use a much different method, all I’m saying is that I’m never going to get a nice smooth rail edge like yours because of the way the various types of wood meet near the rail!

I have cheater coated the whole board before I did the lower lamination so I was concerned about excessively sanding and going into the wood when I was sanding the freelap. Is this something to be concerned about?

I see depth, in this, If you throw your deck lam over this you may or may not get complete adhesion to the wood at Botton of pit. The whole point was with a wood free lap, fiberglass can be totally feathered to the wood, Adding a mare resin could fix it but you double your sanding in those areas. Everything can be fixed, but having tight and booger free laps makes less work to fix. Shiny means not hit by the sand paper BTW

OK - deck knot hole repairs complete, thanks for the tip Huck. I’m not too displeased with how they have come out in the end!

I want to do a second cheater coat on the top deck as I’ve sanded it so much and since putting the cork repairs in I think they could do with a cheater coat to stop them drinking in the resin when I glass over them. Is this a wise plan? Should I just cheater coat over the small patches with the cork or what? I just feel like it’s probably a pretty absorbent wood to glass.

for your consideration, The seams in your wood planks could be problematic with that wide of a gap present. When glassing they will possible be a source for air pockets. I fill seam gaps with resin and milled fiberglass to tooth paste thickness and squeegee in, let dry and sand off. Taping off on each side of gap, applying resin/milled fiber filler, remove tape and let dry will make everything neat and very little sanding to get flush to deck. the knot repairs look nice.

You’re welcome for the tip only that really wasn’t my tip, I fill holes like that with wood, I just taper the edges so that like a cork it gets tighter as you push it in. Before glassing I seal with multiple sealer coats of resin (to me a cheater coat is something completely different) over the whole board, block sanding between each coat, until there are no gaps, and no bumps or high spots. That’s just me you can do it however you want.

Here’s a tip for holes in wood. Take a scrap piece of the same type wood and take a sander to it to make very fine wood dust. Scrape up the dust and put in a small cup and add resin/hardener and mix. Better to add more dust to resin ratio to make a paste. If wood skin hasn’t been put on yet, tape under side to keep resin mix from going through and keep wood skin flat on table. Fill hole and let cure then sand flush so only the hole has resin in it. Same goes for skin already on foam too. If hollow board and wood is already on then paste will need to be thick. This makes the filled hole the same color as wood or even a touch darker but a better finish. Attached pics is an example. The dark knot is walnut wood dust and epoxy.


Works great on small holes. The size of the holes post #21 is doable with a hallow build. What do you would use for the wide gaps in the planks bluefinsurf. I am thinking your pictured board is a foam core. Very nice shape and final product!!!@!

Yes it’s a foam core. Largest hole filled on it was about 3/8". As for a hollow board with holes, I’d probably still do the same steps prior to put skin on frame depending on size. If they were large holes like the ones in this post, I’d probably laminate a piece of glass on under side then fill. Or glue a piece of same wood in it. Me personally, I like the resin idea, but when you are getting close to the half inch size you may run into integrety issues. With the wood plug way, you will need to clear out the rest of the knot since its darker to allow the new wood plug to match. Otherwise it’ll show worse. The object is to get your plug the same size and shape. Best luck is to drill hole out with drill bit and then match the hole size with a hole saw bit that has an inner diameter as the hole. As for gaps between your planks BB30, on my boards which are foam core I tape them together really tight then glass a layer under the wood between wood and foam and vacuum bag it. I dont do hollow boards but I’ve seen the planks glued together first then applied to frame and even a layer of glass done like I do between foam and skin only cured before applying to frame.

How about full length seam gaps?

For that seam in pic since its already on frame, dust paste would work. Going to take a bit of paste and will show but better to fill than to have your resin keep pouring through. Another option is glue and dust. Unless he wants to cut 1/8" strips out along those seams and fill with new wood which it would take a good amount of time. A lot of wood board issues pertain to regular woodwork issues. Researching ways to fill holes and cracks on web provides a lot of good info.

Just for clarity there was no gap here, the wood was tight together and sealed but edges butted together were chamfered, giving a lengthwise groove in the board.

I filled it with resin and sanded flush, there was nowhere for it to drip through.

My impression was this was your first glass job. My first glass job was in 1985. The whole point of my constructive consideration for you is that gaps, divots, or essentially anything not faired smoothly has the potential for trapping air whilst hand glassing your board. The picture I posted and only had reference to has a potential area for an air pocket with glassing. I don’t understand the wood working terms you use but understand the intent. I hope you understand the purpose for not having divots under a hand glass job. Can’t wait to see the result. Stoked for you!!

I get that and I’m hugely appreciative of the constructive comments, I replied about the seams because someone mentioned resin pouring through the gap and it occurred to me that from the pictures it may have looked like there was an actual gap between the planks that resin would pour through into the hollow part of the board.

I understand what you are saying about not having divots/grooves or other places where air pockets could form under the laminate, to this end I used a plastic syringe (I work in a lab) to lay a bead of resin down the groove between the planks and sanded flush, I’m sure it’s not the best way I could have done it (could have thickened up the resin with some chopped up glass roving) but I am not displeased with how it’s come out.

I am also stoked, it’s a far from perfect project but I’m looking forward to getting it wet!

After filling the seam gaps I did another sealer coat with epoxy thinned with a little methylated spirits, and then glassed over the top. Quite pleased with how it went, the cedar deck looks good under the resin, my freelaps were better this time but still not the neatest so it will require some sanding again before the hot coat.

I was tempted to only do the hot/fill coat and not bother with a gloss coat, does anyone have any experience with this? I think in terms of strength my construction should be fairly solid already and I don’t mind leaving it matte rather than polishing to a gloss finish.

If I just do the one hot/fill coat I guess I should install the FCS plugs directly after the laminate coat and leash plug after the hot/fill coat?

When it comes to venting, is there a good reason why I shouldn’t I stall a car type inner tube valve into the board? It’d be tool less to equalise pressure and can have the valve core removed leaving a hole for long car journeys or storage.

Thanks again for all help or constructive criticism. 

The finish is your own choice, no right or wrong anwer, gloss or matte.  Myself, I would want a vent that activates with pressure, vs one that has to be manually activated.