Hi all, hoping I could get some ideas from you guys. I have glassed shaped blanks before but never anything on wood. This is not strictly surf-related per se, but the materials involved are all the same so I figured this would be the best place to ask. For a work project, I will be laminating ADX ply (1/2", no knots) to achieve a nice smooth finish on it. I intend to place logo laminates underneath the glass (just like a surfboard logo, same paper). This will be done using Composite Resource Clear Surfboard Epoxy resin and a single layer of 4 oz glass (no structural strength needed). Here are my questions:
do I need to seal the wood prior to lamination or just sand? If sanding, rough or fine to ensure proper bonding?
should I place the logo lam under the single layer of 4oz glass or add it as a patch on top before hot coating? Similarly, since I don’t necessarily need the fiberglass, what would happen if I just used resin and no fiberglass? Would the lam stay in place?
Thanks for any insight here - I plan to glass some wooden keels soon as well.
Grain filler is needed to prevent air bubbles coming out of the wood…you can use a standard compatible grain filler for the resin…or a thinned cheater coat (squeeged on)…shellac is also a very good grain filler and works with any resin…powder sand with fine grit when its completely dry.
I have built a lot of resin tables with logos over wood. Here is what I did
1)Wiped wood with denatured alchohol.
2)Put a thin epoxy seal coat on. I am looking to get it primed before glassing. There should be an even sheen. If you see dull dry spots the wood needs more priming.Let it dry overnite
Cut out glass cloth and lay out on the wood. Roll back one side of the glass and get your logos ready. Mix the epoxy resin.
Put some resin under the logo and squeegee it down. Roll out the glass and wet out the table.use the squeegee to get out air.(just like glassing a board)
After it drys put a thick finish coat on with a brush. Pour it on and smooth it out. (just like hotcoating a board) Also the wood needs to be level so the resin flows evenly.
This is the last step…after the resin has leveled out and flowed even take a hot air gun and make passes over the resin. This make the resin flow better and pulls the bubbles out.(I have also used a propane torch to do the same thing but don’t recommend it for beginners) Only do this on epoxy
I’ve glassed a good amount of wood with both epoxy on my own projects, and PE and VE resins when working in a toxic hell of a boat yard, and personally would not laminate onto dry wood. Since the plywood is your structure, the 4 oz cloth is more to insure an even thickness of epoxy for waterproofing.
To increase waterproofing, I think that pushing epoxy deeper into the wood via a cheater coat grain not only re enforces the wood, but also increases the water resistance of the wood should the fiberglass shell be compromised.
In projects where the cloth is structural, I think epoxy pushed deeper into the wood allows a better bond between wood and fiberglass.
I have not tried thinning epoxy with DNA, but I do believe the cheater coat should be with thin a resin as possible. Warmed epoxy applied on a warm structure then placed in the shade or a cooler area if possible so it does not blow bubbles, or at least minimizes the likelyhood of them happening.
I have seen areas of super porous wood pull epoxy from the cloth right as I am finishing up, even on a cheater coated board. After that I started cheater coating with a heavily saturated sponge and just kept spreading/ pushing more epoxy in to the dry areas until the epoxy got too thick to work. Some areas of the wood are just thirsty thirsty in my experience.
I do mind scratches in my wood projects, and don’t believe mechanical tooth is a requirement when glassing onto wood. I scrape my wood with a razor blade so I don’t push dust into the pores.
I have also skipped the fiberglass on a hull or 2, just painting on epoxy as an experiment. I will not do this again as it is too difficult to get an even thickness coat without it. The epoxy filled in the concaves and thinned out on the rails and high spots. In my experience, It was just an experiment in shooting one’s own foot in a futile attempt to save weight and material cost.
I have glassed a few wood boards, but not with that particular product.
Glassing wood works fine with or without cheater or seal coat. When applying a seal coat, I generally thin it a little with denatured alcohol, and apply it thin, using a foam roller.
I don't think the grit of the sandpaper used significantly impacts the seal of fiberglass to wood, so sand to whatever finish you desire. I tend to stick with coarser grits because if you work the surface too much with a fine grit, you can start to add subtle irregularities, due to the variation in grain density. And I don't care about a few sandpaper scratches.
I would put the logo under glass, but make sure to get resin behind the logo first. But that's just me. Some people take the other route as described (over glass, under hot coat).
I have finished wood without fiberglass, but when I added a lam (fabric) I put glass over that area.
Thanks huck - that answered a lot of my questions! By putting resin behind the lam, do you mean applying a quick cheater coat directly under the logo area, placing it quickly, and then laying out the fiberglass? Thanks!
What Roger (cleanlines) said is good advice, but doesn’t sum it up if you’re glassing a hollow wood surfboard (hws), as he is describing glassing a table. The air inside a hollow wood surfboard will expand with even a little rise in temperature. As long as it has an escape route, no problem. But if you glassed one side already, when you glass the other side, the air will be trapped. If there is even a small temp increase, bubbles will appear. The air is gonna get out one way or the other. So when glassing a hollow wood surfboard, you should make sure the board is vented, unless you’re glassing in dropping temps, then the air will contract and actually suck the resin into the wood.
McDing, yes. I will follow cleanlines process on the board I have ready soon. It’s not a hws( thanks for explaining).
It sure seemed like air coming up, the glass wasn’t dry, that’s for sure. I was dabbing and babysitting until it gelled., still got these bubbles.
Wood is only 1,5 mm thick, vacuum bagged down onto foam with 6 Oz glass and epoxy under it, let it cure. I then coated wood first with epoxy, but only let it soak in 10 min before putting on glass. So I thought there would only be minimal absorption, and never thought air would escape.
The wood is Abachi, quite absorbant. Heavier than balsa, but pretty light. My shop has stable temperature, it’s insulated and heated by air to air heatpump. Temps don’t vary more than 1c and over several hours. Humidity is low.
My plan now is to carefully grind out each bubble with a dremel tool and patch with glass and epoxy. Then sand it smooth, get it ready for" hotcoat ", if you can call it that with epoxy…
Even if its not a HWS, the bubbles show air, so I’d make it a point to glass in falling temps next one. Easy to do in a shop like yours, just heat it up a bit warmer prior to glassing, then glass as it cools back down.
