I just finished my 5’7" fish for use with kite, which was going well until I applied the 0.6mm veneer. Woods were steamed beech and mahogany.
The core is very light EPS from a builders merchant. I glassed the deck and base with bi-axial cloth and epoxy. After sanding, I applied a coat of RR epoxy to the backside of the veneer, and left it to 'kick. I then applied another coat of epoxy to both the deck and the veneer using a foam roller. After positioning the veneer, I vacuum bagged the assembly. The veneer, especially the Beech ‘rippled’ and did not stick to the deck in places.
I suspect that my vacuum bag was not heavy enough gauge plastic and did not pull down enough, but has anyone got any other ideas of what may have gone wrong?
The gauge of the plastic is irrelevant, as long as the bag doesn’t leak excessively.
More likely is you might have had problems with having even vacuum across the whole piece.
Did you use a breather material across the whole board inside the bag, so that the vacuum distribution is even?
A very thin film of epoxy sometimes doesn’t bond properly, epoxy likes a thick glue line. A solution is to use greater vac pressure to ensure the parts are squashed together enough for the thin film to take, but this runs the risk of crushing the foam.
Better is to adhere the skins using the wetted-out inner glass, this automatically gives you a nice thick glue line.
I put a sealer coat on the wood first, wait for it to kick, then wet out the inner glass on that. Flip onto the board, poistion, and suck down.
Pre-glassed skins can be all sorts of trouble, especially if you leave them to cure without some sort of pressure to keep them flat. They will curl up, or the wood grain will exert itself throught the cloth and can cure wilth ripples. All these things cause issues whwn trying to vac the skin down to a soft surface like EPS.
I did use a breather the same size as the board, but I suspect that the bag stretched and maybe got some small punctures. I now have a much heavier gauge bag.
One question - do you put the suction port(s) the same side as the veneer with the breather underneath? This is what I did, but the problem with this was I couldn’t see the problems as they were under the breather.
I have 6’ semi-gun almost ready to glass, this time I intend to glass the deck and then just as resin begins to kick, apply another coat of epoxy to deck and backside of veneer, then into the bag.
I took the Fish out this morning with kite. No waves, but so far the board exceeded my expectations. Very fast, quick turning, easy to control and screams upwind. Just need the swell now to try without the kite.
Hey Gary, the board looks very nice. You’d never know you had any problems.
Why all the extra steps???
Just take the veneer, put the cloth on it, wet it out, roll alittle epoxy onto the blank, flip the skin on the blank and bag.
My suspicion is that by doing the sealer coat and letting it kick you just curled the wood and locked the curls in with the epoxy. If you would have done the above you wouldn’t have had (as much) a problem.
Even Kit, while I don’t want to question your methods as I know you’ve done a lot more work than I have, why seal coat the veneer? It’s only 1/42". Wouldn’t just wetting out the cloth on the veneer and putting it in the bag seal it just as nice?
Yeah extra sealing may not be necessary with veneer, or might cause probs like you mention… I haven’t made boards with the thin veneers, all mine are 1/16" or greater, I probably should have added that caveat!
I learned the hard way that sealing the inside of the skins is of paramount importance - and also that simply wetting out the cloth on the skin doesn’t always give you a perfect seal… I had a couple of boards that the skins got wet from the inside when dinged.
So it may be overkill, but it’s the sure-fire way i’ve found of solving sealing issues.
Whatever works of course
I guess different cloth weaves may provide a different seal, and how much resin you use when wetting out the cloth, whether you seal the EPS before vaccing the skins on… etc etc. Lots of variables that I found easiest to control by just adding a quick sealer coat. 25g of resin per skin for a shortboard, microwaved to make it real hot, and it tacks up in 10 mins and away you go.
It doesn’t really matter which side you put the breather on, other that obstructing visibility as you say.
I put mine on top, as I press my boards against a rocker table, so I wouldn’t want the cloth accidentally bunching under the board against the table.
As long as the breather laps onto the vac port, and covers the board mostly, then you should be fine. Bag leaks are always a battle.
How did you run your pump, continuously with a bleed valve, or do you have a vac pressure switch so the pump cycles on and off?
One way to ensure that the bag has adeqaute pressure is to have your vac gauge at the opposite end of the bag from your suction line. I don’t bother, but this is a way of diagnosing pressure differences.
Good to hear that your board is working well anyway!
1/42" thin woodworkers veneer over 1lb EPS or lighter is not a good idea.
did alot of those in my early days of experimenting and had your same problem over and over again.
you need 1/16"-1/8" skins over 1lb or less otherwise it doesn’t work out so well unless you seal the foam to create a solid base for the veneer to adhere to.
Thin veneer requires a substrate. supersoft EPS would not be considered a proper base. UNless you did multiple layers or used some layer of glass underneath.
Jarrod(Shwuz) is the only one that had some success with thin veneer over 1lb EPS with his makore skinned Lis fish.
Interesting and timely thread. Sounds like the cheater coat on the veneer is the culprit. I'm about to bag some 1/42" veneer onto some 1lb eps and was considering not sealing the eps as though it were being glassed, but rolling a cheater coat of epoxy onto the bare eps deck, letting it set, sand, then bag the skin. Seems to me like the cheater coat would penetrate the eps a bit before it gelled, creating a stiffer deck and bagging substrate for the skin. Any thoughts or experience regarding this method?
For the fish, I did not put the veneer directly onto the EPS. As I wanted a tough board for kiting, I first glassed with 6oz cloth on top of bi-axial footbeds, sanded, then put on the veneer. For the next board I am considering glassing with 4oz under the veneer, but bagging before the 4oz cloth/epoxy has kicked.
Ha! Know what you mean, (made the pads also btw). I agree they do spoil the looks, but I made the board for kiting, and my poor old feet and legs cann’t take the pounding witout pads.
Gary: Do you like you strap placement? I have made a lot of tow boards and we normal set the strap in a Goofy of Regular Position. Or inserts to go either way..Plus I also noticed that you put your straps dead center?
I ride with the straps very loose so that I can move my feet around, or with no straps at all if conditions are right. Also the straps have some degree of angular adjustment. I must agree that more options for strap position would be nice, but I make all of my own stainless inserts, and the job is tedious!
i was told by a fellow shaper to cut you veneer. cut the glass for the outline. layout epoxy on board. layout glass+veneer. tape up so nothing moves. throw into bag and let it set.
waiting to get into kiteboarding when funds permit
Gary, I am not expert at all, but know that with some woods the veneer will warp up from moisture, paint, resin, wood softener, anything. To possibly solve your mystery: If you have any scraps, wet them out with water, and see if you get similar ripples. I also think that she is a beauty! Sickdog
I do know that the veneer, especially the Beech warps with even the slightest hint of moisture. I used veneer tape which is ‘lick and stick’ to join the wood and inlays on the backside. even this caused rippling.
I do like the idea of applying the glass, epoxy and veneer all in one go, but after the last experience, I am still trying to decide the best method for the next one. The Beech and Walnut veneer is cut and the EPS blank is ready.The base is glassed, deck is microballooned so I am good to go.
Options I have considered:
Vacuum bag assembly without epoxy and use veneer softner to pre-shape veneer.
Out of bag, glass deck, epoxy coat back of veneer then immediately apply veneer and bag.
Concerns - veneer softner may make things worse and not dry when inside the bag.
pre-formed veneer may be difficult to handle, it’s delicate enough when flat.
Apply deck patches and glass deck.
Epoxy back of veneer then assemble when all wet and vacuum bag.
Concerns: veneer may not conform to shape of deck as beech is hard.
Glass deck patches and glass deck.
Epoxy back of veneer, place on wet deck and spray veneer with veneer softner, then bag.
Concerns: veneer softner may affect epoxy bond.
Whatever, I plan to do the job tomorrow, so any comments would be appreciated.
i can see where some of the specifics of your particular layup could cause problems if you follow the most common recipe offered here and in the WMD thread
.....................
lay glass on veneer
wet out glass and veneer
tape assembly on board
place everything in bag
suck it down, adjust and
roller smooth.
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many of the twists you propose make sense;
(veneer softener, cheater coat, etc).
but i dont uderstand why you want to pick one wtihout having a better feel for the consequenses.
I would suggest you make 3 of 4 small samples of your favorite lay-up recipies.
small 6x6 or 12x12 samples could all fit in one bag or a bunch of 1 gallon 'zip-lock' freezer bags.
let all the potential catastophies happen before you invest a lot of time and money on the good stuff.
