Planning to do a T-Flex. Thinking about doing a cutlap at the edge of the wood on the deck. Is that enough wrap onto the deck from the bottom for strength? Tape right along the edge of the wood, cut and cover w/ auto pin striping tape, then lam the deck? Cut the lap horizontally or vertically?
What are you guys doing?
If I understand what I’ve read about epoxy cutlaps, once you lam the bottom you wait until the lam is no longer sticky, flip (putting wax paper between rack and board) and cut?
if you take the bottom lam to the veneer you will get an interface like this.
this assumes that you are not doing a skin on the bottom…in this photo there is only veneer on the deck with a 4oz layer on the bottom (epoxy)
I do not use veneer on the entire deck anymore so for those areas that do not join flush with the veneer, I just press the cured epoxy lam in to the EPS foam and force it flush this way.
I then do a freelap on the deck lam and just fair in the bottom flush before hotcoating.
as for how to cutlap…am I the only idiot that’s been hunched down on the floor doing his cutlaps from the bottom instead of flipping!!!
I free lap the glass an inch or two over the edge of the wood/foam transition (that I sand down flush to the CF) to give the glass a nice point to bond to more glass. that joint between the wood, fiberglass and foam is a pretty stressful point. I suppose you could cut lap it. I use 1# foam on my boards, you may be different. I also use 4 lb. s-glass for the outer lam and 6 oz. carbon fiber on the rails. there are lots of variables here.
[edit] sand down to Carbon Fiber, not foam, sorry. I use CF on my rails.
If doing a cutlap, I would suggest to lam the bottom first and then have the edge of the veneer go over the cutlap edge. then grind the raised part down and lam the deck. cover with a pinline. this way the deck glass gets layed over a flush transistion between the wood/bottom glass and all the layers are bonded really well. thats the way i do it anyways......
Just a thought. I would keep the wax paper away from my board until it is hotcoated. I use poly sheeting as a release. Wax can be sanded away but why take the chance of leaving some on your lam.
Why do a cut lap there? Your going to make a very deep lap that you have to deal with and a sharp failure line. Lap onto the wood far enough so that your spreading some of the load. I’m not sure why you’d cut the lap anyway. A free lap will be stronger.
Yeah, now I plan to bring the lap an inch or so onto the wood. I was thinking cut lap to make it look cleaner; my free laps aren’t super clean and I don’t want to knick the wood sanding them. I had no idea that a free lap was stronger than a cut lap.
I like the sound of the advice that Grasshopper gave, but I’m doing Bamboo on both sides and plan to vac both side on in one shot.
Once you get the blank in the bag and the vac on, roll the edges of the wood into the foam with a hard roller, especially on the deck. The vac will hold the wood down and when you pull the blank out you won’t have that ridge at the edge of the wood. Lots easier to laminate then. Also, getting a clean lap with free lap has more to do with cutting the lap clean with the sizzors than anything. Also, after you cut the lap with sizzors, pull the first 3 or 4 strings at the laps apex before you begin to laminate. That way they won’t fall out during the laminating process.
I thought you were doing a colored lam job on the bottom with a skin on the deck. if you are lam'ing clear yeah do free lap onto the boo skin. Epoxy cutlaps are not fun (especially opaques color with multiple layers of cloth)
On this dumpster dive core I hand laminated the 6 oz carbon bottom and rails with a generous freelap over the deck. The fill coat was applied ASAP to the bottom.
Once the epoxy cured the board was flipped and the freelap ground smooth.
The prefabbed 9 0z carbon/bamboo veneer skin was trimmed to fit with scissors, painted with epoxy on the backside and vacuumed to a freshly epoxy coated deck ala Timberflex routine. The deck skin overlaps the carbon freelap so no cut line vulnerability there.
I had a bit of a step along the bamboo edge (can't really roll it down when it overlaps carbon) but some pigmented epoxy bog was smeared along the step which was masked off like a wide pinline. The rails were scuffed and the deck hand laminated with fiberglass cloth - 'zippered' at the bottom edge. Fill coated as per bottom.
Polyester gloss top and bottom is holding fine.... So far so good.
The deck (9oz carbon/bamboo veneer/4 oz fiberglass) can not be pressure dented with my thumb no matter how hard I press. The bottom (6 oz carbon) isn't quite as strong... but still stronger than a conventional glass job.
Greg Loehr said bamboo veneer is stronger than a 6 oz fiberglass layer. Sounds about right to me.
Thanks to all you guys for the advice. Its important for me to have this stuff down intellectually before I start working on it. Freelap it is.
John - I was wondering if you fill coated the bottom while its still gelling before lamming the deck, so thanks for that tidbit too. I’ve been lamming the bottom, letting it cure, grind laps, lam deck, cheater coat w/ squeegie. I’m going to do the bottom while its kicking on this one.
Also, John, what kind of board is that? Knee, stand up? Looks really cool.
I have had problems with cold temperatures so I fill coat ASAP... as soon as I can get a tape apron to stick, I fill coat. When doing overlaps, the lap areas need to be scuffed to make sure the second layer sticks.
This method ('lam-fill-no flip' as recommended by Leslie Anderson and Ben Sparks - in archives) has solved some issues I had with layers bonding after cold weather blush went undetected.
I hand sanded the backside of the deck skin before bonding to deck. Both the skin and the blank were painted with fresh epoxy before vacuum bagging.
Zippered = just let the lap hang... didn't tuck it. Once green-state cured, 'zip' it with a razor blade along the bottom edge. I find any amount of frothing when tucking the laps shows up big time over carbon.
Let's just say there are bonding issues and then there are your bonding issues. Nice save on those boards!
EDIT: Jeff, I'm sorry. I didn't see the recent update on your flex projects when I typed that. I wasn't trying to be a wise-ass. That really sucks. They looked like nice boards otherwise.
As far as saves, you have to check the updated “two newbuilds” thread. I don’t know if I can save them. I did a few tests last night.
So you say with colder weather you have bonding issues? I never had to scuff lams prior to hotcoating, but then again I used to make boards only in the summer. I did my tests last night with no heat on, but inside our condo. We’ll see. But you’re saying that you need to scuff between steps after curing? So If I wait 24 hours to do the next lam or hot coat I should scuff? I wonder if this is beginner stuff that I just skirted around with beginner’s luck for so many boards?
Finally, that board is so cool. Have you been surfing it? Prone? Not this week I assume. It must be just giant up there right now.
So you say with colder weather you have bonding issues? Yes. It seems like cold weather and delays between coats are two primary culprits behind bonding problems.
But you're saying that you need to scuff between steps after curing? Not a bad idea. I know Ray Meeks has no problems with his process but that's in San Diego where it tends to stay warmer. Even with a hot box I don't like to wait very long between coats. If I can slam a fill coat on an early green state lam and put it in the box I have fewer problems.
So If I wait 24 hours to do the next lam or hot coat I should scuff? I would. It is a method recommended to me by Leslie Anderson at Fatty Fiberglass in FT Bragg. She has lots of epoxy experience and along with Ben Sparks, sticks to the 'Lam-Fill-No flip' thing. Since I started doing it that way, my epoxy glass jobs have improved.
I wonder if this is beginner stuff that I just skirted around with beginner's luck for so many boards? My first epoxy glass job over a Clark polyurethane blank was so fool proof I thought I had it wired... HA HA - my problems were just beginning.
Have you been surfing it? Prone? Yes. On my belly. Some of you younger guys could ride it standing up but the fin placement weird for that. Then again, guys are riding mini-Simmons and Alaias on which I would certainly flounder if I tried to stand up.
I remember your boards at Big Sur and they were so nice. I can appreciate your frustration with things going down hill.
we were always taught with epoxy to hotcoat/fillcoat/cheatercoat what ever the term is these days as soon as the lam coat has gelled enough to keep the cloth in place.
I think Greg Loehr was the one who brought this up in 2004 or so. The hotcoat/fillcoat is to protect the weave while sanding nothing more from what I understand.
I think Greg suggested using a sqeegee to firmly press in the fill coat to the weave to prevent pin holing prior to painting it smooth with the brush.
With PU you just sort of thickly slosh it around and let it settle but I think you need to apply a little more pressure with epoxy. I think I've even read of some that lightly sprinkle on some cabosil/micro balloon filler on the lam before hot coating to fill in a real dry weave.
They say that glassers eventually make the board
but I think it comes down to the hotcoat/sander guy that gets the final smooth look of the product down before the gloss. guys that can do it all are hard to find these days.
Some have gotten so good at their job that the gloss process could be eliminated altogethor saving weight with the sanded/polish finish. GG had a couple of glassers who's sanded/polish finish was comparable to a standard gloss/polish finish.
The problem with some epoxies is the aluzine component rising to the surface after curing which according to most has to be washed and scrubbed off with soap and water prior to laying on another layer of aluzine epoxy like FGH's. I don;t know if Greg's RR has the same problem, most like not from what I've seen. I don't know of a comparable problem with PU resin.
The coolest solution I've seen is the BammBamm and Matt's ResinX technique of hotcoating with a serated edged squeegee and a tad bit of xylene as a thinner. You brush or as they say "baste" the rails first and then do the rest with a squeegee .The ResinX seals the lam with such a thick and glossy finish it breaks my heart to sand it down. Plus you need expensive norton champagne paper to said it to reduce the loading. And bets of all you can handle it lightly in 15-30 minutes with no tackiness to move it to your post cure station.
Ben was the guy who clued us in on glassing the top and bottom of the deck and bottom lams at the same time before you slap on the rails and just glassing those on with some tape when you're done shaping them. I think this is what we believe Bert was doing when everyone saw his various glass tape rolls on his racks in one of his "guess what I'm doing" thread. Always the cryptic master of strategically placed bread crumbs that one.
Jeff
you ever try Paul's technique of painting the wood first with a light coat of epoxy with a 3" roller and the laying the dry cloth over that to soak through? I think some of the compsands guy did it this way to seal the wood pores while glassing to prevent blow thrus and pin holes. Most gave up on pre-sealing their balsa with acetone-xylene/thinned penetrating epoxy to save the weight.
