OK, now I’ve searched and searched the forum and found bits and pieces but nothing specific to my potential challenge.
I’ve mad a one off, EPS core/wood lam short board and I don’t want to mess up on the clarity of the finish.
Here is the breakdown.
1)EPS Core
2)sealed and hand laminated with one layer of 4oz/ both sides/ epoxy.
3)Vacuum glued 3mm paper backed veneer on deck and bottom.
readied the rails for carbon Fiber.
In order to Keep the board lite and tight I want to vacuum bag the laminate.
Here is the challenge. I have done 3 test pieces using scraps and each one has varying degrees of tiny air spots in the cloth that do not go away with a sanding coat of epoxy.
the first test was horrible. I used nylon peal ply and straight up bubble wrap.
The second a bit better. I used nylon peal ply, a thin poly plastic layer without perforations, and breather cloth. Also the veneer had a coat of varathane to seal it a bit.I think that I would like some epoxy to soak into the veneer for strength?(Not sure if this isthe best thing or not)
The third was the closest to the best, but still little pin bubbles here and there. In the third test I uses a very thin nylon release film and then a perforated peal ply and breather cloth.
All cases, I used 18-20Hg of vacuum.
I want a finish that I can add a final brush on coat of epoxy for the ultimate gloss look. I really don’t want to botch this one and I need ultimate clarity for the wood to really show its true beauty. Am I asking too much? Is this the holy grail that masters like Bert hold under wraps?
Any experienced advice would be greatly appreciated. Its bad enough having to surf in super cold pacific Northwest. (Vancouver Island) without having these nasty puzzle bits bouncing around in my head.
try a very thin fibreglass tissue on the outside of the glass but before the peel ply… and maybe perforated plAstic after the peel ply b4 your breather material…
(Kensurf), I was a little fuzzy on what stage I’m at, sorry.
I’m at at the point of covering the wood. it is basically a surfboard without the outer lam layer right now.
(Lavarat), It is a piece of art for my home to reward myself for 10 years of shaping up here in Victoria, BC Canada. Not concerned with the flex too much. Ill post pics when done.
(silly), You must mean "New Zealand Miles? LOL I met him when I was partying in the Igloo down the road. He was playing with the sled dogs and chatting with the villagers. LOL Sorry, had to throw that in. With 4.2 Million people in BC, I’m not sure the odds of meeting him. Possible though. PS; No Igloos, villagers, sled dogs or snow below the mountains here FYI. LOL
(craftee) I only found 3mm paper back so far. It in fact is a wall piece.
(Everyone) I hand laminated the eps because I didn’t want to distort or crush the shaped blank and it would be perfectly sealed and able to withstand the pressure of the rest of the procedures.
The idea of vacuuming the outside is to keep everything really light and layers and laps flat and clean.
Thanks for the replies Keep em coming! you are all very knowledgeable and helpful.
If its really a wall hanger (were you serious or joking, I couldn’t tell?) don’t use any cloth at all.
If I were making a non-rider, I’d just seal it up with epoxy and then gloss with poly gloss resin. Cut & polish & it will shine like a mirror. And with 3mm veneers & cloth underneath, if you get a wild hair to wax it up once a year, it’ll probably be fine.
Surftech “woodies” have no outer cloth… just inner glass, wood veneer, and outer gloss resin.
By the sounds of it you don’t need a whole lot of strength outside of the veneer since you already have your glass under the wood, so I would just do a single layer of 4oz hand-lammed over the outside. You’re going to play hell getting a good finish on vacuum bagged outer glass, so I’d just save the trouble and hand-lam it. Then just sand your hotcoat to like 100 grit and gloss with poly. Then you’ll have a looker!
Seal the wood with an epoxy coat before glassing. Unsealed wood will suck some resin out of your laminate.
Is your stuff peel ply or perf ply? There may be alternatives to or variations of the product you are using. The fabric is going to allow resin to leak through as well as suck some of the resin out of your laminate. Different types of fabric and membranes allow greater or lesser resin flow through the material.
For a maximum resin-rich lay up you might examine that variable. Your biggest obstacle might still be wrinkles in the bag where you wrap the rails. Higher vacuum will squeeze more resin through the perforations.
Laminating over a porous core like a surfboard of foam or wood using vacuum is different from vacuuming a laminate to a slick non-porous mold.
I have some carbon fiber kayak paddle blades that are very thin but rock hard and sound almost metallic when tapped… I think they were molded under extreme vacuum pressure and temperatures that would crush or melt a surfboard core. I bought them as factory seconds and there are some cosmetic flaws where the resin ratio was too dry. If it were transparent fiberglass over wood, I’m sure there would have been visible air bubbles.
One of the guys here on Swaylocks (DanB)did an experiment when making prefabbed balsa composite sandwich skins for his boards… different from what you’re trying to do but maybe helpful info in this thread?
(JohnMellor) Thanks for the info and link. very interesting. I was thinking of using Teflon coated bug screening in one of the test. I want maximum clarity., but I also want it to be light & tight. Also, I want all layer edges (veneer/carbon/fiberglass) to be nice and flat against the surface so that my final aesthetic/sanding coat can be sanded without hitting any edges exposing weave or wood.
To reiterate the results;
The first test with nylon peel ply and a sheet of bubble wrap, then the bag was the worst. It had channels of resin in the pattern of the bubble edges and the most air bubbles in the lam of all tests. I use 16Hg on this one.
The second test with the nylon peal ply and a layer of poly and a layer of breather cloth, had air trapped too. Just not as much. I used 12Hgs on this one. I thought maybe the first one was too high a vacuum and was drawing air up through the veneer rather than simply trapping air.
The third test, when I used nylon peel ply, a perforated release film and breather cloth then bag,only had minuscule pinpoints of air here and there, but had more dryish spots at the pinholes. This test I had pre-coated the veneer with epoxy and let dry. also I drew 16Hg for tis one.
I love a challenge, and this is why I never give up! I could hand laminate this one, but I want to master vacuum bagging for a different flavor of board from time to time.
Here is graphic of my plan before the execution. Its a 6ft 2in Thruster, Quad. **I will keep everyone interested posted with pictures and result findings until I crack the code. lol Meanwhile, anymore info from the gurus would be awesome! Thanks everyone.
At the risk of repeating myself, if the cosmetics are your first priority, you want to hand lam. Last I checked, bert does, as do all of us at compsand.com. There’s just not enough savings in weight to justify the hassle and inconsistent cosmetic results of bagging the outer glass.
If weight is your first priority, then bag it. But it won’t look as good as a hand-lam.
Either way you’re going to compromise something, but when someone picks up your board to check it out, the pin air in the outer lam is going to be far more glaringly obvious than a few extra ounces of weight.
Bagging it shouldn’t make it any flatter or smoother than hand-lamming it. If you have any high spots before lamming it, they shouldn’t be pulled flat by one last bagging. As for sanding and exposing any weave or wood, I’d just prep very well before lamming, knock everything flat before hotcoating, then sand well and do a final gloss coat afterwards. That should give you as smooth a finish as bagging it, with great clarity.
You probably won’t notice a few extra ounces of weight, but I guarantee that if you wind up with blemishes in the outer lam you’ll see them every single time you pick up the board.
I was having the same anxiety about the deck of a fish I’m making. I wanted to inlay two pieces of veneer onto a balsa deck, one as a deck patch and the other on the nose as decoration. I wanted to get 4oz-veneer-4oz-balsa lammed in one step so that the epoxy would have the best chance to bond, but without leaving bubbles or ridges I’d have to sand down later. I didn’t want to I didn’t care so much about the final finish, since I’d be putting on a fill coat anyway.
I couldn’t see how to lam everything onto a piece of mylar, since that would mean putting the veneer down first and then trying to blindly drop the balsa on top so that the veneer ended up in the routed depression. Dropping the mylar or whatnot on top of the finished stack seemed to be asking for lots of trapped bubbles.
After a lot of time reading about Oneula’s veneer problems, DanB’s and Daklaw’s prefabbed skins, and a good dose of analysis paralysis, I ended up with the most wasteful plan possible:
Took a piece of 1/8" masonite and drilled 1/16" holes every six inches or so, then smoothed down the edges of the holes and got rid of the dust. Then I taped a sheet of 3 mil mylar to that and poked a finish nail through the plastic at each hole. On the other side I taped some paper towels as a blotter.
the stack:
RR2000 w/ slow hardener, 1/8" balsa, 4 oz glass, leveneer paper backed walnut(generously scrubbed with denatured alc.)
Balsa sheet on top of some DIY perf ply atop a piece of shadecloth.
Spread epoxy w/ 6% add. F on the balsa and let it soak in.
Mixed up more epoxy (3% add. F) , unrolled the first layer of glass on the balsa and wet it out, spread epoxy on the underside of the veneer and put it in place, then scraped the veneer w/ the spreader from the center of the piece out to the edge to force out air bubbles and extra epoxy. Most of it probably went down between the balsa boards.
Unrolled the second layer of glass, wet it out.
Dropped the masonite mylar side down onto the stack and taped it to the shade cloth underneath.
Discovered that blue tape would much rather stick to my vac bag than to shadecloth or masonite. I got it about halfway into the bag before giving up and retaping. Hooray for slow hardener!
Pulled it out after 6 hrs at ~10" hg - I wanted it to still be flexible enough to handle a concave deck and a little bit of curve at the rails near the middle of the board.
Result: good enough. The weave isn’t filled, but no bubbles, no white spots, and almost no nubs from the holes in the mylar/masonite. No ridges around the veneer either - my holes for the veneer were a little oversize in spots, but the gaps between the veneer and the edge of the hole was filled with a bit of resin. so the end result was still flat. The only problems (aside from the size of the garbage pile) was that even after spreading epoxy/glass on the underside of the deck it was still pretty stiff. Instead of pulling the deck down to the rail, the bag got sucked into the gap. Pulled it out, retaped it much more thoroughly, but missed taping one corner of a butt joint between two sheets of balsa. That corner popped up about ~2-3mm at the rail line, right about where my hand will be when I pop up. groan.
Thanks my friend. You have helped me make up my mind.
Is bagging only good for laminating boards that will be painted then? (eg; EPS Core, 1/8th Divinycell skin/glass/ prime and paint) I did a board like this and I have used it for a few years and it is still like new. I can punch the deck and no marks appear.
With these boards, it just seems like the strength is very high and the weight is nice and low. The only thing is that it is always (for me) necessary to use a spot glazing puddy to fill fin holes before priming.
I really just want to get the process down as a skill and be able to vacuum bag with confidence. Even if not on this project.
I’m with the “Why glass it” view. If you’re not riding it and want beauty, deep gloss and a relatively simple operation then why not just varnish the wood? You only have to look at a few classic yachts to see that the results of well applied varnish rival anything that is being suggested here.
If you want the best use sprayed 2 pack polyurathane.
Lets forget about the wall hanger, I was kidding about that.
I just want the lightest possible wood veneer short board that is aesthetically perfect. Yah, I might hang it on my wall for the summer until the winter swell kicks in lol.
What would I learn if I don’t try, and the materials are too expensive to mess up the outcome.
I am listening to experience and leaning toward hand lay-up. But I find it hard to believe that out of this endless group of minds, someone has not figured out the best way to vacuum conform cosmetic composites to complex shapes without imperfections in the outer layer.
PS; I understand trade secrets, so you could always message me the tips and I’ll be able to get this job done.
With 4.2 Million people in BC, I’m not sure the odds of meeting him. Possible though. PS; No Igloos, villagers, sled dogs or snow below the mountains here FYI. LOL
I could hand laminate this one, but I want to master vacuum bagging for a different flavor of board from time to time.
lol.