Vacuum Bag Veneer Problem

I vacuum bagged my second board with cherrywood/koa skin last night but had a problem I could not see until demolding. There was a raised crease in the deck in one area between the nose and center of the board. I had a slight version of this happen the first board but this is more severe. Has anyone experienced this issue? I used 1 layer 4oz e glass, 1/32" veneeer skin, a layer of perforated FEP, breather cloth and a tube bag with two probes the nose end had a leak valve and gauge. I held 24 inches hg for 2 hours. I did not see a crease before I layed the FEP. It seems like the edge of the veneer creeped up and created a “mountain chain” effect. I will try to undercut one side of the crease and see if I can get it to lay down or I will sand it flush and laminate a new piece of veneer into the gap. Any suggestions on how to avoid this problem in the future would be greatly appreaciated.

pic please

probly too much rail skin ,, not allowing the veneer to contour or flex in the nose rocker area.

there are products that you soak on the veneer to soften it up.

you could wet out the veneer and do a prebag to preshape the veneer before glue up.

Guys doing veneers have commented before about having problems with the vaccum locking down the edges of the veneers before the center - basically forcing the creases.    I think I read one guy was using a yoga mat as a breather up the center to lock down the veneer evenly and someone else said they were using bubble wrap.  


I haven’t had that problems with that yet because I don’t put a lot of dome into my decks and I’m not doing real agressive rockers.  Even so, I work my bag so that it’s smooth over the veneer and rails so there aren’t even any creases in the bag, let alone the veneer.  So far, so good.    I also make sure to do a dry run with veneer and blank before doing it for real with resin.    I make enough other mistakes with my shapes and glassing.  This is one area where I think it’s possible to get it right every time.  

When I vac bag bamboo venners I poke a bunch of small holes through the veneer with a dart. The holes allow the resin to flow through and act as ‘rivets’. Skin is on super-tight. I also use 1.5 oz cloth under the bamboo veneers for extra stregth without a lot of added weight.



Hi flynbri -

Bert Burger's thread had something about this if I recall.  I think he said that's why he uses planks rather than solid sheets.  I think it's also one reason why he decided to go with the solid rail build up.

You're basically dealing with a flat panel that's going to have trouble dealing with the compound curves of the deck crown combined with rocker.  Is your veneer a solid sheet or is there a seam down the center? 

The more I play around with vacuuming, the more I appreciate the workmanship I've seen on the wood grained Surftechs.  They're doing full rail overlaps while I struggle with simple deck and bottom inlays.  The magic of properly placed relief cuts... have any of us accomplished any better?

Creases are one of my specialties!


You can see the crease is at the seam of taped pieces of veneer. My fix was to slice open the seam inject 5 minute epoxy and press until the section was down.  It took a long time because I could only hold down about five inches at a time. Some sections I had to trim the veneer or the two pieces would not butt up to each other evenly.  After glueing it all back down,  I sanded it and it came out fine.  This, by the way, is not the only board I’ve mad that had creases.

I think the creases are caused when you coat the skin on one side (the inside). The veneer absorbs resin on the inside, then that side of the skin expands, causing curling. Some woods do this more than others. I haven’t had the problem with hickory for example.   I don’t know of a good fix for this.  You could try veneer softener.  I have done several tests and it seems compatible with epoxy resin.  It makes the veneer feel slightly spongey. I decided against using the stuff because part of the attraction of wood veneer, for me, was it’s springiness. The spongey feel seems dead compared to normal veneer.



Cork on decks… Problem solved!

I have had this problem all so, slice glue-sand. 


 I have a question for Kensurf related to his post above. Recently, I built a 6’2" kiteboard with a maple veneer deck(my first time using veneer). From checking on Swaylocks, I found Kiteriders post about using a veneer softener solution and “preshaping the veneer” in the vac. bag. That caused me a lot of problems. I applied the solution to the veneer,put it on the board and left it in the bag   under vacuum overnight. The next morning, I took it out of the bag. It had conformed to the shape of the blank and I thought it looked great and went off to work. That night when I got home, to my horror the veneer had curled up in the opposite direction. This caused me major problems lamnating  and I also ended up with a crease like Flynbri.

Luckily, I was able to hide mine under a deck pad, but I was wondering if you could offer any tips or procedures on how to preshape the veneer? I would like to try another board, but am hesitant until I figure out how to prevent the problem.

the veneer I use is paper backed

the veneer factory uses ultra thin veneer and adhears paper with a plastic backing with a hot press roller

I have never had any slits or wrinkles,,,,, knock on wood

but I also know not to push the envelope regarding the flexability of the veneer.

my 2 cnts

Veneer products in Paramount

ask for Rob

Different woods act differently in the bag. it's all about the grain.  Hard woods like Hickory, ash, oak. And figured woods with wavy grain are tough to work with, they just are not as flexible and are prone to crack of buckle.   Bamboo, mahogany, pine, teak, etc are excellent in the bag. Long straight fibery grain will conform real easy.  Also i like 1/40 veneer.  Sometime it't too thick and you have to make sure it doesn't extend too far down the rail.  speaking of extending too far down rail. don't extend too far down the rail. Doing that will only make a super stiff surfboard.

Here’s a picture of my crease slightly sanded, I’ll probably slice, trench, epoxy and do a vacuum strip bag to pull it down. Thanks for all the feedback the more I build the better the technique!

Bummer about the Koa.  That isn’t cheap veneer.

I think you can cut a few steps in your process and get better results.  The ridge was result of the high vacuum and the multiple layers of material over the veneer hiding the crease.  At 24hg you are crushing foam if it’s eps.  No need to go so high.  I think I use 10 or 12 hg on a full deck layer bamboo eps.  You need just enough to get a clean clamp.  Extra vacuum can distort the rocker and cause problems like ridging and sucking the bag under the veneer at the edges.

Also unless your doing a wet layup over the veneer you can skip the breather and perforated film.  The extra porous nature of surfboard foam doesn’t really make it a necessity.    

Once every thing is in the bag and positioned turn the pump off or down just before it starts to tighten the bag.  At this point I gather all the extra bag material to the non veneer side.  Then turn the pump back on or up and slowly pull any extra bag material off the deck that you didn’t get on the first try.  If done properly there will be zero creases on the deck.  You want it smooth and tight.  Once its smooth then pull full vacuum.


What would you use to glue? 


use something to act as a call like they do in real woodworking

a single piece of xps or 1/8" masonite will prevent the gather down the middle from the rails

that’s why I don’t like veneering anymore very difficult to “fix” or recover after something like this.

The secret I’ve heard is to apply the 1/24"-1/42" thin veneer over a pre-glassed board like a surftech that kevin ancel does with his wood and shell venneered boards. 

thicker 1/16-1/8" balsa/wiliwili/cedar planks, cork sheet or the timberflex solution greg loehr came up with works much better