Reverse Lamination

Hey there! I’m looking to glass an EPS blank, with epoxy and doing a uniform tint top and bottom, no pinline ;)!

I’ve done it in the past with a normal laminating process, bottom 6oz, then top 6+4. Tinted both sides the same colour for a uniform coloured board. The problem with doing tint jobs on EPS as everyone knows… resin will seep under the tape, even with the best tape there is and really dusting off the blank and really pushing down the tape on the blank to have good adhesion, even with spackle to seal the blank! Even then, it seems almost inevitable that some resin will seep under the tape and/or infiltrate the smallest hole in the foam structure. When you do your cut line on the top after Laminating the bottom, you pull on the tape, pieces of foam come off with it, in the end you have a messy cut line and, and you possible have to do some small repairs on the foam before the next step which sucks!

I’ve been working only with EPS and like it but whenever I check a pro laminator on Youtube doing a tint job on a Poly blank and cutting the most perfect lap line on the top, with zero seapage at all it really bugs me lol!

I’ve read a lot of threads that mention reverse laminating and am aware of some of the ‘‘down sides’’ in term of fabrication. In my case I’m interested by doing it that way since I would have possible small defects, trying to limit them as much as possible, on the bottom side of the board if I do the top first, and it doesn’t bother me so much to have those on the bottom that on the top.

I’ve also seen some threads, really old ones that mention that laminating the top first would be non advisable since the glass, as it sets will pull on the blank and can weaken the board and make it less durable or more prone to breaking in the surf, or perhaps changing the foil of the board during the fabrication process…Is that really true!!? 

Anybody doing top lam frequently? Tips and advice? Anybody’s 2 cents is appreciated!

Thanks

Marc

I’ve seen resin opaques over spackled EPS.  I’ve seen resin opaques over painted EPS.  I’ve never seen a resin tint over EPS that didn’t look like dogsht.   If I was going to try a resin tint in epoxy I’d lay a single layer of 2oz in clear or white in lieu of spackle and then come back with a tinted lamination over that.  

I almost always laminate the deck first.  I’ve gotten away from using EPS for most of my builds, but when I was using EPS I’d only spackle the bottom after I laid the deck lam (with a cutlap) which makes it easy to fair the bottom out.   I never had a problem with deck durability or rocker sag, but then again I was only going stringerless when the shape was thick+short.    

Obviously, the way I do it isn’t production friendly.   It’s more time consuming.   

Not all of the above, but MOST of it.        You will certainly lose rocker, with a deck first lamination.      Breakage prone, not so much.

When doing tape line colors or even tints on EPS, you can seal the edge of the tape, depending on circumstances, with clear resin or white Gesso.  When I did acrylics, I used white acrylic to seal the tape line then applied the color.  Gives really sharpe tape lines.  Good luck.

all the best, Greg

Get out your “white-out” and white-out that last paragraph, because none of it is true.   My experience with EPS and tints is that they generally are blotchy.  To avoid that I put lots of extra pigment in my Epoxy resin with a dash of white pigment.  This almost opaques the resin.  When I do that I freelap.  You can’t see any lapline at the rail, because two layers almost opaques the rail.  I laminate the deck first when I use Vector Net on the deck.  I do that and cut the tinted cloth at mid rail. Then lam the tinted bottom onto the deck with a cut lap.  Then a free lapped deck of 4oz onto the bottom.   As I said the real problem with Epoxy tints is the blotchy finish. The extra step of sealing the tape edge certainly will help, but also might show under the tint if not done carefully.   Glassing the whole board with 2oz before a 4 or 6oz tint is possible, but also a lot  of extra work.  Paint it.  You won’t have any lap line.

Thanks all for feedback. I’ve attached pics of the eps board Ive tinted, it is pretty opaque but not completely, maybe 75%… and didn’t come out splotchy in my opinion hehe. I had spackled that blank but not the whole board, only gaps in the finished sanded blank. The board I’m making might have a little less opaque colour so perhaps it won’t look “as good” because the foam will be more visible.

You can see in the pic before glassing the top that the lap line is shit though lol, but you don’t see it too much in the finished board so I’m thinking of having that but on the bottom. 

Greg, I’ve seen that mentionnned a lot about sealing the tape line but I’m thinking that by doing that the colour in the tint might.not be consistent on the tape line as it wont penetrate the foam as much as the rest all along the tape line… one would need to perfectly seal a uniform line, as slim as possible in order not to see it it feels like, but maybe it would be better than having seapage if I lam the deck first.

It seems that there is still not a consensur on the reverse lamination as to the effect on the finished board though.

Cheers,

Marc


With respect to my comments about doing deck first, I normally do a fairly flat rocker to begin with and I am normally using a fairly thick center section and a moderate foil.  I’m mostly not doing finely foiled and highly rockered shapes.    So what works for these shapes wouldn’t be appropriate for other more conventional shapes.   The industry norm to laminate the bottoms first was not an arbitrary or unconsidered trend - people had good reasons for making those choices.     

With respect to affecting rocker;   If you glassed the deck and let it sit for a few days or weeks;  Yes it could affect the rocker.  But in the normal glassing process one would normally not let a half glassed blank sit for more than a day or so. The longer you let it sit the more possibility that the rocker could change.  So if you do the deck first, glass the bottom asap.

EXACTLY.

Seal your all blanks with epoxy micro cabosil white pigment past and sand it fine you’ll have cleaner tint and laps. Use the Sand on tape cured resin works well with epoxy.

For short boards, seems like the only way “hand” lamming the deck first could affect rocker is if stand supports are close to the blank center (reducing bottom rocker).

In the past, this would have been more of a problem with “long” foam blanks, ends drooping downward (reducing bottom rocker).  Or if stand supports were near the ends of long blanks, center of the blank would droop downward (increasing bottom rocker). 

All of this would be affected by blank length and foam density.

Seems like Rob at Green Room told me cured epoxy shrinkage is negligible.  If not true, can somebody provide credible substantiation about the actual amount of cured epoxy shrinkage?

Just sayin’