Ok, I know this subject has been brought up MANY times before, but I want to try to get a definitive answer on this.
I’m using 2.4# EPS, do I really need to seal the blank? If I don’t, how much extra resin will I end up using on a 6’ board?
hey man, i recently asked this, and was directed to the archives.
look under eps blank sealing
i got all kinds of responses from no to definately… i guess just read it and make the call.
i am going the wall spackle route because i plan on using pigments in the resin, and want a somewhat uniform absorption.
anyway, it’s worth the research.
I’m in the same boat as you, I plan on doing pigmenting/tinting. I was thinking that NOT spackling would help keep the color uniform (since spackle might have different thicknesses here and there), but maybe on off on that.
I’ve never done an EPS tint, so I can’t say specifically, but I think tinting an unsealed blank would end up with a more blotchy appearance. Sealing it would give you a smoother surface to do tint work with, and better adhesion for your trouble, which by the way is not much trouble at all.
I’ve pulled off all kinds of tricks in the field in the coatings industry. I have been considering one thing for some time now. Instead of pissing down the shrink-free spackle with water, why not use a water based water clear urethane varnish /sanding sealer? Stuff is water soluble, but it has better adhesive qualities and it contains urethane plastic so it will give you a much less porous surface for tinting.
Also, it occurs to me that if you should get a crack in the epoxy and water gets in between the foam and the resin the spackle will not melt if it has been mixed with waterbased urethane. And it may just be something you can apply with a roller or brush. I have experimented with just the waterborn varnish sanding sealer on EPS foam and it does the job of sealing it just fine. Technically speaking spackle by itself is not a sealer. Mixing these two products could provide a middle ground between sealer and spackle, not yet available premixed in stores.
The new Krylon H2O spray paint is perfectly compatible with both EPS & epoxy. Spray your blank first, seals & colors all at once…
I’ve used it - just in white - but its super easy & cheap. Mask it off, it would come out all kinds of nice.
If your blank sealing solution includes white paint, why the additional expense of a rattle can? Just get a qt. of acrylic paint and brush it on.
In my paint experience spray does not go into cracks. For that you need to add a mechanical level to your application schedule. By mechanical I mean brush, roll, or squeege.
For example when spraying any kind of paint on cement block whether conventional water based acrylic, epoxy, or block filler one must either back roll, back brush, or squeege the paint material to force it into the cracks after it has been sprayed on. Otherwise the cracks will show. NO amount of spraying will substitute for the mechanical work.
There is no shortcut. If the cracks are not filled and sealed, the epoxy will still soak in, increasing the board weight and expense. Basically you are substituting something that costs $20-30 a gallon for something that costs $80 a gallon.
The similarity in texture between cement block and EPS is why I use block for comparison. The idea behind light-weight watered down spackle is similar to block filler in concept. Heck if you wanted you could use block filler on blanks. Might be heavier, though it is often also a good sealer.
If I was doing 20-100 blanks a day both sides my recommendation would be to use an airless sprayer followed by back brushing. I would allow 1 minute a side just for coating. More time would be spent moving the blanks from rack to rack. If I was doing 300+ a day like ST I would install line.
I could even mix and spray a lightweight spackle mixture and squeege it out.
There is a reason why Greg Loehr uses a squeege. Sealing cracks. Dont’t forget the point of the step.
Hey Mark,
just wondering if you have tried this yet and how it worked, i thought about the same thing using varathane water based PU as a seal on the blank. I used it once recently to put a coat over the hot coat, just to add some extra uv protection, haven’t really had the board out yet to know how it holds up.
thanks.
I’ve only tried it on test samples. It coats nicely, flows out fast, and is very fast drying because of the alcohol. Does not smooth out the surface, but it can be sanded and recoated, and so why not mix some microballoons with it? Havn’t tried that yet.
But mainly I should point out that Greg’s system is very hard to improve on. At least by me. I’m not yet convinced that water based urethane even with micro balloons is better. If the spackle is applied very thin and allowed to dry thoroughly before epoxy lam coat and the epoxy is sufficiently warm enough and fluid enough to soak into the spackle, then Greg’s method is most probably best. But for colder weather applications maybe then the water based urethanes have a use.
Let me be clear to everyone. Greg Loehr’s current method is the benchmark standard. It will take a serious challenge to change that.
Mostly I wanted to get some discussioon here about other possibilities. That way people will really know for sure that all avenues have been explored. With more people thinking outside the box there may even be a better way.
With more people making the switch away from traditional methods of construction a lot of people are reading this.
Mainly the point is it’s no big deal sealing a blank. Whether plastic blade or brush. Easy stuff, nothing to fear.
Here is a thought. For high speed drying instead of cutting the spackle with just water cut it with part alcohol. That will speed up drying for high and low production.
Hi Mark -
FWIW, SFoam (EPS blank manufacturer) advocates the epoxy/microballoon slurry for blank sealing… http://www.sfoam.com/LamTips.htm
It would seem less likely to dissolve in the event of a ding? Maybe even protect the foam from water intrusion in lighter density EPS?
Hey John,
I know about the S-Foam recommendation. First is it doesn’t form as much a slurry as a paste. But (A) that takes a long time to cure. And (B) as I mentioned above light weight spackle is mainly microballoons. So a thin coat may just absorb the epoxy in the lam coat. And (C) the idea of sealing is to restrict penetration of the epoxy, so depending on the consistency of the “slurry” it may penetrate too far.
The spackle coat works like a sponge. And is thin, light, sandable fast drying and very white. All plus side. And it is not imprenetrable to epoxy.
I have had your concerns in my mind all along. For years. I’ve only been riding Loehrs for five years now, but I have not had any massive delamination. I’ve had cracks fill with water. NO less than a polyester board though. But I can’t say if the water followed or soaked into the spackle. I’d tear a board apart to find out, but that’s too much work. I’ve done a bunch of rapairs on Loehrs; friends and my own. Again have not seen any collateral damage from the water and the spackle. I do not replace my boards every other month. These things hold up very well.
I clicked on one of the links below, the one to the epoxy and urethane floor coating site. Big clue there regarding the durability of both urethane and epoxy. NO mention of polyester. IN fact polyester has never been durable enough for floors. Just throwing that in before a debate gets going. The big two are epoxy which is number one in durability and urethane which is second. My garage floor is epoxy. I’ve done thousands of square feet of floors in epoxy. I’ve done thousands of sq ft of floors in urethanes.
The best is epoxy.
But that does not negate S Foams suggestion in any way. The nice thing is people now have more choices. I do not intend to take that away. And there are five choices on the table now. Spackle and water, spackle water and ethanol, waterbased uv stable urethane, waterbased uv stable urethane with microballoons, epoxy and microballoons.
But my experience is that it is overkill.
Heck, could probably seal boards with waterbased epoxy floor coatings. Solid colors.
Quote:
Hi Mark -
FWIW, SFoam (EPS blank manufacturer) advocates the epoxy/microballoon slurry for blank sealing… http://www.sfoam.com/LamTips.htm
It would seem less likely to dissolve in the event of a ding? Maybe even protect the foam from water intrusion in lighter density EPS?
This is Jim Phillips method. Where are you Jim??? It’d be great to hear of the long-term results of boards built using this method.
Mark -
I hear you on that and appreciate the reply. All of your points well taken.
Choice is good!
Rolliges. The Micro Balloons paste sounds like the way to go. Wall spackle seems so wrong for the serious surfboard maker IMHO. I saw one of Jims EPS/epoxys fish at the Oceanside Fish Fry this year. The board was glassed clear you could see the micro balloon paste under the lam. not all that pretty IMO. The deck had already started to cave in. I have wondered how long that board held up.
John. I don’t know if you remember Jesus’s ESP/Epoxy green longboard at the last Sways gattering. I didn’t get change to talk to Jesus about the construction of that board, the board had some delam issues. I wonder if he used Spackle?
I agree that any water-based compound may work, but just frightens me in a surfboard. The spackle probably costs $2 per board and takes an hour, all told. Epoxy/microballoons probably costs $5 and takes 4 hours - coat, wait 3 hours, flip, coat again, wait maybe 30 minutes, and lam.
Unless you need the $3 to feed your kids or you have a plane to catch, I’d go with the epoxy mix.
As someone who is about to tackle my first eps/epoxy, I am glad to hear that the decks on some of them are caving (as long as they dont delam). I have surfed on surftechs and my biggest complaint has been thay the decks never dent. I like to know where my feet are in relationship to my board. It kinda ruins the looks of the board and screws up the resale, but it works for me.
I know boards aren’t aircraft, but as far a I know the aeronautical industry would never recommend a water based product between foam and fabric.
I’m sure everything works, and after all, it is only a surfboard. But I prefer the glueing and bonding effect of actual resin slurry to seal and adhere to the foam.