Up until now I’ve used only epoxy/micro ballon mix for sealing EPS. And I have gotten really good at getting it nice and thin and even. Well, last night I sealed with light weight spackle for the first time. Soooo much easier. The finish is smoother and fills in holes better and with less material than epoxy/ballons.
Are there any real concerns about getting a good bond with spackle?
Greg Loehr uses spackle to seal…
rick.
I’ve never had an issue. It dries quick and sands easy. I usually do 1 coat for clear boards and 2 coats if i’m doing any kind of color work. I’m sure its technically not as good as microballons/epoxy but it works for me
-Jon
Are there any real concerns about getting a good bond with spackle?
Not here, but then I put it on really thin and hit with drywall screen after.
OH NO !
Not another sprackle thread !
Hey,
Just don’t cake it on and you’ll be fine.
All the sprackle does is slow down the penetration vs. time to harden…Another words so your eps blank doesn’t suck all the resin out of your lam and create an overly heavy board because you keep adding coats and it just’s keepa disckapearin"…or…Geez, I only use 3/4s of a gallon of sprackle on my 5-7, and my board delammed ???
Resin ,epoxy that is, can be mixed w/ micro ballons , D.E. …ETC. To get basically the same results.
(Ps. yes ,I know spackle is spelled s-p-a-c-k-l-e.)
H
Rick, Before doing my first EPS / Epoxy board recently, I did a test on one of the cut-offs from the blank. I prepared four different sections. All were then glassed with one layer of 4 oz. fabric and RR epoxy (fast hardener). I then did my best to destroy each section to see what was the weakest and what was the strongest.
TEST CONDITIONS ON FOUR DIFFERENT AREAS:
EPS only. Sanded smooth. No spackle.
Sanded smooth, no spackle, painted with water-based acrylic.
Sanded smooth, spackle only, no paint.
Sanded smooth, spackle, painted with water-based acrylic.
RESULTS:
Resin soaked in the most, fabric was the driest. Tear off of the glassed-on fabric was mildly difficult.
Resin soak was moderate. More resin stayed in the fabric. Tear off of glass was harder than #1.
Resin soak was minimal. More resin stayed in fabric. Tear off of glass was more difficult than #1 or #2.
Resin soak was minimal. " " " " " . Tear of was hardest of all. The fabric ripped when pulled with enough force.
My conclusions are that the bond to the EPS is not so important since eps is so weak. When more resin stays on top, it creates a strong shell of epoxy resin and fabric. The bond to the spackle itself was good, since when the shell did peel off the spackle stayed stuck to the resin, and the eps broke off.
I think the spackle works good. My recent board had lots of clear resin areas, and the spackle made everything look nice and white.
Doug
Hey Doug,
Great test! I often wondered about acrylic too.
Thanks
Doug, I use spackle thinned with Liquitex acrylic paint right out of the tube. Have you tried that yet? It’s a tip from Drewtang, that works really well for me. I’ve also thinned with “Kilz” with good results, although not as white.
My theory is… you want some penetration, but not enough to suck the resin out of the cloth. The above post mentioned that the bond isn’t that important because the foam is so weak… and there’s some truth to that. But the “shell” will be thicker if some resin soaks into the foam. If done well, there should be somewhat of a gradient of hardness, from the saturated glass down into unimpregnated foam. This is ideal, as it resists pressure dings and delam, bonds the foam to the glass, dosen’t add excessive weight, and maintains an optimum resin/cloth ratio.
All the tests I’ve done have been spackle vs. epoxy slurry. But my slurry is never as thick as mayo… like many here describe it. Mine is much more runny. The consistency will be more like honey (just not as “stringy”). It will flow slightly, by not readily. Once you start pushing it around, it picks up dust and gets thicker. My tests have always shown more foam rips out with epoxy than spackle, so I prefer to do my own boards with epoxy because I don’t mind the extra work.
But spackle works well, and there’s nothing to say bad about it.
Did you try adding some color to it?
Future Fiberglass in Va Beach did the same test and they added one more which was microballoons and epoxy. The spackle won. I’ve posted this on here before and no one believes … maybe now.
Agree, spackle is the best sealer. It’ll be argued on this messageboard for years to come probably. Here’s the one-upper: Spend the extra 15-20 minutes and finish your blank out until it looks like a poly. Can’t get it there? Get better eps or better finishing tools. Then do a really good job lamming it without a sealer. Once you figure that out your deck dents will love you for it. Finish look is second to none. Especially with gin-clear RR.
ps. I just made the 200,000th post in general discussion:)
I have found that spackle vs epoxy/micro is a toss-up as far as glass bond to foam, but the epoxy/micro seal seems to resist [pressure] denting better.
JSS
Doug,
Very well done. That kind of attention to detail, and planning, will ALWAYS result in a superior final result.
Rick, Before doing my first EPS / Epoxy board recently, I did a test on one of the cut-offs from the blank. I prepared four different sections. All were then glassed with one layer of 4 oz. fabric and RR epoxy (fast hardener). I then did my best to destroy each section to see what was the weakest and what was the strongest.TEST CONDITIONS ON FOUR DIFFERENT AREAS:
EPS only. Sanded smooth. No spackle.
Sanded smooth, no spackle, painted with water-based acrylic.
Sanded smooth, spackle only, no paint.
Sanded smooth, spackle, painted with water-based acrylic.
RESULTS:
Resin soaked in the most, fabric was the driest. Tear off of the glassed-on fabric was mildly difficult.
Resin soak was moderate. More resin stayed in the fabric. Tear off of glass was harder than #1.
Resin soak was minimal. More resin stayed in fabric. Tear off of glass was more difficult than #1 or #2.
Resin soak was minimal. " " " " " . Tear of was hardest of all. The fabric ripped when pulled with enough force.
My conclusions are that the bond to the EPS is not so important since eps is so weak. When more resin stays on top, it creates a strong shell of epoxy resin and fabric. The bond to the spackle itself was good, since when the shell did peel off the spackle stayed stuck to the resin, and the eps broke off.
I think the spackle works good. My recent board had lots of clear resin areas, and the spackle made everything look nice and white.
Doug
do you have any photos of these tests?
Future Fiberglass in Va Beach did the same test and they added one more which was microballoons and epoxy. The spackle won. I’ve posted this on here before and no one believes … maybe now.
Greg’s only done this tens of thousands of times, so why listen to him? Let’s reinvent the fricking wheel instead and re-make all the mistakes he’s already made. I know some of you love your hypothesis and theories here, but experience trumps everything. To boot, he’s made mondey doing it, not merely massaging one board in his garage for weeks on end. OK, I’m done now.
I think the key is the ratio of balloons to epoxy. You’ll get (and I have gotten) different results with different ratios. The most common mistake it making the slurry too thick. Too thick and you don’t get the ideal penetration. I agree that spackle will work better than slurry if the slurry’s too thick, as the spackle dosen’t truely “seal” the foam as does slurry.
I’ve had minor dings that have not taken in water to the degree I expected due to the fact (and this is only my theory) that the foam has taken in enough resin/ballon mix to provide some degree of “seal” even below the surface.
Again… there’s nothing wrong with spackle. I talked to you about this on the phone years ago, and still agree for most people it works great.
I have built a dozen boards or so and I have used light weight spackle with great success. The boards turn out lighter and still strong. I have had no problems with delam, exccesive compression on the deck etc. I have been performing R&D on these boards weekly. Two years later the boards are holding up unreal. Just remember to get a good cure before surfing them.
So what ratio/consistency would you recommend when mixing epoxy:microballoons for sealing EPS? More like mayonnaise rather than peanut butter?
Easier
cheaper
can seal both sides at the same time
faster drying
better cosmetics
airbrushes better
easier to mix
less toxic
easy clean up
spreads better
sands wayyyy better
equal in strength
lighter weight
Done lots of both. I didn’t beleive it either at first. I finally saw the light.
Yeah all those things!!
Hooray for spackle!