crystalizing problem....

General Discussion
1

well i think ive heard about every way to avoid the problem…and also tried using those methods. but certain colors just seem to crystalize no matter what i do…

i use quality paint, make sure each coat is dry before the next , keep coats as thin as possible, and to the best of my knoledge also make sure all paint is thoroughly dried before glassing…

anyway none of this matters now, because im looking for any way to fix the problem after it has occoured…

i realise you can combat it to an extent during glassing, but in my recent cases it is something that appears hours after the resin has kicked…

any ideas…?

2

If you are referring to the worst airbrush color ever concocted, the red airbrush, your paint

choice is going to be a HUGE factor. Even with quality acrylic latex, you can get the gassing.

When cutting the paint use clear acrylic (I found “Future” acrylic floor wax is great) instead

of water. It works very well.

Also, you may benefit from leaving your lams wet in key areas like concaves, sharper rail

areas, and tips.

3

thanks man , but , ive heard and tried every way to prevent this…future floor finish the whole nine yards…the actual color that gives me the most problem is green…

of course any ideas on how to prevent it are great, but im looking for somebody who has found a way to fix it…

about 2 hours after gell i noticed a couple small spots and planned on trying to rub some resin on it and maybe some would get through and lessen the problem, if not it wasnt a big deal…

then the next morning the whole board has those damn sploches…

uggg anybody found a way to lessen the effect…?

some styrene…? acetone? resin…? i dont know…

4

Obviously you haven’t tried everything.

I haven’t had a green airbrush “crystallize” in 30 years of board-building.

Years ago I had problems with large areas of red and sometimes black.

After changing paint formulations the problem went away. In this way

I must say that I have ‘fixed it’.

I still think I can offer you some help. I bet the paint must be suspect.

What is the brand? How many brands of green paint have you tried with

this same result?

Lastly, is this polyester resin with MEKP or UV etc?

5

Crystalisations are a Poly issue, they don’t happen with Epoxy.

Crystalizations (which is the glass job not adhering to the paint job) are generally caused by 3 things:

  1. Moisture traped in the paint that work its way up to the surface during or after glassing. You really must of caked it on and it was glassed while the paint was still moist.

  2. Too dry of a lamination on the paint job -or- the lamination went off too slow and drained -or- the lamination went off too hot and shunk thus stretching itself off the painted foam.

  3. The most common reason for crystals is caused by paint that is rubbery or glossy in nature, which the resin does’nt bond well to. Most artist acrylic paints like Liquitex and Nova Color dry rubbery. That rubberiness is a good quality if you are creating art on canvas, paper or a wall mural, which is what theses paints are formulated for. That rubberiness is what causes the crystals. You can modify these paint and make them not rubbery (chalkier) by adding Calcium Carbonate to the paint. That chalkiness creates a better mechanical bond with the resin that will prevent the crystals. The Day Glo flourecent paint has Cal Carb already in it thats why it doesn’t crytalize. Flat latex house paint has Cal Carb in it that why it does’nt crystalize. Rev Chem will sell you a 50 pound bag of Cal Carb powder for about $10. The stuff is cheap. A general mix is approximately: 1 part Cal Carb, 3 parts Paint (I use Nova exclusively) and 1 to 2 1/2 parts water. You can adjust this based on your painting technique and weather conditions. An easy way to mix this is to use an electric hand blender in large cup. That will get the lumps out so you don’t have to strain the paint.

I can paint a surfboard solid red with Nova Color Naphthol Crimson with Cal Carb mixed into it and not get crystals. I can paint a surfboard solid black using Nova Color Black Gesso (which has the Cal Carb already in it) and not get crystals.

Now, if you add too much Cal Carb to the mix the paint will dry too rough and feel like sand paper. The laminator will probably raise a big stink about that.

I have heard that you can also use talc as an additive but have’nt tried it.

6

Nova color is a top choice for paint.

Line chalk works as well as a flatting agent…

7

Calcium Carbonate is chalk and also called Lime which is used in masonry and agriculture. I tried the stuff that you can buy at Home Depot or Lowes but it was’nt as pure as the stuff you can get from Rev Chem which is refined for use as a filler in paints and plastics.

8

yeah its a poly lamination… ive allways heard the stories about red being the worst but green seems the one for me … like i said it wasnt too thick and it was as dry as it was ever going to get…(sprayd lightly, drying in between…let sit for a couple of days in the sun)

used liquitex thinned with future…allways seems to be a good combination, except with this color…not the first time , and green is allways in question.

guess ill have to either switch paints and/or start adding calcium carbonate / talc/or line chalk…so thanks for sure on that …guess i did hear something new.

meanwhile ill try and fix the problem after the fact on this board…its probally impossible to fix after is been laminated, but ill let you know if even a small ammount of progress is made…

hopefully i can figure something out because i have another board up in the rafters , half glassed ,with the same problem from weeks ago ,with the same color GREEN.

9

You said green so I’m guessing youre most likely a using a Phthalocyanine based green (read the fine print on the jar, tube etc.). Phthalocyanine green is a transparent dye based pigment. It is is a deep (dark) colorant that when diluted with a clear will give you a nice range of vivid green tints. Liquitex markets a variety of premixed green colors that are mixes of Phthalocyanine Green with yellows, blues, black or white. Depending on the mix, the degree of transparency/opacity will vary. If your color is opaque enough, you can touch up the cystalized areas on the sanded hotcoat and shoot another coat of resin over it to seal it. If you’re concerned about the added weight from that extra coat of resin, you can mix your color into a water bourne (that’s water bourne-not water based) clear like Breakthru or Diamond Coat and use it as a finish coat. If your color is too transparent, it will tend to darken up as you apply it over your orignal color. You could also tape off and paint a design/panel over the crystalized area to hide it.

10

yep your right, phthalocyanine is one of the pigments…

what i have here is a solid color green airbrush, covering the entire bottom and wrapping the rails…

this board is getting a gloss coat anyway so maybe repainting the entire green area before gloss could be an option…the only thing is i will have to use that same green again, hopefully i wont end up with a new set of problems…but i get the feeling i will… i dont know , maybe it will end up an improvement from what i have now anyway. i really dont like the idea of having a layer of paint this size between coats of resin…maybe its not a issue…?

11

It can be an issue. If the paint dries shiny, the gloss resin won’t have much to stick to and you’ll have a weak mechanical bond. Again, if you add some Cal Carb to your paint, you’ll get a better surface for the gloss to bond to.

After the paint is dry, lightly sand it with with some 320 or 400. Add a little sufacing agent to your gloss batch (gloss resin has surfacing agent in it already, you’re adding more to it). That will help it flow out. Be extra careful when you tool down the gloss bead (the bump where the deck and bottom gloss overlap on the rail) so you don’t hit the paint bellow it. Use a flat file instead of a razor blade.

12

thanks, looks like that will be the route i will end up taking…

i realise ill have to be really careful not to get into the paint while sanding out the gloss and smoothing down the bead…

i figure if its shiny i can hit it with a scotch brite pad or something like 400 grit as you suggested…

i am going to start adding some cal. carb. in the future …

as for now , you say the kind of stuff i can get at home depot isnt really worth using…? i know you say the cal. carb from rev chem is really the way to go … but is there anything that could take its place fairly well that i could pick up at the local hardware store…? or possibly a paint supply shop?.. i guess maybe i should call around and ask for some calcium carbonate, and see how confused the people get…

13 
Howzit have, As the resin heats up and cures it draws any moisture in the paint to the surface and that causes crystallation. Try adding some tempra to your paint to get a drier paint finish and I make a mixture of 60%acrylic thinner with 40% water because if you use 100% acrylic thnner the paint will turn foamy when you shake the paint to mix it and it takes a long while for the foam bubbles to disapate. I do know 1 glasser who does a thin layer of resin over reds and blacks to seal the color and prevent crystallation but this adds weight to the board. I use this technique for covering areas where I paint blac over red for emphasis but since I only cover the black it doesn't add much weight. Aloha,Kokua
14

I’ve found the stuff before at a paint store. They called the stuff whiting. It comes in half gallon paper milk containers and cost about $5. If youre in the San Clemete area, Merrel Paints has it. You can use the stuff they sell at Home Depot. You can find it where they have the concrete stuff. Its sold as Lime. It’s just not as refined. Kokuas post about adding tempera paint was the way I used deal with the crystal problem until I figured out that the clay filler found in tempera is cal carb. Tempera paints are cheap paints made with low pigment amounts and a cheap binder (usually gum arabic). In order to add body to tempera, a filler is added. That filler is usually cal carb. And Cal Carb is why Temperas don’t crystalise.

15

yeah the tempra is something i will look into…im sure it would cost a little less than my process and if it works then it works…

anyway, i was thinking and realised that i have never had any other colors crystalise, other than green in some combination… so it becomes obvious to me that it is something in the paint ingredients, not my techniques of spraying or drying or glassing… and ive done red-blue-black and every other color with no crystalizing issues…

so i found some cal carb at the paint store, labled whiting in a milk carton, so it should do the trick.

as i was mixing it in with the paint , someone says whats that ? and they say they add it to their salt water fish tank to neutralize the acid levels…

so that gets me wondering, why does calcium carbonate sound so familiar to me in the first place…

im thinking neutralizing acid now, and go check the bottle of antacids for hartburn/indigestion…and sure enough cal carb is the active ingredient…

so i am starting to think that not only is the cal carb preventing the paint from being too glossy, an even more important reaction may be happening…it is neutralizing the acids in the paint which would otherwise cause a bad reaction with the resin…such as oils and acids in fingerprints can cause the same…

so ive repainted the area including the cal carb…it covered the problem areas pretty well,and it turned out pretty textured, about like some 220-320 sand paper.

thats about what i would expect when painting something with texture onto a non pourous surface…

i might hit it with some scotch brite just to be safe, depending on how much paint i have left, incase i scotch brite a little too much in the wrong area and need to fix it…

ive put no gloss on it yet , hopefully it all goes well…

ill let you know what happens…

16

In agriculture they use it to neutralize the acidity in soil. It’s what your bones are made of. Coral reefs too. 4% of the earths crust is CC.

Your assumtion on the Cal Carb neutralizing the acidity in the paint may in some cases be a valid one if the paint formulation is acidic in nature.

All the research in paint formulation I’ve done and the talks I’ve had the chemist at Nova Color, points to creating a good mechanical bond. A similar everyday example is with house paints-why you have to sand the sheen off a glossy surface before you can paint it or the paint will bond poorly to it. That grittyness gives the resin something to bond to.

Now since you are now dealing with paint on the sanded hotcoat, if you gently light sand it with 400 and blow the dust off with an air hose it should take the gloss well.

17

No one has said anything about the simple alternative: a colored lam coat. But that’s a lost art, isn’t it? You have to get the blank really very nicely fine sanded to pull it off with a dark color; you ought to use UV cure so you can control the gel time; you have to use a steady hand on the squeegee, so no ex- or current speed freaks need apply.

Yeah, I had a bad crystal problem with a sprayed red board once, and ate it b/c the customer thought so poorly of it. Shoulda lammed with red, would have prevented all the hassle, been quicker, and produced much more solid color with much more depth. Live and learn.

18

You know thats something I have’nt see since the seventies. I remember seeing it done at Casters then. Theye called it COF (color on foam). They would do teardrop panels, rail spears-you name it. Then they would glass them clear freelaps. Beautiful work.