Crystalization, what is it?

General Discussion
1

Okay, so I am doing my first bird, a newbie. Been looking through this site for a while to find information etc. I am nearly ready to glass my blank (an old board stripped down).

I only just found out about crystalization and would like to know what it is. I have searched around and haven’t found a proper explanation of what it is. I am thinking of painting the board green with a white rhino head coming down from the nose. Will crystalization occur, what would cause it, how can I stop it from happening? Any ideas on how to paint the board, what with, acrylic, latex? Any tips would be grateful.

2

Ah my friend the Devil Crystalisation…

The curse of a laminator!

It happens with dark colours on foam…red, blue, purple, black and green.

I’d need to be a chemist to explain exactly why it happens, but I’ve seen it, I’ve sprayed boards that have done it, I’ve had laminators warn me off using those colours…

It has to do with applying the paint too thickly, it has to do with humidity, it has to do with the paint…It has to do with not putting clear laquer over the colour…

Anybody really know? It’s unpredictable…I’ve had allover red boards glass with no trouble whatsoever.

The only sure way to prevent it is to only use those colours on Filler coat, not foam…

Speedy

3

paint the blank with color altered resin

be it epoxy or poly

pigment or tint

it is sand - able

and ultimately

compat - able

crystaloizzzzaytion

dont exist

on planet X

llife and glass ing on planet XXX

fantasy becomes reality

when you move to planet X

…ambrose…

what was in that ice cream?

4

Ryano, what Speedneedle says is on it. Crystallization is unpredictable and probably most often happens with darker colors.

It looks like whitish “crystals” or salt grains on the foam. They show up against the darker colors.

I have an easy suggestion by which you can avoid it: don’t paint the blank, tint or pigment the resin. Now I have to warn you that your blank needs to be quite well finished to get a good lamination. No little dents, holes or scratches in the surface of the shaped blank. Sanded to 100 is okay, but you can’t have scratches or tearouts like where the surform didn’t quite cut the foam, or where the finger plane dragged foam when you last planed down the stringer. These little irregularities will fill with a little extra resin and show up darker against the rest of the lam.

If you lam is clear or yellow tint, you can get away with almost anything… maybe why so many boards are clear nowadays. It wasn’t this way in days gone by (I’m dating myself). If your lam is pigmented to opaque or nearly so, you may pull it off nicely, even with scratches on the foam. What it boils down to is, how well can you finish the blank? UV cure poly and a little catalyst to be sure (if the color is dark) will get you through a colored lamination.

You don’t say how dark you want your green. I don’t know what kind of paint you think to use, or how thickly you will slather it on. These factors make a difference.

One thing I know: I will not spray a board red, again. Whatever/whyever, the last one crystallized like crazy, and had some other weird sunlilght/color effects that were not attractive. Sold that one at cost.

5

I’ve been told that acrylic chemically bonds to polyester resin and I’ve airbrushed the hot coat once before. After it was sanded of course. You might want to try the same thing. Came away in a couple of small areas though. You might want to try spraying the lam before hotcoating as well. Both of these things should help avoid crystallization.

6

print your ryhno on rice paper then lamher in there… easy do it your self on your computer

7

Speedneedle got it right. It shows up at the most inoppertune times. Be careful with dark colors. Lightening them up even just shade can make a differance. I was having trouble with some ink jet printed lams until I went to the silkscreener and had him change the blue ever so slightly.

8

Ryano,

In the last year we have had to do a bit of research on this issue. The word “crystallization” is a misnomer to begin with. What appear to be tiny bits of crystal are actually tiny bubbles of delamination. Looking through the glass the bubbles look like tiny crystals but when we carefully dissected several boards we found this not to be the case. There was not any crystal formation. What there was were tiny bubbles where the resin had delamed from the paint. The delam is where the resin separated from the paint. To understand this we better we sought the guidance of longtime Swaylockian Atomized who we hold in extremely high regard in these matters.

What we learned is this: The two biggest issues that effect this are heat during glassing and the quality of the filller in the paint. If the lamination is too hot OR too cold the “crystallization” tends to be more prevalent. This occurs more with the darker colors which absorb more heat and tend to show the problems before the issue would appear on a lighter color. Also the chemicals used in the pigments can be more troublesome on the dark colors and also at times some yellows.

As to the fillers many of the less expensive paints cost less because they are made with lower quality components. Cheaper pigments, binders, etc. Fillers is an area that this is true. Paints that use fillers such as talc will have more problems then one using calcium carbonate. You can help fight the problem by adding calcium carbonate to the paint. (16 ozs paint, one cup calcium carbonate and about 4-6 oz water.) This will help the adhesion and often lead to avoidance of those nasty “faux-crystals”.

Atomized is an incredible resource. Credit goes to him for most of the above and, Atomized, if I got it wrong please feel free to set me straight. Thanks.

9

we also found that cheap paints will grystalize much easier…

one trick seemed to prevent a lot of crystalization is to put the sprayed blank in the sun for 20 mins a side… it worked great!

10

keep everything simple for your first board

if you must paint do the foam with water based tempra’s

let dry completely then glass er up

11

Crystalizations are a Polyester issue, they don’t happen with Epoxy.

Crystalizations (which is when the some areas of glass job did not adhere well to the paint job) are generally caused by 3 things:

  1. Moisture trapped in the paint that works its way up to the surface during or after glassing. Most likely caused if you really caked the paint on and it “skinned over” trapping moisture or you didn’t allow paint to dry well enough and glassed the board too soon.

  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 shrunk when it kicked thus stretching itself off the painted foam.

  3. The most common reason for crystals is caused by paint that is formulated with a binder that is rubbery or glossy in nature, which Polyester resin doesn’t mechanically 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 intentionally formulated for. That rubberiness is also what causes the crystals. You can reduce the rubbery property of these paints by adding Calcium Carbonate to them which will make them dry as a chalky surface. That chalkiness creates a better mechanical bond with the resin that will help in preventing the crystals from occurring.

Way back in the 1980’s when Neon colors where in vogue and most surfboards where getting painted with Day Glo flourecent paints, crystals where never an issue. Day Glo flourecent paints had Cal Carb already in them, which made them dry chalky and thats why they never crystalized.

Flat latex house paint has been used in combination with artist acrylics to paint surfboards. It usually contains Cal Carb, Silica or Talc as a filler to give it body and to kill the sheen in the binder which is why it will rarely crystalize (try using gloss house paint and see what a crystal nightmare you’ll get).

Other commonly used paints for airbrushing surfboards are Poster Paints (also marketed as Tempera Paints) which are made for school art projects and crafts. They are cheap price wise and also cheap in the ingredients that they’re formulated with. They usually have a low pigment content, a weak binder and plenty of filler to give it some body. The filler in Poster Paints is usually Cal Carb. That’s why they dry chalky and again that chalkiness is what keeps them from crystalizing.

A chemical supply house such as Rev Chem here in So. Cal. will sell you a 50 pound bag of Cal Carb powder for about $10.

A general mix is approximately: 1 part Cal Carb, 3 parts Paint and 1 to 2 parts water. You can adjust this based on your painting technique, the kind of spray equipment you use 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.

You’ll know if you adding too much Cal Carb to the mix if the paint dries too rough and feel like sand paper. You’ll also know it when the glasser raises a big stink about that.

Crystals are notorious for happening over darker colors. A good reason for this is that the blank is essentially a white porous surface. When you paint it with a dark color, in order to get a uniform coating without the white of the foam showing thru, you will tend to use more paint. More paint will start to plug up the pores in the foam, trapping moisture and if the paint is already rubbery to begin with, you’re probably going to get a good crystal problem going. Because of this surfboard blanks formulated with big open cell structures can create problems.

Beyond all this the quality of the atomization of your spray equipment, spray technique and experience are essential.

I hope this is helpful.

12

how often do you get crystalization using Cal carb? Using proper painting technique.

13

It’s pretty rare now. I’ve see it happen when the laminator did too dry of a lam to the point of getting pin air. I’ve done boards that are solid midnight blue, dark brown, burgundy, black without any problems. One thing you do want to do with dark colors is to do a couple of light coats with drying in beteween coats instead of one heavy coat. Ideally you want to achieve uniformity with the minimum amount of paint. Let the paint dry thoroughly before you glass. Also tape off the stringer.

14

I wish I could go plain old clear but the blank was taken from an ancient single fin with big water log problems etc. The stringer is in bad condition and I might have to fill some holes and gaps. If I don’t paint on the foam and paint before the hot coat or gloss coat will that be any better?

15

It’s not a good idea to paint on the bare glassed surface before you hotcoat the board. You’ll most likely burn into the paint when you’re sanding the hotcoat. You can paint the board on the sanded hot coat but, you’ll have to thoroughly scuff up the paint with a scotchbrite pad before you gloss over it. Adding some extra surfacing agent to the gloss will help it flow out better over paint. It’s a little tricky to knock down the gloss bead on the rail without hitting the paint underneath though.

I would suggest that you do a resin opaque instead, since it appears that the blank is in pretty bad shape. That would cover everything up and if you wanted, you could then spray some design on the flats before you glossed it.

[/u]

16

bitchin

…ambrose…

17 
I can't say why it happens, but I have found a method that pretty much puts an end to it!  Simply spread UV resin over the colour, Kick it off, then, lam as usual.  I always do this now with the darker colours.  I just did a 5 board batch, all with a black tail spray top and bottom.  It was raining on the day I HAD to stard du to a time constraint, so I didn't UV the bottom first.  I had never seen such bad crystalization in my life!  So I Pre-soaked the deck before I laminated and it came out fine.  Had to go back and re-spray the bottom over the hotcoat, and that really blows..
18

That really is the best way to deal with it if you’re presented with a painted blank that looks like it’s definitely going to crystallize. At a glass shop I used to work at, we had a customer that would bring in these blanks that had murals painted on them. She had hand painted the murals with tube liquitex acrylics and the stuff looked like it was generously applied with a trowel. No kidding, it was really caked on. By encapsulating her artwork with a coat of resin before glassing, the glass job would be bonding to that coat instead of that rubbery paint she used. Her boards where mostly wall hangers so the extra weight added from that coat wasn’t much of a concern.

19

Just watching a kiddies show, I know I shouldn’t but they finger painted with rice flour paste. I was thinking that this could be a possibility for colouring a board as we use rice paper for logos. Just an idea. Anyone tried it, any thoughts?

20

I never tried it. The rice flour is most likely used as thickener. The same as in asian cooking when you add corn starch to sauces in order to thicken them. BTW the rice paper most laminates are made of is made from the fiber of the rice plant not the grain. It also can be made from mulberry bark, bamboo fiber and hemp. The edible rice paper like the kind you you use in making spring rolls, is made with rice flour.