I have never messed with UV resin but I think it would speed up my ding repairs tremendously. I do have a question about its use with dark pigments. Can you mix the UV resin with dark pigments (even opaque white) and it will still kick all the way through? Doesn’t the opaque pigment block the sun from reaching the bottom of a fill so you get the very top kicked and the bottom still soft?
Howzit Gregg, Using UV resin with dark pigments is not a good idea since the UV rays can’t penetrate through the pigment to kick it off. I have used it with dark pigments for resin stains on the foam and it will work for that, but not for laminating a board.Aloha,Kokua
Kokua, every time i read about UV resin and pigments i always thought “how opaque is too much opaque”.
I mean, if i use resin pigments or tints and after laminating the board i can still see where is the stringer (seeing it, not feeling its shape), the UV catalyst would be enought to have this board cured with good results?
Thanks!
To follow up on Coque’s question… if the pigment is dark and the inside is slow curing will the hotcoat help at all? I mean will the catalyst in the hotcoat react with the uncured lam resin below and help it kick? Just curious because I forgot to add catalyst to my UV pigment lam. It seems to have set nicely but I’m afraid of the areas that I cannot see/touch.
Hey Mr. jimmychuck, pretty sure the process is called “cross-linking”. Also, the UV under the opaque will most likely get near completion even with opaques but there are a couple of problems. First, this reaction could be extended out for a very long time. I’ve seen it take days to kick an opaque white (which reflects UV quite well) as witnessed by the drilling of a deck plug hole; RAW resin down against the foam! Second, some pigments (even tints) will react to the outer layer of resin kicking and the deeper resin staying raw. I’ve seen the entire layup produce an off-gassing that looked much like sheets of “pin air” and that compromises the water-worthiness of the board.
A good trick is to put a small amount of MEKP (2cc or so per side) and you still have ridiculous time to lay up the board. This seems to get the reaction to get to completion when flashed in the sun, and allows for logos with lots of ink (like ours) to stay where they should… (nothing worse than a big, fat bubble in the middle of your logo… …on a customer’s board; not that I’d know what that was like…)
Thanks my friend. I was too excited when I started mixing the pigment into the resin and forgot to add the MEKP. It looks pretty set already but I’m afraid of what lies underneath. I’ll proceed with deck (with MEKP this time!), hotcoat and gloss and see what we see. Hopefully I’ll get some ‘crosslinking’ along the way… if not no worries. There’s always #3!
Oh are there any issues with curing UV resin with MEKP straight up? I’ve only got UV resin right now but I don’t want to wait until the weekend to finish up the board so that means MEKP curing in the evening. Just wondering if there’s any trouble with just mixing in the MEKP as if it was plain ol’ resin.
You know, it’s funny because my company has been doing quite a few tests in that area.
Basically, we found that you can build the board with MEKP, finish it, then cure it further by giving it a good amount of UV exposure. (1 hr btm, deck, rails). We found the boards were strong, but what we have not been able to explain is the initial foot dents that are about normal or slightly softer. Then about three sessions later, the boards get ROCK hard, the foot dents stop.
An old time board builder told me you get the same thing by glassing with MEKP (only) and sticking the board in the sun for an entire day, FOR EACH SIDE! Sounded far-fetched but we tried it. Not sure on this one. In fact all this “testing” has been empirical by just looking at the board and letting team riders perform single-blind tests. No actual measurements were taken.
Jimmychuck, there’s no problem mixing UV resin with mekp, as you should do with fin boxes or leash plugs, it’ll cure as regular resin with merk.
Also, once here was posted (i think it was Kokua) a great trick when doing hotcoats. Add some mekp, so before you expose the board to sunlight, the parafine will raise and the resin will kick slowly, once it’s geled, you can expose it to the sunlight, so you wont have those pinholes that appear when the hotcoat kicks so fast.
Go and finish this board man!
It will kick in the sun light…eventually, like 3 days. The problem is if your doing a cut lap the top layer of resin will kick, but when you cut into it with the razor blade it’s all gooey and smears out under your nice tape line. If you use UV alone with a pigment it will take twice as long to laminate as if you just used 1/2 the required catalyst. So moral to story as is, just as stated by everybody else: if your going to use UV with a dark color put some catalyst in it…like 5 cc per 16oz, and walk it out into the light. It will still take 30 mins to kick.
-JaY
Thanks Resinhead!
How Dark is to dark…a very good question and one that I do not have a definitive answer on.
I can say this though, I have done a few rather medium/dark tints and have had no problem. the oldest board I have that is the darkest is about three years. No problems. I’ll post some pics of it if I can get around to it.
The color is if I remmeber right a royal blue. but yes you can still see the stringer. So perhaps that might be a guide to go from. If you can still see the stringer, then light should be able to penetrate through to the foam.
hmm.
I sense some testing to come out of this one of these days. Perhaps this might be a good time to begin…
Drew
Just a note on how UV light penetrates based on color of tint…I’ve been working with UV light extensively in my dissertation the last couple of years and the extinction of UV light (UVA,UVB) is very rapid in CLEAR water, a few centimeters at best. This means that UV light probably does not reach the foam even on a regular lay-up with no pigment. What likely happens is that the tint interferes with the catalyzation process versus shading out the UV. I could be wrong as I have never tried to measure UV transmission through a piece of resin. I have a UV light meter and will try it when time allows, I’ll let you guys know when the results are in!!
Dr. Retodd (no PhD…yet)