I am wondering what’s the best way to “thin down” some UV curing resin for application as a sanding coat? I would like it to lay flat and “sheet” off the board as I let it smooth out before curing. Otherwise, I always get brush marks or other “dimples” that just end up needing to be sanded out. Too much extra work. Can anyone offer some advice?
I have seen someone do it. They lay it flow out so the brush marks are gone and the wax rises then flash it.
Thanks for the help. Bbut I think I may be working in conditions that are colder than they should be. I think the resin stays thicker, more viscous. As a result, it doesn’t seem to want to lat flat, allowing the brush marks to go away. I am wondering if there is an agent / addative that will “thin out” the thickness of the resin, giving it better flow. I am wondering if just putting my resin can in a bucket of hot water will bring up the temperature enough to allow the resin to be thinner in viscocity? Can anyone help with this question.
Styrene?
Jon
when its 60 degrees or colder i will throw the resin in the microwave for about 15 secs to thin it out.
then after you have hotcoated let it sit for about a minute and let it flow out, do one last pass along the bottom of the rail to catch any drips then set it off in the sun/light box.
I like the idea, but does the resin leave a smell in the micro wave or the house? The wife won’t go for that Idea. But it makes me think that I might get away with immersing my resin can in a bucket of hot water, in order to bring the temperature higher. I will give it a try. Thanks to everyone for the comments. And does anyone know if Styrene is the proper additive for thinning out resin?
Styrene is definitely the proper chemical to thin out resin. It will thin it out, but it also makes it more brittle and makes it shrink when curing, in my experience. I think, and someone correct me if I’m wrong, you can add 2% to 5% to the resin to thin out without major negative effects.
Jon
I’m assuming you’re adding a styrene/wax solution to the resin. Are you letting it sit a few minutes prior to exposure to UV light? The trick with sun cure resin is to “flash” it like DV says. Stand with the board in a shady spot where you can rotate your body and board into sunlight for a 10 or more count, then return it to the shade. Do this a few times until you see the wax rise to the surface. Once it’s on the surface, you can set it in the sun and let it kick the rest of the way.
the resin will leave a bit of a smell in the micro, if that is not an option than use a blow drier and stir the resin around while you heat it (about 30 sec). hot water would work but it seems like it would take a while.
you dont want to use too much styrene because it tends to evaporate out while the resin is curing (especially if you put it in the sun) leaving that orange peel effect and it is pretty hard to sand.
also make sure that you are properly shake up the surf agent before you add it to the resin and then stir the mix well.
Jon,
Thanks for the info, I may try heating the resin so I don’t make the mistake of using too much styrene. I will try a safer method before I get too brave. But thanx for the quick response.
Ross
Yes, I am using a “surfacing agent”, which I know contains wax. And I do let the board sit for a while to allow the resin a chance to run, or smooth out. I have never heard of the “flash” method. While I am waiting for the resin to smooth out, I can notice the wax rising to the surface, and I like to wait at least that long. And I have already learned from the mistake of not shaking / mixing the surfacing agent, so I wont let that happen again. But I will experiment with the flash method, there are times when it seems the wax has risen to the suface on most of the board, but not all of it. Occasionally I run intoo small "gummy " areas when I am sanding. So I will try the flash method. Thanks for your suggestions.
Ross
Of everything I have heard about this, the blow dryer method seems the safest. I really think that if the resin were thinner, it would settle, and “sheet” off the rails better, leaving me less intensive sanding to complete. I have learned the hard way about making sure the wax in the surfacing agent is in a liquid state, and mixed thoroughly into the agent before mixing it in with the resin. That was a nightmare. Thanks for all your help, I’m glassing a “Bonzer” this weekend, And I’m pleased with the way it looks so far.
Hey Ross… I use epoxy and have the same problem with brush strokes showing through on my gloss coat.
What I’ve done is, after doing the last brush strokes, I take the blow dryer and run it over the entire board… section by section. I can see the solvents evaporating out of the mix, the surface gets smooth/glassy then I move onto another section. I’m in a cold area too and the wood burning stove only heats up a small section even if I have it going for awhile.
It usually ony take about 5 minutes to warm the epoxy floss coat with the blow dryer.
Hope this helps.
Les
All sounds like good advice. As well as "blw drying the resin before I brush it on, I will try the blow dryer while it is settling. I would have to think it can only help. Thanks for the suggestions.
Ross
From this quote, it seems the resin never lays flat. The resin should level out prior to kicking. If it’s not, it may be that you’re not adding enough surfacing agent. You can add too much, but it takes quite a bit to be too much. You may up your percentage and see if that doesn’t help it lay out. How old/new is the resin you’re using? That can be as much a culprit as anything.
I am down to my last gallon, which i purchased in September of 2008. it may be up to 7 months since I purcased it. However I have had this problem even after immediate purchase. One person described the the condition as the “orange peel” effect. I don’t have too many issues with brush stokes not leveling out, but I do get the orange peel texture, and it sems that it ends up leaving me with excessive or unnecessary sanding to remove it. i do tend to go heavy, rather than light on my addition of the surfacing agent, but I don’t think I have ever had an issue with too much surfacing agent. What do you think?
“0range peel”= too much catalyst and, or, not enough surfacing agent
Yep! This is how suncure with SA reacts if you immediately go for full cure without letting the wax rise to the surface. You’ll get a blotchy surface that is pretty much unsandable.
Ross, if you’ve got enough surfacing agent and it’s laying out flat after brushing it on, then the problem is likely the way the resin is kicking.
Yeah, catalyst is not the issue with UV resin, so it must be the SA. I’ll try to add a little extra and give it more time to settle. That, and trying to thin out the resin by using heat may help. I like the idea of using the blow dryer to warm up the resin, both before I brush it onto the board, and again after I’ve brushed it on. We’ll see how it goes. Thanks again for the comments.
Ross, the UV catalyst may very well be the issue was the point I was trying to make. If you brush it out, then walk it out into UV and leave it without “flashing” it first, you’ll get the hard to sand, orange peel effect because it will kick too fast to allow the wax to surface.
Is your resin really that thick? If it’s the consistency of motor oil, it’s fine, if it’s more like molasses or thicker, then you do need to heat it or thin it or both before application.