I have couple of questions regarding thickness of polyester resin:
When using FRESH polyester resin for laminating… do you thin it with styrene before glassing even if it is fresh… or you just pour resin and kick it with catalyst without thinning it…
If I have 1/2 gal of 1 month stored polyester resin and want to use it for laminating a board… The resin is too thick… can I thin it with styrene and use it as freshly new resin? …what happens if I add too much styrene and use it too diluded?.. What is the ideal thickness of laminating resin?
You didn’t define ‘experienced’, so I’m gonna jump in here, since I do have ‘experience’ …just not that much.
I’ve never thinned my lam resin, and it works just fine. I got some styrene awhile back and tried thinning some hotcoat for some random idea I had one day… nothing went wrong per-say, but it didn’t do whatever it was that I was hoping it would (certainly not the first time that’s happened). So I don’t do that anymore.
Many mention it in ‘home-made’ gloss resin… but I just buy my gloss.
When the styrene evaporates your resin gets thick… so putting some back in to thin it out should be fine… but I have to ask, how did your resin thicken up so much in a month? I’ve used resin several months old, you could hardly tell the difference.
If your worried you could always buy a new gallon for laminating, and save that half gallon for setting up fins and plugs and what-not.
I think the resin thickened so fast because I forgot to tight the gallon cap… big mistake…
I use Sylmar resin only for laminating …it is very expensive down here in Costa Rica… and use cheaper clear resin for leash plugs, fcs plugs, etc…
I don’t know why, but I alway add a bit of styrene to my laminating resin even if it’s freshly new… that’s why I’m asking if there is something wrong with it… will the resin loose it’s strength or cures slower ??? … I don’t know…
My ten cents worth, from the semi pro single A glassers league.
Thicker resin=slower / less saturation into the foam=lighter board. That is only if you work the resin off the board once wetted out. Thinning Lam resin soaks into the foam and out of the cloth, making a heavy weak board. I might be a nut, but I like laminating with thicker resin, then pulling the excess resin off the board.
I thin my hotcoats, just for the same reason above. But I thin them to the tune of just a few drops of styrene per oz. of resin, that way they don’t get brittle.
Cabeto, your request for an experienced glasser scared me a bit but anyway…
you seem to live where it is nice and warm and you could have an evaporation problem because of that. first, try to store the resin cool, second, close the lid. and to know what is thick and thin you have to assess your resin thickness first so you know what you talk about. its like with the girls, thin for one, not thin enough for another…
to do this use a funnel with a small spout and pour a certain amount of your preferred thickness resin in, lets say 1 kg or 1 liter. meassure how long it takes for the resin to run through. now you have a base to work on and if in doubt do it with the resin in question and compare. thin if required and be careful, work only in 1% steps. In no time you are the experienced one…
Howzit Cabeto, Your resin thickened because some of the styrene evaporated. This means that the resin will kick faster since there’s less styrene to evaporate which how resin hardens when it interacts with catalyst ( chemical reaction), so definitly add some styrene to it. I can’t tell you how much to add since I don’t know how thick the resin has become. Maybe you could get some fresh resin for your laminating and use the older resin for hot coating or ding repair. Aloha, Kokua
On the other hand, your thick resin is now better for leash plugs and fins and such the less styrene means less gassing off and better adhesion to the plugs…
Hey Cabeto, styrene monomer acts like a knife to the polymers in resin, preventing the mers from making longer (and stronger) chains. True, styrene is already in the reain but it is in pre-set amounts that seem to be reducing more and more each year. Fresh lam resin should not require any thinning especially where you live; if it is formulated for surfboard builiding. Beware of adding too much styren since the outward effect will be brittle performance and quicker yellowing/browning when exposed to prolonged sunlight. As mentioned, try very hard not to let the styrene evaporate out of the resin solution. In Costa Rica I can only imagine the styrene as quickly boiling out of the resin. It is best to glass in a cooler temperature environment, say below 80F, especially with the humidity factor there. Do you have A/C? because 78F would be ideal. Also, how warm is the resin you are looking at, with respect to the surrounding area, because if it is more that 20F lower than ambient this may be the reason for thickening. Storing in an indoor cabinet could possibly have this effect on your resin. The viscosity test using the funnel is ingenious; seems like prevention is your best cure to the styrene issues you are experiencing…
Thanks a lot guys… now I know what to do and what not to do with resin and styrene… and what to expect if I add too much styrene…
I will stop adding styrene to freshly new Sylmar laminating resin and use the old one for hotcoating…
Hey PlusOneShaper thanks for your suggestions… were I live is usually 80 to 82F sometimes colder also it’s really humid… Recently I started kicking my laminating resin with 1% MEK for a 15 min geltime (1qt = 10cc) before I was kicking it too slow 25 minutes geltime… I like it faster, less air bubbles, lighter board…
The thing is as I mentioned before I always added a bit of styrene to my resin, now that I will not thin my resin…do you recommend using the same MEK ratio 1%… should I use less MEK?.. will the resin kick off faster if it’s not thinned?
Hey Cabeto, you are right on track with pushing up your catalyst to 1 percent and this is true without the extra styrene. Work FAST; try to get your “wet work” done in about eight minutes. As you’ve noticed, this gives you a lighter, stronger board. Hope this helps. Good Luck…
Howzit Cabeto, Costa Rica and Kauai have about the same weather so we should be using about the same mixtures. The first thing I noticed about C.R. was how much it resembled Kauai except for the fact that you get about the same rainfall as us but in 6 months instead of a year. Aloha, Kokua
Hi Kokua… yes in fact we have the same climate or very similar… our rainy season goes from may through november… I have never been in Kauai but have friends that have been there…
By the way what mixture ratio do you use when glassing with polyester…?
Howzit Cabeto, I use UV resin these days so I don't do much laminating with catalyst. Do you have a hygrometer in your shop to measure the humidity? Aloha, Kokua
No I don’t have one yet … but I think I must buy one…
Unfortunately we don’t have UV resin down here… I will love to try it, but the best I can get here is Sylmar and MEK…
I’ve only glassed shortboards (total of 201) …biggest a 7’0’’ hybrid…
A client asked if I could make her a longboard, classic noserider 9’2’‘, I know I can shape it, but I’m kind of scared with the glassing… I just finished her a 6’5’’ swallow tail hybrid (pink) and she loved it…