Yellow spots in uv resin?

I just finished the lam coat on my fish ( finally glassing it! ), and i noticed that there is a big yellow stain where i first poured. I mixed it pretty good, but i used a file i had handy ( lack of planning is my middle name! ). Has anyone ever had this problem??. It seems to be setting o.k, although not as quick as i thought, its been around 15 mins, and the top is still a tiny bit tacky to the touch when you take your finger off it, although there’s no resin on my fingers. Other than forgetting to wear a long sleeved shirt ( this is my second board i have glassed ) and my right hand being partly “lammed”, the stuff is really good, much better for me to use than the mekp, and i took my time, and got only a few small air bubbles that i didn’t see until i got it in the sun. i found that using my hands on the rail laps was MUCH better than the squeegee. Its also a much better looking job than my first board, and no kinks, wow!. If im lucky, i will get the deck done by tonight, woo hooo!!. Oh, of course, pics will be supplied when its done chip!

P.S next time i’ll wear thongs too ( the aussie type for ya feet, not the underwear type! ), the bottom of my feet are all lammed up hahah

P.P.S im stoked!

My guess: The first place you poured was also the first place you used your YELLOW squeegie?? I’ve had them bleed (and so have others)

My squeegee is yellowed from when i cleaned it in acetone. Im also thinking that a lam coat doesnt go fully hard, as there is no wax in it. Hmmm, im gunna leave it overnight, and see how it is tomorrow. Its amazing how much dust and shit can stick to the board in a small space of time. Oh well, its how it rides that counts at the end of the day.

Cheers

Lam coats should go fully hard. 15 min is a bit short to tell if everything will go smooth. Wait 45 - 60min (depending on temp of room) and you should feel a major difference in tack. Resin used? weight vs volume for measurement?

cheapo disposable nitrile gloves will keep your hands clean when glassing. They are also tougher than latex gloves, which tear more easily, and to which some are strongly allergic.

You didn’t mention using a respirator. You should. Though UV resin goes off real quick, and probably for that reason doesn’t release so much solvent into the air, you take more time lamming and will inhale an evil amount unless using a charcoal canister respirator. But there are always more backyard board builders coming along to replace those who burn out.

I glass barefoot, waste very little, and still have to go outside and use some water to help scrape the blots of the soles of my feet, on the concrete.

Hi There Beerfan,

I use UV catalyst on all my boards during the laminating process. Not on hot coats or gloss coats though. When I first started using it , I had the same problem with the yellowing spots. Mixing is the key. Gotta make sure it is completely mixed in, even yellow specs on the sides of your container need to be mixed in.

Also , leave a little longer in the sun , 15mins may get it to gel but a bit longer will help the overall curing process. They will also cure overnight and you will find a lot less tacky in the morning.

Hope this helped

Paul

Samurai Surfboards

Howzit Samurai, I add the powder then roll the 5 gal tub around the yard for 15 to 20 minutes before using, never had the yellow. Who makes those yellow squeegees that bleed, the ones I use never bleed. One time I laid my rubber squeegee on the dry glass on the deck while wetting out the laminate in another area and when the board kicked after the lamination it had a yellow spot where the squeegee was sitting, very strange.Aloha,Kokua

Hi There Kokua,

The UV I use comes in a liquid form, easier to use than powder but still got to be carefull with the dilution. Your right though the more you mix the better chance you have got.

Nice to meet you, I have been watching your posts for the last six months great to here from you.

Paul.

Quote:

I mixed it pretty good, but i used a file i had handy ( lack of planning is my middle name! ).

P.S next time i’ll wear thongs too ( the aussie type for ya feet, not the underwear type! ), the bottom of my feet are all lammed up hahah

Was this a metal file by any chance? could the yellow stain be a minute amount of rust that has transfered from the file to the resin?.

If you get acetone on glove and then touch the board they will leave a yellow brown mark, but you said you didn’t wear gloves so I guess thats not it, and the look like fingerprints too so it’s easy to spot the cause.

I used thin rubber surgical gloves, but they tore on my fingers, so some got through. Yeah, the file may have been rusty. I should have planned better, but i got a 90 minute window of opportunity, so i went out and got stuck in. Was supposed to finish today, but, again, no time. Thanks guys for all the advice. I will definately mix more, with something better than a rusty file.

I have made every kind of yellow spot known to mankind, some of them were on surfboards, even.

Possibly unmixed MEKP, though it sounds like you didn’t have any in there. Maybe squeegee bleed, Did you have gloves on? Many types of gloves bleed yellow crud initially. What it sounds like to me, though, is acetone dripping off you gloves or squeegee. It only takes a tiny amount of acetone to burn the blank and make a yellow spot, expecially if it is dirty. Make sure your hands and squeegee are dry before touching the board. You might have had dirty old yellow resin on your gloves, which the acetone freed up to run off onto your board. It’s probably acetone, acting alone or in concert with some yellowish spooge from your gloves.

( lack of planning is my middle name! )

Hi Beerfan

Time for some planning. We still need to Hot coat and sand and maybe gloss. I use small wood sticks for mixing resin. You can make your own. Make sure all your tools are clean. I installed a paper towel dispenser above my work bench. Sometimes I just stop working, grab a towel, wipe off the squeege, and then start working again. If you plan on glassing on Friday, get everything set up on Thursday. Yeah that’s it , suck down a few beers and make a list of what you will need to complete the project.

You can do it!!!

Ray

Howzit bammbamm, Chempro gloves will not bleed and last quite a while since they are made for chems not dishwashing. They run about $ 4.00 a pair or cheaper if you buy by the box. I figure you can get about 40-50 boards out of a pair. Aloha,Kokua

[edit] oops, sorry wrong yellowing thread.

I buy 18 mil latex from off the web. 12" cuff, no yellow stuff ever, less than a dollar a pair, shipped. For epoxy, I have a dental hygenist friend who gets me surgical latex for $.065 a glove. Gotta buy a thousand, tho. I’m good on gloves, and it don’t cost me much, either.