Poly Catalyst Questions?

I've been using UV resin and want to start using regular Poly resin.

But I have a couple of questions.

What is the proper ratio for catalyst to resin?,

and if you reduce this ratio will it extend gel time but still harden or does it just not go off.

I want to start glassing at night and will this affect curing?

Thanks for any help!!

A very difficult question to answer because of so many variables. Generally most laminators use 12 - 15 cc’s in a quart for laminating.  But I’ve seen a lot of guys use 30 … their fast.  If it’s cold you have to use more.  If it’s hot less.  I’ve used 2cc’s on fin panels and they always went off fine … As long as you have some hardener in it it will eventually go off.  But if your resin is too slow it’ll drain into the blank making the board heavy.  If you shoot too fast your caught … big mess.  It takes experience to get it right and to know how much on what day.  The resin can even vary drum to drum.  You’ll be going along shooting at 15 - 20 and you get a new drum and suddenly your getting beat. Now your shooting 12. The next drum comes and the laminates are draining … too slow.  So your back up to 20.  As I said, lots of variables.  

Thanks for the reply Greg!
It’s great to have someone with your
Experience on here to answer these kinds
Of questions
I’m a IHB local I live about 2 blocks from
Yours and Sammy’s factory! Thanks again!

    Howzit Greg is pretty right on about the differences in drums and definitely knows what he talksabout. Me I used a little more catalyst but that was just how I was taught. Instead of going to catalyst just buy someUV lights and set them up next to your reguar lights and when through squeeging the board just turn on the uv lights to cure the board. If you are used to using catalyst then just go with it but if not then try the extra set of  lights. Aloha,Kokua

there's nothing you can do about varying strength from drum to drum, you will have to deal with what you get.  I've been "caught" by hot batches but finally I got serious about it, as follows...

1.  always know how much resin you are using.  I mark my mix bottles (washed castoffs from the kitchen) in one cup increments.

2.  I got a small disposable syringe to measure catalyst by the cc or ounce.

3.  I made a catalyst chart with cups of resin in the first column, and catalyst amounts across the top row.  1,2,3,4 cup rows, and 0.5%, 0.75% and 1% catalyst amounts.  I found that in my local weather here in Honolulu it's about mid-80s Fahrenheit and likely 70% relative humidity.  I found that at my rate of laminating, 0.75% catalyst gave me about 20 minutes of working time. You will have to do the unit conversions from cups to cc's o ounces (one milliliter equals one cc).  I tacked the chart to my garage wall and followed it religiously.  Also noted down how much resin I actually needed for the sizes of boards I was commonly glassing.  As in racing and many other endeavors, PROPER PREPARATION PREVENTS PISS-POOR PERFORMANCE.

4.  I used 4 cups to do a single 6 ounce lam on a 10 footer, 22 inches wide, with very little spillage or waste, and I waste very little.

5.  Regards to Loehr's comment that it will eventually harden if there's any catalyst at all, there is a "best" catalyst ratio for poly resin and it's about 1%.  But that requires damn fast laminating, too quick to do longboards, though you might pull it off on a shorty if you don't mind wasting resin.  I used 0.75% catalyst and didn't worry about it.

Eventually I went solely with UV cure and didn't have to sweat the catalyst any more.  I'll never go back to just catalyzed resin, but I do refer to the catalyst chart every time I lam with color.

   Howzit Honolulu, I basically used about the same amout of catalyst for what ever amout of resin I used since the more resin meant a longerboard which means longer lam time. 6' board bottom I used 15oz resin 12 cc's cat. 9'0'' longboard 22 oz resin 12 or a little more catalyst. Under 10 minutes from start to finish for a long board maybe 7 minutes for shorty, then I started using UV resin and fell in love since it kicked right when I wanted it to plus it got rockhard and was ready for next step without any wait for cure. Aloha,Kokua

Hey Kokua, that almost constant catalyst amount must play havoc with the mix ratio, but if it works, the strength gained or lost is the customer's problem. (ahem)

I wet the bottom (or deck) then fold the rail cloth onto the bottom (or deck) to wet it out there.  Once all the rail glass is wetted, flip it down and lap to the deck (or bottom) starting from the center and moving to the tips.  This way makes for VERY LITTLE on the floor, but if using catalyzed resin it can't be saved. 

UV cure meant even less waste, I could go with maybe a half cup on the floor when glassing a longboard.  This leads me to be referred to as Frugal MacDougal in some circles.  I doubt any production glasser, or most backyard glassers, bother to conserve resin as much as I do.  But resin is now, what, $45 a gallon?  When I glassed my first board in '68, it was $7 a gallon. 

   Howzit Honolulu, Actually the mix ratio worked just fine and there was no strength difference just time difference but I see where you are coming from. My mentor could do a 7' board in about 3 and a half minutes. We had one of those cat measurers that you could dial in the catalyst amount and all the laminators used 1 push down of the knob but the owner/mentor would do 2 1/2 pushs and it blew me away how fast he was. The main thing was to not let the resin take to long to kick so it didn't soak into the blank. When it came to doing the lam I poured a bead of resin just above the draped rails then wet it out then did the bottom flats and any resin left went back to the rails then I wrapped the rail. I would catch as much resin as possible back into the container and put that back into the 5 gallon tub. I didn't buy drums due to the hassle of getting rid of them since you couldn't just take them to the transfer station and throw them away but I could put a 5 gal in a trash bag and nobody was the wiser, but I did take the tops off and either catalyze what was left or just put the topless UV resin can in the sun. Not bragging but the people whose boards I glassed would tell me my boards were constantly the strongest and lightest they ever had and that was enough for me and that included some really long time shapers. My shop was always full and and shapers would wait to get blanks into my shop. I love making surfboards but it is not a choice now since my cancer ordeal and I really miss it bu my health comes first. Aloha,Kokua

Up to 2% in my experience with the stuff. You can reduce the ratio (I used 0.5% for UV poly). Any less than that and you might be waiting for a bit.

thanks for all the replies, the info will really help!!

just want to glass at night, got some boards for customers

and my "real job" has me going in earlier so sun light is at a

premium and with the change in seasons I'll be really screwed