Resin kicked FAST. RANT**

General Discussion
1

So I’m glassing the deck of my second board today… my first board went great. Bottom/deck/hot coat all fantastic. Now I’m on my second board, glassed the bottom… perfect. All is well. Today when I glassed the deck OMG what a surprise I stumbled into. Idk WTF happened, but I didn’t even get to wrap the rails before my resin went jelly on me. I freaked. My heart sunk and my boards life was flashing before my eyes. Both rails looked terrible they were all globby and dry… they would barely wrap. So I freaked out some more and decided to rip all the glass off before it was too late. I salvaged the board and prepped it for a second shot, and now I’m just licking my wounds, dumbfounded on what I did wrong. Anyone else been here?

the temp was 70 but it must’ve been 80+ in my shed. 30oz of resin. 9cc cat. Maybe I took to long idk it felt like 5 minutes. 

2

I am an epoxy guy know but when I worked with poly I used to use as little cata as possible, it always cured. Mix more resin you need and work fast from middle to rails, let falling resin on laps, push out resin from deck to rails and tuck them. For me It’s faster and efficient to pull out resin when you work with poly. 

3

It happens. And there’s several things that can affect how fast resin goes off. 

First, what catalyst?  It comes in varying strengths. Check the bottles if there’s more than one. Catalyst doesn’t improve with age either. Methyl Ethyl Ketone Peroxide ( MEKP) , well, it’s a peroxide, not the most stable molecule going. Fresh stuff is stronger. Old stuff can be utterly useless.When in doubt, pitch it and get new.

Next, how long did it sit after mixing? If it sits in a container, it’s an exothermic reaction, it gives off

Heat. This is the big one and probably what bit you…It’s happened to me …I was going to say a few times but I’m a slow learner. it’s more than a few. 

Chemical reactions mostly go faster with heat. And it’s not a straight-line graph, it swoops up. Resin temp (how long it sits catalysed in the container), air temp, surface temp of what you’re putting it on, how thick the coat is (thicker, they heat up by themselves)., they all kick the resin off faster or slower. The charts you see are for a standard temperature, generally 70°F (20-22°C), under that it takes longer, higher than that it takes less time, maybe a lot less. 80°F or more? Yeah, a lot faster.

Bright light. It may be it acts like a heat lamp, the UV in there may help drive the reaction, I dunno. And this is with plain resin, not the UV hardening stuff. 

What slows it down? Color, pigments and tints. Humidity. dry air seems to go faster, high humidity slower…and sometimes I swear it’s a little cloudy when I do a job on a humid day. Fillers, though with something like Aerosil you are putting it on relatively thick, I go light on catalyst with those to account for that.

So, what are you gonna do?  Work at night, when the shed has cooled off, that’s one. Cut the catalyst to 2/3 or 1/2 of  the ‘chart’ value if you are stuck with working in heat. Mix fast and work fast, don’t let it sit and turn to Jello in the container, and it will. . 

Last but not least, and only my own nickel and dime theory:

Polyester resin hardens via catalyst. That catalyst for all intents bites off the ends of the polyester molecules of the liquid resin which in then join up to make longer chains of those molecules. Unlike the liquid resin, these are solid at room temperatures. 

You ever notice, hot batches tend to be brittle? Here’s my thought; slow batches are stronger and tougher. They make longer molecular chains. Go with minimum catalyst.

hope that’s of use

doc…

4

Like Doc said, catalyzed resin starts heating up as soon as you mix it.

In a “big deep” cup, the heat generated feeds back on itself – low surface area to volume ratio.  The hotter it gets, the faster it kicks.  The faster it kicks, the hotter it gets.

Add to the list of factors, you want a container with higher surface area to volume ratio – to help dissipate heat while working.  Not that I would recommend using a paper plate, but think paper plate vs. 20-oz drink cup. 

5

Dang, awesome info thank you for all this. I’m gonna take this all into account. I was thinking about glassing in the morning before noon. Or maybe at night as the temps drop into the 60’s.

I glassed during peak daylight hours/hottest part of the day. My shed has a big window so the sunlight can definitely penetrate through. Maybe I’ll cover that up next time.  

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Thank you! Makes a lot of sense and something I would never think of. 

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I’m using MEKP. I got it about a month ago from shapersupply.com. I did mix then place two logos which took a tripped me up a bit because the one wrinkled on me. So the resin was sitting still there in the bucket for probably a minute. 

 

nexr time I am definitely going to mix a little resin in a cup just for the logo paper, take care of that and then catalyze my larger batch. 

 

For 30 oz of resin, what would you suggest the lowest amount of MEKP could be. I believe I used 1 percent which was 9cc. 

8

Yeah, logos and such bite a lot of people too. 

Anyhow- fresh MEKP- check. Good. A couple of days won’t make it go sour on you unless, say, you leave it in the sun. The proverbial ‘cool, dark place’ is best.

And I do mean sour, spent catalyst has a strong vinegar-ish odor. I suspect the stuff breaks down to acetic acid (vinegar)  and formic acid (ant sting poison).  Don’t go and sniff it, really bad catalyst smell is strong enough that you’ll know and the MEKP isn’t something you want to be inhaling in any concentration anyhow. 

How much to use? Play it against temperature, maybe hang a cheap thermometer in the shed? 70° F, I would go with the 9ccs (the amount off the chart) . back it off to say 6ccs if it’s up around 80°F and if it’s much warmer than that, wait for it to cool off?. 

For what it’s worth, you may have seen those ‘Don’t leave your dog in the car’ warnings, how it gets a lot warmer inside a car with the windows up than it is out in the air? You may find it’s warmer than you think inside said shed. Your resin stored in there will be warmer too. Which is where your cheap thermometer comes in.

The other thing is that chemicals like catalyst and resin break down over time. Heat accellerates that as well, so if you have a cellar or someplace cool and dry, stash them there when you can. It’s generally cooler and at the same time ( I’m in the Northeast) leftover resin doesn’t get really cold and crystallise on you. I’m here to tell ya that when you have a rush job early in the season and you need it done before you can get fresh resin, trying to filter out the chunks sucks…

hope that’s of use

doc…

 

9

Absolutely, lots of help ty. 

10

Maybe try some resin research epoxy…

11

I used 0.5 to 1.5 % with orthophtalique surf polyester (SILMAR) and poly/acryl hybrid. More with isophtalique resin, one’s I have is less reactive. 

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There are other tricks like putting resin in the fridge on a hot day… that can help.  Various brands mix in various amounts of accelerator agent so it’s generally a good idea to follow each brand’s specific directions for MEKP to resin ratios. 

Maybe get yourself a thermometer for the shed and look up the cure rate variability associated with temperature changes.  10 degrees either way can make a big difference.

 

  

13

Put a clock on the wall and glance at it once in awhile.  30oz. Is about 2 pints or a quart.  9cc of MEK is perfect for that amount of resin.  You need to work faster and have a plan when you pour and squeegee.  Lack of planning and speed is your problem.   You might have saved it by quickly pouring uncatalyzed resin on to the rails and squeegeeing fast as possible.  The two resins blend and slow down the set.  I don’t think in your case that trick would help because by the time you realized you were in trouble; It was already too late.  Also if it was actually 80 degrees and not 70, you shaved 5 minutes off of your working time, which at 70 would have been 15 or 20 minutes.  10 cc in a quart or quart and 1/2 is perfect.  Some guys do 15cc.  You need to take a look at a chart like Greenlight does with temps, amounts and set times.  Then try to work within those parameters.  Wet everything out as quickly as possible and get to the rail ASAP. Then come back and work the resin.  Getting rid of dry spots and pulling excess resin off.

14

A few years ago I stopped placing my logos under the glass when laminating boards.  Makes life so much easier.  For someone who doesn’t glass boards all the time the logos can create a lot of drama which is something you really don’t need going on when you have resin kicking.  For a while I was putting the logos under pieces of 2 oz cloth on top of the lam.  Now I skip the cloth on top…actually I put a scrap of cloth over the logo to squeegie it out and then wait a couple of minutes and then pull the cloth off which leaves the logo perfect.  Then I hotcoat.  Doing it this way you just have to be careful not to sand into your logos.  The logos actually look better on the finished board this way too.  They have a lot more pop.

15

Another option is to use the UV-cure resins.   

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I did print out a resin chart from greenlight so I knew I didn’t over catalyze. You’re right I need to work faster and have a better plan. I watched a YouTube video on a method “pros” use on working from far rail to close rail then working the board in thirds and so on, Needless to say I am not a pro and can’t work like one, man they made it look so easy lol. 

I agree with you and need to drop the “technique” I need to quickly saturate the deck. Wet the rails and wrap then go back and pull excess. 

 

i did film my bottom lam and it took about 20 minutes before the resin started to gel up. The temp that day was probably 65 - 68 degrees 

17

Thanks actually just saw a video on the from Arakawa boards Instagram. I think I’ll try it. 

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I’m glassing the deck today. I’ll let you guys know how it goes. Temps are just below 70 and cloudy. 

19

Glassed the deck and it went great. Thanks for all your guys advice it went a long way! Glad I made this post because I learned a lot from it. 

Dropped the analytical strategy approach and just saturated everything and went straight for the rails. 

30 oz of resin again and backed the MEKP down to 8cc. Temps were about 70. Took about 20-25 minutes for the resin to start gelling up. 

 

3024×4032 2.79 MB

4032×3024 3.31 MB

4032×3024 3.3 MB

3024×4032 3.23 MB

20

Twenty minutes would be the limit.  Beyond 15 or 20 minutes and you are on borrowed time.  At 10 or 15 minutes I start thinking about how I’m doing.  Still got that butt crack and nose tabs to go.  Gotta finger the bubbles out of the hard rail etc.  Man!  I better get with it.  The resin in the pot is not a good indicator for me as I have my amounts dialed in and don’t usually have anything left in the pot.  Speeding things up is the reason I use a small cotton roller on the rails.  Using the 1/3, 1/3, 1/3 method slows things up if you ask me.  I pour nose to tail down the middle and then squeegee toward the side I am standing on.  Spreading nose to tail, tail to nose in a long “road grader” motion.  Then Iusually jump to the other side and do likewise.  Then I work on each rail, getting the hanging glass cloth wet. Hopefully most of it is already wet due to the cascading resin off the flats.  Once most of the rail is wet(even if there are a few dry spots) ;  I tuck it from middle to tail, middle to nose.  Then I switch to my little 3" roller to wet out the dry spots at the rail.  Then go back and start rewetting and doing what they used to call “drying” or pulling off excess resin. I’m also looking for dry spots during this stage.  It’s at this point that you can start working the tail and nose tabs and finger press the bubbles out of the rail.  You might consider using UV on the next one and just go thru the process in slow motion a couple of times until it becomes mechanical.   I use Silmar 249A.  Usually OB 3.  I think the Silmar you are using is the one with Acrylic in it.  Harder to work with and harder to saturate.  That’s why most laminators have quit using it after giving it a try.  I could have bought several half drums cheap from my supplier.  They were returned by the glass shops.  I tried it for one five.  Dry spots where they shouldn’t be.  I finally used it up by mixing it with regular 249A.  Lowel