Epoxy help

Hi guys, as i was saying i am learning how to use two part epoxy.  I have plenty of experience with poly resin, but all my favorite boards happen to be epoxy now and they all need some work so i need to figure this out.  First time i used two part epoxy i followed the 2:1 epoxy to hardener ratio and the stuff bubbled out of control and was unworkable.  I’ve been sticking mostly to solarez in the blue tube since.  But now i have some repairs were the solarez wont cut it.  Got a new brand of two part epoxy this time and was very conservative with the hardener, no bubbling but the crap is taking forever to set up.  Here’s some pics of repairs that i did 24 hours ago.  One is a leash plug with the epoxy qcel mix and the other is a carbon fiber patch for a future flex board.  on the leash plug its still gummy but  getting firmer and the carbon fiber patch is the same but i could still lift off the patch if i wanted to.  Im still a long ways away from being able to sand into these.  Should i be patient with this and give it a few more days to try and harden or just strip it all off and start again?  Worried if the mix of epoxy to hardener isnt just right it might not be as structurally sound.  thoughts? I got a big bottle of epoxy so i am determined to figure this out. thanks in advance. 


Hey mgcorrei,

First things, don’t ever be conservative or generous with the hardener, do your best if neasuring by volume to get it exactly to 2 parts resin to one part hardener.

I have always measured by volume, ie. cups and never had a problem.

Next up, make sure to use a surf brand of epoxy, i.e. greenroom , fiberglassHI, resin research, etc… what brand did you buy?

Before removing the tape and leash plug, you can try heat curing it in your car, for a couple hours, don’t let it get above 110-120 F. 

Otherwise if you decide to tale everything off, and reapply, a couple of tricks I learned from the sways experts, are before mixing resin and hardener, you can heat up the resin for a couple seconds depending on how much you are mixing. . When you mix, move the mixer kinda slow, for a minute to two monutes depending on quantity. A good sign it is mixed, is it will be cloudy, then will clear up.

Other tricks are to put it on thin, and use a roller.

 

 

 

If it were me, and if a do-over were possible without too much hassle, I’d scrape, and do over.  Its your call.  If its starting to gel, it should set up eventually, from my experience.

I use Resin Research epoxy.  I measure carefully, and by weight (spring scale).  I mix thoroughly, and not fast enough to whip bubbles into the mix.  I have never had these type of issues.  

MG- re-read the instructions that came with the epoxy. Make sure you do not have the containers reversed.  Is your brand really 2 parts resin to 1 part hardener?  Make a small test batch, by the numbers. Its working life should be close to the label. If that works go from there. If not dig deeper.-J

I picked up the composit resource epoxy from mitch’s surf shop, so its gotta be good stuff.  I don’t have time to work on the boards until monday so if theyre not cured and sandable by then i figure im better off just striping them and starting over, i got plenty of materials.  I’m going to find a measuring cup and do this precise at 2:1. I just checked on the boards this evening and they’re a bit firmer. a few more questions

  1. After how many hours should i be able to sand into the epoxy given that i mixed it correctly?  My stuff says it sets up in 30 min, not sure if that means i can sand it or it kicks in that time

  2. Does mixing in qcel require any extra hardener?  Should i mix the epoxy and hardener then add the qcel, or go epoxy qcel then hardener?

3)  melikefish, you mentioned i could heat up the epoxy before adding hardener.  Are you talking about putting it in the microwave?  if so how long?  doing this speeds up the drying time? 

love this website!, thanks!

My experience is that it varies, but you can sand it when its sandable, haha.  You know, when it doesn’t gum up the sandpaper.  Keep in mind, if you sand before fully cured, take extra care to avoid breathing the dust, or getting it on your skin.  Wash your clothes and clean up good after working with this stuff.

I always mix epoxy and hardener, then add the thickening agent.  Or sometimes add all three, and mix together,  I have never mixed epoxy and thickener, then added hardener.  But I’m not saying my way is right, I have never tried the other way.  

…so you bought a resin repair kit???  Did the instructions tell you anything?

Exothrem is always fun to deal with…that’s what you should have with your leash plug…masive heat in a small spot…but your mix is wrong…so it may or may not cure

What I see is a ding repair that needs to be done with RR and not with an epoxy repair kit. Follow the instructions that came with the resin. Some resins are 2;1…some are 4:1

and I buy stuff from Mitch’s in Solona beach…Bought a 7’6" blank there a few months back…i buy epoxy resin from somewhere else…

Epoxy resin …gotta follow the rules

 

Definitely make sure you have the mix ratio right. I couldnt find that resin online, I just found something from US composites.

For mixing filler, i do the same as Huck, mix first then add thickener.

For the microwave it all depends. I think last time for about an oz of resin, i had it in there for 3 seconds. Be careful though if you put it in too long, you will let the smoke out:)

As far as time to sand, it all depends, i am not a professional so don’t have a schedule, but if i heat cure it in my car, i can sand after about an hour and a half, with a low grit. I found using a machine before it cures all the way, you will end up gumming up pads alot. Also I can wet sand it sooner since the paper doesnt get hot and gum up.

The more epoxy in one place at one time, the bigger the exotherm. Maybe think of pouring the plug in multiple batches between gels. Place a wet towel on the bottom to act as heat sink. 

Epoxy resin and hardener is like lots of little shaking hands, …you need the right balanced number to get a strong bond. Spare hardener “hands” just mean spare hardener hands…no extra bond.

Resin Research Kwik Kick sets fast and has minimal exotherm…awesome for EPS boards with FCS plugs!

Good luck!

Yep i ended up just stripping it and doing it over again.  Mixed it at a strict 2:1 ratio, measured out with the bottle caps of the product.  I then stirred it slowly for a good 2 min.  It came out just as it should this time, kicked in 30 min and hard as a rock after letting it sit overnight.  I did a bit more hardener in the batch with the qcel mix and backed off the qcel a lot just enough to give it that jizz like look, no problems at all, no bubbles nothing. Stoked!!!

McC - I use Composite Resource & Resin Research, and they both have their good and bad qualities.

A couple of notes specific to CR:

  • if you’re going to err, it’s best to err on the side of your hardener being a hair under, rather than a hair over.  If you get too much hardener, you’ll get a very hot exotherm.

  • CR gets hotter than Resin Research “Kwik Kick” or Resin Research “Slow,” and about the same as Resin Research “Fast,” anywhere you have more than a film of it (for example in fin boxes or leash plug holes).  This is kind of a negative since CR cures slowly but heats up like RR “Fast.”  CR is about the same cure time as RR “Slow.”  If you’re installing leash plugs or fin boxes in poly, you will do better using RR “Kwik Kick.”  If you’re installing plug or boxes in EPS you should only use RR “Slow” as all the other options can easily get too hot when they kick and melt the EPS foam.

  • CR is GREAT for hotcoating – much better and will lay down much flatter and prettier than any of the other options as long as you’re not trying to hotcoat in temps that are too high or at a time when the temperature is rising instead of falling.  When you get good at glassing, often your final CR hotcoat will only need to have the seam sanded to produce a really pretty result (as long as you get the bubbles out with a heat gun or alcohol mist).

  • Back to first point: unlike RR, CR is actually less sensitive about having too little hardener in the mix.  You’ll notice that your measuring cup pretty much cures on its own, even if all you did was use it to measure and pour (without any mixing in it).  It’ll cure at different rates if your hardener amount varies, but even if you get it a little light it will still cure – it will just take longer.  The disaster scenario with CR is mixing with too much hardener.  You will just about always get a violent exotherm if you mix with too much hardener, unless temperatures are really cold.

FWIW it’s generally not recommended that you measure your amounts by the capful/cupful.  The reason being that there is always some residual epoxy left in the cap/cup between each pour and it throws things off.  The more times you fill and pour to achieve the required amount of material, the greater the chance for significant error as the residual discrepancy will be cumulative.  

It is also not recommended that you tweak your proportions when working with fillers.  Calculate your resin/hardener proportions first, then add filler to the proper mix.

If it turned out OK, great.  You got lucky.  For consistent results over time, stick with the recommended formula.  Eyeballing here and there or tweaking your mix will eventually cause you grief.  

I’ve even seen a post here by one of the moderators which implied that he adds a bit of extra hardener if it’s cold outside… don’t do it.  He got lucky too.  

 

 

Epoxy doesn’t like cold weather - best remedy IMO is to keep the glassing room warm

Im in san diego so i don’t have to worry about cold weather screwing up my epoxy, its been about 70-80 F and sunny all week. I agree i probably been getting lucky using the bottle caps to measure, but all the batches ive made so far have come out great. I swiped some of these ketchup containers from work, these should work better for measuring. Looking forward to finishing off all my epoxy repairs this weekend! THat includes the pendoflex, hess, and hypto krypto. 

Invest $25 into one of these electronic scales.  Money well spent to make sure your ratios are accurate.  Comes in super handy when you have to make those small fixes (like your leash plug).  

http://www.target.com/p/taylor-digital-food-scale/-/A-11011109#prodSlot=medium_1_1&term=electronic+food+scale

I aways mix micro balloons in my leash cup mix to reduce the density and therefore the heat of exotherm.  still plenty strong.  mix in some chop fiber if you want and score under the glass to allow some resin to seep under that lip.  never had one pop out.

I don’t know what the fark you people are talking about…tons of bad advice on the internet…

Go here…http://www.swaylocks.com/forums/first-epoxy-glass-job-s

Read it…learn it…live it…Stop F…ing around…Follow the rules. Buy Resin Research. Scale or volume it’s ok. Clean mixing cups. No solvents. Clean shop. clean hands.

When adding filler, always mix the epoxy first, then add the filler, otherwise some epoxy will stick to the filler material, just like it sticks to the side of the cup, and harden poorly.

Also, filler doesn’t keep the mix cooler. It insulates and traps heat. If you think it kept it cooler, probably, you added the filler first, it screwed the mix, and it didn’t heat because it didn’t cure.

Listen to John an Ray. Both have lots of experience.

Well Mr. Everysurfer, if that’s your real name, you are wrong. i mix it all in after mixing the epoxy for the reasons you mentioned.  But adding microballoons reduces heat production through reduced density. Basic thermodynamics.  I will grant you that John and Ray know more than I do about board building.  But I know the secret to a happy life so it sort of all evens out.  

 

I just want to add to this thread an observation about temperature and humidity (and maybe other factors I’m not taking into account?).  Without the intent of arguing, I’ve read with interest – usually after some glassing disaster or another – the comments over the years about glassing in both cold (under 70 degrees?), optimal (around 70 degrees?) and hot (over 74 or so degrees?) temperatures, and my own backyarder results haven’t been in line with them.  I wonder if any one can offer explanations or insights as to why. [Bold to highlight my actual question, buried in my as-per-usual-too-lengthy-in-the-interest-of-including-relevant-details post.]

With Resin Research “Fast” I’ve had my best hotcoats – least fisheyes, but occasionally with some surface blush – on cold, rainy days (even in post-noon hours when temps are rising); I’ve had my worst hotcoats – most, worst fisheyes, unacceptable and having to be wiped off, without fail – on warm, dry afternoons between 11am-3pm.  In the latter case – warm/dry – I only attempted those hotcoats over a sanded hotcoat where the board was likely to be watertight already, or to only have a small number of pinholes.

Details:

  • I glass in two areas, (1) a carport with a white, corrugated fiberglass roof – the sun comes through it, and I’m under that portion of the roof, which ends up being radiantly heated in the afternoon, and (2) a wooden shed – wooden on all sides – that heats up when the sun is on it in the afternoon.  Every time I’ve attempted to hotcoat with RR Fast in either space between 11am-3pm I’ve had horrendous fisheye-ing.  In the shed, it doesn’t matter whether the door is open or closed (with the shed door open, the glassing rack is in the shade.  Again, the only times I’ve tried to get away with glassing during those hours is when the board should have already been sealed via a hotcoat that ended up being sanded and treated as a sanding coat.

  • I’m in Santa Cruz, about 6 or 8 blocks from shore.

  • The carport/fiberglass roof spot is over concrete slab, the shed is over damp ground.

  • There’s a sensation on the skin either above a certain temperature that feels like radiant heat touching the skin, either signalling a certain temperature or rising temperature – any time I’ve hotcoated when that sensation is present (probably somewhere in the mid 70s and higher, I’ve gotten fisheyes).  Below that, never a problem.

  • In both spaces, I’ve hotcoated down into the 50s without problems.

  • Again, best hotcoat results with best ability to hotcoat at any time of the day has been when it’s rainy and cool all day – even under the carport in daylight with the sun behind clouds but over the carport roof.

I’ve had similar, parallel results hotcoating with Composite Resource under the same sets of conditions.

I know I’m a dummy for trying to hotcoat during hours I already know to be problematic, but I’m one of those people who likes to test out different sets of conditions (and who is impatient to put yet unfinished boards in the water).

Main point:  I have never had any problems with hotcoating due to cold (down to mid 50s), but have almost always had them in hot conditions, yet I know people who heat their glassing rooms up to temps above the ones I regularly have problems in with the same resins.  What’re the likely factors determining the differences, here?