Contaminated MAS hardener container with LV resin!

While returning the epoxy removed while priming the pumps I found I was stupidly pouring the LV resin into the slow hardener container. My only excuse could be I must have seen B in "Blue"  written on the yogurt container. The amount was probably about one pump worth of resin.

Thinking I had some time before I pumped out and mixed some epoxy for laminating bulkheads and it seems to have worked and hardened okay.

Is it a bad idea to continue to use the hardener?  My thought is if I don't move the container the hardener will only react to the resin in contact with it. That their is likely a difference in density and the two won't readily mix. Does that make any sense?

I don't like the idea of spending $80 on more hardener. But rather that than ruin the boat with bad epoxy. 

Thanks any help, thoughts, or wisdom,


4 replies:

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RE: Contaminated MAS hardener container with LV resin!

Digger I'm inclined to agree with your take on what'll happen inside that hardener container. Resin & hardener typically do differ a bit in density (why different ratios are used when proportioning by weight vs. volume) but not enough that it'd come into play in this instance.

I'd approach this by pouring the hardener out of the container it's in now into something really clean while watching closely for a lump of hardened resin you can extract. Likely as not that resin contaminant's effectively isolated itself by reacting with hardener it came into contact with even if it's not a solid mass but a softish kinda blob thing.

Going one step further might have me getting one if those paper cone filter things used for straining paint. Has a bit of cloth at the point, usually fits in a large plastic funnel if you think the paper's not stiff enough by itself. Maybe warm-water bath the hardener before straining it so it flows more easily too.

My two biggest concerns would be that the contaminated hardener might clog the pump I use with it then throw off further dispensing, or that during the filtering procedure I'd contaminate it further somehow. Done carefully the latter shouldn't be a concern while the former's reason enough to do something towards removing the contaminant.

RE: Contaminated MAS hardener container with LV resin!

If it were me, I would dispose of the suspect hardener and buy new.  It is possible that the hardener may be just fine, but there is really no way to know.  From a chemisty perspective, your assumption that the two layers will not mix because of different density is incorrect.  The molecules in liquid are in constant motion and infact they will mix.  It is called Brownian Motion.  The common high school demonstartion is to mix oil and water in a container.  Initally there is a fine line separating the two but over time the line disappears even if undisturbed.  Over time, whatever resin molecules are in the container will migrate and find forever mate resin molecules.  It is likely that this will occur at the molecular level so trying to strain them out with a filter would not be successful.  Depending upon the quantity of resin involved, these tiny "clumps" of cured resin may alter the volume ratio of the hardener and may prevent a full strength cure when mixed with resin in the future.  In the grand scheme of boat building, spending $80 to make sure that you have good full strength epoxy seems like money well spent.       

RE: Contaminated MAS hardener container with LV resin!

i would consider calling MAS technical support and see if they have a perspective.

i have had once, in my building history, some kind of epoxy problem, and it was a total bear to remove and redo a large section of improperly cured epoxy i removed the better part of a gallon of resin from the inventory and bought a new gallon.

so while $80 is not chump change, absent MAS telling me its ok or doing some reliable testing to confirm its all ok, i would relegate any remaining use to some nonstructural arts and crafts.  i just don't think its worth all the potential aggravation.

if this was a composite aircraft, it would be easy.  you could not use it.  boats we get to take a bit more risk.

fwiw...i do think testing what's left can be done.....if it cures and gets hard as appropriate....i expect you are fine....but i see a lot of potential aggravation with all the things you now need to work through and just not sure its a great trade that may never work out.


RE: Contaminated MAS hardener container with LV resin!

  Thanks for the replies!

Spclark, my intitial hopeful thought regarding density doesn't seem to have played out. What I've seen since seems to prove out what Mark N wrote about Brownian motion.   I feel confident the epoxy I mixed up immediately after my error. But when I tried to pump out a batch the next evening the hardener pump would not return to the top of the stroke and it felt like there was spring keeping it compressed.  Unscrewing and taking a look at the pump it looked kind of goey, thick, at the bottom of the straw rather than nice and syrupy. I was able to pump out some of the hardener into a container last night and looking at it today after work it just don't look right.

Mark N, thanks for the description of the dispersion of differing liquids. When I was trying to figure it out the closest I could remember was with gases and how they will expand to fill a space.

Hspira, I did call and talk with MAS tech support yesterday after work. The summary of the tech-person was, "Hmm, that's a tough question. I THINK you'll be okay. Let me check though with R&D to see what they say. R&D's not there, let me get your number and I'll call you back." So far he hasn't called back.

I agree with you all on the price of my mistake and came to the decision last night to put in an order for more hardener and pump set.  Compared to the price of the boat kit, sail kit, spacered inawale, kit, and every thing else along with it it's a small price to pay for my learning experience.

Far less than a single credit in college -- a bargain! :)


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