Epoxy Curing...feeling foolish

So, this must be a common problem but I ask anyway...

I am building a NE Dory and started epoxying the bulkheads yesterday morning.  I have worked with West Marine Epoxy before and I THOUGHT I mixed the ingredients sufficiently.  I spent at least a minute mixing each small batch. 

This morning (almost a full 24 hours later) there seems to be some uneven curing of the epoxy.  I used very small batches and even checked to see if the containers I mixed in had cured...they gelled and that's all.  

If it were totally uncured I would just scrape and try again but all three peices seem to be pretty bonded together.  What should I do?   If it is a case of poor mixing, will it cure over time or do I need to figure a way to start again?

 I'm trying to think of a positive spin for this little hiccup...So far I've come up with "at least you screwed up at the very beginning instead of halfway through."  Can anyone do better?

8 replies:

« Previous Post       List of Posts       Next Post »

RE:UPDATE Epoxy Curing...feeling foolish

So I spoke with Mark and CLC and it seems like I just didn't mix long enough.  That was stupid.  L

Luckily the parts came apart and I only needed to scrape off the goop.  I'm now doing a test to see if my pump ratios are correct with a small 1 pump batch of epoxy to see if it hardens in a reasonable amount of time.  Then, I am heading to the store to get some denatured alchohol to really clean the parts.

Lesson (hopefully) learned.  


RE: Epoxy Curing...feeling foolish

I ran into this problem on my first build, and found that pumps can be very unreliable when mixing small quantities. I now use measuring cups for all mixing. Be sure too to get into the corners of your containers when mixing. -Wes

RE: Epoxy Curing...feeling foolish

I don't use pumps.  I've never had an issue with "not mixing enough" even with just 15-20 seconds of mixing.  I may have less experience than others but I can't believe that's a realistic scenario from someone who isn't deliberately trying to leave things unmixed.  I'd be far more likely to believe the ratio is off than it wasn't mixed properly.


RE: Epoxy Curing...feeling foolish

Yeah, it sounds to me like the ratios were way off. If you're using pumps to measure your resin and hardener Erik, make sure you're using them correctly. MAS epoxy is 2 parts resin to 1 part hardener. BUT, the pumps are calibrated so ONE stroke of the resin pump dispenses twice as much volume as ONE stroke of the hardener pump. So to mix it correctly, it's 1 pump stroke (not 2 strokes) of resin for each 1 pump stroke of hardener.

I personally don't use pumps and don't know if it's possible to screw the pumps into the wrong containers, but that would mess things up too.


RE: Epoxy Curing...feeling foolish

Im a diehard pump believer and user with both MAS and WEST S. Ive NEVER EVER had issues EVER.  Ive been using epocy on and off since 1998.  My pumps dont goof.  I do however make sure they fully extend OUT after each pump compression cycle.

 Geeze... I think Ive gone through...  $600 worth of epoxy too.


Not a hitch.


Sounds like the ratios were way off.



RE: Epoxy Curing...feeling foolish

A also never use the first pump of resin or catalyst if its sat for a while.  Dont want any air bubbles - so the first pump is always a purge. Adds up to peanuts. If that.  Again make sure the pump handles return to full extension everytime.



RE: Epoxy Curing...feeling foolish

I know this is an old post but I have to chime in here.  I am using MAS epoxy and pumps which came with my Skerry kit and you can see that one pump of the hardener puts out about half of what the resin pump puts out.  The really wierd thing is that I've now gone through one gallon of resin and the gallon of hardener is also empty.  Like I said, the ratios look right and I've never had a problem with the mixed resin curing or going off too fast.   I don't think the hardener was half empty when I got it.  Point is that you really have to try to screw it up and the mixture will cure even with really screwed up ratios as long as it is mixed thoroughly. :-) My semi uneducated opinnion anyway.

« Previous Post     List of Posts     Next Post »

Please login or register to post a reply.


Special Financing with Blispay

 CLC's Fall Kit Sale