Epoxy Failure, or...

[SBrookman]

A rather inauspicious start for my next project, a 16' Barto/Brady Melonseed. With the model done and the temps finally getting above frigid I made it to the shop and got 16 slices of 3/16" black locust cut for the stems. I brought them and the epoxy (West system w/205) into the basement (fairly constant 55) and gooped and clamped them.

I returned 2 days later and it looked pretty good, I unclamped and began to clean it up. I was feeling pretty happy getting the first part of the boat underway until I was just about done, of course, when the laminations gave up interest and starting going their own way!
I've never experienced epoxy failure before, and was glad that it happened now, rather than on the boat, would be even better if it never happened! Thinking that maybe the epoxy was cold soaked when I brought it to the basement, even though I gave it hot water bath, I cleaned up the veneers and reglued just the inner stem (6 lams) this time. Clamped it overnight (55 again) and in the morning it looked fine. Until I returned a couple of hours later to find this:

Can epoxy go bad, it had been cold soaked all winter? Did I not clamp it long enough for the 55 temp? Gougeon says problems can occur below 40 degrees with 205. Well, it was fun to start. Won't be quite as much to restart.

[Ian McColgin]

That's distressing. It could be getting the epoxy to set but I've not had trouble even with old epoxy that had been through a few winters.

Alternative thought - could it be the locust? I use epoxy as a combination lube and sealer when setting black locust trennels but it's not serving as a glue there - the trennels stay in by fit. But I've handled lots of black locust and knowing it's grain I'd be interested to know if it lends itself to glueing? Anyone?

[stromborg]

What is the epoxy left in your mixing pot doing? Has it set up or remained soft? I've been warming my shop up to about 60 while I work and letting it drift down to it's "normal" of 40-45 this time of year. The west/205 I'm using is usually set up pretty hard after 24 hours, rock solid after 48. I wonder if your mixing pumps are out of calibration?

Steve

[SBrookman]

Maybe the pumps. The first batch I used up, just crusty film left as usual. The second batch I had 1/4" left, it turned into a solid plug, BUT it popped right out and there was a bead of resin on the bottom. I've never seen that before. I have another pump which I will try.
I did a search on epoxy and BL and didn't find any definitive. I did laminate a BL transom cap for Vika with no problems but the bend was much less severe.

[JimConlin]

If West 105 epoxy resin is exposed to cold, it will partially crystallize. These crystals won't go back to a liquid state until they're warmed to about 120F, IIRC. The crystals can clog the mustard pumps and the only practical way to clear them out is to clean the pumps with solvent (acetone). I'd clean my hardener pumps too (with water). If your pumps are clogged, your mix ratios won't be right.

Even if your shop is 55F, I'd get my epoxy warmer than that before measuring and mixing. West 105/205 will eventually cure at 55F, but the resin is viscous and the mustard pumps are sluggish at 55F. If the resin is too cold to pump, the pumps suck some air on the back-stroke. If there are bubbles in the pumped stream, this is happening and your ratios are off. Whatever your shop temperature is, keep your resin warm.

I've never heard of a problem with epoxy and black locust.

[v10builder1]

Don't get discouraged. Scrape or sand it off and try something different.

I am a BIG fan of epoxy, but I use the marinepoxy brand from boatbuilders.com - bought a kit to get started when I got started and have never used anything else, so I don't have knowledge of the other fine brands. The marinepoxy is a 2:1 ratio, I am using their medium speed hardener, and using 1 OZ/stroke pumps to mix.

I have used about 3 gallons of this stuff, and maybe I am lucky, but NEVER has the mix failed to cure or hold. This brand/type is extermely viscous, so you better add plenty filler if you are doing other than coating a flat horizontal surface.

My epoxy material has been pretty cold, as low as the + twenties farenheit, and I have not had any crystal problem at those lows. I try to get the shop to 60 F and let the work warm up, too, and I have a 250W heat lamp I shine on the epoxy (don't get it too warm or a 2+1 OZ batch will kick before you get it applied) for a while.

In my experience, it takes much longer to cure in colder tremperatures, and I try not to stress the joint before at least a week of cure. I work mostly with plywood, and I do not know black locust, but I expect either that wood does not saturate well, or you did not coat the surfaces and let that cure before doing the glue-up, or that the joint was either clamped too hard or stress was applied to the glue-up before the cure was complete.

I don't mean this next comment to be anti-hardwoods, but you can glue up quality plywood and make frames, etc., in any shape you want, and as thick as you want. Coat the finished product with epoxy, and you have a strong water resistant assembly that can join to other structural elements and hull/planking with fewer fasteners. Epoxy isn't cheap, but fasterners are becoming expensive, and I never seem to have the right inventory anyway.

Get it warmer, leave it clamped longer.

Boat on.

Joe

[Peacefuljourney]

black locust isn't the problem, I use it all the time. Epoxy failure happen often on this forum, on boats and everywhere. But everybody keep telling it's a good adhesive and it's the fault of 100 other things... Anyway I won't start the war of adhesive again...

Sand with 60grits the strip before gluing to give the glue a good grip, heating blanket can also be good.
If you dont trust epoxy after those 2 failures, do like me...Resorcinol ..

[Ian McColgin]

Thank you all for info on epoxy issues with epoxy that's not only been cold but likely is still a bit cold despite shop temp having been brought up a bit.

And especially thank you for the thoughts about black locust. Laminating black locust is well outside my experience and even though none of the remarks mentioned actual black locust laminating experience, it seems there's no reason to think that it's one of the woods that takes special care for glue up.

[James McMullen]

I don't think it's the locust either. Mixing ratio error and or cold or both is my suspicion. The pumps can certainly get out of calibration--especially if the cold has allowed lumps of crystals to build up in there. Also, the greater viscosity of cold resin might just make it harder to physically mix it as thoroughly as possible.

This time of year we keep our glues and paints--all of them, not just epoxies--in the heated office instead of out in the cold shop. Our epoxy metering pump sits on a shelf right over the wall heater. We have a second Hot Box out in the back tent made from that building insulation foam with a simple lightbulb inside for a heater to keep the metering pump in when there's a big project out back. Warm and snuggly epoxy is happy, friendly, reliable epoxy.

[rob]

I have done a lot of epoxy work with BL....and I have had a few failures. I know the late Dave Corcoron of Bullhouse boatworks also made a lot of his hereshoff backbone pieces from epoxy laminated BL. For me, every time it has happened the epoxy and wood it was in contact with took on the deep reddish color tone I see in your picture. It has only happened for me when the I was pushing low temp work and/or when the wood was not fully dry....I simply won't use sub optimal conditions anymore. I think under those conditions the epoxy begins to react chemically with the locust before it cures out...but it is just guess work on my part..I have pushed other woods under the same iffy conditions and not had problems.
It's a rough image you posted, but to me the cured epoxy looks pretty off color. Sometimes you can get that with old hardener, and I have been told it is harmless. But you can also get that with a bad mix with too much hardener...like when the pumps clog or the resins are too cold/viscous.

[SBrookman]

Reddish color! I just opened a new can of 205 and it was obvious that it was a different color from the old can. You might be able to see it here, the old stuff is the middle the new just the right, barely an amber tint.

So I've taken almost everyone's advice, sanded w/80, cleaned the pumps, warmed the epoxy and now I've reclamped just 3 lams around a frame mold and I'm leaving it for a couple of days. I'm hoping it was the discolored 205, which was maybe 2 yrs old, but stored in an unheated shop.

[Dusty Yevsky]

A couple of other things to check. How much clamping pressure? Bending the strips
around the form will provide plenty of force and adding a lot of clamps might squeeze
out too much epoxy. Also, how thick is the glue? If the mix is too thick the bond will be
poor. Try painting the surfaces with unthickened epoxy and let it setup for 15 min and
then apply thickened epoxy. Lastly, make sure the surfaces are rough enough for the
epoxy to get a bite. Strips right out of the planer might be too smooth.

[Baltimore Lou]

Folks have talked about cleaning the pumps. I wonder if you'd elaborate. Clean hardener pumps with water? How do you ensure it is all out of there before putting hardener through them again? Pump acetone through resin pump? I'd like to do this but worry about its effect on the next batch. Does the acetone all evaporate before you load it again? Thanks!

[wizbang 13]

west hardener is water soluable. so y can clean the hardener pump real well with warm running water.
resin, no. vinegar kinna works.
I keep the previous , empty set of epoxy cans to "pump through" after the pumps have been sitting , well, beating upwind for 200 miles.

[bluedog225]

My 2 cents. I've used much older west with no problems. Crystallized, thawed, refrozen. I'd ditch the pumps. they are nothing but trouble. Dispense by volume into two cups. Removes one fairly likely avenue for error forever. You can use dixie cups and water and use a ruler and marker to get your ratios right. Good luck.

[JimConlin]

Folks have talked about cleaning the pumps. I wonder if you'd elaborate. Clean hardener pumps with water? How do you ensure it is all out of there before putting hardener through them again? Pump acetone through resin pump? I'd like to do this but worry about its effect on the next batch. Does the acetone all evaporate before you load it again? Thanks!

Hardener pumps can be cleaned with warm water and resin pumps with solvent. Acetone works and I expect that lacquer thinner would be OK.
In both cases, you can get the last bits of water or solvent out of the pump by turning the pump upside down and operating it a few times.

[Songololo]

Is the old can not perhaps a West Systems 207 hardener? It has an amber color ... http://www.westsystem.com/ss/207-spe...lear-hardener/

The 105/207 mix ratio (3:1) is not the same as for 105/205 (5:1) ...

[SBrookman]

>>Is the old can not perhaps a West Systems 207 hardener? It has an amber color <<

No, it says 205 on the side of the can. Same stuff I used to build the last boat. Plus I've never purchased 207, although I almost used the 207 pump today as a replacement (it comes in the same mini pump package.) I've had epoxy for longer but don't ever recall seeing the color change. And the cap/pump was never removed.

I did wash the hardener pump in warm soapy water and it cleaned up real good.

[Reynard38]

I've been using west system on some black locust on my Coquina. No problems. Shop is around 65 degrees.

[Reynard38]

I've been using west system on some black locust on my Coquina. No problems. Shop is around 65 degrees.
3/16 sounds thick for BL laminations with that tight a radius. Were the clamping pressures high? Could
be a glue starved joint.

[chuckt]

I'm no expert but I have been doing a lot of epoxy work this winter and am getting very slow hardening times at 50 degrees with West products and the epoxyworks products. I've had to heat things up or wait days for things to fully cure. Below 50 degrees I feel I'm not getting curing at all.

[epoxyboy]

Folks have talked about cleaning the pumps. I wonder if you'd elaborate. Clean hardener pumps with water? How do you ensure it is all out of there before putting hardener through them again? Pump acetone through resin pump? I'd like to do this but worry about its effect on the next batch. Does the acetone all evaporate before you load it again? Thanks!

I never had trouble with the WEST resin pump, but the hardener one definitely crudded up and got innacurate, and I wound up pumping hot water through it every about once every three months or so. By the end of a three year build I was still on the original resin pump, but was on the second hardener pump - and it was on its last legs. Trouble is you haveto buy the set.

Pete

[Bob Adams]

The orange hardner will work fine, that's just showing age. However, cold viscous epoxy + pumps + trouble! Warm it first and confirm the pumps are delivering the right amount. The pumps are cheap. I replace mine periodicly.