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sphenix-hcal-l - [Sphenix-hcal-l] Fwd: EJ500

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Subject: sPHENIX HCal discussion

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  • From: Edward Kistenev <kistenev AT bnl.gov>
  • To: sphenix-hcal-l AT lists.bnl.gov, sphenix-emcal-l AT lists.bnl.gov
  • Subject: [Sphenix-hcal-l] Fwd: EJ500
  • Date: Tue, 7 Aug 2018 18:41:33 -0400

Here is the best instruction manual I’ve ever seen to epoxy use. It came from Chuck Hurlbut who is currently executive sales manager at ELJen and worked with many of us in PHENIX times. Feel free to ignore or to follow. 
Edward

Begin forwarded message:

From: Chuck Hurlbut <churlbut AT eljentechnology.com>
Subject: Re: EJ500
Date: August 7, 2018 at 6:04:37 PM EDT
To: Edward Kistenev <kistenev AT bnl.gov>

Hello Edward,

Absolutely.  I certainly do remember you, Edward.  And it is good to hear from you after so long a time.
It appears that both of us are still busy doing what we enjoy.

I have just returned from a week of travel and meetings and am catching up.
The "amine-blush" always comes from the hardener which is where the amine chemistry is.

Concerning Epotek 301, that is a good product as far as my experience goes.  We actually use it in certain optical joints where a moderately low-viscosity optical epoxy is needed.

Most of the time, we use our EJ-500.  Several where ever possible.  It has nice optical properties, is, in general, easier to use in achieving large optical joints.  This is largely due to two factors:
(a) EJ-500 has higher viscosity
(b) EJ-500 is not a brittle-setting cement.  The cured epoxy has a small amount of flexibility which, in my experience, gives a tougher joint.

About 15 years ago we made a specific change in the nature of the hardener by going to blend of amines which have higher molecular weights.  In our own experience, this improved the overall stability with regard to long-term retention of its optical transmission in the near-UV region.  A side effect of this change is that any unreacted hardener would be less likely to migrate out of the joint. 

When preparing a batch of EJ-500 we have three general rules of rigorous discipline.
(1)  Weigh out the two components when we are preparing a batch of the epoxy.  We used to do measure out the two components by volume and occasionally had results that were less than optimal.  Weighing out the two components took care of that problem.  In my own thinking about this, the weighing of the ingredients eliminated having excess hardener.
(2) Avoid very small batches.  Always make up a 15gram or larger batch.  It is my own experience and also the experience of others, that batches that are very small, say 5 grams, that one often has trouble with the hardening.  I have talked to too many people over the years who have experienced that same thing.  No one has a sure-fire explanation for it, but it is a common experience.
(3)  Always mix it very well.  My own personal rule is that when I think I have mixed a batch sufficiently, to add another minute of more mixing.I have to admit that I am not a patient person when doing those kind of things.

I think that's the best thing I can suggest with regard to avoiding the amine-blush phenomenon.

Best regards........Chuck


____________________________________________________
Charles Hurlbut
General Manager

Eljen Technology
1300 W. Broadway
Sweetwater TX 79556

Ph: 325-235-4276 ext 2005
Toll Free: 888-800-8771 ext 2005
Fax: 325-235-0701

Visit our website: www.eljentechnology.com
____________________________________________________
On 8/6/2018 11:35 AM, Edward Kistenev wrote:
Dear Chuck,

you may still remember my name from  time when we both were part of PHENIX project (1990’s). 

In recent years we at BNL went through research project aimed towards developing large area scintillating tiles with WLS readout for hadronic calorimeter upgrade to PHENIX (sPHENIX).
For a number of reasons we followed our local colleagues and used EPOTEC-301-1 epoxy resin to embed fibers (mostly because of declared optical quality and low viscosity what is somewhat helpful with embedding). We got good results in general but they were not stable - blamed technological problems and worked on improving the procedures and environment. At the end we attempted to study the epoxy itself and found that it is prone to developing surface plaque, what was not really familiar to physicists users of a product - “amin blush” - name became a household item last week. 

We understand that to some extent it can be a common feature of all epoxies but our experience with EJ500 and BC600 never prepared us to intensity and extent of its spread with Epotec. Fighting it is possible but require investment in temperature/humidity controls and teaching the operators and may result in production delays.

Our vendor recommends to switch to EJ500 which is effectively free of known “amin blush” manifestations. We are going to follow on this proposal. I wander if you may comment on this matter and suggest specific procedures and/or conditions or what needs to be improved/controlled in the standard open air embedding procedure to make sure the outcome is as best as it can be. Any such help will be greatly appreciated.

With respect
			Edouard Kistenev, PHD, Brookhaven National Laboratory, LI, NY.





  • [Sphenix-hcal-l] Fwd: EJ500, Edward Kistenev, 08/07/2018

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