Epoxy Setting Speeds

      Epoxy characteristics vary by formula. Some companies offer more than one hardener speed. Thorough mixing is key. December 2, 2006

Question
There are generally two types of hardeners available in the market for epoxy adhesives, fast and slow setting. Do they give the same bond strength on drying? Can the fast and slow setting hardeners be mixed in definite proportions to give a specific or median drying time, so as to get a setting time of say 2 hours or 4 hours or 6 hours?

Forum Responses
(Adhesives Forum)
From contributor E:
That's going to depend on the type, or ratio of hardener to resin, and the formulator. The specs range all over the place on tensile strength, elasticity, chemical and water resistance, etc. Some require very careful measuring of ratios, some you can be a little sloppy with. Some you can vary ratios to change working properties and even mix slow and fast hardeners, and some you can't. The best thing is to talk to the manufacturer/dealer and tell them what you need the epoxy to do and what you desire for open time and clamping time, and let him tell you what he has that will meet it.

One thing to remember with epoxies is that the hardener and resin don't really like to mix easily. You need to follow the mixing times and procedures laid out by the formulator. Most people way under mix their epoxies and then complain about inconsistent results.



From contributor K:
I agree with all that contributor E said, and would like to add that time and temperature are dependent on the other. The warmer, the faster the cure, or shorter the pot-life. There are a lot more than two hardeners.


From contributor A:
The other guys have it about right. Epoxy resin needs specific resin/hardener ratios to maintain a complete chemical reaction. Most companies supply 2 to 5 or more hardener speeds. The older resin systems (like West System) have an incompatible hardener system. No mixing is allowed. Newer resin systems (like MAS, System Three) have hardeners that are mixable. The usually offer fast, medium, and slow. (The medium is simply a 50/50 ratio of fast and slow). Most people buy fast and slow and mix any ratio they prefer. I also prefer the MAS and System 3 resins because they also have two resins (thick and thin), which you can also mix in any ratio. They are mixed 2:1, so in large quantities it's easier to mix, versus West Systems 5:1 system.

Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?


Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: Knowledge Base

  • KnowledgeBase: Adhesives, Gluing and Laminating

  • KnowledgeBase: Adhesives, Gluing and Laminating: Glues and Bonding Agents


    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.



    Refer a Friend || Read This Important Information || Site Map || Privacy Policy || Site User Agreement

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2014 - WOODWEB ® Inc.
    All rights reserved. No part of this publication may be reproduced in any manner without permission of the Editor.
    Review WOODWEB's Copyright Policy.

    The editors, writers, and staff at WOODWEB try to promote safe practices. What is safe for one woodworker under certain conditions may not be safe for others in different circumstances. Readers should undertake the use of materials and methods discussed at WOODWEB after considerate evaluation, and at their own risk.

    WOODWEB, Inc.
    335 Bedell Road
    Montrose, PA 18801

    Contact WOODWEB











  • WOODWEB - the leading resource for professional woodworkers


      Home » Knowledge Base » Knowledge Base Article