Australian Facetors' Guild Limited

Epoxy glues and humid weather

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  • 03 Jan 2022 9:35 AM
    Message # 12233343

    Does anyone have trouble using epoxy glues to transfer stones in high humidity .? I am having trouble getting Dextone, Devcon and Kwikweld to set - the outer surface of the mix gets hard but the inner part stays  crumbly.

    Any help please - I'm getting desperate

    John Maine


  • 04 Jan 2022 6:30 AM
    Reply # 12235462 on 12233343

    Hi John,

    I am having trouble at the moment as well.  Have just re-dopped  my comp entry for the second time and thought it was the mixing ratio.  It is humid lately, if problems persist I’ll try storing my glue in a jar with desiccator crystals.

    I can’t imagine the humidity would affect the glue once mixed and set, the chemical reaction changes the glue’s composition.  It seems more likely that moisture is getting into the glue before it is set,  otherwise the glue would let go once you used water on the lap.

    I have noticed that if the tube has been used for a while, I get better results if I squeeze a good blob, say a 1cm length from each tube and discard it, it could be that moisture is seeping into the end of the tube over time.  I thought the separate parts were oxidising, especially the grey part which seems to crust around the cap.

    Anyway, try squeezing a blob from each tube and discarding it, then dropping with fresh glue.

    regards

    Gordon

  • 04 Jan 2022 8:18 AM
    Reply # 12235644 on 12233343

    Never had a problem with 5 minute araldite. But have always used the individual tubes and not the twin plunger type. Also squeeze out 2cm of each to ensure exactly equal amounts. I sling the tubes after 12-18 months and buy new ones.

    Frank.

  • 04 Jan 2022 9:11 AM
    Reply # 12235728 on 12233343

    Hi John,

    Repco have a large  range of epoxy fillers and adhesives including Devcon,  JB Weld, also Witworths or any marine goods supplier that sells fibreglass etc.

    Bunnings have a large range also located near the "Builders Bog" etc.

    I had the same problems and did some research at the time and found my problem was that the 2 part epoxy was 2 years old. Once opened it begins to deteriorate and should be used within 6 months, I had a good run using "Epifill".

    Also humidity is a big factor so you should cure the resin with heat if the RH is above 80%. Also most are rated to cure with an ambient temperature of 25 deg. C. and the curing time increases quite dramatically below this temperature.

    Mr Google has a number of sites which give a lot more information.

    Cheers

  • 05 Jan 2022 6:22 AM
    Reply # 12237940 on 12233343

    Hi All,

    Dennis’ comment about epoxy “going off” has resonance.  The more I think about it the more I suspect it is oxidation.  The tubes come sealed and it is only once the seal is broken that the clock starts ticking.

    yesterday I squeezed about a 1cm blob from each tube of my JB Quick.  After that the black tube was quite liquid and when mixed did not set hard.

    I stuck a tooth pick into the tube and stirred it, then capped both tubes and I needed them.  This seems to have improved the set, but I suspect I have only mixed good epoxy from the bottom of the tube with oxidised/hydrated epoxy. From the top of the tube.

    I have also started storing my glue in a jar with packets of desiccant to see if that helps.

    regards

    Gordon

    Last modified: 05 Jan 2022 6:23 AM | Anonymous member
  • 05 Jan 2022 8:33 AM
    Reply # 12238318 on 12233343

    Flash,

    The water vapour must get into the epoxy during the mixing process.

    I always fold the two together ( as in cooking) rather than stirring with a stick to minimise water vapour getting in, but that didn't work this time. I have been reminded by a local facetor that the same problem has occurred at this time of year since the demise of Tite-on.

    I have bought some 5 minute Araldite and Super Araldite and will experiment today. A good day to experiment - the temp. is 24 and misty rain so the humidity will be right up there.

    I have also received tips to keep the caps tightly on the tubes and to keep keep them in the frig.

    Will keep you posted

    John






  • 05 Jan 2022 9:10 AM
    Reply # 12238358 on 12233343

    Just another aside, having worked in an underground coal mine where roof bolts were used as roof support and were installed using a 2 part epoxy "sausage" setting in 15 seconds, we always ensured that when the cartons of "sausages" were delivered to site we stored them in a cool area then transferred them underground as soon as possible.

    Any cartons discarded underground with unused 'sausages" showed the hardener going brown after some time and  separation of the ingredients of the resin component which made them unusable.

    Just an observation.


  • 05 Jan 2022 10:04 AM
    Reply # 12238427 on 12233343

    HI John,

    Storing the epoxy in the fridge could prolong its life but you would have to remove it from the fridge to allow it to come up to temperature. Most epoxies recommend no lower than 10deg C.

    Here is some interesting points I found.

    "The average shelf life of epoxy resin is 12 months unopened and 6 months once opened. Depending on the type of epoxy you’re using, it may have a shelf life of two to three years. Epoxy hardeners tend to have a shorter and more sensitive lifespan of only one year."

    "epoxy hardeners should be used within 1-year from the date of manufacture, as they tend to be more sensitive than the resin."

    Apparently the hardener is more "sensitive" because it absorbs moisture more readily.

    Interesting topic!

  • 05 Jan 2022 10:26 AM
    Reply # 12238471 on 12233343

    Dennis ,

    You comment about keeping epoxies in the frig. I recall some years ago a facetor told me he kept his Tite-on in the frig. When he was getting ready to use it he would take it from the frig. and put the two tubes in his shirt pocket. By the time he was ready to use  it his body heat had raised it to a working temperature.

    The trouble with all the available information on the internet you start

    looking at one subject and it leads onto another tack.

    John



  • 05 Jan 2022 11:01 AM
    Reply # 12238516 on 12233343

    Following your posts with interest John, both here and on the other forum. I can’t remember where I got the info about discarding the epoxy after 12 months or so, but that’s what I do. Also mixing way more than I need to ensure I have exactly a 50-50 mix. Clean the stone and dop with meths and careful not to touch those surfaces with my fingers. As for storage, it stays in a cupboard in the garage. That side of the house faces the setting sun, so here in Brisbane during the summer months it would be subject to mid-30s nearly every day. Never had a problem, no ovens, fridges, nothing.

    Frank.


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