Differences between Epoxy brands

    A question for the experienced gun builders. Is there a quality difference between Epoxy brands for small wood bonding jobs. I know West Marine epoxy is the industry standard for laminating gun blanks. But for a small job like adding side stalks to speargun will a 5 minute epoxy, the kind that comes in syringe with a 1 to 1 mix ratio, be good enough? I prefer the convenience of the syringe. Also does slower curing epoxy ultimately make for a stronger bond?

    it will work fine ,but you want the slower curing version ,fast cure resins are always weaker far than a slower curing one .the heat produced during curring makes it brittle
    phil

    Thanks Phil. I saw that with fast curing epoxy a lot of heat is generated at the point of curing. Are you saying that with slow curing epoxy there is no such point/no heat? I just assumed that the same thing happens with slow curing epoxy only much later when I'm not around to see it.


    Also with something like West Marine epoxy where the resin stays the same and the hardener controls the curing speed. Will the slower curing hardener produce a better bond than the faster hardener?

    the same amount of heat btu is produced but over a longer time period so it has time to dissipate without doing damage to the resin .
    as for the west system ? it depends on temp ,at the same temp say 75f the slower one will be much stronger but if the temp id 50f you would want to use the fast hardener because the slow would cure so slow that you may get incomplete cure because the components have time to settle out (im not sure if this is really what happening but its what it looks like) or if you use the fast at 90f it might catch on fire
    phil

    I agree with Phil. The ambient temp. makes a big difference in cure time. A slow curing hardener in a cold garage in a northern winter is a recipe for a bad lam. A cure that is too fast in a high heat, high humidity tropical climate can actually cook off before the pieces are positioned properly, affecting the joint and giving you a bad lam. I've used the twin tube 5 minute schringe thingies for small jobs like gluing a plug in, and they seem to work just fine.


    I've also used Titebond III for small stuff like gluing a butt pad on. For something like ballast wings that would be ok, but if the joint is going to carry a lot of load I would mix the 2 part epoxy, even if I had too much (Like the glued on muzzle of the dirty water rollergun). I just have more confidence in the 2 part if I really need a lot of strength in the bond. Since I've only used West Systems for 2 part I can't comment on one brand compared to another. Phil?

    i used to have this issue a lot when doing glassing for car stereos...it is wicked hot here in MIa and especially in a garage. I would have to use a little less of the activator because it would reach the curing temp way before i got to soak the glass.
    this doesnt directly apply, but be sure to consider that it is hotter here than most of the instructions will contemplate and you might have to adjust amounts or time to accomodate

    i like to spear fish

    I never adjust the quantity (of hardener), that's a big no-no. It's calling for uncured epoxy. Always mix in the correct ratio. Use the correct curing time depending on the job at hand or mix smaller batches if possible.

    Quote from Wood Guy

    I agree with Phil. The ambient temp. makes a big difference in cure time. A slow curing hardener in a cold garage in a northern winter is a recipe for a bad lam. A cure that is too fast in a high heat, high humidity tropical climate can actually cook off before the pieces are positioned properly, affecting the joint and giving you a bad lam. I've used the twin tube 5 minute schringe thingies for small jobs like gluing a plug in, and they seem to work just fine.


    I've also used Titebond III for small stuff like gluing a butt pad on. For something like ballast wings that would be ok, but if the joint is going to carry a lot of load I would mix the 2 part epoxy, even if I had too much (Like the glued on muzzle of the dirty water rollergun). I just have more confidence in the 2 part if I really need a lot of strength in the bond. Since I've only used West Systems for 2 part I can't comment on one brand compared to another. Phil?


    i have used quite a few brands and the major difference for what we use it for between them is viscosity ,the final cure hardness and clarity . west it middle of the road , gflex is very resilient ,has a honey thickness ,and yellow , and the one i use is on the harder side ,thin,and very clear. for your average guy with limited experience with fillers i think gflex will produce the strongest glue up ,but the other two will be about the same as g flex with proper filler use .


    titebond III is a very good glue and i wouldn't hesitate to use it i have 7 guns in costa rica glued up with it(epoxy coated and they are all still together after 4 years and one is used every day by a local) a wood working mag did a test a couple years ago and it tested as strong or stronger than epoxy
    phil

    Quote from LunkerBuster

    i used to have this issue a lot when doing glassing for car stereos...it is wicked hot here in MIa and especially in a garage. I would have to use a little less of the activator because it would reach the curing temp way before i got to soak the glass.
    this doesnt directly apply, but be sure to consider that it is hotter here than most of the instructions will contemplate and you might have to adjust amounts or time to accomodate


    never ,never , and never vary the mix for epoxy it is not a variable ratio and will screw it up and may never fully harden .also never mix the a and b from different brands . you can only vary the hardener amount for polyester resin which is not suited for gun building
    phil

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