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Difference between epoxies?

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Forum topic by Jimothy posted 10-08-2018 06:02 AM 572 views 0 times favorited 9 replies Add to Favorites Watch
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Jimothy

33 posts in 1361 days


10-08-2018 06:02 AM

Hey everyone. I have used epoxy several times on wood… The epoxy I used always used dried clear, but I accidentally bought a different one (same brand though) that dried black, and on the cover, wood isn’t specifically listed as a compatible material, but it does say it bonds metal, plastic, and more so I’m assuming wood is included in the “and more” and that it will work on wood aswell. i’m hoping that the fact that it dries black instead of clear is just an aesthetic difference and not a structural one? Is there such thing as epoxy that won’t work on wood?


9 replies so far

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CaptainKlutz

1502 posts in 1915 days


#1 posted 10-08-2018 10:01 AM

Epoxy will typically stick to wood?
Sure, well maybe: if it was clean and dry.
You can always contact the adhesive mfg for help with wood bonding.

Sorry, not enough information posted on the epoxy you bought to enable a really useful answer. :(

FWIW – Asking ‘what is difference’ is a very open ended question:
Epoxy is very generic name for 2 part adhesive. It is often used as marketing name to describe different adhesives that are very different in chemical composition and performance. Have spent 25+ years working with ‘experts’ in developing polymer systems. Volumes of books are written on the subject of epoxy chemistry and performance. A polymer chemist can spend a life time working with epoxy chemistry and never know everything about ‘epoxy’.

Start here if you really want to know differences between epoxies:
https://en.wikipedia.org/wiki/Epoxy

Best Luck.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

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Redoak49

4046 posts in 2409 days


#2 posted 10-08-2018 11:00 AM

What wood did this happen with?

I use Bob Smith epoxy and have not had any problems of it turning any color.

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lumbering_on

578 posts in 911 days


#3 posted 10-08-2018 02:05 PM

Are you referring to JB Weld?

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MrRon

5572 posts in 3664 days


#4 posted 10-08-2018 03:16 PM

Epoxies like JB weld have a metal powder in it . It is formulated for metals like steel and aluminum. Although it will bond to wood, it was not intended to match aesthetically.

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WoodenDreams

623 posts in 331 days


#5 posted 10-08-2018 07:09 PM

Does the package say what color it dries to. There is a epoxy that’s black, and designed more for a non-porous surface. you should be ok, but it may not penetrate deep into the woods pours. They also make epoxy for concrete and stone which is not for wood. I usually use the wood epoxy that has a yellowish tint. but I have used clear epoxy on glass & clear plastic.

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Andybb

1932 posts in 1024 days


#6 posted 10-08-2018 07:31 PM

Need more info.

Most woodworkers refer to “epoxy” as a generic 2 part product of the 5 min or longer setup time. There is 5 min epoxy like you get from the big box stores for bonding things and there are products like West Systems and Total Boat that are used as coatings and finishes. I am assuming that you are referring to the bonding type of product as you would have to add color to the other products to get them to be black. Does it turn black or does it come out of the tube black? What are you using it for?

-- Andy - Seattle USA

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MrUnix

7407 posts in 2620 days


#7 posted 10-08-2018 07:42 PM

Is there such thing as epoxy that won’t work on wood?

Not that I’ve ever seen…

Generally, epoxy is epoxy and it’s the additives that change it’s properties. Some stuff helps make it stronger, some makes it better at gap filling, some make it better as an adhesive, some makes it more useful for fillets, etc… But none that I am aware of would cause it not to stick to wood (or any similar porous type material).

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Jimothy's profile

Jimothy

33 posts in 1361 days


#8 posted 10-09-2018 01:40 AM

Actually my information was unclear. Coming out the tube, one part was silver/grey and the other black. Once I mixed up the parts it became uniform black. The joint is poplar to pine and its in a location that is not seen so visually it doesn’t matter. Just a matter of strength.. I’m not at the shop at the moment and don’t have the brand name but I don’t think it was jb weld.

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lumbering_on

578 posts in 911 days


#9 posted 10-09-2018 01:53 AM

It may not be JB Weld, but it sounds similar. The black is a steel reinforced epoxy, and it definitely can be used on wood, although I don’t tend to use it that way. It’s actually stronger than the clear epoxy, but it won’t make much of a difference in what you are using it for.

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