# can i use fibreglass resin in place of epoxy?



## Itamar J (Aug 7, 2010)

many of Jorges tutorials call for epoxy
could i substitute it for fibreglass resin or wood glue?
just curious


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## slingshot_sniper (Feb 20, 2011)

I would stick to what is proven to work and be reliable....epoxy IMO









That said he always say he vise tests his designs without any epoxy...he adds it just to hold in place IIRC...so I guess any glue could work.


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## Hrawk (Oct 25, 2010)

From what I understand, polyester resin (fibreglass resin) is not as strong as epoxy resin which is why it requires the silica fibres.

Stick with epoxy to be sure.


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## JoergS (Dec 17, 2009)

I have no experiences with wood glue or any other type. Epoxy works well, is totally reliable.


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## jskeen (Feb 7, 2011)

There are lots of different types of epoxy, or i should say lots of different two part resin's that are (sometimes erroneously) grouped together and called epoxy. Epoxy really only refer's to a specific copolymer formed from two different chemicals, but, like Q-tip and Kleenex, has become a generic name for any two part adhesive. That being said, different epoxy's are best for different applications. Some are good for a broader range than others, but almost all have some specific application that they are NOT good at. The trick is avoiding the weak situations of the specific one you are using.

Fiberglass resin is formulated primarily to be mixed with glass fibers and then set but still release from a mold. This release requirement means that it is not very good if used as a straight adhesive to bond two hard surfaces together. Catalyzed urethane finishes are a form of two part adhesives formulated primarily to form a clear, bubble free thin coating on a surface. JB Weld is a machineable adhesive made to have high compression strength for unsupported applications and bond well to metal. For bonding wood to metal, you really want a somewhat slower setting epoxy, such as a devcon 30 minute, as the slower set time allows for more of a chemical reaction to occur between the epoxy and the surface of the metal, giving it a better grip. For wood to wood, or wood to plastic, a 5 minute epoxy is quite sufficient, as the porous surface is easy to bond to, and the tensile strength of the material itself relatively low, so the joint is unlikely to be stressed beyond the relatively low strength of the adhesive. Casting resins such as silmar 41 or alumalite are designed to provide glass clear cured product with very high fill. They provide little adhesion between two surfaces.

Between wood finishing, knife making, pen making and casting blanks for all of them, I've played around with lots of these, so feel free to ask if you have a specific question, and while I probably won't know the answer, I might know where to find it 

James


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