This has been bothering me for awhile. I tend to automatically add filler when performing repairs with epoxy. Sometime ago I stumbled upon the following info on West System site:
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While certain fillers will increase the density of epoxy, this does not correlate to higher physical properties or increased adhesion strength. Epoxy is strongest without filler added to it, but the fillers are necessary to:
While I understand that in many cases (e.g fillets, vertical surface repair, etc.) higher viscosity is very useful, it just became a habit to always add filler. The statement from the manufacturer seems to say I should not do that unless required. Opinions?
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While certain fillers will increase the density of epoxy, this does not correlate to higher physical properties or increased adhesion strength. Epoxy is strongest without filler added to it, but the fillers are necessary to:
- Increase the viscosity of the mix
- Bridge gaps
- Prevent the epoxy from soaking too far into the wood
- Prevent glue-starved joints
While I understand that in many cases (e.g fillets, vertical surface repair, etc.) higher viscosity is very useful, it just became a habit to always add filler. The statement from the manufacturer seems to say I should not do that unless required. Opinions?