Epoxy Primer , is it needed when using epoxy resin as a glue

[SHUG]

I have used epoxy primer when applying underwater two-pot coatings but my current question relates to using epoxy resin as a glue in plywood boat construction.
Should the plywood mating faces be primed before epoxy glueing? Thanks

 

[Tranona]

No just apply epoxy to the surface and hold parts together. Usually worth thickening epoxy with silica to strengthen the bond.

 

[VicS]

Loadsa info on using epoxy resins on the Wessex resins website.

http://www.wessex-resins.com/westsystem/index.html

 

[macd]

+1 for Tranona's remarks.
If it's a 'stitch and glue' construction, you'll definitely need some medium to stiffen the epoxy mix. Same goes with any filleting.
Microfibres are even stronger than silica or microballoons, but much harder to sand.
Don't over-clamp epoxy joints as you might with conventional woodworking adhesives: just use enough force to squeeze a little of the epoxy out.

 

[fluffc]

If you are joining two pieces together - eg for stitch and glue or similar, then when you make up a batch of epoxy, first use a brush to wipe unthickened epoxy onto the joint.

Then thicken the epoxy in your pot with microfibres to peanut butter consistency, and apply over the 'naked' epoxy.

 

[gjgm]

Yes they should be primed, but that only means pre-coating a minute or so before recoating so that you don't end up with a dry joint as the ply absorbs any epoxy.
If you prime and it dries,you need to wash off the blush and sand....zzzzz !

 

[oldsaltoz]

If you are joining two pieces together - eg for stitch and glue or similar, then when you make up a batch of epoxy, first use a brush to wipe unthickened epoxy onto the joint.

Then thicken the epoxy in your pot with microfibres to peanut butter consistency, and apply over the 'naked' epoxy.

+1.

 

[maxcampbell]

No just apply epoxy to the surface and hold parts together. Usually worth thickening epoxy with silica to strengthen the bond.

Epoxy should go on bare wood. Paint surfaces with unthickened epoxy to allow soaking-in - especially important with end-grain, then butter up with thickened stuff. Do all the steps in a joint before any of the epoxy hardens - (ie don't paint with unthickened then allow to harden then return with thickened stuff). Silica is more of a viscosity controller than a strengthener - microfibres give the strongest mix.

 

[SHUG]

Thanks for the advice and useful comments.