Can silicone lubricant from a syringe effect epoxy properties?

[carlossus]

Hi all,

I'm using a two part epoxy (Hysol Ea9303na) to bond BK7 glass to titanium alloy with a 50C 12hour cure.

Sometimes I'm seeing debonding occuring under high tensile stress at the glass bond side. Other times the bonds withstand much higher stress without degradation.

Most variables (bond thickness, adherend cleanliness, surface preparation, mix ratio etc.)are well controlled.

It occured to me today that we decant one part of the epoxy using a syringe which appears to have a residue on the plunger straight out of the packet. I assume that this is silicone lubricant.

Can anyone offer any experience, anecdotal or otherwise as to the potential effects on epoxy bonds of incorporating this silicone into the mix?

I typically mix about 3g of adhesive in a batch so the silicone level could be significant.

Many thanks,

Carl.

 

[MikeHalloran]

Silicone prevents anything from sticking to anything, including shoes to floor.

Get some (e.g. Hamilton) glass syringes with ptfe plungers.



Mike Halloran
Pembroke Pines, FL, USA

 

[carlossus]

Thanks Mike,
I've been reading quite a bit about silicone (oils) effects generally.

It seems likely that it is negating the effects of any surfactants in the adhesive so degrading its wetting ability and hence adhesion.

I'm still grateful for anyone with any real experience of this.

Cheers,
Carl.

 

[MikeHalloran]

Another solution is to get some wide teflon tape and stretch/ wrap it over the syringe plunger like a condom. It takes some practice, but it can be done, and it's surprisingly durable.

Scientific supply houses carry ptfe tape in 1" and 2" widths for sealing glass taper joints and such. It also makes nice thin gaskets.



Mike Halloran
Pembroke Pines, FL, USA