Obsidian
Aerospace
- Mar 29, 2006
- 9
Hi All ,
I've got a major problem bonding anodised aluminium plates together to form a tensile lap shear specimen .
The film adhesive used is Redux 308 NA and my problem is that the failed bond looks exceptionally porous . There are large voids within the glue line , possibly up to a couple of millimetres in diameter ,
and these are significantly reducing the surface area over which the film adhesive acts .
The film adhesive itself is cured at 170 Deg c for 60 minutes under a residual vacuum of 6 in Hg and an autoclave pressure of 22 psi ( the actual component is a honeycomb sandwich component ) .
We've tried various things such as varying the pressure , bagging the test piece differently etc. but nothing appears to work to reduce the " perceived " porosity in the bond . The film adhesive has a volatile content of < 1% .
Has anyone seen this effect before and , more importantly , how was it rectified ?
Any help much appreciated , thanks .
I've got a major problem bonding anodised aluminium plates together to form a tensile lap shear specimen .
The film adhesive used is Redux 308 NA and my problem is that the failed bond looks exceptionally porous . There are large voids within the glue line , possibly up to a couple of millimetres in diameter ,
and these are significantly reducing the surface area over which the film adhesive acts .
The film adhesive itself is cured at 170 Deg c for 60 minutes under a residual vacuum of 6 in Hg and an autoclave pressure of 22 psi ( the actual component is a honeycomb sandwich component ) .
We've tried various things such as varying the pressure , bagging the test piece differently etc. but nothing appears to work to reduce the " perceived " porosity in the bond . The film adhesive has a volatile content of < 1% .
Has anyone seen this effect before and , more importantly , how was it rectified ?
Any help much appreciated , thanks .