Bonded patches with bond line control

A method of bonding a patch on structure, comprising:

• applying a layer of adhesive to an area of the structure;
• placing a spacer on the area of the structure, the spacer comprising both a plurality of beads and a screen, the screen having a first thickness substantially the same as diameters of the plurality of beads, the screen further comprising openings sized to allow the plurality of beads to pass through the openings;
• using the spacer to control a second thickness of the layer of adhesive, the layer of adhesive extending over substantially an entirety of the area;
• following placing the spacer, placing a patch on the spacer and over the area;
• and
• compacting the patch against the layer of adhesive.

A method of reworking a composite aircraft structure in the field, comprising:

• preparing an area of the structure to be reworked;
• forming a patch including forming perforations in the patch;
• applying a layer of adhesive and a plurality of beads to the area such that said layer of adhesive extends over substantially an entirety of the area;
• placing a spacer on the area, the spacer comprising a screen, the screen having a first thickness substantially the same as diameters of the plurality of beads, the screen further comprising openings sized to allow the plurality of beads to pass through the openings;
• using the spacer to control a second thickness of the layer of adhesive to be about the first thickness of the screen;
• removing the spacer, wherein beads of the plurality of beads maintain the second thickness of the layer of adhesive;
• applying the patch to the structure over the beads;
• removing excess adhesive from the patch;
• thereafter placing a caul plate over the patch;
• placing an anti-caul plate between the caul plate and the structure such that said anti-caul plate surrounds an outer periphery of said patch;
• installing a pressure applicator over the combination of the patch, the caul plate, and the anti-caul plate;
• using the pressure applicator to apply pressure to the patch through the caul plate, wherein the anti-caul plate limits the pressure at the periphery of the patch;
• installing a heat pack over the patch;
• and
• using the heat pack to cure the layer of adhesive.