Subject: Adhesive for sensors in masonry walls
The following is posted on behalf of David Bittermann I am looking for an epoxy (or modified epoxy, or other similar resin) to set moisture sensors in thick masonry walls. Two moisture sensors are to be installed in tandem at various depths within a single 1-1/4" diameter horizontal bore, such that they sense the temperature and humidity conditions of respective isolated air chambers to be formed within the bore. Two epoxy plugs will be installed in the bore. The first will be placed in a zone between the deep sensor and the shallow sensor, and the second outboard of the shallow sensor. The required characteristics are: 1. Ability to place by an injection tool (hand operated plunger gun) to plug a 1-1/4" bore from a depth of 24" to a depth of 13", without leaving residue on any intermediate surfaces. 2. Ability to adhere to potentially damp masonry without the use of a primer. 3. Ability to bond to masonry sufficiently to prevent moisture or vapor from traveling along the length of the plug at the interface with the masonry. 4. Viscosity low enough to inject, but high enough to retain a vertical face in the 1-1/4" bore without slumping prior to cure. 5. Low compressive strength, low hardness, moderate flexibility. 6. Ability to substantially remove by re-drilling the bore, so that sensors can be withdrawn and replaced through removed plug. 7. Ability for reinstalled plug material to adhere to cured remaining residue of previously removed plug. 8. Material must be readily available in non-bulk quantities. David Bittermann National Park Service NCRC/BCB 400 Foot of John Street Lowell, MA 01852 978-970-5128 david_bittermann [at] nps__gov *** Conservation DistList Instance 12:16 Distributed: Thursday, August 6, 1998 Message Id: cdl-12-16-010 ***Received on Thursday, 6 August, 1998