Berntsen 2" diameter Bronze Survey Caps for Rebar
All Berntsen bronze survey caps for rebar are orbital formed from silicon bronze alloy which is highly resistant to chipping, cracking and breaking. They feature the SureGripT plastic insulator that locks the cap tight on to the rebar or pipe and helps prevent dissimilar metal corrosion. They feature a deep hex socket that won't "wobble" when tapped on to the rebar.
A good survey cap for rebar or pipe must virtually eliminate dissimilar metal corrosion. What typically happens is that the survey cap loosens over a short period of time. This confirms metallurgical theory. Aluminum is less "noble" than steel and an electrical current will actually flow from the aluminum (+) to the steel (-). Corrosion will occur in the anode (+) area of the battery like combination of metals in the presence of moisture (air or soil acting like an electrolyte).
Berntsen originated the SureGripT insulator/wedge which effectively isolates the survey cap from the steel and de-forms around the ribs of the rebar. The hex shape fills with the deformed plastic material and the survey cap is locked on with a super tight compression fit. Great force is required to remove the cap.
How to install Berntsen Survey Markers
Tools: Berntsen suggests these tools to help with your installation.
Pre-Installation: Save time in the field with a little preparation in your shop.
- Cut your rebar to your desired length using a hacksaw or power press.
- Remove any burrs and/or mushrooming on the end that will be receiving the survey marker
- For maximum grip, bevel the end of the rebar that will be receiving the survey marker
Installing the Rebar:
With a felt-tip permanent marker, place a mark about 1½" from the end of the rebar. This mark will be your guide to assure the cap is tightly and completely seated on the rebar.
Drive your rebar to the desired depth. Remember to leave enough rebar to install the survey marker.
Installing the Survey Marker:
To restrict any "sinking" of the rebar into the ground when applying the survey marker, clamp a vice-grip pliers to the rebar at ground level. The handle of the pliers will prevent the rebar from sinking into the soil as you drive on the survey cap.
Some surveyors pre-install the survey marker onto the rebar prior to entering the field and then drive the rebar and marker assembly with a urethane faced dead-blow hammer.
Once you have your rebar and cap to the desired depth your installation is complete.
Berntsen Survey Markers Installation Instructions Video