:confused:Here's an odd question

[Arcturus]

Here is a head scratcher for you folks. I am a construction manager and my current project has us moving some walls around. The floor has 2 concrete slabs, the structural and the heating slab. The lower 6" structural slab has rebar in it and the 4" thick topping slab has copper radiant heat pipes. I brought my detector to the jobsite today and it either gets overloaded or jumps between 32 and 34 over all areas. I have tried lowering the sensitivity to 2 and it still reads 32-34 in all locations and the pinpointing is not helping me at all to focus on either number. I'm using the stock concentric coil.

Any suggestions? The new walls need to be secured to the floor either using a Hilti gun (22 caliber nail shooter) or epoxy set all-thread rods. I need to miss those pipes!

 

[Digger]

I'd suggest you try an electronic pinpointer instead of your detector. If your top slab is 4-inches thick, those copper pipes aren't very far from the coil, not to mention the rebar. And with the detection depth of that 9-inch coil, I would imagine it is being overwhelmed with signal return from the copper AND the rebar. At 2 - 4 inches, a good electronic pinpointer should do the trick. (If you don't have a good one, this would be the time to buy it and charge it to the job )
Locating a copper pipe is much different than locating a coin or target that is insulated (by dirt) from an adjacent target. That copper pipe you are looking for is laid out in a pattern that will appear as one BIG target to a metal detector. Phone companies, CATV companies and Power Companies have special locators for buried cables. If you are acquainted with someone from one of those utilities, you might ask to borrow their locator. I've never located copper radiant heat pipes with them. But if the pinpointer don't work, you might have to give them a call. JMHO HH Randy

 

[Arcturus]

. At 2 - 4 inches, a good electronic pinpointer should do the trick. (If you don't have a good one, this would be the time to buy it and charge it to the job ) That is excellent advice!!:
Locating a copper pipe is much different than locating a coin or target that is insulated (by dirt) from an adjacent target. That copper pipe you are looking for is laid out in a pattern that will appear as one BIG target to a metal detector. Phone companies, CATV companies and Power Companies have special locators for buried cables. If you are acquainted with someone from one of those utilities, you might ask to borrow their locator. I've never located copper radiant heat pipes with them. But if the pinpointer don't work, you might have to give them a call. JMHO HH Randy

Sounds good! It is a lot easier than breaking up the slab for location which is what we had in the bid.
Thanks!

 

[tjhoosier]

Randy is correct about the utility companies. Not sure where you live, but here in Indiana we use contractors to locate cables for us ( I work for the big telephone company). But other utilities use locate companies also. Gas, water, communications, electric all use a company or companies to locate pipes and cables in the ground, so when someone needs to dig they know where those things are. It's the law here in Indiana and I'm sure it is in other states too.

 

[KurtB]

You could try using the edge of the coil. I use this method when I forget my pinpointer.

Kurt

 

[Arcturus]

Ding ding ding!!!! We got a winner!! I put the coil parallell with the shaft and held it perpindicular to the floor and it worked! radiant heating every 6". sensitivity to 15. I could probably dial that in a little better with a little fooling around, but it is too consistantly every 6" that I know its gotta be right.

Thanks Kurt

 

[Joe Z]

That's pretty neat ......... I gotta try that