Ace 250 and rebar

[JoeMoto]

I've been hunting an old, small local park recently. Next to the jungle gym there are 3 or 4 small concrete steps. They are all placed in a half circle shape and are about 2' x 2' and around 4 or 5" thick. The pea gravel from the play area has overflowed the area and was covering the steps.

When detecting over the smallest one I'm getting tones that indicate between a penny and a dime at 4-6" deep. Rebar is iron, so it should show low on the scale, right? There are multiple tones on each sweep.

Before I take a crow bar flip the step over I thought I'd ask, how do other Ace users machines indicate on rebarred concrete?

 

[NM5K]

Concrete often looks "hot" on mine. Like you say, I was
assuming rebar, but after thinking about it a while,
I'm not so sure. IE: sidewalks..Do sidewalks actually use
rebar? Not sure...But many I see being built just use a
wooden "frame", and no rebar. Another example is the large
concrete patio that is outside our sliding glass door.
It shows "hot" and rings up as a coin every few feet of
walking across it. Not sure if it has rebar or not, but
I'd consider it more likely than the sidewalks. It sure
looks hot on the machine, thats fer sure. I noticed when
trying to find coins that ring up near sidewalks, sometimes
pinpointing can get a bit squirrely. But I've noticed this
with other targets that have a lot of other metal in the area.
Myself, I think if you hunt close to concrete, and have trouble
weeding the targets from the concrete, a sniper coil would be
good to have. I plan to get one myself before too long, as
I've had this trouble sometimes when near concrete. It makes
it a bit tricky when using a bigger coil. I think the small
coil would make things a bit easier when around areas like
that. Our patio is so hot, you would think it had a bed of
quarters under it.. Not sure why... But I was assuming
some rebar. Now...You would think rebar would ring up as iron,
but I've seen other large low conductivity metals ring high
in certain conditions. IE: a large very rusty nail will often
ring as a coin, or will blip back and forth as a coin, and a
lower conductivity metal.
MK

 

[BigCatDaddy]

You got it!! It's the rust!! Wait till you dig up a big rusty hunk that reads as a dollar, quite disappointing! There is probably something in there that is rusty, be it the rebar or square wire mesh in all concrete pours for sidewalks, patios. They will give you fits, even with a sniper coil, although not as bad. Put that crowbar away, boys and just work as close as you can to it.

 

[saika/ace250]

see if the pipoint drifts at all, if it does it is 99% sure to be rusty iron. The end of a rusty iron bar can scream silver sometimes, but it almost always dances around a bit.

 

[NM5K]

The end of a rusty iron bar can scream silver sometimes, but it almost always dances around a bit..........

Yea, I agree. Most bunky rust iron targets will usually
bounce around a bit. IE: coin-nickle, coin-iron,
back n forth..If you see a bouncer like that, it's
usually trash iron, etc..
MK

 

[saika/ace250]

let me clarify, you are right it will not target solidly but it will also not pinpoint on the same spot repeatedly. If the pinpoint drifts, it is bigger than a coin and or iron....you will have had fair warning.
-------------------------------------------------
The end of a rusty iron bar can scream silver sometimes, but it almost always dances around a bit..........

Yea, I agree. Most bunky rust iron targets will usually
bounce around a bit. IE: coin-nickle, coin-iron,
back n forth..If you see a bouncer like that, it's
usually trash iron, etc..
MK

 

[JoeMoto]

The piece of concrete with the strongest and most returns is only about 18" x 24" and 5" thick. I may have to flip it over just to be sure.

Went out relic hunting an old homesite last weekend and was picking up alot of tin and old iron. Most of the iron wasn't indicating iron, but rather up in the penny and dime areas. I did end up finding an old OK tax token though.

 

[saika/ace250]

I remember about 20 years ago I got all excited about a really odd piece of asphalt that gave me a solid hit that would not disc out. I found it on the beach. I took it home and chipped away at it, nothing. The signal just vanished.
Good luck with the ceeement slab, if it is loose it may just be a hidy hole for someones cache.

 

[Steve missouri]

JoeMoto: Most concrete in Playgrounds have rebar or steel wire in then, it's there to hold the concrete toghether over the years. All of the playground equipment is anchored to large blocks of concrete, Old playgrounds have usually moved the swings, jungle gym's, etc. once or twice over the years, leaving the blocks under ground. On most Detectors, actually all of the many Detectors I have used over the last 20 years, will give an excellent silver reading, also the depth will read 6-8 inches, true depth being 12-20 inches. Concrete steps will also do this, I seriously doubt you will find any coins or a catche. However if you are observed working with a crow bar on the steps you may find a police officer, and find that you have gotten yourself and everyone else banned from ever hunting there again, possibly also every other park in the area, something to think about. Steve.

 

[Spanky]

JoeMoto, I wouldn't waist time on the effort.... rebar does show up on the detector as well a WWF6x6 (welded wire fabric on 6" centres). I must admit its tempting to do it but being the slab is outdoors and is approx. 6"thick it probably would be difficult to put it back into place exactly the way you found it once you scanned under it. The ground has probably be compacted and disturbing the soil will cause the pad to not sit the same and you may get some locals a little upset that your disturbing the area.
Not sure if you noticed or experienced it yet but also high alloy bolts,nuts and studs will also give you the same belltone as a coin.