Whites tm 808

[phormula1]

I am looking for a metal detector that will help me to detect metal objects in a large (20') tall pile of wood mulch. We will need to regrind this material in our machine and have had problems in the past with encountering metal plates, large bolts etc. I recreationally go metal detecting with friends and thought the tm 808 may work if used it while scooping into the pile with a loader. One problem is that the pile is on a reinforced concrete slab. Does anyone have experience with the tm 808? Would you expect that the rebar would give me too much trouble with false readings? Would it detect large bolts 6' deep into the pile? Thank you, any info is appreciated!

 

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[Tom_in_CA]

Yes, the rebar in the ground below your search area is going to give your TM808 fits.

And as for the question on whether the 808 will detect "large bolts": It depends on what you mean by "large" . The 808 will ..... if you really tried ....... find objects only a small as a domino size. So I suppose if the bolt you speak of is a very large I-bolt or tent-peg sized affair, then perhaps. But that's if you're reeeallly finely tuning it, to find objects as small as a playing card or domino. Realistically, the 808 is for objects soda can sized or larger. THEN it shines and excells

 

[Jim in Idaho]

You need a big mineral jig in your operation. That would remove all the metal, rocks, etc. Probably do it with a vibrating screen too.
Jim

 

[boogeyman]

You'd probably be better off just using a detector with a large coil. Run it in all metal. As far as the rebar goes, locate it & mark it with some upside down paint to help ID where it's at if it's between the lines, grab the rake. The TM808 will miss the stuff that'll chip blades & you should be able to eye ball the bigger stuff.

Another trick is to pick the bucket up about 6' and dump it slowly on the ground. Have the guy on your crew with the best vision & long attention span to spot. Don't grab the guy like me that has lousy vision & NO attention span.

 

[phormula1]

You need a big mineral jig in your operation. That would remove all the metal, rocks, etc. Probably do it with a vibrating screen too.
Jim

Thank you for your input Jim. We typically grind material that we are familiar with (wood pallets, boxes, dunnage). This is a rare occasion when we get material that has been rough ground by a third party. The last time that we got material from this source there was A LOT of foreign material mixed in. I ran it through a machine that has a magnet to remove the metal. It was hard on the machine and I needed to have someone operate it and load it with a loader for a day. I am cautiously optimistic that this new material will be clean but last year we had $47k in damage when we encountered a large piece of cast iron. It is unlikely that I will get anymore of this material in the future so it is not practical to add a new machine to process.

 

[phormula1]

Yes, the rebar in the ground below your search area is going to give your TM808 fits.

And as for the question on whether the 808 will detect "large bolts": It depends on what you mean by "large" . The 808 will ..... if you really tried ....... find objects only a small as a domino size. So I suppose if the bolt you speak of is a very large I-bolt or tent-peg sized affair, then perhaps. But that's if you're reeeallly finely tuning it, to find objects as small as a playing card or domino. Realistically, the 808 is for objects soda can sized or larger. THEN it shines and excells

Thank you for your input Tom. Do you expect that I'd be able to identify which readings would be caused from the rebar?

 

[phormula1]

You'd probably be better off just using a detector with a large coil. Run it in all metal. As far as the rebar goes, locate it & mark it with some upside down paint to help ID where it's at if it's between the lines, grab the rake. The TM808 will miss the stuff that'll chip blades & you should be able to eye ball the bigger stuff.

Another trick is to pick the bucket up about 6' and dump it slowly on the ground. Have the guy on your crew with the best vision & long attention span to spot. Don't grab the guy like me that has lousy vision & NO attention span.

Thank you for the input. I did something similar to what you recommended. I spread it out about 9" thick and went around with a industrial magnet and picked out the metal. It worked well but would be a daunting task for such a large pile we have currently. Also, I did the work myself to make sure it was done right. It is difficult to find someone who cares about getting a job like that done thoroughly. Our machine can handle nails, lag screws, etc. It is the larger plates, 3/4x12" bolts, etc. that can keep me up at night. The piece that caused all the damage last year was about 20#.

 

[Tom_in_CA]

.... Do you expect that I'd be able to identify which readings would be caused from the rebar?

No. A detector (of any sort) that you attempt to operate where the base BENEATH it is metal (or has metal to the degree you speak). And can not differentiate or "ID" which is which. Example: If you put a quarter on the seat of a '57 Chevy, do you think you could find a machine that can tell there's a coin there, and differentiate it from the Car ? Same logic, but ... well ... on a different scale

You'd need to spread the material out on naked ground to detect accurately.

And I notice you've said a few new things: That smaller individual nails and such do not harm your machine. You're only worried about the bigger stuff ("12 inch long pegs" blah blah) that are your concern. In that case, yes: a tm808 can be made sensitive enough to find those things, while conveniently ignoring small stuff like individual screws, nails, etc.... Or you could also use a standard machine, and just dumb it down (desensitize it, lower the sens) to the point where only larger objects beep .

But in either case: No, they can't be operated where the background base is metal itself.