rebar date?

I ask all my rebar and they said she is too old and ugly to date. 😉

I have all but given up trying to date found monuments based on outward appearance. It seems to depend a lot upon the soil conditions (pH, moisture content) in the South. Sometimes the old ones seem to be young and at times a 5 year old monument will look eaten away from rust. I have seen some that were set 10 years before rusted to look like the top and been sharpened like a pencil, and others that are 30 years old that still have a burr on the top from being cut.

It is anyone's guess; but if I found that, and it wasn't in a normally flooded area, I would believe it had been in the ground between 10 and 50 years. There is no sure way to tell that I am aware of without the date from the map or description from when it was set - and even that isn't a 100% guarantee. We are assuming it's an original monument, but they sell rebar at Home Depot.

Sadly our resident re-bar expert from Austin, TX has been absent since the format upgrade. I bet he could shed some light on it...but not without being a little aggravatingly condescending first....;-)

I wonder if our friend has noticed the new "comment" button which generates a thread chain similar to the previous format?

That poor rebar has been exposed to some nasty stuff over time. Here, I would guess it to be 80 years in the ground, but that is purely a guess.

A lab may could give you an estimate based on soil type and corrosion. Unless the date was extremely important and the client was willing to pay for lab results, I would say it appears to be old.

DANEMINCE@YAHOO.COM, post: 338178, member: 296 wrote:

need help finding a date for this rebar. thanks for your help

The patterns on rebar can be related to a patent date. They can also be used in a nore limited fashion to relate them to common use periods. In reality the deformations reveal the purpose more than the period.
The key is remembering you may figure out the period of manufacture but you cannot assign that to the time it was placed in the ground. ..

thebionicman, post: 338231, member: 8136 wrote: you may figure out the period of manufacture but you cannot assign that to the time it was placed in the ground

This is especially pertinent with regard to those of us given to collecting all the longitudinal scrap iron we come across and subsequently setting it to mark property corners.

thebionicman, post: 338231, member: 8136 wrote: The patterns on rebar can be related to a patent date. They can also be used in a nore limited fashion to relate them to common use periods. In reality the deformations reveal the purpose more than the period.
The key is remembering you may figure out the period of manufacture but you cannot assign that to the time it was placed in the ground. ..

Exactly. Rebar monuments can be determined to have a "not before" date, but not much else. My best use of rebar ID was the commonality among the found pins, indicating points from one survey or another.

I worked for a civil firm in the early seventies that was ran by staunch (cheap) old retired lt. colonel. We still had a stack of cut rebar, purchased in the late forties and fifties, in the garage...and used it daily.

From what I see in the photo, I'd say that is almost certainly a rebar that was rolled in 1947 or afterwards. I'd be interested to know what the bar diameter measures, but from the photo it appears to be a #6 bar with deformations spaced at 0.375 in., which would conform to modern (post-1947) rebar specs, i.e. spaced at no more than 0.7 x bar diameter.

The height of the deformations also appears to be post-1947. Before 1947, shallower, more widely spaced deformations were typical.

I'd expect that the deepest section of the bar shows the least corrosion and that would be what I'd clean up with a wire brush to measure and photograph. You might also get lucky and find a mill mark if it's a long bar.

Note the longitudinal rib that is visible in the photo along the center of the visible side of the bar.

From what I see in the photo, I'd say that is almost certainly a rebar that was rolled in 1947 or afterwards. I'd be interested to know what the bar diameter measures, but from the photo it appears to be a #6 bar with deformations spaced at 0.375 in., which would conform to modern (post-1947) rebar specs, i.e. spaced at no more than 0.7 x bar diameter.

The height of the deformations also appears to be post-1947. Before 1947, shallower, more widely spaced deformations were typical.
I'd expect that the deepest section of the bar shows the least corrosion and that would be what I'd clean up with a wire brush to measure and photograph. You might also get lucky and find a mill mark if it's a long bar.

Note the longitudinal rib that is visible in the photo along the center of the visible side of the bar.

Welcome back.

Did anybody hear me fall out of my chair?...:-X

Good to see you here Mr. McMillan! Hope you stay awhile, our ragged flock has been wandering aimlessly without your guidance....

Ditto!

It figgers that it was rebar dating that set the hook!

Ditto!

I'd think what would be most useful in establishing the provenance of the rebar would be a local comparable that could definitively be linked to a particular surveyor and time period.

Kent-

Good to see Austin and you are alive and well !

Alexandra and I have missed your sagacity.

Cheers,

Derek

Williwaw, post: 338291, member: 7066 wrote: I'd think what would be most useful in establishing the provenance of the rebar would be a local comparable that could definitively be linked to a particular surveyor and time period.

[Hmmm. I'm wondering why this doesn't appear as a reply to Williwaw placed under his post.]

The identification of the rebar type as to period is the first cut though. If, for example, one is wondering whether a rebar was set in, say, 1925, the fact that the bar itself was of a type only manufactured after WWII would render further inquiry moot.

Had the bar that Dane posted been correct as to supposed period, the logical next step would be to examine as many other bars reportedly set as a part of the same survey to see what common characteristics they have, if any.

I made a survey of a 1950's subdivision that had a variety of old rebar, both in size and in pattern of deformations, in place at the corners. However, when the whole thing was examined and which lines were actually staked in what order was taken into account, the whole made convincing evidence that certain rebars were original and others were subsequent replacements.