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notmrjohn 10-17-2012 11:03 AM

2 Attachment(s)

The reason the bubble doesn't line up with lines perfectly is because the bubble is not always the same size. The liquid and gas do not expand and contract due to temperature changes same amount or at constant ratio to each other.

In addition manufacturing process is just not that precise, temperature and air pressure variations cause different amts of liquid and gas. I have six foot level with 12 vials, Few bubbles match in size. Not a big variation, but detectable.

I dunno the size of your footings but I'd say a person with average eye sight and "guesstimating" skills isn't gonna be off by more than you can accurately build forms and pour concrete. At any rate you are going to be well within tolerances, as long as your level is accurate, have you checked it with end for end top to bottom flip test?

There are digital read out levels available.

Or use what the extra-terrestrials used when they made the pyramids.


notmrjohn 10-17-2012 11:03 AM

2 Attachment(s)

The reason the bubble doesn't line up with lines perfectly is because the bubble is not always the same size. The liquid and gas do not expand and contract due to temperature changes same amount or at constant ratio to each other.

In addition manufacturing process is just not that precise, temperature and air pressure variations cause different amts of liquid and gas. I have six foot level with 12 vials, Few bubbles match in size. Not a big variation, but detectable.

I dunno the size of your footings but I'd say a person with average eye sight and "guesstimating" skills isn't gonna be off by more than you can accurately build forms and pour concrete. At any rate you are going to be well within tolerances, as long as your level is accurate, have you checked it with end for end top to bottom flip test?

There are digital read out levels available.

Or use what the extra-terrestrials used when they made the pyramids.


MoreCowbell 11-12-2012 08:38 PM

2 Attachment(s)
Quote:
Originally Posted by JoeD View Post
If you are that concerned about the contact patch between the post and the footing then I would pour the footing and let the the concrete start to set up. Before it is solid place the post on the pad and level it. The concrete will be a perfect fit the bottom plate of the post. If you mix the concrete dry enough you could probably place the post right away.
I sort of ended up doing just what you described. I hung the column from above about 1/2" above the finished height of the footing surface and wrapped the baseplate with plastic wrap. I then placed the concrete and let it stiffen up for a few hours so the L-bolts would stay in place then lowered the column enough to where it just barely pressed into the concrete. After the concrete cured I removed the plastic and bolted the column down. The pictures explain it better than I can. Thanks.
Attachment 4521Attachment 4522

MoreCowbell 11-12-2012 08:38 PM

2 Attachment(s)
Quote:
Originally Posted by JoeD View Post
If you are that concerned about the contact patch between the post and the footing then I would pour the footing and let the the concrete start to set up. Before it is solid place the post on the pad and level it. The concrete will be a perfect fit the bottom plate of the post. If you mix the concrete dry enough you could probably place the post right away.
I sort of ended up doing just what you described. I hung the column from above about 1/2" above the finished height of the footing surface and wrapped the baseplate with plastic wrap. I then placed the concrete and let it stiffen up for a few hours so the L-bolts would stay in place then lowered the column enough to where it just barely pressed into the concrete. After the concrete cured I removed the plastic and bolted the column down. The pictures explain it better than I can. Thanks.
Attachment 4521Attachment 4522


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