Making marks on concrete

[chadjans]

Okay need to make marks on concrete. We all know the standard chalk line and spray with clear but are there any other options especially free hand circles and similar seems how it is now 2008?

[DSW]

You'd be surprised how many don't know about spraying chalk lines with clear to make them stay. I've found guys in construction that didn't know that trick.

What are you trying to lay out? I've had to do a lot of odd layouts on concrete. Do you just want material suggestions or an idea on how to lay out something specific?

My marking tools are usually pencils, chalk sticks, Keils (construction crayons), spray paint, perm ink markers ( sharpies usually the older ones from my supply), Chalk line. All depends on how acurate my lay out needs to be. One trick with using a pencil. I use std round pencils as opposed to square lumber pencils. If you turn the pencil as you draw your line you continually sharpen the point. It will still wear out as fast but your line satys the same width.

Tools themselves. Straight edges, framing square (I also have a large 3-4-5 folding square), lazer square, string line, hose for free curves, thin boards or steel for arcs. small dia circles- cans, trash cans, buckets so on. I've built compasses from 2xs and swung arcs. string line and pencil to swing arcs, ovals and so on. If you work in smaller free arcs, they sell a rubber coated flexible lead staight edge at drafting supply houses for drawing free curves.


I've see this done on walls but not floors, projectors. I would look at the digital projectors that you can get to shoot your laptops screen up on a wall. Put up you drawings and adjust your distance until it matches a predetermined distance. Used to use this method to scale and enlarge plans with an old optical tranparency projector and plans printed on mylar.

Hope this helps

[plunkinberry]

DSW has covered a LOT of options. What are you trying to lay out and how long do the marks need to remain accurate? What are you trying to do?

[uglyscout]

In the survey world if we need to mark concrete fairly perzactly and permanent - we spray paint the line/area roughly - let it dry - and then scribe with a concrete scribe (you can use a sharp nail) exactly where we want/need the line.

It will last a few months even outside and if the line is scribed well enough it will outlast the paint and stay around for years....

[chadjans]

I work for a casework manufacture and need to layout fume hoods and casework for cordination with other trades. So pinpoint accuraccy isn't needed. Have been using chaulk and a pencil for years but it gets old.

Generally just spot four corners and center lines. Sharpies don't last here with all the dust. Get a few lines and then they are dead. Pencil works the best except you can't see it. Especially after it is sprayed clear but if you look hard enough it is there.

Don't need info on straight edges and such just some new options on marking...

[DSW]

My guess is the spray paint then scribe or mark with pencil or sharpie would work and give you a good contrast. A good sweep or quick dusting with a blowgun won't hurt. I have also used spray paint and a shield to mark corners and lines. Take a square of cardboard and set the corner at your corner and paint around the edges. This leaves a sharp line that is easy to see. If you don't want the paint to show make the cardboard L shaped and paint the inside of the corner rather than the outside. It's not super accurate but should be +/- 1/8".

Keils mark well on concrete, show up well, don't erase as easy as chalk and come in various colors. The lines are a bit wide however, sort of like what kids chalk will make but they can be sort of sharpened. Most home centers stock them.

Colored kids chalk and clear spray will also work.

On footings we usually nail the corners with 3/4" fluted nails. This gives a permanent mark that won't disappear even if it gets buried under dirt and mud. You just have to be semi careful with the shovel. Again they are often painted to show the rough wall outline from the nail. I use a similar idea if I need a fairly accurate perm mark. I lay out my point and use a small masonry bit to drill a hole at the corner. I'll often use a small nail in the hole to hook the tape on to measure from.


There are also a number of paint type markers usually used on steel. Your LWS should have them. They most likely won't like a lot of dust but may be ok with a good sweep, blown off or a quick vac job.

Hope this helps. good luck

[miniwally]

Sanford NOBLOT Ink pencil number 705

Mark like a normal pencil. Make damn sure that this is what you want it to be, erase and redo if needed.
Spray with water or better yet with clear laquer and it turns to a very durable almost permanent mark. Works very well on Concrete and pretty well on wood.

Be warned that the humidity in the air will set it off over the course of several days so don't mark something and leave it if you don't eant it to become permanent.

I get them from my local office supply store.

[chadjans]

Not much humidity here in Arizona. Thanks for the suggestion I will give them a shot.

Chad