Concrete Sign Form Ideas

[reiser25]

I have a customer who wants to make a sign out of concrete for his construction business. He contacted me to see if I would be able to cut out some type of form for him to use. My first thought was to use 2" pink board insulation and machine away material to create the "mold". It is a fairly simple sign (4' X 8'). The shape is the state of Iowa with the words Upper Iowa Construction across the front. I am going to run a sample and see how it turns out but wanted to get some input from the forum to see if anyone had some better ideas. Thanks!

[john_l]

There is a book called "Concrete Countertops" written by an author named Cheng. I got it at Borders. There was a lot of really good advise in there regarding making moulds. The focus was for counter tops but I have found the same instructions work well for concrete signs as well.

[joe]

You'll be time and money ahead to machine it out HDU and hopper gun a stucco concrete surface like this one.


5748

Concrete "in slab dimensions" is extremly heavy and requires some knowledge and skills to pour without errors. We cut Extira letters, for several casting companies to do just what your considering. The idea seems easy but it isn't.

Joe
www.normansignco.com (http://www.normansignco.com)

[scottbot]

I have done a couple sign moulds using blue styro. The main problem I had with it is that the styro is so delicate. Even vacuuming it can damage the surface. I had the vacuum hose slip out of my hand and put a bunch of dents in the styro that I had to fill.
In the end I got the job done and the customer was happy. Now he wants another sign done. He is in the concrete business so understands how to work with it. Although he ignored me when I told him to use Pam cooking spray as a release agent. He used his usual release agent and it didn't work. They had to pick at it for a long time.
A mistake I made was cutting too fast. The Bot could handle it but the styro couldn't and tore instead of cutting. I had to fill those areas. I design the job in normal view because it was easier to visualize but lived in fear that I would forget to flip it before I cut it. So far I haven't done that but I won't be surprised if I ever do.

I like Joe's idea. I looks a lot easier.

[rb99]

Could you pressure wash the styro out if it sticks?

RIB

[joe]

Richard,

Concrete isn't that tough until it's matured for a while. The best solution is to stay away from EPS blue foam and use a tougher material. We bevel cut all our letters from Extira, in reverse, and they fall out, clean and smooth.

[navigator7]

I'm in the concrete placing biz....or was. Now I stamp, stain and scare up work.
One of the reason's I'm here is to create custom looks not possible yet in my area.
I pumped some concrete for a customer/contractor wanted to insert an 8' oval bass relief of a 67 camero into the wall of a car wash he was building.
It came out ok but...
If he could have vibrated more and made sure there was exceptional relief on all sides, it would have been perfect.

In all the special cases i've seen making a concrete "something or others", the lack of vibration and going cheap on materials does not pay any dividends.

Go with fiber. footing and slab mixes are generally 5 sacks of cement per yard.
When you are trying to pull out perfect detail you need to be in the 7 sack range and small aggregate.
If outside, don't forget air entrainment for freeze thaw.