Curved Sign

[hbrannon]

I am new to signs, but have gotten a couple of jobs making signs for entrance ways to housing developments. I have been using HDU to make the signs, many of which are surrounded by brick or stone in the monumented entrance. I have been asked to do an oval sign for a curved wall. I visited a neighboring suddivision that has a curved sandblasted sign. The material seemed rubbery and flexible. Anyone had any experience with curved signs and flexible materials that could be routed?

[jhicks]

Hugh, the "Die Bond" aluminum substrates can be bent but I wouldnt call them flexible. The thinner sintra and or color core stock is easily formed or would conform to a radiused wall but its not clear what you are trying to accomplish in terms of thickness or applique vs carved surface/logo/letters etc.
There is a PVC based molding material often referred to as "flex trim" which contractors use for arched window casing trim but never heard of it in sheet stock.
Other than these I dont know what you have discovered but am interested. Many of the plastic stocks can be bent with heat and pressure if thats what you need.

[hbrannon]

Thanks Jerry, I am trying to find out the signmaker of the curved sign. I'll follow up with any info I find.

[bleeth]

Hugh: It could be that he carved a "female" that was flat and used it for a mold. The resulting part, assuming a flexible latex compound for the male, would then be quite flexible.

[hbrannon]

Dave, that would make sense and it does appear to be a flexible substance about 1/2 " thick. It may be from a mold.
In my search to find a way to make this sign, I contacted SignFoam about the flexibility of their HDU. They stated that while it is not flexible, kerfs could be routed into the back to allow it to bend. It will however try to straighten out so fastening can be a challenge.
Anyone heard of this?

[chodges]

We are a large sign shop, and we do a lot of sandblasting. The material you are looking at is definitely not Sintra. Our sandblasting room has Sintra on the walls because sandblasting won't affect it - the sand just bounces off without eroding the Sintra at all. And we use a HUGE diesel compressor to blast stone, etc.

Any material that "feels rubbery" probably wouldn't sandblast well enough to make a 3D sign.

And, to my knowledge, all substrates that are thick enough to sandblast are also rigid enough to not bend without breaking.

My best guess is that they made a mold, then cast the sign from the mold using latex like Dave suggested.

Hope this helps!

[joe]

Charlie speaks the truth!

I'm sure several of us could help if we had a photo to look at.

So what size is this sign?
How thick is it?
How is it mounted?
What type of texture is the surface?

We just don't have enough information.

[hbrannon]

Joe,I'll get some pictures over the next couple of days and post them along with dimensions, etc.

Charlie, have you had any experience with creating blasted or routed signs that had to conform to a curved surface such as an entrance to a housing subdivision? Someone locally suggested routing the sign on 1/2" HDU and laminating it in the proper curve to additional sheets of 1/2" HDU to the desired thickness (1 1/2"). Do you think this would work?

Thanks for all the help guys, seems like my "first" jobs at anything always turn out to be some of the most challenging!

[chodges]

I really wish I could be more help here.

We have sandblasted limestone that was already milled by a stone company to conform to a curved surface, but that's not what you are trying to do.

The materials we typically sandblast (SignFoam, wood, stone, Extira, etc.) are very rigid - especially in thick slabs. I don't think any of these could be permanently bent to a curved shape without breaking.

If I were trying to do what you are, I would probably start with the sign background - make this by laminating (glueing with "Stickit" spray-on contact adhesive) thin (1/8" thick) sheets of Sintra clamped to a shop-made wooden form until I got the curved shape I want.

Then, I would rout two sets of the individual letters for the sign out of 1/8" thick Sintra. Individually, these could be bent somewhat without breaking, and making 2 sets would allow me to stack & glue them to achieve 1/4" thick letters. More sets of thin letters could be bent and stacked to produce thicker finished lettering.

A heat gun will help a little on the bending part, but (since Sintra is really extruded PVC) don't over-do it - the Sintra will get "hot spots" and bend unevenly, and you will have a real mess.

This is a really painful way to get where you want to go, but its the best approach I can think of. I hope your price allows for a lot of labor time!

[joe]

Charlie,

I agree this is much too elaborate a process. Lets see what the photo's tell us.

Perhaps the substrate is 1.5" HDU with routed or sandblasted copy. Then the back of the panel has vertical, table saw groves, 1/2 deep every four inches. It will snake around a corner. We've done it. "Sign Foam" brand is more flexable.

[beacon14]

I have very little experience with sign foam but some experience with making flat things curved. You might try kerfing two thin pieces of foam as Joe suggests, then gluing the kerfed sides together and holding them against a curved form while the glue dries. A rigid glue like polyurethane glue will work better than contact cement. You would have to experiment with the foam thickness, kerf depth and spacing, etc. but as long as you are not routing very deeply this would let you rout the sign flat and bend it fairly easily, and it should hold the curved shape once the glue sets up. Many shallow kerfs close together will work better than deeper kerfs spaced farther apart.

Hope this helps.

[hbrannon]

Hey guys, I finally got back out to the sign to take some pictures. I carried someone a little more knowledgeable with me. As it turned out, I didn't need the pictures. The entrance sign (60x30 oval) was coming loose a little from the brick where it was just screwed in, and as the say in the NFL "after further review"; the substrate is 3/4" HDU just bent over the wall and screwed into place. They probably should have used some glue since it is seperating as the HDU is attempting to straighten out. On a back street in the subdivision, I found a smaller sign (36 x18" oval) out of 1 1/2" HDU. It was curved as well, but had kerfs cut in the back as David and Joe explained. My sign is 60x36 oval and I think I will try the
1 1/2" HDU and Kerf the back. Hopefully problem solved. Thanks for all the help. This is my first time at really using the forum, and you guys are GREAT.

[john_l]

When kerfing the back of a HDU sign to curve.. hold the vertical kerfs just a little short of going through the edge. It saves edge patching and cleanup. and still bends around easily in most cases. The kerfs are also cut on the bot.

That's what I've done anyway.

[phil_o]

I've heard of a product called "Wacky Wood" It's a bendable plywood. Has anyone tried using this product for curved items?

[Gary Campbell]

Phil..
We use bending plywood fairly often for radiused work. It is a plywood with all the plies having parallel instead of perrendicular grain orientation. Most that I have seen is approx. 3/8" thick and is sold in two 4' by 8' versions. Version 1 is long grain(you could bend an 8' column with a 4' circumference) and version 2 is cross grain(you could bend a 4' barrel with an 8' circumference) It glues up well and we usually use it with 2 or 3 laminations.
Gary

[beacon14]

I've heard it called wiggle wood. You can also get 1/8" bending plywood, it's made of two plies perpendicular to each other so it bends either way. The 1/8" that I've seen tends to have a smoother face - the 3/8" is made with courser stuff and works well when stapled to a framework then laminated over. I also use it to make curved forms for veneering curved panels. For the panels themselves I'd use the 1/8" bending ply. Five or six layers plus veneer on both faces make a real nice curved door.

[robtown]

Drifting a bit here... but... You can also get a kerfed MDF product that allows for a smoother finished face. Rockler sells smaller pcs but I got 1/4 4x8 at AWPC in Atlanta.

Also, depending on your sign and the requisite curve, it seems that it may be just as simple and easy to take pcs of HDU and cut smaller sections with a small bevel on each edge to be joined and use gorilla glue to put it together. (like making a barrel...)

[joe]

Rob,

I've done this and it's easy but I'd stay from Gorilla glue.

It's fun to cut out a shield, then slice ut up into sections with beveling cuts. When put back together, it's very impressive.