sign foam or ??

[nancy barry]

I am taking classes at local community college on using a shopbot. MDF will not work for the projects I want to to.. Someone suggested sign foam or other high density foam or epoxy foam. A search takes me to large manufacturer sites..

I am in MD.. Are there any local suppliers that would carry something of this nature or does anyone have usable scraps that I could purchase?

Another suggestions for materials? Size might be as small as 3x3 and only up to 7x14..

thanks so much.
nancyB

[Scott Shepherd]

What thickness are you looking for? 3" x 3"? 7" x 14"? PM me if that's what you need.

Signfoam is quite expensive in the fact that I haven't found anyone that sells less than a full sheet. In your area, Harbor Sales, Piedmont Plastics, and N. Glantz all carry it, I believe. It what you need is inches, not feet, let me know and I can probably help you. I have more odd shaped drops than I have room for at the moment.

[Keith Outten]

Nancy,

Can you use PVC?
You should be able to find PVC boards at your local Borg store in a variety of widths. PVC machines like butter, it cuts and carves real nice.

[Art Mann]

Nancy,

Can you use PVC?
You should be able to find PVC boards at your local Borg store in a variety of widths. PVC machines like butter, it cuts and carves real nice.

Yes! I experimented with HDU when I first started out but found it was expensive and not very durable. Keith and a few others got me started using PVC sheets for sign material and I have never looked back. My preferences for brand names are Versatex and Azek but I have used Lowes store brand too. You can get the material in 4 foot wide sheets as well as dimensional lumber sizes and you can get several thicknesses but you will probably need to locate a specialty building supply place or special order it in those cases..

Sign foam has its place but I think sheet PVC is a better alternative in many cases.

[Ross Moshinsky]

There really isn't enough information to give you a definitive answer so I'm going to give you some general info.

1. People often refer to HDU as Sign Foam similarly to how people refer to tissues as Kleenex. There are many brands of HDU. I don't do much with HDU but most people in the industry say Duna > SF4 > The rest. Another hint is if you call Duna, they will likely send you a sample pack with some decent sized chunks of material. HDU is not a cheap material and doesn't come in small sheets. A full sheet costs hundreds of dollars.

2. The next material commonly used, often in the sign world, is PVC (some people call it Sintra). This is not hard like PVC pipe. It's more foamy. It comes in two different grades: Interior and exterior. Interior will be lower density and more foamy. It also has a different expansion rate. There are lots of different brands. I've cut a bunch of the interior stuff and it's more or less the same. Exterior I've cut Azek, Komacel, and Ex-Cel. I didn't like the Ex-Cel brand. PVC is typically cheaper than HDU but doesn't come nearly as thick. You're looking at $100-250 for a sheet of PVC for .5"-1.0" thick stuff.

3. People way too often refer to MDF as all being the same. There are lots of different varieties of MDF. The stuff you get at Home Depot vs Medex(for example) is night and day. Medex is very dense, carves well, and is a very good interior material to work with. If you need something a bit lighter, Trupan (LDF) is often another good alternative. Even good MDF is much more cost effective than PVC but again, really shouldn't be used in exterior applications although some might suggest otherwise. Extira is the only exception I know of. That's specifically made to go outdoors but I don't think many people recommend it for many applications anymore. For good stuff, you're looking at about $40-70 for MDF/LDF for .75"-1" thick.

[nancy barry]

I do not know if I can use PVC or not. I will ask in class.. I love the gals at my local Orange Box store..

thanks for the suggestion.

[nancy barry]

Thanks very much to each of you for the answers and for the information in them. I knew that I could find some knowledgeable mentors here who are willing to help me find the best material for what I want to produce.

I am entering a whole new world of materials about which I have no clue other than what some other folks have said in terms of "use this".. My end goal is a plaster(hydrocal , dental plaster or other kiln friendly material) mold onto which I will place a piece of glass, put this in my kiln, heat to a temp range, hold, cool, anneal and then use the finished piece in a stained glass panel. I will attempt to attach an image of one I sold earlier this year and also an image of a commercial slumping mold. The plaster mold would be dried and cured in the kiln before glass is put on it for slumping purposes. The commercial ones are about 1/4-3/8" thick. The "image" on the plaster mold is the male/positive. The glass slumps over it becomes the female/negative of the image. I hope this description makes sense. I do have goals of some very small images on a 3inch by3inch square and also some larger images that would be about 7inches by 14inches or so. Glass is approx. 1/8 inch thick as a sheet before manipulation. Many of my images are the same as ones I use for etching with my laser. They are .CDR files and I hope that if I save them correctly that they can be imported into or exported from Corel into the software for the ShopBot. I do not know what software is being used by the shopbot until Mon when I attend the first class.


For the class, we will use an mdf material for our sample and then have the opportunity to supply our own material for carving.The instructor has a degree in architectural ??? and is very knowledgeable on the machines in the lab.She suggested the sign foam when she saw what I was attempting. I know so little about mdf that I had not clue that there is good quality mdf.. that might suit my purposes. I want a material that works well, is easily available in the Baltimore, MD area and is reasonable in cost. I think that 1" thickness will most likely work but I am not sure. I know that I have to start out with simple designs and work on to more difficult. I am learning 3d software also.. OH MY!

butterflysample.jpgTILE SAMPLE.jpg the tile is smooth background. Texture is from a screenshot of this commercial mold.

again many thanks for all of your help and suggestions!