Pattern making question for you foundry guys

[neonman]

I'm scaling a 2hp Baker Ball Hopper Monitor at 3/8. The gas tank is like a cylinder about 2 1/4" dia 5" long with a half sphere at each end.

On the front, the word Monitor is written in a nice raised letter script. I have artwork. The method I use for making patterns like this one is to make a positive out of an easily workable material, pour silicon rubber over it, and use that negative as a mold to make the real pattern out of polyester resin mixed with very fine sand.

The question is what is a way to put the script on the master pattern, and be able to do a really nice job? Any ideas?

neonman

[steve]

try the craftstores they often have small wood or plastic letters also the bakery section - small edible letters to decorate cakes.
you could find someone with a cnc router- i watched one at some tourist trap making wooden keychain fobs with your name engraved.

[PTSideshow]

Get a current copy of the home machinist magazine Nov/Dec 2006 check out page 58 for the article by Otto Bacon on using a rubber stamp to make a cast name plate. should be able to mount it on the tank pattern and get any script you want.

[CCWKen]

It's been a while but I made one out of brass shim stock. I used .005" stock. I pressed the stock over a pattern with a hard rubber snubber. I trimmed the brass down and just contact cemented it to my form. Some dope and little feather sanding made the edge invisible. This works good if you don't need extreme relief.

[Your Old Dog]

I would use Hard Jewelers Wax as used in lost wax casting as I have some. Failing that, I would melt down a candle and carve it using little handmade scrapes till I got what I wanted. If I screwed it up in one area I'd repair that area with stick of wax and a iron soldering iron. The most popular tool for working this stuff is a flat piece of metal, sharpend on one of the long sides and then shaped like the letter "U" and then taped or wired to a small wooden stick to hold it all together. Rolling a small twist drill bit between finger and thumb will allow you to hollow out for b o p 8 and such type letters.

If I wanted a nice patter to work over I'd trace the lettering with an awl onto some sheetmetal and then make a "smokeprint" of that and deposite it on the wax as a blueprint to do my sculpting with. If you don't know what a smokeprint is you can search for here as it's been up a couple of times.

[timh]

Try some of the companyes that sell wax or foundry supplys they carry letters just for doing this sort of thing.

[neonman]

Guys, thanks for the ideas.
I was in the shop thinking about the responses, then I saw it, and then it hit me.

Bondo! I rolled about 1/16" of bondo on the wood pattern with some wax paper, and when it hardned I glued the artwork into position. I used a small rotary dremel tool with a small carbide burr to cut out the script. Looks just like the original.

You pattern guys might want to try this. It's quick and gives good results for this kind of application.

neonman

[CCWKen]

Bondo? What's Bondo?

Yep, that works too. Glad to hear ya gotter-dunn.

Where's the pictures. Some of these guys can't read so ya gotta have pictures.

[neonman]

OK, CCW you asked for a pic, here it is. I posted it on my web site along with some pics of castings I made in bronze last week end. The gas tank pattern is not done, but the hard part is. Its cherry wood & bondo so far. The core prints
will be drilled & glued into the ends, and some other features need to be added. This stuff will probably be pvc.

http://www.lonestarengineworks.com/drawingBoard.html

NOTICE: I'm not selling anything on this post, but I do on my web site.
If this gives you heartburn, DON'T GO THERE!

neonman

[Your Old Dog]

Guys, thanks for the ideas.
I was in the shop thinking about the responses, then I saw it, and then it hit me.

Bondo! I rolled about 1/16" of bondo on the wood pattern with some wax paper, and when it hardned I glued the artwork into position. I used a small rotary dremel tool with a small carbide burr to cut out the script. Looks just like the original.

You pattern guys might want to try this. It's quick and gives good results for this kind of application.

neonman

I was just going to suggest this machineable wax I came across today in enco catalog http://www.use-enco.com/CGI/INPDFF?P...MITEM=505-3626 as it looked fairly inexpensive but the bondo is a good idea too! My friend used to be a apartmanager of 160 unit complex. He said the cops were routinely breaking down one of his metal doors. He used bondo to rebuild the door frame part that breaks out when they hit the door with the ram I don't think it was the high rent district!! Glad you got it figured out.