Molding rubber?

Plays_with_Toys · 10-12-2009, 07:16 AM

I'm trying to replicate a non-RC part in rubber. It's currently plastic, roughly a flat sheet shape (though it has some indentions/designs on the front face that are maybe .030" deep). The overall dimensions are roughly 3"x3" by 0.1"

I need to switch to rubber to allow for some flexibility as the plastic piece tends to crack after repeated flexing. I'm pretty lost on what to use in terms of the actual poured rubber and also a lower priced mold resin that can be used for DIY/prototyping purposes. I plan to make the mold by pouring around the component. The mold will have no parting line, just open top.

The ideal poured rubber component would be:
1) flexible but not floppy- actually a floppy disk or thin piece of plastic like it would have the right stiffness properties, but able to be flexed without cracking.
2) Some abrasion resistance
3) Easy to pour while retaining mold details and leaving a flat (bubble-less) top surface
4) Dyable. If not- then a black rubber
5) Low cost/lower quantities available, again it's DIY not bulk production.

Anyone able to answer even parts of this? Any help is appreciated.

6x6bigdollars · 10-12-2009, 08:26 PM

Why don't you try that stuff called Dip,they use it on Tool Handles it like a rubber,it Flexes,I think you can get it from the Hardware Store.

rmdesignworks · 10-12-2009, 08:56 PM

plasti-dip,,brush on or spray on,,available at lowes or home depot,,,apply in thin layers though to avoid bubbles

as far as a mold compound,,try the stuff at rail road shops for making scenery rock,,its just latex rubber,,brush it on,,they carry it at hobby lobby

Plays_with_Toys · 10-13-2009, 07:01 AM

I've been looking more and more into this. Looks like a silicone based rubber can be used. It's thick, but you're able to make a poured mold (much easier than brush on). It also has good release properties.

I don't know that plastidip would work correctly. The part material it looks like polyeurethane rubber is the way to go with. Just have to figure out the proper durometer.

Essentially looking at a setup like this: http://www.youtube.com/watch?v=JyQmEG9qmfw

Looks like it's about a $60-$100 process, but I'll be making several of these, so that'll help recover costs.

EDIT: Looks like the reoflex line of polyurethane is the way to go. Availabe in 20-60A shore hardness. Silicone mold rubber is easy enough to find through art supply stores, some of it is even food safe (searching DIY articles, found a lego ice cube tray made from the stuff). Also, Reoflex is color tintable. So I guess I sort of answered this on my own, but there you go, it's there for anyone else looking to do some kind of small scale casting/molding.

Plays_with_Toys · 10-13-2009, 07:24 AM

Here's some links:
Silicone Molds:
http://www.dickblick.com/products/sm...o-30-silicone/

Urethane:
http://www.smooth-on.com/Urethane-Ru...143/index.html

Urethane Color tint:
http://www.smooth-on.com/index.php?cPath=1118_1213
(apparently any thing that can tint urethane based paints can be used in the rubber)

rubberguy · 10-13-2009, 01:47 PM

Try shoe goo, or e-6000 comes in clear or black. Super tuff
stuff .

SunnyUSAF · 11-04-2009, 06:03 PM

check www.alumilite.com they have mold making supplies for casting hard resin and several types of urethane rubber, very economical, and stupid easy to use.

10-12-2009, 07:16 AM	#1
Plays_with_Toys I wanna be Dave Join Date: Jun 2004 Location: Centennial, CO Posts: 2,144	Molding rubber? I'm trying to replicate a non-RC part in rubber. It's currently plastic, roughly a flat sheet shape (though it has some indentions/designs on the front face that are maybe .030" deep). The overall dimensions are roughly 3"x3" by 0.1" I need to switch to rubber to allow for some flexibility as the plastic piece tends to crack after repeated flexing. I'm pretty lost on what to use in terms of the actual poured rubber and also a lower priced mold resin that can be used for DIY/prototyping purposes. I plan to make the mold by pouring around the component. The mold will have no parting line, just open top. The ideal poured rubber component would be: 1) flexible but not floppy- actually a floppy disk or thin piece of plastic like it would have the right stiffness properties, but able to be flexed without cracking. 2) Some abrasion resistance 3) Easy to pour while retaining mold details and leaving a flat (bubble-less) top surface 4) Dyable. If not- then a black rubber 5) Low cost/lower quantities available, again it's DIY not bulk production. Anyone able to answer even parts of this? Any help is appreciated. __________________ back from the dead. Holy eff RC crawling has changed since 2005...

10-12-2009, 08:56 PM	#3
rmdesignworks CAD/CAM DESIGNER Join Date: Jan 2006 Location: wrenching on something... Posts: 2,261	plasti-dip,,brush on or spray on,,available at lowes or home depot,,,apply in thin layers though to avoid bubbles as far as a mold compound,,try the stuff at rail road shops for making scenery rock,,its just latex rubber,,brush it on,,they carry it at hobby lobby __________________ Beware the fury of a patient man....J.Dryden ROCKY MOUNTAIN DESIGN WORKS USRCCA 2010 RULES Last edited by rmdesignworks; 10-12-2009 at 08:59 PM.

10-13-2009, 07:01 AM	#4
Plays_with_Toys I wanna be Dave Join Date: Jun 2004 Location: Centennial, CO Posts: 2,144	I've been looking more and more into this. Looks like a silicone based rubber can be used. It's thick, but you're able to make a poured mold (much easier than brush on). It also has good release properties. I don't know that plastidip would work correctly. The part material it looks like polyeurethane rubber is the way to go with. Just have to figure out the proper durometer. Essentially looking at a setup like this: http://www.youtube.com/watch?v=JyQmEG9qmfw Looks like it's about a $60-$100 process, but I'll be making several of these, so that'll help recover costs. EDIT: Looks like the reoflex line of polyurethane is the way to go. Availabe in 20-60A shore hardness. Silicone mold rubber is easy enough to find through art supply stores, some of it is even food safe (searching DIY articles, found a lego ice cube tray made from the stuff). Also, Reoflex is color tintable. So I guess I sort of answered this on my own, but there you go, it's there for anyone else looking to do some kind of small scale casting/molding. __________________ back from the dead. Holy eff RC crawling has changed since 2005... Last edited by Plays_with_Toys; 10-13-2009 at 07:18 AM.

10-13-2009, 07:24 AM	#5
Plays_with_Toys I wanna be Dave Join Date: Jun 2004 Location: Centennial, CO Posts: 2,144	Here's some links: Silicone Molds: http://www.dickblick.com/products/sm...o-30-silicone/ Urethane: http://www.smooth-on.com/Urethane-Ru...143/index.html Urethane Color tint: http://www.smooth-on.com/index.php?cPath=1118_1213 (apparently any thing that can tint urethane based paints can be used in the rubber) __________________ back from the dead. Holy eff RC crawling has changed since 2005...

10-13-2009, 01:47 PM	#6
rubberguy Newbie Join Date: Mar 2009 Location: sactown Posts: 5	Rubber molding Try shoe goo, or e-6000 comes in clear or black. Super tuff stuff .

10-12-2009, 08:26 PM	#2
6x6bigdollars Pebble Pounder Join Date: Jan 2005 Location: Kirkville Posts: 178	Why don't you try that stuff called Dip,they use it on Tool Handles it like a rubber,it Flexes,I think you can get it from the Hardware Store.

11-04-2009, 06:03 PM	#7
SunnyUSAF Newbie Join Date: Oct 2009 Location: Minnesota Posts: 4	check www.alumilite.com they have mold making supplies for casting hard resin and several types of urethane rubber, very economical, and stupid easy to use.

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