Can you answer this question?

[daddycreswell]

Long story short I am looking to make concrete molds of RC bodies. What type of concrete can I use that is smooth when dry? Thanks

 

[dawgee]

could you use plaster of paris?

 

[6768rogues]

Plaster of Paris is a good suggestion. You can also consider cementitious mixtures with tiny aggregate. Maybe something like sand mix combined with type S mortar, to have small aggregate and the plastic working qualities of mortar. A couple of bags won't cost much and you can experiment.

 

[daddycreswell]

could you use plaster of paris?

Plaster of Paris is a good suggestion. You can also consider cementitious mixtures with tiny aggregate. Maybe something like sand mix combined with type S mortar, to have small aggregate and the plastic working qualities of mortar. A couple of bags won't cost much and you can experiment.

I used Plaster of Paris for my first mold, I just wondered if I made it from concrete if I wouldn't have to be so careful with the mold. I treat the plaster one like a child and try not to crack it.

 

[squarles67]

Male a rough mold out of concrete and line it with plaster of paris

 

[wnstwolf]

not sure what your end game is here but could you look at West Systems and use an epoxy or fiber glass? once cured they are quite strong and you could then fill it with low expansion open cell spray foam and have a pretty solid shell/mold?

I could be way off for what you are after but thought I would thro it out there

 

[daddycreswell]

not sure what your end game is here but could you look at West Systems and use an epoxy or fiber glass? once cured they are quite strong and you could then fill it with low expansion open cell spray foam and have a pretty solid shell/mold?

I could be way off for what you are after but thought I would thro it out there

My end game is to vacuum form R/C bodies from that mold.

 

[rippered]

Use concrete for counter tops ?

 

[Jim B]

What's an "R/C Body"?

 

[malibu101]

What's an "R/C Body"?

Radio Controlled car

 

[Jim B]

Thanks. My imagination was running wild.

 

[zhaddock]

Use unsanded tile grout

 

[Freejack]

I don't think you'll want to use a cement but rather epoxy or some sort of polymer.

I think in some cases Araldite iron filled epoxy resin is used then pass back over it with a void filler. I have seen that done in smaller 1/24th scale slot car bodies.

Jake

 

[sac02]

Yes, why not some sort of polymer perhaps? I don't know much about molding R/C bodies and what type of polymer they will be made of, but my first thought was polyurethane, it is easily moldable and available in any durometer you can ask for. Or epoxy may have less potential for interaction with the r/c body?

 

[plow]

Are you using a release agent?

 

[7echo]

Check out the Smooth-On products.

Some information can be found here...

http://www.rctech.net/forum/
http://www.rccrawler.com/forum/
http://scalebuildersguild.com/forum/

 

[404]

Long story short I am looking to make concrete molds of RC bodies. What type of concrete can I use that is smooth when dry? Thanks

Non Shrink Grout. There are versions at HD and Lowes. Can be mixed with water to ratios where it is a flowable liquid and still set up. Or use less water for a stiff mix if you are sculpting like clay.

Are there going to be holes in the mold to pull air thru? Am unclear on the method you are planning on.

Regards,
404

 

[bgoodwin]

I use Durhams rock hard water putty instead of plaster for making molds. It seems stronger and is easier to seal the pores. I have also used fiberglass resin to create some molds with. Take a look at the Alumilite products this stuff works really well for molds also http://www.makelure.com/ProductCats.cfm?Category=Casting Materials

 

[tncatadjuster]

I use Durhams rock hard water putty instead of plaster for making molds. It seems stronger and is easier to seal the pores. I have also used fiberglass resin to create some molds with. Take a look at the Alumilite products this stuff works really well for molds also http://www.makelure.com/ProductCats.cfm?Category=Casting Materials

ROCK HARD is great stuff for this application.

 

[Leaflessshadetree]

What about using foam (maybe even low expanding foam) to make the shape. Then a skim coat of epoxy or fiberglass resin. Sand to a smooth finish.

 

[daddycreswell]

Non Shrink Grout. There are versions at HD and Lowes. Can be mixed with water to ratios where it is a flowable liquid and still set up. Or use less water for a stiff mix if you are sculpting like clay.



Are there going to be holes in the mold to pull air thru? Am unclear on the method you are planning on.



Regards,

404

No there are no holes in it. I want to make a mold of the body pictured.

Sent from my dumb apple products my work makes me use.

 

[Strouty]

What is the final product going to be made out of? Are you trying to make a hard shell like Tamiya has or are you just trying to customize things?

 

[daddycreswell]

What is the final product going to be made out of? Are you trying to make a hard shell like Tamiya has or are you just trying to customize things?

For the final product I will be vacuum forming lexan over the mold.


Sent from my dumb apple products my work makes me use.