8 replies to this topic

[rvec]

I have several sets of wheel inserts that I like but wanted more. I decided to try and cast some in resin. I had used all of my mold rubber for another project so; I decided to try to make my own silicone mold material. My first attempt was a failure. I mixed 100% Silicone with cornstarch. The mold hardened but failed to pick up the detail of the wheel inserts. My second try was using 100% Silicone mixed with acetone. Today I poured the mixture. It looks like it worked but I will have to see if all the detail was picked up and I can use the two part resin for a successful cast.

I followed the procedure for making the mold as shown in a YouTube video.

 

The process was simple and straightforward. I questioned how much acetone to mix with one container of 100% Silicone. Looking at the video he appears to use about one half of the container of acetone with two full containers of Silicone. I used the same ratio for my mix and it seemed to work well. Wear a respirator and gloves for the project. The stuff stinks and you don’t want it on your bare skin. The first image below shows the raw materials and the set-up of wheel inserts before the mold pour. The inserts were attached to the bottom of the receptacle with two sided tape. The second image was taken after the mold was poured.
 

I will have to wait 12-24 hours for the mold to dry. Then pop out the inserts and pour the two part resin into the resulting cavities. I will let you know how it works.

 

 

[MattD]

Rich, that's the hard way, isn't it??     It's a science experiment!

[rvec]

It is the hard way but Hobby Lobby is 70 miles away so I thought I would try this.  Cheap experiment

[Brian Czeiner]

I tried that procedure to reduce costs. I found I needed a release agent to get the rtv off of the originals. My concerns for paint adhesion steered me away from this method. Maybe you will have different results.

[Jens Scale Racing]

...or you find what you are looking for here: https://www.scalerac...saetze/15-zoll/

 

[rvec]

Jens,

 

Cool stuff

[Dave Crevie]

Acetone will dissolve plastic. Be careful how you use it on plastic model inserts.

[rvec]

Acetone will dissolve plastic. Be careful how you use it on plastic model inserts.

 

Warning comes to late for a pioneer. The deed is already done.  I will find out today if the mold rubber I created dissolved my precious plastic inserts.  We learn from our mistakes and hopefully we do not repeat them.

[rvec]

Project was an epic fail. Although I was able to make a mold, the acetone warped the plastic inserts.  The mold was really useless.  Even if the item(s) were of a material not impacted by acetone, the mold lacked a lot of flexibility and the inserts stuck to the mold and ripped it. The ripping problem might have been solved by using mold release but the point is moot.  Plastic cannot be used in a molding process the mixes acetone and 100% silicone. So the answer is to buy commercial molding products.  I have used the Alumilite molding and casting materials with very good results. They are expensive but they do work!