Close

Page 1 of 2 1 2 LastLast
Results 1 to 15 of 24
    1. Kit: , by (Active Member) bills69camaro is offline
      Builder Last Online: Jan 2021 Show Printable Version Email this Page
      Model Scale: 1/8 Rating:  Thanks: 3
      Started: 03-07-12 Build Revisions: Never  
      Not Supported

      This is the tire I will be molding & casting Molding & Casting a Rubber tire it's a Dunlop SP Sport 8000.
      The RTV Molding & Casting a Rubber tire I like to use is a clear platinum base. It's easy to see what you're cutting around and you can cast regular resin Molding & Casting a Rubber tire , clear resin Molding & Casting a Rubber tire , and rubber parts.




      Here I glue a styrene gate to the tire and glued the tire to a foamcore base. It's hard to see because my shot is over exposed. The gray rod is PVC I bought at a industrial supply house and turned it to size on my lathe. The reason for the pin is to make it easier to cut RTV core (shown later on).





      The box with all the elements in place ready for RTV to be poured. The box measures 3" W x 5 1/4" L x 6" H. I cut a piece of foamcore 6" x 17" and score it at the 3" and 5 1/4" dimensions and fold to make the box. I then hot glue the corners for extra strength, and also glue the box to the base.





      I mix the RTV and vacuum it to get the air out. Thats a must if you want a nice mold.<br>The formula I use to mix the right amount of RTV, L x W x H divide by 16 x .625.

      3 x 5 1/4 = 15.75 x 6 = 94.5 divided by 16 = 5.906 x .625 = 3.691 lbs. To convert .691 to ounces, multiply .691 x 16 = 11.056 ounces. I add a couple of ounces extra for waste. Total amount of RTV&nbsp; 3 lbs 13 oz.





      The RTV degassed and poured into the mold.





      After the mold is poured I place it back in the vacuum chamber. The tire is hollow so air will be trapped in the top inside of the tire, the pocket of air will be taken out so we can have a nice clean hollow tire.





      The mold out of the box and the PVC pin taken out, cutting the mold open begins. The mold is cut in the center down to the tire on all four sides. While cutting I wiggle the blade, that makes a jagged cut. When you're ready to cast and put the mold together the jagged cut will act as a lock and keep the
      mold halves from sliding and insuring a clean part.





      Here the mold is cut all around and opened so you can see the master. The mold core still needs to be cut and is keeping the mold from being open all the way.





      With the sides cut we start on the core. If I didn't make a center pin this would be solid RTV and very difficult to cut open. With the pin out there is a void and the RTV is a lot more flexible, making it easy to cut. It has to be cut down to the rim of the tire for the mold to be opened.





      The core is cut allowing the mold to be opened. The tire master is still on the core, unfortunately the master has to be cut off the core.




      Here it is cut in half and off the core.



      The mold is together , the pin in place, and taped with 2" clear packing tape to make it air tight. I then make a paper funnel and hot glue it to the mold, the rubber resin is poured into the funnel. The paper is heavy card stock 110 lb. I then place the mold in the vacuum chamber to be degassed. This takes 2 or 3 minutes. After it's degassed I open the valve on the chamber and let air back in the chamber, the rubber is drawn into the mold cavity. The mold is placed in a pressure pot for curing.


      After a 3 to 4 hr. curing time the mold is opened to show the newly cast tire.



      The tire is flexible and is pulled off the core.



      Nice flexible tire



      I hope my explanation was understandable.

      Bill

      Sorry I posted a pic twice and missed one all together. Not sure how to delete pics and add new ones.
      Show Complete First Post

      Show Your Support

      • This build may not be copied, reproduced or published elsewhere without author's permission.
        Please note: The first post will be displayed at the top of every page.
    JOIN THE SMC ALLIANCE NOW

  1. Tage's Avatar Yearly Subscriber
    Name
    Daniel
    Join Date
    Jun 2008
    Posts
    605
    Thanks Bill, that was very well done.
    Duke of Burl
    QUOTE QUOTE #2

  2. nascarnbroncosfans's Avatar Active Member
    Join Date
    Apr 2009
    Posts
    64
    I would gladly send you some front and rear tires of an rc car, a special / specific Rc car tire to cast. The factory no longer makes replacement parts and has been out of production for 5 years or more. Let me know either way. Thank you.

    Kevin
    Boyd Coddingtons Rc American Hotrods
    QUOTE QUOTE #3

  3. bills69camaro's Avatar Active Member
    Name
    bill
    Join Date
    Feb 2010
    Posts
    81
    Sorry Kevin, I tried to send you a private message but I get a reply that I can't send messages.

    Bill


    Molding &amp; Casting a Rubber tire
    QUOTE QUOTE #4

  4. nascarnbroncosfans's Avatar Active Member
    Join Date
    Apr 2009
    Posts
    64
    you can email me direct at nascarnbroncosfansATmsnDOTcom
    QUOTE QUOTE #5

  5. BrassBuilder's Avatar Yearly Subscriber
    Name
    Mike
    Join Date
    Jan 2007
    Posts
    372
    Bill,
    Thanks so much for posting this! This really explained the process well. I'll be sure to post back when I finally start making my tires.

    I'm looking around on ebay for a vacuum chamber. Do you have any recommendations for one?

    Mike
    Last edited by BrassBuilder; 03-10-12 at 07:02 PM.
    QUOTE QUOTE #6

  6. dpride's Avatar Active Member
    Name
    David
    Join Date
    Sep 2011
    Posts
    81
    Bill, are you using BJB rubber for the mold?
    QUOTE QUOTE #7

  7. bills69camaro's Avatar Active Member
    Name
    bill
    Join Date
    Feb 2010
    Posts
    81
    Mike, I made my own vacuum chamber. I got a 60 qt. aluminum pot from a restaurant supply on the net. You also need a clear top, a 1" piece of plexy glass is what you need, and a vacuum pump. Together it set me back about 800.00. There was a time when you could buy them for 1200.00 to 1500.00. I'm not sure if anyone makes them anymore. Your best bet would be ebay.


    David, I get my RTV Molding &amp; Casting a Rubber tire from my work, it's convenient for me, I don't have the hassle of ordering and shipping.
    I do use BJB resins.

    Bill


    Molding &amp; Casting a Rubber tire
    QUOTE QUOTE #8

  8. BrassBuilder's Avatar Yearly Subscriber
    Name
    Mike
    Join Date
    Jan 2007
    Posts
    372
    Quote Originally Posted by bills69camaro View Post
    Mike, I made my own vacuum chamber. I got a 60 qt. aluminum pot from a restaurant supply on the net. You also need a clear top, a 1" piece of plexy glass is what you need, and a vacuum pump. Together it set me back about 800.00. There was a time when you could buy them for 1200.00 to 1500.00. I'm not sure if anyone makes them anymore. Your best bet would be ebay.
    Bill
    I'm scoping out ebay for some used equipment. I'd like to do my tires closer to what you did in lieu of making them solid. While solid tires are....well...quite solid, they use a lot of resin Molding &amp; Casting a Rubber tire . Since I need to make 11 of them, that is a lot of resin Molding &amp; Casting a Rubber tire .

    A couple of questions....I see you cut that channel into the mold to pour the resin Molding &amp; Casting a Rubber tire in. To me, it doesn't look big enough for pouring the resin Molding &amp; Casting a Rubber tire and letting air escape (obviously that is not the case since your tire came out quite well). Did you have to pour resin Molding &amp; Casting a Rubber tire in and vacuum it multiple times to get all the air out and enough resin Molding &amp; Casting a Rubber tire in?

    Did you use plain old plexiglass for your lid? Or did you use the GP rated stuff? The GP stuff is supposed to be a higher quality and withstands stresses better. I think the stuff might even be bullet proof. After looking around, I think I'm just going to make my vacuum chamber instead.

    Mike
    Last edited by BrassBuilder; 03-12-12 at 11:34 AM.
    QUOTE QUOTE #9

  9. bills69camaro's Avatar Active Member
    Name
    bill
    Join Date
    Feb 2010
    Posts
    81
    Mike, the gate is big enough, I make a paper funnel or cup if you will. The funnel gets hot Molding &amp; Casting a Rubber tire glued to the mold, I then pour the rubber resin Molding &amp; Casting a Rubber tire into the funnel, the rubber wont fill the cavity because air is in the cavity stopping the rubber from filling it. Then I
    put the mold into the vacuum chamber, the vacuum draws all the air out of the mold, this takes about 3 minutes depending on the pump you have, you shut the vacuum pump off, open the valve on the chamber it starts to fill with air, all the air in the mold was removed and the rubber is stopping the air from filling with air and instead of air the rubber fills the cavity. One of the pics that didn't get posted so here it is.

    Hosted on Fotki

    We use 1" plexi glass at my work. When I bought mine I explained what I was using it for and asked if 1" would do the job.
    They told me there wouldn't be any deflection and it would stop a bullet. I didn't ask for a better grade of plexi. A 24" square
    piece cost me 80.00 about 6 years ago. If you have any questions I'll try to answer them the best I can.

    Bill


    Molding &amp; Casting a Rubber tire
    QUOTE QUOTE #10

  10. BrassBuilder's Avatar Yearly Subscriber
    Name
    Mike
    Join Date
    Jan 2007
    Posts
    372
    Ohhhh....I see. You filled the cup with the rubber resin Molding &amp; Casting a Rubber tire , put it in the vacuum chamber and the vacuum sucks the resin Molding &amp; Casting a Rubber tire into the mold displacing the air....if I read all of that correctly....which makes sense from what I've seen of YouTube videos.

    The good news is the price of plexiglass has not gone up in the last six years. I can still get a 1" thick piece for around that $80 mark yet. I just wanted to make sure you didn't use some expensive bullet proof grade of stuff for it.

    Thanks Bill! I think you got everything answered now. That last pic helped immensely.

    Mike
    My website:
    http://www.firesteelhobbies.com/index.html

    Feel free to look around. I have all of my projects on the website.
    QUOTE QUOTE #11

  11. Jack Reynolds's Avatar Active Member
    Name
    Jack
    Join Date
    Dec 2011
    Posts
    18
    Hello Bill. Can you recommend a way of making tire tread in an existing tire? I have created the tire (A smooth treaded replica of the 3 tread indy 500 tire of the fifties) but am looking for a method to carve or apply the very simple design. Thanks.

    Jack Reynolds
    prova_jr@yahoo.com
    QUOTE QUOTE #12

  12. bills69camaro's Avatar Active Member
    Name
    bill
    Join Date
    Feb 2010
    Posts
    81
    Hi Jack, I make a drawing to scale and cut out each tread with my X-acto knife, glue them in position on a piece of .005" sheet of
    styrene Molding &amp; Casting a Rubber tire and wrap around the tire.

    I did a tutorial on making a tire from scratch in the tutorial section!

    Bill


    Molding &amp; Casting a Rubber tire
    QUOTE QUOTE #13

  13. Jack Reynolds's Avatar Active Member
    Name
    Jack
    Join Date
    Dec 2011
    Posts
    18
    Thanks Bill I'll try the styrene Molding &amp; Casting a Rubber tire . Jack.
    QUOTE QUOTE #14

  14. Shiggy's Avatar Member
    Name
    Chardonnay
    Join Date
    Sep 2013
    Posts
    2
    I really want to do this but for a much smaller tire. Can you post the exact brand and style of the products you use for both mold and tire?
    QUOTE QUOTE #15

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Quick Scale Calculator

 
Scale Calculator   Scale Factor   Real Size:     + Deluxe Scale Calculator
  1: th   Which equals Convert measurement: Reset or clear:  
  Any Scale   Scale Size:     + Deluxe Metric Calculator
 
Top