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Post by indydog on Jul 11, 2022 16:21:20 GMT -5
I'm not sure if any one will find this interesting, but I love Lances "how to" posts, so I thought I'd post this. We all have built that 10 year old OOP kit that we find is missing a part or has a broken part. One option is to try and buy a replacement, if you can find one. The other option is to cast a new one. I recently started one such kit and this is my solution. Here is my problem. When I started to sand the tires, I discovered an air pocket. I figured I would fill it will super glue, but it was larger then I thought. The tire was basically unusable. So I cast a new one.  I used Alumilite Mold Maker for the mold.  I also used their casting kit.   |
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Post by indydog on Jul 11, 2022 16:31:34 GMT -5
I used a 2-piece mold. The first step is to make something to use as a mold box. I use a simple plastic container. If you make your own, make sure to seal the corners so the rubber doesn't leak out. Mount the master in the center of your box.  I use rice that I pour into the mold box to give me an idea of how much Mold Maker to use.  You then measure the rice and mix the Mold Maker. Since I made a 2 part mold, I only had to measure the bottom half.  In this case.... 50cc. Pour the Mold Maker into the mold box. Pour it into the corners and let it flow around the part.  Use some kind of mold release on the bottom half, I coat it with a thin coat of Vaseline, and pour the second part. You will need to make alignment areas to help align the mild halves. I use wood dowels set in the rubber. |
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Post by indydog on Jul 11, 2022 16:43:00 GMT -5
Once the rubber sets, pop the mold out of the box and this is what you should have. Cut out a pour hole on one edge.  Clamp the two halves together and you're ready to pour. Don't squeeze it too tight or you will deform the cast.  A bit on mixing the resin. I use small cups like you see in the hospital. Mix the resin 1 to 1 and mix it to a uniform color. Work fast if you are using the fast setting type. You will only have a few minutes before it begins to set. Once mixed pour it into the mold. I sometimes use a pipette to put the resin in the mold. And here is your new tire!  I use the quick setting resin, but there are other kinds that can take up to 24 hour to set. I think the slow setting resin gives better detail as it has time to work itself into all the cracks and crevices. There are also different colors... I have used the clear, white and tan. The clear can be tinted to provide color. While pricey the Mold Maker is good for perhaps 7 or 8 molds depending on their size. |
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Post by Gary Davis on Jul 11, 2022 17:01:34 GMT -5
Good tutorial Mark. I've been casting tires for about 15 yrs now. I use Smooth on and it works great. I also use their mold star 15 resin for the tires. It's already black, so I don't have to tint or paint it.
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Post by indydog on Jul 11, 2022 17:53:01 GMT -5
That's what I like about our hobby Gary, there is always more then 1 way to do something.
I'll have to look into the mold star 15. Would be nice to try black resin.
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Post by Calvin on Jul 11, 2022 19:46:58 GMT -5
Very impressive. You really thought out the 2 part mold process.
I make pocket molds for my tires.
90% of my molds are pocket molds.
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Post by Gary Davis on Jul 11, 2022 20:30:55 GMT -5
I make my molds for the tires pretty much the same way you do..... Including the dowels for markers. It really keeps the two parts lined up. I think you will like the smooth on Mold star 15. It's an easy 1-1 mix. I do it by scale, so it's not hard. I haven't had the cahonies to try the envelope mold....yet. Calvin does it and so does Harold Bradford. I also use a med syringe to fill my molds. It helps eliminate trapped air. Plus I pressurize the mold @ 40 psi too. you really don't have to do all that, 'cause your tire came out looking Great!
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Post by Calvin on Jul 11, 2022 22:20:34 GMT -5
You have to use a very flexible rubber to do pocket/envelope molds. It saves time (alot) and money. It literally takes me 5 mins to make a tire mold. I use old appxie sculpt containers and just super glue the master tire with pour hole and it's done.
Then when I pull the rubber mold out a take small pliers and work it out. then use an x-acto knife and cut it out.
There's really no science behind it.
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Post by indy on Jul 11, 2022 23:35:31 GMT -5
I enjoyed your behind the scenes videos of your casting process, Calvin.
Jordan
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Post by Gary Davis on Jul 11, 2022 23:36:13 GMT -5
I understand. I've been casting for quite a few yrs. I do use a very flexible rubber...but to cut it down the middle is way past me..LOL You're castings are great Calvin...I really like them. Don't stop what's working for you.
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Post by Calvin on Jul 11, 2022 23:45:02 GMT -5
I enjoyed your behind the scenes videos of your casting process, Calvin. Jordan I've been piling up footage, lately. It's just a pain to film as its such a messy situation. Lol I did get a go pro head ban. I have an idea! Just live stream my whole day on YouTube 😂 What could possibly go wrong with that? |
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Post by Calvin on Jul 11, 2022 23:48:03 GMT -5
I understand. I've been casting for quite a few yrs. I do use a very flexible rubber...but to cut it down the middle is way past me..LOL You're castings are great Calvin...I really like them. Don't stop what's working for you. New blade and cut straight 😉  My thought process is very minimal lol |
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Post by bobbyc on Jul 18, 2022 4:26:02 GMT -5
That's really ingenious using the rice to determine the height of the first pour, as is your choice of mold container and using the dowel to hold the master exactly where you want it. I'm not familiar with the term "pocket mold". Can you explain that to me? I made molds using Smooth-On products before, but not 2-part molds like you illustrated.
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Post by jamesharvey on Jul 18, 2022 9:49:16 GMT -5
This isn't something that I do very often but have been able to make a few parts as needed over the years. I am low tech and not highly skilled. I have found "Amazing Mold Putty" and "Amazing Casting Resin" from Hobby Lobby to work well for me. Each box is $19.99 currently. I have found them easy to mix and use with simple directions (pictures and words). Good luck with whatever you use.
Jim
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Post by bobbyc on Jul 18, 2022 11:12:40 GMT -5
Thanks!
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Post by IndyCarModels on Jul 18, 2022 20:16:14 GMT -5
You guys do great work. After this posting, I realize how much I don't know!
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Post by racermagic on Jul 19, 2022 13:05:17 GMT -5
You guys do great work. After this posting, I realize how much I don't know! Common feeling for me here. Its Almost like going to school every time I log on...the talent level is SUPER INCREDIBLE. |
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Post by Calvin on Jul 19, 2022 20:51:39 GMT -5
I'm not familiar with the term "pocket mold". Can you explain that to me? I'll post a video about it, soon. |
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Post by Calvin on Jul 20, 2022 0:32:36 GMT -5
I just posted a YouTube Short on how to make a "Pocket Mold"
FYI, I don't recommend this rubber as it cures too fast
FYI #2 This is a YouTube Short which is made for short attention spans and Smart Phones. YouTube is pushing them more to keep up with Tiktok
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