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Post by superba on Jun 22, 2006 22:19:33 GMT 1
Lee and Jerry:
This is the most helpful post I have seen todate on this great Web Site.
I have been casting two part molds for some time, but your tutorial has provided insights on several key areas.
When making the first part of the two piece mold, preping the master has always proven difficult. I have always hated the entire process.
I have been using strips of cardstock adhered with elmers glue to close off wheel openings. I have filled in window openings with elmers glue.
A time consuming process and repeated many times when the glue would not set in the window openings. Typically, I have to let the master and base dry for 12 hours before I can pour into the mold box.
Once the first mold was completed, all cardstock and glue must be cleaned out with warm water, also a messy process. No matter how much time I spend, there always seems to be remenant glue stuck in the mold, which ultimately requires more trimming and cleaning of the produce model, particularly around the vent windows and side window.
I had never thought of using clay as a base for the model let alone for closing off wheel openings. Using clay is so logical, I feel stupid for not using it in the past.
I am making three molds this weekend, you have saved me a signifcant amount of time and trouble by teaching me about a better way of making molds.
You have shown me a new way of doing something that has always limited the fun factor and reduced the number of molds that I am willng to produce.
Thanks so much for taking the time to create this posted string
Joe Fay
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skunk
87thScale addict
5th B-day
Posts: 2,762
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Post by skunk on Jun 23, 2006 4:17:02 GMT 1
Yay! This might mean that there will be more Superbas available than hitherto!
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Lee
Senior Member
Posts: 1,899
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Post by Lee on Jun 23, 2006 4:54:21 GMT 1
Joe, you are most welcome. The information shared on the message board over the last two years has helped everyone improve their work. No one person can think of everything.
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Post by superba on Jun 23, 2006 17:24:05 GMT 1
Skunk is correct, this will help me get beyond my absolute hatred of mold making.
Lee, your right about no one idea, but for me personally, the clay thing gives me new meaning to my life......clay, versus cardstock and elmers glue, man life will be good.
Now if I could find a new way to mill solid castings, the second worst part of model making?
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Lee
Senior Member
Posts: 1,899
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Post by Lee on Jun 27, 2006 5:24:47 GMT 1
Jerry bought a small power tool like a Dremel, but much smaller and lighter from MicroMart. It is like holding a big pen. Makes removing material much easier.
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skunk
87thScale addict
5th B-day
Posts: 2,762
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Post by skunk on Jun 27, 2006 7:00:04 GMT 1
Lee, please tell me more about this magic mini dremel.
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Lee
Senior Member
Posts: 1,899
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Post by Lee on Jun 28, 2006 5:32:25 GMT 1
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Post by jackfitz1944 on Nov 27, 2006 1:10:57 GMT 1
Lee, I have been making molds and casting autos for about a year. Your story will improve my success at getting good castings. I don't use a vacuum chamber but I still have most of my castings turn out (some with air pockets). I would be interested in purchasing some of your products (cars). Jack
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Lee
Senior Member
Posts: 1,899
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Post by Lee on Jan 27, 2008 6:07:55 GMT 1
This is just updating. We switched from building foamcore boxes for molds to using little plastic containers. The first picture shows them in use: When we do the second part of the mold, we pop out the mold, flip it over, and put it back it the same plastic box. Then we use tape to make the box walls a little higher.
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gdcd74
Apprentice
the boy from oz!!!!
Posts: 45
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Post by gdcd74 on Oct 3, 2008 12:52:45 GMT 1
Hey guys, some interesting stuff here on this thread. I notice you guys have a solid vehicle you are casting. Well i have only been casting for a very short amount of time and have attempted a normal dissasembled car, yes, if i could complicate things anymore i would. Anyway things are moving along and i am nearly getting perfect castings. Things i learnt: 1. Dont use too much release as it must not allow the resin to flow and creates a vehicle that looks like it got shot at by a whole battalion with M60's and M16 rifles 2. Put heaps of thought into the way you orientate your vehicle as you will need to pour and vent it. I found a pour sprue tube should go to the lowest point of a vehicle, ie the roof of an upside down car . The vents go to the highest point of the vehicle , ie the bumpers. The best thing i found to use as vents was roundish tootpicks . Snip the end to create a flat surface, dab a little superglue(real little) on and stick to the underside of your bumper. Just pull out before you pour your casting together with your master. Even if you overfill the mould and resin goes up the vents , it slides out easily(being round) and the narrow point of a tootpick allows for minimal clean up work once its snipped off. Coincidentally i am in the process of creating a two part mould that is fully vented around the perimeter of the car except the wheel arches. It will have extensions glued to the master vehicle so that when pouring it will create the vents. basically the inner mould is suspended via some overhead timber/metal work with a "moat" type of vent all the way around. 3. Another thing i learnt was I was stirring for too long before pouring in the cast till someone on this forum told me to stir for about 15 seconds and then pour allowing enough time for the resin to flow into all the crevices and most importantly of all the bubbles to rise and escape. INSTANT POSITIVE RESULTS. I will however try Talcum powder as a release mechanism on my other moulds as i have read about this several times and would like to know if it really works. Let you all know. I suppose the most important thing i would like to say in reading some peoples comments is, i only started playing with resin a couple of weeks ago and say 5-10 rejects, 5-10 okay, and 5 real good cars later i am now getting consistent results. I guess, you need to experiment. I have decided to and design the above more complicated mould i want to build . My aim is to get 99-100% casting everytime. As i said i am only new to this but with a bachelor in Engineering Degree behind me i am aiming high. I would like to know what other peoples success rate is. Basically i dont want to look at castings that look like attempts at copying something. Maybe i am being optimistic. My biggest hate at the moment is window opening and cleaning the flash - i dont like uneven file marks. In saying that i have got some ultra fine sandpaper(wet and dry) as we call it here in OZ and glued it on icy pole sticks to create rigid files the exact width of my windows. I found that my file set was good for getting the bulk out but the fine sandpaper finished the windows off nicely...so maybe try that aswell, it works for me. Mind you i did destroy about 2 kg of silicone rubber while learning (say $50) and about 100grams each of part A and part B resin(say another $50) so expect to waste aleast $100, make a mess , get frustrated, angry , depressed, feel useless BUT take a step back , walk away , go for a walk, a drive something different and think about how you can improve each pour. I have started with an ultra complicated task and i reckon im not far off sorting it out once and for all. MY ADVICE------GET CASTING!!!!!! ;D ;D ;D ;D ;D ;D ;D ;D
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Post by superba on Oct 7, 2008 1:42:37 GMT 1
Try and Try again, utlimately, you find casting very enjoyable!
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Post by stevette66 on Jan 20, 2009 19:26:19 GMT 1
Great thread Lots of info. I also do some casting and find it very enjoyable. I like to cast hollow bodies the best. Steve D
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skunk
87thScale addict
5th B-day
Posts: 2,762
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Post by skunk on Jan 21, 2009 2:42:26 GMT 1
Great thread Lots of info. I also do some casting and find it very enjoyable. I like to cast hollow bodies the best. Steve D We demand pictures! Oh, and welcome.
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Post by stevette66 on Feb 23, 2009 2:53:31 GMT 1
Well thanks for the welcom . I will try to get some pictures. He goes... lets see if this works Steve D
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Post by stevette66 on Feb 23, 2009 2:56:08 GMT 1
Well I guess this works!!!! These are the two Sport Caps I casted Steve D
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