# Resign Castings - HELP PLEASE



## iRace (Nov 5, 2008)

Okay, a couple basic questions:

I've been using "Mold Builder" by Castin' Craft to create a flexible mold of my existing T-Jet bodies and then use a two part acrylic resign for the final product.

Many problems with this, but the most significant would be that I have been filling the entire mold with the resign. I then dremel out the excess... NOT worth the effort. I figure I could create a mold of the inside of the body, put them together and then inject the mold with the resign. 

There must be a better way...
I know nothing nor have any ideas how to inject the resign.
I need the screw posts that the T-jet bodies utilize.

Is acrylic the proper solution or should I be using something else?

I've been searching the forum for answers but I am spending so much time on each threat produced by my searches, so forgive me if these answer have already been posted. Great info here...


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## resinmonger (Mar 5, 2008)

*Searching, searching, found it you have.*

You seek the Truth. The Truth is out there.

Start your search here with the liknks below.

Posts 19 and 20 of this thread are especially good but read through the whole thread. Some major league casters offer tutorials in this one.

http://www.hobbytalk.com/bbs1/showthread.php?t=242636 

Ths baby covers some specific issues that one can run into.

http://www.hobbytalk.com/bbs1/showthread.php?t=214815

Here are some of the more popular starter kits. This will give you an idea of the commonly used materials.

http://www.alumilite.com/ProdDetail.cfm?Category=Starter Kits&Name=Super Casting Kit

http://www.smooth-on.com/index.php?cPath=1217

http://www.micromark.com/COMPLETE-RESIN-CASTING-STARTER-SET,8174.html

And yes, I had these already book marked because I have found them very useful in my own attempt to become a sub-junior apprentice caster. You will find that the castingmeisters on HT are very open to sharing there processes. Guys like Roger Corrie and Gary Fast will take you through a step-by-step process. This is like the Ferrari F-1 team showing you how they design and build a car. Yeah, we're pretty lucky.

Hutt, the information pack rat. Ummm rats, now I'm hungry... :drunk::hat::freak::dude::tongue:


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## 1976Cordoba (Sep 20, 2000)

Do a two-piece squish mold. Here's a good how-to:

http://www.alumilite.com/HowTos/SlotCarMold.cfm

And here is a casting how-to:

http://www.alumilite.com/HowTos/SlotCarCast.cfm

I followed these directions and was able to get pretty good results and I am just a total hack. :thumbsup:


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## TomH (Jan 17, 2006)

I haven't used "Mold Builder", but that sounds like it may be your problem. That product might be for a one piece type mold. In order to do a slotcar, you need in almost all cases to build a two piece, or a three piece mold made out of silicone rubber that the guys have posted on their links above. Spend the money on the good stuff and you will be much further ahead in the long run if you plan on having good results. Don't expect to have a great cast the first time. It takes a little trial and error to learn what works and what doesn't. Casting is fun to do if you like that sort of thing. Plenty of master casters are here on this board to learn from that have posted "How tos" . The Alumilite link has a video on casting a small car out of resin that isn't too bad (a bit simplistic) to get you started in the right direction. Casting small cars is a bit different than some of the material on the bigger scale casting you might run into on the web. They use sprues (vents) more than we do. Most of our stuff is squish type molding where we pour in the resin and pop in the second piece of the mold and the excess resin squishes out.


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## TomH (Jan 17, 2006)

Now that I think about it, you may have created a one piece mold. In your mold, mix a very small amount of resin and pour it into the mold cavity. This is called slosh casting. Keep the resin moving all around the mold. Try to coat your whole mold while turning the mold around. The resin will begin to harden..don't know how long your resin will take to do so as all resins have different times, but in my cast it takes about five minutes. If you do it right, your mold will be coated with a thin film of resin. Any excess puddles will form on the low spots first. If it is too thick turn the mold over and let the excess run out of the mold. Keep repeating this process until you get the thickness you need for your cast. It will take four or more small batches of resin to get where you want..patience!!
Pop it out of your mold when it all gets hard enough and dremel or sand out the wheel openings and clean up the bottom of the cast and you should have a casting you can work with. If you screw up, you can repeat the process from scratch, or you can pop in the first cast back into the mold and thicken up the thin spots. Remember, it is much easier to build the resin up than to put too much in and have to sand away to get your cast thinner. Thinner is better.


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## grungerockjeepe (Jan 8, 2007)

Race, listen to the Hutt, for he is wise. Seriously, the alumilite website is the best one-stop resource for casting out there followed by smooth on. Alumilite makes a starter kit that has most everything you need for $70, and you cant go wrong. 

I recommend some legos for making re-useable mold boxes and investing in a cheap digital scale for measuring out the mold rubber. You should also get a set of clayworking tools which are cheap. The best hint I was ever given for resin casting (and I think the other veteran casters will back me up on this) is that a good master is 90% of what makes a nice casting. Any clay used to fill the master needs to be smoothed over and worked into the seams--especially if like me, you want to mold the glass right into the body. Its more time consuming than leaving a few errant globbers, but your castings will be easier to work with, and will look professional.

Smooth-On makes great mold material, but its a little viscous and tough to de-air for my tastes. Alumilite's resin is top notch, if a bit pricier but it holds its shape over time, where Ive had S.O. stretch out over snap on bodies. For screwpost applications thats not a concern.


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## HadaSlot (Oct 22, 2007)

Oh yeah, playing with Lego's at 41. My 6 year old was absolutely amazed. The two piece seems backwards in my mind but with the visuals is quite easy. Yes the slosh is easy if you get all the bubbles out. Pouring in very slowly in the tight spots (once you have found them by the first few tries) and the get the rest covered. The problem I hade with slosh cast are the windows when it gets to thick and the time, like you stated, to correct. Study the two piece and I think the time you spend figuring it out will outweight the time it takes to grind out the inside of a miscalculated slosh pour. David


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## grungerockjeepe (Jan 8, 2007)

This is just my opinion, but I think slosh casting is to be avoided. Sure, it can be mastered, and there are slosh casts that turn out nicely, but they all have that same problem of too thick here, too thin there. On a screwpost mounted body its a lot less of a problem, but trying to adapt up snap on chassis mounts to something like that would be a nitemare. 

Also, chassis that snap mount are generally a lot more powerful so once you've spent hours trimming, painting, and decorating your slosh cast car, one good whack into the wall could well find a too-thin spot, ruining your masterpiece. 

This is a minor thing to some, but lets face it: a slosh cast piece looks like it was made in someone's garage. A body made from a 2-piece mold looks professional. A little extra effort goes a LONG way if you ever decided to sell your work and you'll see it in what they bring. But dont do it for that. Make the cars that YOU would want to own, and you cant go wrong.


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## fastlap (Nov 11, 2007)

*hope to help*

Hi Guys,

Hope to add some advice here. 

I too started with the slosh method. I only have one thing to say about sloshing. *Very hard to duplicate multiple bodies or parts!*

It took awhile, but I eventually graduated to 2-part molds. Roger's tutorial is about as good as it gets to get the method across. I would study his until you get the idea. 

I feel the 2-part mold is the most cost effective way of getting duplication at our level. Also, the Aluminite site is good too. I also like the MicroMark site for products. I personally use the Micro Mark 1:1 RTV silicone for my molds. It seems to be a good bang for the buck for myself. Here is the Mold Rubber webpage for MM
http://www.micromark.com/ONE-TO-ONE-and-RAPID-MOLD-RUBBER-32-FL-OZ,7883.html

I get my resin locally here in Chicago through Eager Plastics. I use their EP8036 Casting Urethane. Here is their website page to their casting products.
http://www.eagerplastics.com/cast.htm

Lastly, grungerockjeepe stated it best a couple posts back. I agree that 90% of getting a good cast is perfecting your "Master". I spend 95% of my time modeling the Masters and 5% making the molds/casts. Casting is the easy part. Follow Roger's tutorial and remember this very important thing. 

"It took all us casters some time to get it close. It will take the rest of our lifetime having fun trying to "perfect" our casts. Have fun and be patient."

Gary


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