the stuff...they...call...RESIN!

[69_charger]

some thing i am wondering about.....

1. how do you make the molds, and take the things out of them?

2. what are the molds made out of?

3. what kinda resin do you use? like, brand and where to get it...

4. how long does it take to cure?

thanks for the help fellow modelers!

[jeffb]

try youtube, theres a few good vids on resin how to..

[Casey]

some thing i am wondering about.....

1. how do you make the molds, and take the things out of them?

2. what are the molds made out of?

1) The mold type depends upon the part you wish to copy. A one-part mold is the easiest, and is the best choice when the part has a flat side which will either not be visible when used or is hidden Examples include the back face of a wheel, the bottom of a valve cover, or any part which is cast in two halves (say a transmission half). If the part can be molded solid (unlike an injection molded kit part's transmission half, which is not molded solid) and has a flat side, a one-part mold is the easiest way to go.

When you get into more complex shapes where there is no flat side and you must use a two-part mold, things get a bit trickier. Your mold will depend upon the shape of the part and the part's features. For example, if you want to make a copy of a wheel which has spoke detail on both sides of the wheel, you need to use a two-part mold. To make a two-part mold, you first select a container of build a box which is slightly larger than the part, fill the bottom with non-hardening clay, embed the part to be cpoied in the clay (or add more clay to the existing clay bed and embed the part in the additional clay), then pour mold rubber over the part and clay. When the mold rubber has fully cured, you can remove it, and prep the mold half and part for pouring of the second half of the mold. Once the second half is cured, separate both halves, remove the part, and you have a two-part mold.

2) Which type of mold rubber you use depends upon the part(s), how long you want the molds to last, which type of resin you plan to use, etc. The deeper the undercuts on your mold, the more elasticity the mold rubber must have to avoid tearing when you de-mold the part.

There is a lot to learn and the learning curve is steep, but if you enjoy learning, doing things right, and aren't discouraged by an initial parts cating success rate of 10%, you'll do well.

3. what kinda resin do you use? like, brand and where to get it.4. how long does it take to cure?

3) Again, it depends upon you skill level, your equipment, what you plan to do with the parts once they're finished, and so on.

Try www.alumilite.com and www.smooth-on.com for starters. I've used both companies mold rubber and resin, and each has slightly different properties. You really do need to try them out yourself and see what works best for you. It's expensive to learn that way, but once you find the combination which works best for you, you can start re-couping some of your investment.

4) Resin cure times vary with the type of resin you choose. Some cure very quickly (5 minutes), and others take much longer (24 hours). Again, trial and error is best.

[Smart-Resins]

Yes, I second that! also, on such stuff as say two half trannys and engines, you can cut the tranny off and glue the two halves together. also can bondo things in to make them solid if it helps. I will add to Caseys by saying your attention to the master is one of the most important part of the resin pieces coming out usable! If you can see it or feel it on the master, the part you want to make a mold of, you will be able to do it on the copy!So another words, if you leave the seem or mold lines on, they will be on the copy. If you sand them out, but do not smooth them out by working down to a fine grit, you will still see it on the resin copy! aso, when pouring the rubber for the mold, pour from one corner and let it flow across the part filling it in. If you spy any bubbles, make sure to use a pin and pop them!! They are the casters worse night mare when starting out! Some thing goes for the resin! I personally like resin with a 10 minute pot life. Pot life means how long it takes to cure, or get hard. This way I have enough time to spy out air bubbles and pop them before placing into the pressure pot! also, that is something not needed, but I find it really helps. I run mine around 35-40 lbs pressure! A small 2 gallon pot can be found at harbor frieght for around $40-$50 when on sale and can easily be converted to be used for this process. I use smooth-on product as I personally think it works better the alumilights stuff and is cheaper shipped. I buy it through Mister art wich has been the cheapest place I can find it. I did start out with alumilights stuff though and its not bad. Just thier intro ductory stuff has a shorter pot life and made it very hard to give me time to pop bubbles and get it into the pot! I have found that gold bond or other talcom powder or plain jane baby powder with no oils or fragerences works good in the mold. If you do not have intentions of getting 20-50 parts out of the mold, you can heat it up int the micro for a minute, then powder. It does help, but it also shortens the resins pot life. also my preference is to chill the resin some before using! also again personal prefference is to pour out the amount of rubber needed, warm it for about a minute, then pour it into the mold box. again, some will agree and some will not! Its all really what works best for you! Many go through les steps then I do and perhaps thats why some can handle doing after market resin. My stuff usually turns out pretty good, but it becomes such a task, then I am not cut out for aftermarket, only a few sales to cover my costs when needed! Jody

[69_charger]

wow! thats alot of reading, thanks for taking te time to tell me this... do you really need a pressure cooker to make the rubber molds?

[Smart-Resins]

No you do not, as I said. I started out playing around for a while, but decided I wanted to get one after about 6 months and not getting the results I really wanted. So it really depends on what you want. I would seriously google youtube videos on it to get a good idea, then get Alumilights starter set, about $75 or so. Play around with that! Once you get compfortable with it if you want to progress, progress in the direction you wish to go! every one is different, esp. when it comes to resin casting! Some of my learning curve was helped by Bob ob LSM, then I slid into learning more from Chris Buck and then there was a bunch of trial and error as well as tid bits picked up here and there. Jody

[RyanSilva]

My advise is, how much $$ do you plan on spending, and how far do you want to take it, quality wise?

I use Dascar resin and Smooth-on exclusively, they work perfect for my needs.

If you want bubble free parts...get a pressure pot. Not a cooking pressure pot but a Paint pot like Jody said. Yes the initial price is a turn off but it increases your usable resin items by a vast amount. Do you need one to cast? no not at all..it just helps with creating less waste/unusable items.

Get a shipping scale, you can find them cheap for about 10 bucks or more at harbor freight, use this to weigh your silicone and catalyst..seems intimidating but its a great tool and is really easy to weigh silicone.

Most of my wheel molds are 200grams of silicone and 20 grams of catalyst.

I do my smooth-on shopping from http://www.theengineerguy.com/cgi/commerce.cgi?display=home

Nelson and Sarah are great people. They're located in georgia, and their prices are not inflated.

My suggestion for stuff to buy are some cheap Popsicle sticks, some sulfur free modeling clay, a mold box..anything flat with 4 sides really that wont leak. I use these white paper cardboard boxes from michaels for a buck each. doublesided scotch tape, for sticking parts to your moldbox...clear plastic cups for mixing.

Resin? Smooth-on smoothcast 320 or 321. Both are tan, one takes longer to cure. 320 gives you around 2 1/2 minutes to mix and pour..pop bubbles squeegee off the top of the resin, while 321 gives you about 5minutes.

Get 1 trial kit..costs 25 bucks.

Get a trial kit (2.2lb) of Smooth-on Moldmax 20 silicone....much better than the Oomoo series that tears and breaks apart.

PM me if you need any clarifications

[69_charger]

well, i just wanna try it first, maybe make a little part like a kw sign, or small part of suspension ( like the thing that says pete air leaf)

[Smart-Resins]

My suggestion certainly is to keep to simple one part items to start with. I did not know that smooth on had a trial package. I certainly would suggest try that! The popsicle sticks, cups and clay can be found at any good hobby store or online for even cheaper. I think I got my 1000 sticks for about $5 and I cut them in half, so thats 2000 for $5! Yes, I got my scale at harbor frieght for about 10 as well. Also, if you ever do decide to delve into two part molds once you feel comfortable, here is a tutorial Chris Buck shared with me that I have posted on my forum. Thanks. Jody

http://kustomcarz.proboards.com/index.cgi?board=resinworking&action=display&thread=124