best type of resin & rtv rubber

[Sixx]

In your honest opinions, what is the best type/brand of resin & rtv rubber out there? I've been sculpting some things and would like to cast them. I have done a few castings of small things, ie; a hood with scoop for a new Challenger, some tires & wheels, so I get the gist of casting, just looking for some good resin & rubber. I've used Alumilte & Micro Marc's stuff, not too happy with the Alumilite, M.M. is okay but...

[Sixx]

Hey thanks Jacen! I've got the degasser & pressure pot, that's how I got a decent cast one the hood. I find that the Alumilite just sets way too quick, had it set on me in less than 30 seconds while I was mixing it! Couple of times I did get a good one out of it, just too much $$$ to have it do that. I do like their RTV tho. Sixx

[Gregg]

For the Silicone, I have been using Alumilite's Quick Set. It sets up in four-six hours.

I love it!!!!!

I have only used the Alumilite resin, A&B's, now using only the white resin.

Used to use the tan color one before.

The Resin Corner has the first series of the in-depth resin casting articles/how-to's in it.

Once the issue has been out for a short while, I will post the articles and how-to's online.

Thanks to Art Anderson for all his help in teaching me about resin casting.

The gang at Alumilite has been great also.

Always available to answer my endless phone calls and annoying emails.

[Chief Joseph]

The resin & rubber I use in my commercial work is Smooth-On. Their Smooth-Cast 321 resin is super-easy to work with and has a 6-8 minute pot life. That's important for me because I mold a lot of complex parts that require special handling and I like to pour a whole bunch of resin in each casting cycle to maximize my productivity. They have some newer platinum rubber called Mold Star which sets up in just a few hours and has virtually no shrinkage, plus you don't have to bake it or sacrifice the first casting to get the excess alcohol out of it like you do with tin-cured rubber. It's available in a soft and a firm version, and will yield many castings. I've tried Alumilite, Ace, and Polytek products too-- all of them will work, but for all-around performance I choose Smooth-On. They make a whole range of different products to meet the needs of all kinds of craftspeople. No, I don't own stock in them The distributor I buy from is The Engineer Guy in Atlanta, www.theengineerguy.com. Super customer service.

[Chief Joseph]

How are thier prices Joseph?

Not too bad. The smaller sizes are of course more costly than buying the gallon sizes.

[Sixx]

Thanks guys, Gregg, I can't wait man!! Joseph, I've read alot about Smooth-on through Amazing Figure Modeler magazine, that does appeal to me, tho I'm not gonna give up on Alumilite...maybe I've got some cruddy stuff, it's not 6 months old yet? I'm not too worried about the rubber, I like both the Alumilite & Micro Mark stuff. Man Gregg, now I'm really chomping at the bit for the next issue!!!! LOL!!!!! Jacen, thanks fer that tip, never thought about that! Here's a shot of that hood & scoop

that was done with Micro Mark's resin, my avatar to the left...the blower scoop was sculpted & cast - again, M. Mark, here's a better shot

Thanks again for your info guys !! Sixx

[Sixx]

Hey Joseph, do you degas smooth - on rubber?

[Sixx]

I forgot...that blower scoop was sculpted from Aves epoxy-sculpt

[crazyjim]

I've been using Smooth-On without too many problems. I use the gravity system that's readily available anywhere on Earth.

[Chief Joseph]

Hey Joseph, do you degas smooth - on rubber?

I have switched to Mold Star rubber for just about everything I do now; Smooth-On claims that it does not need to be vacuumed and that is true up to a point. It mixes much thinner than their other rubbers and has a long open time so the bubbles have time to rise. I still vacuum it because most all my casting is done under pressure and I don't want any trouble. Their older formulas of Mold Max tin rubber and Smooth-Sil platinum definitely required vacuuming. If your master is good and solid, you can pressure-cure the rubber after you've poured the mold instead of vacuuming it, but the master had better be solid.

Your blower scoop looks really nice! I've always heard that Micro-Mark sells repackaged Smooth-On products, at a much higher cost. I've never had any in my hand so I can't confirm that.

Edited December 2, 2011 by Chief Joseph

[Casey]

As stated, there are various brands and models or both resin and silicone rubber, so it's best to decide what you want, then find which products match your need most closely.

For instance, if you want a lot of time to allow air to be evacuated, use a slower setting resin. Alumilite's tan resin sets very quickly-- too quickly for any complex shapes or undercut parts IMO. Choosing a slower setting resin will give you more time to de-gas, mix, and pour, but the tradeoff is a longer curing time.

Same thing for the rubber you chose. Research the different hardnesses available, and chose the one which best meets your needs. Sometimes a softer, more flexible rubber is best, and other times a firmer mold rubber is the best choice. There is no single perfect brand and model of resin nor mold rubber for eveything, so you need to experiment through trial and error to find what works best for you. For beginners, I would suggest a very slow setting resin, to give you time to get used to the casting process and the steps you must follow. Using a fast-setting resin will only lead to frustration and wasted money.

In my experience, Alumilite's White (or Amazing Casting resin, exact same product) casting resin gives me the most consistent results, and is less affected by an imperfect mix ratio, at least compared to the Smooth-On's Smooth Cast 300 resin. Resin is affected by temperature and humidity, so the more consistent you can be in regards to both, the more consistent your final product will be.

What works great for one person may not work for you, so take in all the advice you get, try different products and methods, and use what works best for you.

[Chief Joseph]

For beginners, I would suggest a very slow setting resin, to give you time to get used to the casting process and the steps you must follow. Using a fast-setting resin will only lead to frustration and wasted money.

That is the truth!!

[RyanSilva]

I have not used micromark or alumilite products, but have used John greer, smooth-on,polytek. I always come back to smooth-on smoothcast 320 and 321. I started casting many years ago using oomoo silicone, but it was only good for a few casts, I then moved to mold max which was a lot better for production casts, then I used Mold star 16 to get my feet wet with platinum cure silicone, and recently bought 16lbs of dragonskin 10 fast

I pressure cast my silicones and resins, I wouldn't have it any other way.I use to order from theengineerguy but it takes a full week to arrive with ground shipping, so I use reynolds advanced, its in boston so it comes next day using ground shipping! If I order in advance I go to dickblick and but the 2lb kits for 20 bucks!

Buying the gallon kits works out much better in savings, however you should have some chemical resistant containers ready with a dry gas blanket to keep your resin from going bad to soon. You reduce the risks of bad resin when you work with smaller bottles, using the gallon kit as a refill.

[my66s55]

I have been casting for about 6 + years and after trying some different products, settled on Smooth-On. Dragon skin always gives me a good mold and smoothcast 305 resin a good cast. I have not needed to use any pressure pot as I have never gotten bubbles on any cast. I cast anything from carbs to full size model car bodies bodies. It also helps having a distributor in the area.