WTB Silicone for molds

[raypalmer]

Brick and mortar, all the online places are going to screw me on shipping. What kind of stores stock pourable silicone? The local art supply has it but it's fancy artist's silicone and they want 40 bucks for like a pint of it.

Any ideas?

[Johnnycrash]

Any ideas?

Just one; Pay the shipping. It's the price one has to pay to get the right stuff.

[DennisH]

Where are you located?

Check the major manufaturers' webites and see if they have any dealers in your area.

[Joseph Osborn]

Got a Hobby Lobby nearby? Snag their 40% coupon and get the Alumilite High Strength 3 tin silicone kit. It's $30 retail but the coupon drops it to $18. Still way too expensive because it's only one pound, but it is good quality stuff (the only thing from Alumilite I've ever liked anyway).

[raypalmer]

I'm going to have to eat the shipping I guess.

Or drive into Toronto on my day off, I just have to drive in there for work so much I really hate doing it during me time

Ok so this seems like the place to buy from. But which silicone to buy? And while I'm there I may as well get resin too. Which resin?


These silicones all have virtually identical descriptions and prices? Which is best for little parts?

http://www.sculpturesupply.com/detail.p ... +Silicones
http://www.sculpturesupply.com/detail.p ... +Silicones
http://www.sculpturesupply.com/list.php ... +Silicones
http://www.sculpturesupply.com/list.php ... +Silicones

???? Experts please weigh in.

And is this a good clear resin for little parts? http://www.sculpturesupply.com/detail.p ... +Plastics I'm looking to recast parts that should be clear but come opaque oob.

[scratchy]

I'm not an expert, but I have two suppliers,.... one in Vancouver, and one out in the 'Burbs.

[Johnnycrash]

Experts please weigh in.

Depends on what you are trying to cast. But a good RTV would be the Mold Max 30. It's stiff enough to hold it's shape without external supports, but soft enough to allow significant under cuts. This is a Tin based condensation cure rubber. Stay away from the Platinum based rubber, they are harder to work with for the beginner.

The Mold Max 15T is VERY softy. The Mold Max series use the number following them to denote it's shore hardness. The larger the number, the harder/stiffer the rubber.

As for resins... I use the SmoothCast 320. This is a fast setting resin; 3 minute pot life, and demold time of 10 minutes. Work fast or else. Smooth Cast 321 is a slow set resin; 7 minute pot life, and demold time of 30 minutes. But, for smaller parts, you should leave them in the molds for TWICE the recommended time. It's due to the low cross sectional area for curing. Just trust me on that.

For clear casting... Clear Cast 202 is your best bet. It's tricky to use, as are most clear resins. They need more precise measure than most polyurethane resins. And the CC202 works well in the MM30 molds. Although the molds should be baked for several hours after curing or let "mature" for a week before casting in clear. This bake/time will allow complete off gassing, which will inhibit the clear from setting.

[Tankmodeler]

Experts please weigh in.

But a good RTV would be the Mold Max 30.

Agree. The 40 is also good, but not as useful for items with undercut fine detail and the 20 is good for the fine detail, but has a tendency to tear out a bit easier, being softer. Teh 30 is a very good compromise.

Stay away from the Platinum based rubber, they are harder to work with for the beginner.

Yes, they are much, much more sensitive to contamination (and thus not curing). The platinum rubbers are much better and much tougher, but a serious PITA to work with.

As for resins... I use the SmoothCast 320. This is a fast setting resin; 3 minute pot life, and demold time of 10 minutes. Work fast or else. Smooth Cast 321 is a slow set resin; 7 minute pot life, and demold time of 30 minutes.

In a production setting the 320 is good, but for home casting I find the 321 a bit more forgiving, especially if you are not pressure casting or doing it so often that you get really good at it. You have time to mix, pour and then poke the air bubbles out of the corners befiore it starts to set up.

But, for smaller parts, you should leave them in the molds for TWICE the recommended time. It's due to the low cross sectional area for curing. Just trust me on that.

That's really good advice!

Another bit of advice is to make sure you stir both parts of the resin really well before using. The yellow portion looks like it has separated so the stirring immediately seem needed, but the cleaqr (int he blue bottle) has also separated but yo can't see that. Stir the crap out of both parts before using the first time and then stir well before each other session (especially if separated by more than a day or so). I only pour small amounts at a time (.75-1.5 oz) and after I pour the two parts into the mixing cup I stir for upwards of a minute to 90 seconds before pouring into the moulds. I still have a couple minutes to pour plus a couple minutes to get the bubbles out of the corners.

But, if you know all this and only want to get resin in the Toronto area, yuor ouly real bet is to drive in to Scupture Supply and buy on site. Check their hours because I'm not sure they are open all day Saturday and I don't think they're open on Sunday.

HTH

Paul

[outlander]

WWW.SPECIALTYRESIN.COM This is where I get my resin from. WWW.USCOMPOSITES.COM is where I buy my silicone rubber from. This degasses naturally within 48 hours. You can use clear resin in it with no problem. The resin I use sets up in two minutes - not enough working time for small parts, but works great for regular casting. You might want to invest in a screened funnel to keep it from getting bubbles in your resin while pouring.

[Max Nex]

http://www.micromark.com/SearchResult.a ... bber+resin

I've used this rubber and CR-300 resin with good effect.
(after a learning curve-I was a newbie then)

[Mottom]

A few years back I was at this place and if I remember right there prices were ok.

http://www.plasticworld.ca/default.asp?pID=51