Resin casting... am I crazy!?

[jcf]

Is the resin a polyurethane or a polyester casting resin?

[The Wooksta!]

The clear resins I've had have been polyester.  The last one went solid in the tin...

Canopies.  Unless you've a pressure chamber, you're likely to get air bubbles.

[strobez]

Thanks for the reply guys. 

First off, I'm not sure what the deal with the resin is.  After closer inspection it seems it's a repackaged shop kit.  So basically there's just two bottles... marked Crystal Resin A and B.  I dunno... we'll wing it and see what happens.

I also poured my first mold today and made my first mistake.  I should've mixed the silicone longer.  The one I have is a 3% mix ratio... so once I added the small amount of part B and started mixing and everything turned pink.  However, as I started pouring (trying to be quick and do a "high pour" to minimize bubbles) I realized I hadn't mixed it well at the bottom.  Near the end of the pour I started getting a bit of whitish clumps.

Now a few hours later and the pink part is already rubbery... while the white part is still a bit like molasses.  I'm not quite sure what to do about it... will the white part eventually solidify? If not, when I crack open the mold, I might still have enough of it to be functional.  It won't be pretty, but if it works...

At least it smells of lavender.  I guess that's what happens when you buy your silicone at a candle shop. 

[kitnut617]

I also poured my first mold today and made my first mistake.  I should've mixed the silicone longer.  The one I have is a 3% mix ratio... so once I added the small amount of part B and started mixing and everything turned pink.  However, as I started pouring (trying to be quick and do a "high pour" to minimize bubbles) I realized I hadn't mixed it well at the bottom.  Near the end of the pour I started getting a bit of whitish clumps.

Now a few hours later and the pink part is already rubbery... while the white part is still a bit like molasses.  I'm not quite sure what to do about it... will the white part eventually solidify? If not, when I crack open the mold, I might still have enough of it to be functional.  It won't be pretty, but if it works...

In my experience    the only thing to do is learn from it and start again   

[strobez]

Well, I checked it when I woke up this morning. I think you might be right.

However in a last ditch effort, I mixed in a few more drops of the hardening compound.  I've either created a new way to make an asymmetrical 2-part old... or I've created a rubber door stop for my son's room.  Either way, everybody wins! 

[PR19_Kit]

... or I've created a rubber door stop for my son's room. 

[Dizzyfugu]

Apparently the crystal clear resin is used to permanently encase the perfect miniature sushi dinner setting you've created.   

I have successfully used clear resin to "preserve" a fish finger pyramid... Successfuly, and it had three levels! Was a "special" birthday present... made with love. 

Anyway, you can use clear resin for casting, but you will find that it has a different consistency from opaque material. I found the stuff for instance hard to sand, because I found the clear stuff to be (and remain) a bit sticky.

[strobez]

Well, I'm happy to report that my son is now enjoying his new doorstop... 

However, the part of the mold that was mixed properly worked fabulously... so it's off to round two!

[strobez]

Success! After "Mold Mix 2: Fully Blended" I believe I have created an actual, albeit simple, 1-part cup mold.  I'm giving it a test run as an ice cube tray, since I only had time to poke it a couple of times this morning as I left tor the office - amidst a few calls from my wife to stop playing with my toys and get to work 

Still, I'm feeling that early glow of success... you know the one, that brief moment of hope and glory before it all comes crashing down... so I think I'm ready to try moving right along to "Mold Mix 3: Revenge of the Two-Part Car Mold" (the title is a work in progress).

[NARSES2]

Well, I'm happy to report that my son is now enjoying his new doorstop... 

Still, I'm feeling that early glow of success... you know the one, that brief moment of hope and glory before it all comes crashing down...

Yup, I do know that feeling  Glad you are getting there 

[Old Wombat]

Still, I'm feeling that early glow of success... you know the one, that brief moment of hope and glory before it all comes crashing down...

Oh, so well!

[strobez]

So... I think I succeed. It's too early to call it, but the early returns seem positive.

After getting the negative side of my two-part Mold in place, I started in on the resin and did a recreation of the 3 bears story... too hot, too cold, just right.  My first cast I was so worried about the quick set I failed to mix it properly.  It came out sticky and partially clear... oops.

The second cast I was more nonchalant and ended up trying to shove the top of the Mold into a puddle of suddenly (and very quickly) clear goo turning white.  Hence the giant blob squished out the side.  The third time I mixed thoroughly and poured quickly... and you can see the results for yourself.

[PR19_Kit]

That's amazing, well done indeed. 

How did you make the two part mould though? I can figure out the main bit of the lower part, but how did you make those four locating studs for the upper part without bonding the whole thing together?

[loupgarou]

I see you have already gone to a difficult mould. A two-part one and it came out well, congratulations. 
And I imagine you used the trick of blocking the window openings with scotch tape or similar preparing the mould.
As the resin appears white, I suppose you have already bought a more appropriate kind, instead of the transparent one.
BTW, that car looks like a Fiat 600, not a 500. 

[strobez]

Well, as I mentioned earlier in in thread, I was able to successfully craft a one-part mold, so I moved on to a slightly more complex one. The car body shell seems to be about the easiest next step in terms of graduating to a two-part mold. I tried to create an air vent, but i'm not sure I accomplished anything more than adding a bit of sprue.

Anyway, to make the mold, the first thing I did was pack the inside of the car shell with clay. Then I made a flat clay base and pushed a plastic cardboard fence into it. Then I placed the car inside and used more clay to plug any gaps along the perimeter. After it was sealed, I keyed the mold by punching those round locating posts into the clay using a bit of styrene tubing.

After that, it was mix up a bit of silicone, pour and pray. 

I waited a full day and then cracked open the mold, pulled the car and the clay out, cleaned it out carefully and then plunked I back in the mold. I flipped the mold over, sealed the gaps with clay and painted everything in sight with Vaseline...

Then I put on the robe lit a candle, made made few incantations, and poured the second half.

It's a good thing I went that extra step too, I had to squeeze and scrape to get enough silicone to cover the mold fully.  I guess my calculations were a bit off.

Anyway, in the end, I got a mold and put the resin I got yesterday (which was an whole 'nother adventure with a Korean chemicals wholesaler in itself) to good use this morning after the silicone had set.  I was a little worried about the locating posts... they almost didn't want to separate.  But in the end they did.  The only things I would have done differently is a) not to bother with a vent hole on a pour and push mold. And b) build up more of a clay base under the car.  Some silicone got under the car, so I had to carefully trim the excess away before I poured the second half because I was worried it would lock the mold shut.