|
|
Post by Starry Eyes on Dec 23, 2013 8:35:13 GMT -6
late Saturday afternoon I decided to get started on Big Jim, Don Culley and I's project .. I set up the casting box, did the clay work, and poured the first of a 2-part mold .. as of today (Monday) the RTV rubber has STILL not setup ... mixed properly, but it was a little "cool" in the basement so after mixing and pouring on Saturday I brought everything upstairs but it still has the consistency of a wet marshmallow .. going to give it a couple days and see if it sets up before attempting the de-molding process for step 2 of the 2-part mold .. yeh it's just a waiting game at this point ..  
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 23, 2013 9:24:27 GMT -6
Hi Chuck,
I have had similar problems since they changed the forulation on this stuff.
Give me the old 4hr. cure stuff any day! Mine seem to set up ok in about 10-12
hours, accept for the very bottom. I'm usually too impatient to let it set for
days, so I end up just wiping the sticky crap off an go on. Your situation with
this one however seems a bit worse.
Just my opinion, so take it with a grain of salt...
This calls for a 10 to 1 racio, I'd bump up the catalyst a hair, say 10 to 1.2.
There's always extra catalist left over when the silicone is gone. I've probably
got 7 or 8 unopened bottles of catalist in the shop.
WARNING! If you ever have to clean this uncured silicone off of a chrome part, the
chrome is coming off too!
Good Luck to ya Brother! Keep us tuned in!
Bill
|
|
|
|
Post by Starry Eyes on Dec 23, 2013 9:44:24 GMT -6
Yep.. I too have had an issue or two over the years Bill .. you and I have discussed ! .. it is a sticky mess when one decides to remove (yuk) .. very unpleasant ..lol... I'm going to wait it out a day or two before "tossing in the towel" .. then I'll pull the plug and de-mold and start the cleanup process for round two .. nothing like opening up your window and tossing $50.00 out the door I always say ! ..
|
|
|
|
Post by old school modeler on Dec 23, 2013 12:04:56 GMT -6
Have been there too, good luck. Perhaps a nearby lightbulb for some mild heat if you still have one of the old incandescent, inefficient, illegal 75 or 100 watt ones left around.
|
|
|
|
Post by Starry Eyes on Dec 23, 2013 13:38:59 GMT -6
Have been there too, good luck. Perhaps a nearby lightbulb for some mild heat if you still have one of the old incandescent, inefficient, illegal 75 or 100 watt ones left around. Placed it in front of the fireplace about 4 feet away .. according to the thermostat it's a toasty 80+ degrees .. I cast the parts on a glass base so the glass is transferring heat as well .. time will tell !!.... next thing we know the light bulb police will be coming and taking or illegal bulbs..lol..... |
|
|
|
Post by Starry Eyes on Dec 24, 2013 8:59:40 GMT -6
De-molding today .. I'm an hour into it and this isn't good .. these are things that people WANTING to resin cast should see .. one does not always get picture perfect results... this isn't a regular occurrence but it can hit your pocket book and make you take notice! .. So all the guys here who are thinking about taking the plunge into the casting world take note ... this does and WILL happen sooner or later for various reasons . One may ask "how can this have been avoided ?".. Temp. and humidity were well within range, missing ratio was done by weight not volume... the only thing that can not be ruled out is the shelf life of the product.... Merry Christmas !  
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 24, 2013 9:49:24 GMT -6
Man O' Man Brother Chuck... I'm sure sorry to see that! Maximum Bummer!
I know it does'nt mean squat now, But your silicone looks mighty white!
Does'nt appear to have that creamy butter color the catalyst gives it.
I'm not trying to preach about directions, but I never measure my ratio.
I mix in the catalyst then compair it to the strait silicone. If there
is not a distinct difference, I add more.
I had this happen once with the pink stuff, I have'nt used it since.
|
|
|
|
Post by Paul B. Canney on Dec 24, 2013 11:24:12 GMT -6
De-molding today .. I'm an hour into it and this isn't good .. these are things that people WANTING to resin cast should see .. one does not always get picture perfect results... this isn't a regular occurrence but it can hit your pocket book and make you take notice! .. So all the guys here who are thinking about taking the plunge into the casting world take note ... this does and WILL happen sooner or later for various reasons . One may ask "how can this have been avoided ?".. Temp. and humidity were well within range, missing ratio was done by weight not volume... the only thing that can not be ruled out is the shelf life of the product.... Merry Christmas ! Odd... Robert Hayes swears by Alumalite  |
|
|
|
Post by Starry Eyes on Dec 24, 2013 11:27:39 GMT -6
Man O' Man Brother Chuck... I'm sure sorry to see that! Maximum Bummer! I know it does'nt mean squat now, But your silicone looks mighty white! Does'nt appear to have that creamy butter color the catalyst gives it. I'm not trying to preach about directions, but I never measure my ratio. I mix in the catalyst then compair it to the strait silicone. If there is not a distinct difference, I add more. I had this happen once with the pink stuff, I have'nt used it since. Oh it's pink alright !.. must be the lighting in the photo plus the white paper towels in the mix ..lol. yep I'll never use this Alumilite Pink "High Strength" again .. it's the second time it's bit me.. such is life !  |
|
|
|
Post by magnum4342 on Dec 24, 2013 13:11:02 GMT -6
Job one: Get the hell away from allumilite! Job two, it's VERY obvious your mix was way off, and setting it near a warm place like a fireplace or heat register was totes bonehead. RTV silicone cures based on the amount of moisture in the air so setting it near a heat source merely r-e-t-a-r-d-e-d the setting process. I use graduated mixing cups, both pill size and six ounce size to mix my 10:1's. The mix HAS to be exact. Yes you can accelerate curing by adding a touch more catalyst, but then you run the risk of air bubbles that cure inside the mold before completely gassing out. Bottom line is, if you're a novice you need 180 S resin and tin cure silicone 10:1. Try this company. He is the direct supplier for Smooth-on and Steve will treat you good. Just tell him Kevin in W.Va. sent you. He ships by Fed-ex, and there's never a shipping fee.
rtvmoldmaking.com/cgi-bin/p/awtp-product.cgi?d=rtv-mold-making&item=36037 Feel free to ask him any questions or concerns. I've worked with him since I was a novice and have never had an issue. 
|
|
|
|
Post by Starry Eyes on Dec 24, 2013 20:37:08 GMT -6
Bless you magnum !! It was in fact mixed 10:1 or 2 oz. of base to (1 scoop) 6cc of catalyst . ... After setting at room temp I was desperate to try anything to get this crap to "move"... I've heard a lot of positive things about Smooth-on and I think now is the time to change vendors brother ! I sincerely appreciate your candidness , and friendship in guiding me towards the light !!! This is what friends in the modeling community do - help each other !! Thanks again for your input !!
Always good modeling-
Starry
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 25, 2013 6:16:51 GMT -6
Hmmm?
|
|
|
|
Post by Starry Eyes on Dec 25, 2013 8:48:45 GMT -6
For what it's worth I also found this stuff.. I have used Smooth-On a coupe different viscous.. There's a Smooth-On dealer in Kansas City about 4 hours from my house .. thought the link below was interesting "stuff" and wanted to share as well ...
.. www.composimold.com/
|
|
|
|
Post by mykturk on Dec 25, 2013 10:55:32 GMT -6
For what it's worth I also found this stuff.. I have used Smooth-On a coupe different viscous.. There's a Smooth-On dealer in Kansas City about 4 hours from my house .. thought the link below was interesting "stuff" and wanted to share as well ...
.. www.composimold.com/ Hmmmmm. Imagine recasting your favorite kit in chocolate.  |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 25, 2013 11:21:22 GMT -6
I am by no means an expert, but I have mixed up a fair amount of rubber in my time. One of the best suggestions given to me was to treat the base as if it were bondo in the can and mix it (reconstitute)as best you can before adding catalyst. Likewise, shake the catalyst thoroughly. Beyond an expired shelf life, can't really say what happened here. I've had 3 Y.O. rubber however work well by mixing well.
My two cents, HTH
|
|
|
|
Post by magnum4342 on Dec 25, 2013 11:35:12 GMT -6
Absolutely correct. Pre-stirring the base and a little shakeup of the catalyst is the way to go. To avoid too many bubbles (which you'll get anyway) either allow the base to sit and gas out a bit. Twenty to thirty minutes should do. Also, when pouring, start at one corner and allow the stream of falling resin to be as long and thin as you can. This will help break up air bubbles as you pour. You'll actually see the little buggers pop. I've heard of other guys getting three, or four year old sil to work just fine too. Unfortunately there ain't no stretch to the resin. When it's shelf life is up it's done brother! Thank you for the kind words as well.  I am by no means an expert, but I have mixed up a fair amount of rubber in my time. One of the best suggestions given to me was to treat the base as if it were bondo in the can and mix it (reconstitute)as best you can before adding catalyst. Likewise, shake the catalyst thoroughly. Beyond an expired shelf life, can't really say what happened here. I've had 3 Y.O. rubber however work well by mixing well. My two cents, HTH
|
|
|
|
Post by Starry Eyes on Dec 25, 2013 14:19:30 GMT -6
The shelf life is what I'm focusing on.. I do remix the base and store it in a room temp / dry place .. All that I had issues with was purchased at Hobby Lobby here locally and who knows in our small community how much inventory they rotate... I am very anal about my storing , mixing, and stirring ... Another fellow modeler mentioned to me the possibility of cross contamination from a sulfur based clay causing reaction... My math on mixing ratios were correct regardless of the color hues seen in the above pics/photos .. Nevertheless Magnium made a valid point to get away from Alumilite especially with all the other companies on the market ... My next purchase will be Smooth-on
|
|
|
|
Post by magnum4342 on Dec 26, 2013 16:00:42 GMT -6
He may very well be right about the clay as well. A factor I hadn't considered. Sculpey is the only clay I'll use. Never a problem with it. Compare pricing between Smooth-on amd my guy before you buy. I think you'll find a better price at the source. Like I said, my guy is S-O's supplier. It's like having a friend at the factory.
|
|
|
|
Post by Starry Eyes on Dec 26, 2013 16:04:57 GMT -6
He may very well be right about the clay as well. A factor I hadn't considered. Sculpey is the only clay I'll use. Never a problem with it. Compare pricing between Smooth-on amd my guy before you buy. I think you'll find a better price at the source. Like I said, my guy is S-O's supplier. It's like having a friend at the factory. Boom ! |
|
|
|
Post by magnum4342 on Dec 26, 2013 16:09:19 GMT -6
OMG! Starry did your mind just explode?! I'm so sorry!  He may very well be right about the clay as well. A factor I hadn't considered. Sculpey is the only clay I'll use. Never a problem with it. Compare pricing between Smooth-on amd my guy before you buy. I think you'll find a better price at the source. Like I said, my guy is S-O's supplier. It's like having a friend at the factory. Boom !
|
|
