Casting Acrylic Blanks

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crokett

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Dec 4, 2012
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Mebane, North Carolina
I got a casting kit as a late Christmas present. I got the resin kit, red and yellow pigments and some sparkles. I don't have a pressure pot. I am planning to use PVC pipe as molds. My plan is to mix the resin, let it set for a little, mix in the pigment and some sparkles, pour it into the mold and then vibrate it with a power tool to get the air out. Is there anything else I need to do? I was considering attempting a cast with the tube in place, but decided if it doesn't go right I don't want to waste the tube.
 
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Just my way of doin things, im sure there will be others that will chime in also.
I pour my resin into plastic see-thru cups i get from WW, then i place them into a small bowl of warm water(this will help you with the air bubbles) to thin the resin, then i mix my color into the resin, once i have the color mixed, i then add 5 to 7 drops of catalyst, stir, and pour into my molds.
But i use a pressure pot also. But the warm water will help with the air bubbles. Pour slowly also to help with the bubbles.
 
Thanks I will try that method, one more question - does temperature matter when doing this? I have an unheated shop. I didn't think so since it is a chemical reaction that cures the resin. 2 part epoxy still works for me, but it takes a little longer to set in colder weather.
 
If you are talking about polyresins YES temperature matters! It should be at least 60 degrees and then it's slow setting. You can get around at to a degree by making a warming box ... Heat it with a light bulb. Be sure to maintain adequate ventilation!
 
I'm assuming you have a polyester resin casting kit. It does have an odor which some consider to be offensive. Used in the basement and you can expect it to permeate the rest of the house. I would be more concerned of the fire hazard. Have your read the MSDS sheet for polyester resin? If not, you should. Here is an excerpt:
Section 2. Nature of Hazards and Precautions

A. Fire Hazard
Polyester resins are flammable and have a flash point (Abel closed cup of approximately 32°C) (90°F) if containing only styrene monomer. Resins containing some methyl methacrylate monomer have lower flash points dependent upon the methyl methacrylate content. The requirements of the Highly Flammable and Liquified Petroleum Gases Regulations Act 1972 apply. In particular:

i) Polyester resins must not be exposed to heat or sources of ignition.

ii) Smoking must be prohibited in areas where polyester resins are handled.
Happy and safe casting.
Do a good turn daily resin!
Don

crokett said:
hmmm ok next question, if I were to bring it in and do the casting in the basement, does it give off any noxious fumes or stink a lot?
Click to expand...
 
I do my mixing and pouring in the garage. After it has set up for a couple minutes I bring it into the house. I place it on a shelf above the washer and dryer. My wife walks by it all the time and doesn't even notice the smell.
 
If you use a pressure pot warming resin is not a need to because the pressure will eliminate the bubbles. I cast all my blanks in our side room. I shut the door to the other part of the house and open door and all is well. As stated before temp is a big role. It needs to be on the warm side for it to cure in a timely manner. As far as mixing your pigments into the resin. You can put your pigments in as soon as you pour your resin. but to get the best results dont mix the two together until they start the gelling phase if you dont you will get a two colors that merge and the who know what you will get.
 
So if I wanted to mix two colors, would I mix two smaller batches of resin, color each then mix those together after they gel, or mix one batch and put both colors in after it gels?
 
If i'm mixing 2 colors, i have 2 cups of resin. Then pour them at the same time into the mold. I might warm just one color of resin and not the other to get a swirl effect (dont know if that really helps or not ) I forgot to mention that the 5 to 7 drops of catalyst is per ounce of resin. Once i have the resin mixed in my cups, i might pour them then or i may wait a minute or so, then pour it into my molds, then straight to the PP. Now for smell, the resin i get from AC Moore crafts, it has a smell to it. The resin i get from The Pen Wizard, has very little to no smell to it.( i would not hesitate to use it in the house if i had too).
 
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Many people (including me) do not use a pressure pot UNLESS casting "embedded" items such as sea shells, watch parts, etc.

In fact, I have found that I get BETTER results just using warm water (and ultra sound) to thin the resin. Additionally, NOT using a pressure pot allows you to pour more blanks faster.

After I get my resins thinned to water consistency(I add colorants BEFORE thinning) I then add catylist, mold the resins, wait 10 minutes and then post cure in a cheap toaster over at 150 degrees for 30 minutes.

ONE WORD OF CAUTION; My method should never be left unattended as there is a very slight fire Hazzard associated with post curing resin.

Respectfully submitted.
 
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