Advice Please

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MDWine

MDWine

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Joined
Mar 22, 2005
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Manassas Park, Virginia, USA.
I want to cast a clear resin with a clear tint. I want the resulting cast to be highly polished, but clear to see what is inside.

I have looked through the library and the threads and it seems Liquid Diamonds is my best option. (working time is not a hindrance, as I work slow anyway!)

My questions, for which I could not find definitive answers:

1. air bubbles, do I NEED a pot? IF I DO, pressure or vacuum? (I don't really want to buy/store/operate one if I don't have to!

2. I want clear color in the piece... nice clear color so to see what is in the piece. If I understand, an india ink would color the material but remain reasonably clear.

I am I on track? Anything else I should know.
Artresin looks interesting?

My only experience with casting was 8 or 10 years ago using the powders to create opaque blanks, nothing as demanding as what I want now.

Thanks in advance!
 
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i have used artresin and it will do what you are asking and when comparing specs with liquid diamonds, they are extremely close in performance and use. i don't use liquid diamonds though because it (or any other resin that i have found) doesn't have the same anti yellowing properties as artresin. most resins do contain uv inhibitors but artresin contains additional chemistry to combat yellowing. this technology not new and is also used in paints, plastics,etc and it's interesting to me that other resin companies don't use it.
anyway, you can pull a vacuum and get rid of many bubbles but to really ensure the least amount or no bubbles at all, you need a pressure pot.
for tints, artresin makes some and there are many more out there. do a search for transparent epoxy tints. test first to make sure the resin will cure properly.
 
I've used Silmar 41 polyresin and Castin' Craft transparent dyes with outstanding results.

There is a fine line between too little and too much dye being added though, and the amount varies for each color. The clarity is outstanding though.
 
RE: Air bubbles - I don't have any peactical experience, but have done quite a bit of casual literature research on the topic. I couldn't find any specific data on polyester, but there is a lot of stuff available on epoxy resins due to use in carbon fiber composites. Unfortunately most of this data is with respect to the strength of the final part and not appearance. Anyway, to make a long story short, vacuum is good for removing bulk gas if the pot life allows, but pressure is necessary to eliminate fine bubbles. Not only does the pressure compress the gas into a smaller volume, it actually causes the gas to dissolve in the resin. When the gas dissolves, it essentially disappears. Obviously, there is a limit to how much gas can be dissolved and how fast it can happen. If the part has a lot of pores that trap gasses, you might want to do a two step, vacuum then pressure. But based on my research I am thinking that at a minimum a pressure pot at about 45psi will be needed to avoid bubbles.
 
Hi Michael
I use silmar resin for most of my casting and find that the Alumilite dyes work the best , the casting craft dyes work well but looked a little cloudy to me .
As for bubbles the best way I have found to avoid them is to warm the resin . Use a warm water bath to warm the resin but be very careful to not to get any water in the resiun or it will be ruined . Also be very around any high heat source like toaster ovens since the resin vapers are explosive . I made a heating chamber from an ice chest and a fish tank heater (it gently warms the resin and molds to about 90 degrees) that allows me to hear the molds and the resin before mixing then put the filled molds back in till the resin starts to set . The best way to avoid bubbles is to not introduce them in the first place , mix well but gently avoiding the bubbles to begin with .
 
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I have successfully cast carbon fiber blanks without pressure using LD. I did use vibration to help coax bubbles up.
 
Excellent information, and VERY MUCH appreciated.

I want the operation to be a simple as possible, with a little "hardware" as possible. I'd like to avoid the pressure and/or vacuum steps if I can.

I'm slow, and I work slow. I don't mind taking my time to mix and color and pour. We had very good results with our 'slow processing' some years ago, and managed to cast a lot of blanks with very little bubble problems.

One process I read is to use a torch to heat the mix, but with alcohol dyes that might be chancy... but I could warm the parts somehow in a small container... have to noodle and test.

I am still open to discussion, and currently assembling the tools and parts I will need. I do want to try making my own silicone molds so that I can minimize the quantity of the components (wood and casting materials).

The resulting pendants I want to make will be roughly 1" x 2" or in that vicinity... small and light, but the cast has to be slightly tinted but absolutely crystal clear.

Thanks again for all the input, and keep it coming. Remember that I am S.L.O.W... so it may be a while before I start mixing and casting. I will show steps and progress pictures when I begin... we love our pictures, don't we!! :biggrin:
 
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