RGABEL
Member
I have an idea for some tube-in clear cast blanks. Is there a reason to use one casting resin over another?
Clear casting - Epoxy vs Alumilite
- Thread starter RGABEL
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its_virgil
Member
Alumilite is a brand name and not a product. I assume you mean Alumilite Clear or Clear Slow which are both urethane resins. Alumilite Clear and Clear Slow require pressure pot casting. A byproduct of the chemical reaction between parts A and B is the production of carbon dioxide. Pressure is needed to keep the CO2 in solution.
Aliumilite Amazing Clear Cast is an epoxy resin and can be cast without using pressure. There are several epoxy resins available to use.
To answer your question: Yes. Both have their uses, their good and bad points.
Do a good turn daily!
Don
Aliumilite Amazing Clear Cast is an epoxy resin and can be cast without using pressure. There are several epoxy resins available to use.
To answer your question: Yes. Both have their uses, their good and bad points.
Do a good turn daily!
Don
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RGABEL
Member
Don, I always forget that Alumilite has "traditional" epoxy products. I am talking about Alumilite Clear Slow vs an Epoxy resin. The material will be adhered to the tube with a 3M spray adhesive, not CA glue. The fact that the urethane does not work well with CA makes sense why I see certain castings done with an Epoxy as the parts are attached with a CA glue. I have done a few Epoxy casts for other items and always use a pressure pot even if "not required" as it is cheap insurance.
Kenny Durrant
Member
I think the Clear Sloe is a better overall resin. I use it whenever I can. Like mentioned before they each have their purpose but the clear slow has a higher hardness and doesn't seem to yellow as fast or as much.
MRDucks2
Member
Urethanes tend to be (a lot) more sensitive to moisture in what you are casting with it. Epoxies tend to be more tolerant of moisture.
Don, do you find the urethane vs epoxy blanks drill or turn differently?
JohnU
Member
Like Don stated, both have their pros and cons. You will find Epoxy resins tend to stick very well to objects with less concern for sealers or humidity on objects. Urethane is very picky and will stick better to warm objects with no moisture. The working time and curing time is much shorter with urethane resin. Epoxy resins can take up to 7-10 days to fully cure before you should turn it. There are so many epoxies on the market for different projects from thin and deep pours. UV blockers are a huge issue in all resins when clear casting. My experience, I have found epoxies to yellow quicker over time than urethane. Some say the resin is turned down so thin that it isn't a concern but that really depends on what the object color is your casting and how light is the background. I personally think urethane resin like Clear or clear slow turn much smoother with less chip outs than any epoxy I've turned but that's my opinion. If you're worried about CA and urethane resins, try clear nail polish as a glue. It works well in any resin.
Best of luck!
Best of luck!
RGABEL
Member
Where does Silmar 41 fit into selection? I have used several different Epoxies on other projects (not pen related). When I have mixed too much I have found some molds to use for different items (pepper mills, bowls, handles) with mixed results. I know that Silmar 41 is popular with some tube in casting and is "economical" when compared to some other options. My Alumilite clear slow is "old" but works well enough for color casting. I am debating between Clear Slow, Liquid Diamonds (used this in the past with good results), or trying Silmar 41. (I have read about the smell and will mix in my garage and have a respirator). If I do use Silmar 41, where is a good place to purchase it?
JohnU
Member
I use Silmar often. It is the only resin I have success with on snakeskins. It takes about 18 hours to cure and can be a bit tacky but shines up great with no needed finish. I get it at either US Composites or Composite Envisions. If you try it only use about 3-4 drops of catalyst per ounce of resin. The instructions say 7-10 but that's for fiberglass applications. Thicker pours get hot so you do t want to add too much or it will crack during curing.
Bill12345
Member
I am having bad luck with my clear casting - I am trying to cast painted tubes in a mold - would you recommend a pressure pot outfit for a beginner who makes great pens? - My pen making skills are excellent - but now that I am experimenting with different materials that are cast, I am having some trouble - Help please
JohnU
Member
I'm sorry to hear that Bill and I hope I have some suggestions that will help you out.
Painted tubes can be a challenge. Some paints aren't made to handle the heat that curing resin generates, and will shrink, wrinkle and pull away from the tubes. I like to use engine and grill paint. They all have high temperature resistance. Also, some materials need to be sealed so resin sticks and doesn't react negatively. A few suggestions are clear nail polish, modpodge or auto clear coat.
As for pressure tanks, some resins say you don't need one but I recommend always using one. 45-55 lbs of pressure will always work. For a tank you have two options… build one or buy one. I have and currently use both. You can buy a harbor freight paint pot for about $80 and put a shutoff valve and pressure gauge on it all for about $100. I know there's a lot of people who will say bad things about harbor freight but if you use it properly it will work just fine. The ready made tanks are great but cost more. I also own California Air pressure tanks and would recommend them.
Feel free to PM or email me with any questions.
Painted tubes can be a challenge. Some paints aren't made to handle the heat that curing resin generates, and will shrink, wrinkle and pull away from the tubes. I like to use engine and grill paint. They all have high temperature resistance. Also, some materials need to be sealed so resin sticks and doesn't react negatively. A few suggestions are clear nail polish, modpodge or auto clear coat.
As for pressure tanks, some resins say you don't need one but I recommend always using one. 45-55 lbs of pressure will always work. For a tank you have two options… build one or buy one. I have and currently use both. You can buy a harbor freight paint pot for about $80 and put a shutoff valve and pressure gauge on it all for about $100. I know there's a lot of people who will say bad things about harbor freight but if you use it properly it will work just fine. The ready made tanks are great but cost more. I also own California Air pressure tanks and would recommend them.
Feel free to PM or email me with any questions.