Silmar 41 or Alumilite

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Which do you prefer and why?

I am in need of some resin and want to decide which to order.
I have been using Silmar 41 with good results, but everyone says how good Alumilite is, so I am confused.

Please help,
Steve

 

[BRobbins629]

The things that most agree on are:
1)Silmar has an strong odor, Alumilte has a mild odor
2)Silmar is less expensive than Alumilite
3)If you are making clear casts, both will do better with a pressure pot, but it is essential with Alumilite to eliminate bubbles. Alumilite requires higher presure than Silmar to eliminate bubbles.
4)If doing colors, Silmar can be cast without a pressure pot, Alumilite requires one.
5) The degree of brittleness for Silmar can be higher than Alumilite if excess catalyst is used. If the right amount of catalyst is used, both turn well.
6) Alumilite cures very fast, and is usable within minutes. Silmar cure is more dependant on catalyst concentration, pigments and the temperature where it is cured. Most wait at least a day to turn Silmar while Alumilite can be turned within minutes of casting.

There are many examples of beautiful pens made from each of these so you really can't go too wrong either way.

 

[MesquiteMan]

Here is my take on the subject. I am very pro Alumilite and am one of the first on this site to use it regularly. I tried a number of different resins when I was perfecting the cactus pen blanks. I used PR, Epoxy, and Alumilite and Alumilite has been my choice ever since.

1. Alumilite has virtually NO odor. You only really smell it when you have your face right over you mixing container. You could very easily mix and cast in your Kitchen if your significant other would let you! PR will surely get you kicked out of the house. It is a very strong odor that for me seemed to linger. Also when drilling a finished blank, the PR blank will stink while the Alumilite blank does not.

2. Alumilite runs around $160 per 2 gallon kit. That is 2 gallons of mixed resin so the price is $80 per gallon unless you buy it in quantity like I do and then your cost is only $55 per gallon. PR is certainly cheaper at a little more than 1/2 the cost.

3. Alumilite can be shipped without any hazardous material fees, no matter how much you ship. It is considered non toxic whereas PR is listed by the IARC (International Agency on Cancer Research) as possibly carcinogenic.

4. PR is highly flammable. Alumilite must be preheated before it will ignite.

5. Alumilite is a 2 part system, equal part of A and B by weight. There are no drops to count and you do not vary anything due to environmental conditions or mass of casting. It does not matter if you shop is hot or cold, Alumilite still works just fine.

6. Alumilite blanks are not brittle at all. I had a pr blank that had the tubes installed. I accidentally dropped it on the floor and it cracked. It was a blank made by one of the pro PR guys that says PR is not brittle if done right. Alumilite will not crack if you throw it on the floor! It is virtually impossible to blow up an Alumilite blank while turning. I have taken a blank while square and really jabbed a gouge into it to see what happens. It just turns away and does not give the shattered glass look.

7. The Alumilite Corporation is an AWESOME company to work with and buy from. Alumilite is made in the USA in Kalamazoo, MI. I am not sure if Silmar is US or not?


If you want to try Alumilite, send me a PM and I will tell you what to do to get a free trial set!

 

[Blind_Squirrel]

Originally posted by MesquiteMan

3. Alumilite can be shipped without any hazardous material fees, no matter how much you ship. It is considered non toxic whereas PR is listed by the IARC (International Agency on Cancer Research) as possibly carcinogenic.

According to the MSDS, Alumilite part B, while not toxic, is hazardous under the criteria of the Federal OSHA Hazardous Communication Standard 29 CFR 1910.1200 http://www.alumilite.com/pdf/msds/Alumilite Water Clear.pdf

You want to be careful when working with either product. I have plenty of air flow when I am pouring either one.

 

[BRobbins629]

I would also recommend looking at the MSDS for Part A which talks about it being harmful or fatal if swallowed.

A hazard analysis of any product or procedure usually takes into account the probablity of occuracne along with the severity. In the case of both materials, there are certainly risks of exposure, risks of fire, and risks of curing under pressure. As with all chemicals, safety precautions and proper protective equipment should be used including eye protection and gloves with either PR or Alumilite.

While one compoment of PR (styrene monomer) does indeed appear on a list of suspected carcinogens, it is there due to studies on mice. Human exposure of the same chemicals in industies where there is significanty higher concentrations than we are exposed to has shown no increased evidence of cancer in multiple studies. Again, read the whole MSDS for these products and judge for yourself.

Note that curing Alumilite requires significantly more pressure than PR. I believe most use about 60 PSI, but perhaps Curtis can confirm. PR can be cast at 0 psi. If one were to investigate the number of accidents and injuries that have been related to operating pressure vessels at 60 psi, I would expect that there are more documented cases of severe injury than cancer cases associated with the use of PR.

As I mentioned in the previous post, both of these materials can and have been used safely by many members here.

 

[MesquiteMan]

Originally posted by BRobbins629

Note that curing Alumilite requires significantly more pressure than PR. I believe most use about 60 PSI, but perhaps Curtis can confirm. PR can be cast at 0 psi. If one were to investigate the number of accidents and injuries that have been related to operating pressure vessels at 60 psi, I would expect that there are more documented cases of severe injury than cancer cases associated with the use of PR.

This is certainly not correct, Bruce. Alumilite does not require high pressure. I probably started the thought that it requires high pressure since I do indeed cast at 70 psi. I do so because I can. I also do nothing but embeded items. In the case where there is so much surface area and cracks and crevices for air to be trapped, I feel that the pressure helps get the resin into these areas. I also did the same amount of pressure when I was experimenting with PR.

I have had Alumilite do just fine with 30 psi. I believe that is what Alumilite themselves recommend. Also, if doing a colored cast, you can just as easily cast Alumilite with 0 pressure as you can PR. Both will have some bubbles but you can not see them since you can not see through the resin.

As far as the safety of casting at 60 psi...that is a real stretch, no disrespect intended, Bruce!

 

[BRobbins629]

As far as the safety of casting at 60 psi...that is a real stretch, no disrespect intended, Bruce!

With the same respect Curtis, I was just making the point about the relativity of the 2 hazards - I do run an air compressor in excess of 80 psi though not at that level in my pressure pot. I still think the risk of getting hurt with high pressure and even 30 psi can be dangerous (think exploding car tire); not a stetch if you've ever been hit by a ruptured pressure hose or fitting - is greater than getting cancer from casting PR.

I think I fully appreciate the reasons you do use Alumilite and I always enjoy your posts of pens made from your creative blanks. I do however, and this is my opinion, think you over imply the dangers of PR relative to Alumilite. I was just trying to provide some balance hopefully without being too offensive.

 

[MesquiteMan]

Bruce,

You certainly do not offend me at all! I do not own any interest in Alumilite and certainly do not take anything personal about any of this! I prefer Alumilite since I can produce cactus blanks more consistently, faster, and provide what I feel is a great product for my customers.

I am VERY sensitive to anything to do with cancer since my mom had breat cancer at 42 and my dad just recenly underwent cancer treatment for nasopharangeal cancer caused by breathing too much wood dust as a carpenter for 40 years. His type of cancer is very rare in Americans but has a direct link to carpenters and anyone who does a lot of plywood cutting. He used to frame the houses that he built while he was still a builder (before I bought him out!). Having both parents with cancer makes me very high risk acording to my Drs.. Anything that has a warning that it may be cancerous I try to stay away from as you can imagine. I certainly concer that PR MOST LIKELY will not cause cancer in the average person.

And as for being hit by a ruptured hose or anything at all related to pressure...I guess I have just been lucky. I am around air compressors and air hoses at least 4 days a week. I am a bulder but I personaly do all the trim work in the homes that I build (I am too darn picky to sub it out!). I also have my own employees that do all the framing on my houses and I am my own superintendent. I currently own 5 different air compressors, about 20 hoses, and about 15 air guns in all. I also own 2 pressure pots. So far in 12 years we have not had a single incident with air pressure related failures.

Have a good one and once again, you would really have to try to offend me! I have thick skin!