Poly Resin vs Alumilite

[AngryRhino]

Hi All,

I'm thinking about venturing into casting, and I'm a little confused so far on the difference between Alumilite and Poly Resin. Can someone tell me what the difference is in what you can cast with each type of resin?

Also, is there a difference in the equipment you would use with each?

I've read through the docs in the library, but it feels like you should have a base knowledge of the process before going there!

I'm not sure if I want to do a pressure pot or the ultrasonic cleaner yet (leaning towards the ultrasonic + toaster oven.)

Any help would be appreciated!

Thanks!

 

[Russianwolf]

Given those two choices, I'd pick Alumilite. PR I will never touch again under any circumstances.

If your shop (casting area) is outdoors you may be okay either way. But if attached the fumes from PR will fill your house and can take days to go away. Most of us don't find it pleasant and they are not good for you.

I'll let the others tell you what you can do with each. I found that both have their negatives and went another direction.

 

[BeSquare]

I actually don't mind casting with PR, but we have a pretty well ventilated basement we're working in. I do prefer the water clear alumilite when I'm doing tube in casting though. Just feels cleaner/clearer to me when it's done.

I like the flexibility of PR in so far as what I've been able to use to dye it though. Has worked well for me.

Previous post is right though, it is a lot about preference, and both can turn out great results!

- Rich

 

[healeydays]

I too like the flexibility of PR and color creative choices I have vs Alumilite that doesn't like some of the things I use. Alumilite is also alot more fussy with humidity and any moisture.

 

[OOPS]

Before buying a setup to cast blanks, you might wish to consider buying some Alumilite blanks made by others as well as some made with PR. Each has their own properties and you might find one much preferable to turn. Personally I prefer Alumilite because its comparatively odorless when turning, drills much more quickly without melting, and turns much more nicely. Others I am sure will disagree, so that's why I would suggest making your own comparison first.

Do not minimize the odors coming off PR pours. Some people have gotten quite ill from the fumes, particularly those who attempted these pours inside a closed house. Personally, I would never use PR in a house, and only in a detached building with the ability to open the doors and blow the fumes out quickly. In college chemistry, the professor would not allow us to bring MEKP (the hardener in PR) into the lab--it had to remain under the fume hood at all times. Even though many handle this chemical in a cavalier manner, it should not be considered relatively safe just because it is sold in a craft supply store.

 

[BeSquare]

I didn't mean to minimize it, guess I should be specific when we are doing it, we set up a box fan in both of the basement access windows blowing out to remove the fumes.

 

[AngryRhino]

What are the other casting mediums besides PR and Alumilite? I thought those were the two main things used?

Also, I'm in Florida -- humidity is ALWAYS high, and so is the temperature most of the year.

 

[Ed McDonnell]

Here are more opinions to add to the assortment of opinions that you will get with a question like this.

All resins have some health risk associated with them and appropriate safety gear should be employed while working with them. I use gloves, goggles and an organic vapor mask. Just because you can't smell something doesn't mean it isn't hazardous under certain circumstances.

You hear a lot about the issues with styrene fumes and MEKP when people talk about PR. Alumilite and epoxy both have their own issues which don't seem to get a lot of air time. If you don't know what they are, read the MSDS for the product.

Some people will say they work with resins with no protective gear and never have a problem. I remember as a kid the farmer who ate spoonfuls of DDT to prove it was safe. To each their own. I wear protective gear when working with resings and I didn't eat DDT (at least not by the spoonful).

Which resin is "best" depends on the application. I'll switch between PR, urethane (alumilite) and epoxy (clear casting) depending on the application.

PR is the least expensive to play around with. You can do a lot without any expensive equipment as long as you have a suitable place to work. A well sealed basement or any room inside the house is not a suitable place.

Alumilite is a "pricier resin" with a much shorter working time than PR (which can be a plus or a minus) and will require investment in a pressure pot to get consistently good results.

Clear casting Epoxy can range from pricey to very expensive. It's got a much longer working and curing time than PR. Again, this can be a plus or a minus depending on the application.

Alumilite and epoxy will have better machineability than PR. This has some advantages for custom pen makers. It also makes the material more resistant to assault by pen makers who may not have completely mastered the arts of turning and sharpening.

Ed

 

[AngryRhino]

Thank you Ed, this has helped a lot.

It sounds like to me, that I should start out with PR. If I'm reading things correctly, an ultrasonic cleaner from HF should help eliminate the bubbles.

That means I can get started with a gallon of resin (which should come with the catalyst,) some molds, some colorants, and the ultrasonic cleaner and be able to get my feet wet.

Is this correct?

 

[Ed McDonnell]

Thank you Ed, this has helped a lot.

It sounds like to me, that I should start out with PR. If I'm reading things correctly, an ultrasonic cleaner from HF should help eliminate the bubbles.

That means I can get started with a gallon of resin (which should come with the catalyst,) some molds, some colorants, and the ultrasonic cleaner and be able to get my feet wet.

Is this correct?

Only you can decide what resin is best to start with. I don't remember you saying what kind of blanks you are most intererested in making. in my opinion, PR is a good resin to start with to see if casting is something that interests you before you buy expensive equipment. There are some things you won't be able to do without a vacuum chamber or a pressure pot, but those things can wait for later.

Don't forget to add the safety gear to your list. 3M makes very affordable organic vapor masks. Nitrile gloves are inexpensive at lots of places. Good safety googles (not just safety glasses) are cheap insurance. You may think it impossible that you would ever get a splash of resin or MEKP in your eyes, but if you work with the stuff long enough..... Why take a chance?

US Composites sells Silmar 41 and offers sampler packs of opague and transparent pigments that would give you plenty of combinations to play with. You can add a couple micas when you are ready.

There's nothing wrong with reading the docs in the library multiple times. Each time you go through them a few more things will start to make sense. Especially if you have some hands on experience between readings.

Good luck and stay safe.

Ed

 

[InvisibleMan]

Thank you Ed, this has helped a lot.

It sounds like to me, that I should start out with PR. If I'm reading things correctly, an ultrasonic cleaner from HF should help eliminate the bubbles.

That means I can get started with a gallon of resin (which should come with the catalyst,) some molds, some colorants, and the ultrasonic cleaner and be able to get my feet wet.

Is this correct?

This will be fine. For kit pens, the expense of Alumilite wouldn't be worth it to me. Even for custom pens, I've had no issues making pens with PR, but it is more brittle, so if dropped, the custom pen may be garbage. With a kit pen, you can just swap in a new part.

 

[Brooks803]

Only you can decide what resin is best to start with. I don't remember you saying what kind of blanks you are most intererested in making. in my opinion, PR is a good resin to start with to see if casting is something that interests you before you buy expensive equipment. There are some things you won't be able to do without a vacuum chamber or a pressure pot, but those things can wait for later.

Don't forget to add the safety gear to your list. 3M makes very affordable organic vapor masks. Nitrile gloves are inexpensive at lots of places. Good safety googles (not just safety glasses) are cheap insurance. You may think it impossible that you would ever get a splash of resin or MEKP in your eyes, but if you work with the stuff long enough..... Why take a chance?

US Composites sells Silmar 41 and offers sampler packs of opague and transparent pigments that would give you plenty of combinations to play with. You can add a couple micas when you are ready.

There's nothing wrong with reading the docs in the library multiple times. Each time you go through them a few more things will start to make sense. Especially if you have some hands on experience between readings.

Good luck and stay safe.

Ed

I have to agree with Ed 100% on everything. Safety gear should be #1. His goggle remark is spot on. Stuff happens no matter how safe you try and be. I use PR and Alumilite daily. Each has their own place for me.

 

[PenMan1]

I get a better shine using PR resin.

If I need to make threads in a pen body, Alumilte is MUCH, MUCH easier to thread.

PR really requires no specialized equipment other than warm water and a 100 watt light bulb. Thinned PR resin releases air bubbles as well or better than pressurized PR.

Alumite really needs pressure and a PRECISE scale is helpful.

PR (Silmar 41)has no structural integrity.
Silmar 404 has plenty of structural integrity but does not dry clear.

Alumilite has structural integrity, but costs almost twice as much.

As Brooks says, both have their uses. For a pen that has copper tubes underneath the resin, I generally use PR because of the reduced cost factor. If I'm making something custom that has no tubes or requires threading, I'll use Alumilite.

So both are useful. I DO recommend starting with PR, simply because the start up costs are substantially less.

 

[robutacion]

There is been a great number of very accurate and responsible suggestions given in this thread so, is no point in me repeating any of those but focus on areas that haven't been clarified yet (if I read everything right...!).

I have no experience with Alumilite or any of the polyurethane resins, here is Australia is prohibitive to buy that stuff, the price of a 20lt drum of epoxy/polyurethane resin is about AU$1,250, while a good crystal clean Polyester resin (PR), costs about AU$250 plus shipping on both cases...!

So, is not difficult to work out why I only use Polyester resin to make my Resifill (castings). If the prices were identical, I would be using both of them why...??? Because, the epoxy/polyurethane resin is a much better option if you are making blanks where wood is used as part of the cast.

The adhesion capabilities of the Polyurethane resins are far superior than the Polyester so, and considering that that I haven't seen any reference to what type of blanks you are thinking in casting, I though that would be important to clarify this point.

You seem to be avoiding the pressure pot issue but, if you are going to make wood/resin blanks, you aren't going to get good results without a pressure pot. A certainly amount of pressure (PSI) is required to force the resin into all holes, cracks, crevesses and other, without it, the resin will not penetrate.

Removing air bubbles from the resin, is a much easier job under pressure then vacuum, remember that the vacuum will force the resin to bubble-up as if was "boiling" at the same time the resin is gelling so, you may get a few nasty results out of the try.

Another negative (unless you want that to happen) thing about casting and vacuum is that, if you are making a multi coloured blank, using 2 or 3 colours where you waited the ideal time for pouring and manually created the "effects" such as swirls, waves, etc., taking those molds/blanks to the vacuum, will totally spoil any of the effects you deliberately created as the vacuum will "bubble"/boil the resin and all colours added with it so, if left there long enough and the resin takes a while to gell, you endup with one colour that is the combination of all colours you added as if you mixed then thoroughly, this is what the bubbling/boiling action of the vacuum will do, and if the resin sets not long after the vacuum/boiling has started, you may not endup with a single colour but you certainly will not endup with the effects you created before you put them in the vacuum chamber.

The bubbling/boiling action, is indeed the formation of very large bubbles that come to the surface and "explode" like a volcano and not tiny little bubbles as you may think...!

Sure, you can take advantage of this "special effects/mixing maker (vacuum chamber) pour your 2, 3 or more colours, take the molds to the vacuum chamber and pull vacuum for 1 minute or 2 and then, take the molds out of there and put them in the pressure pot before it starts gelling, that will pull all the bubbles out, otherwise, they get "trapped".

So, if you didn't know that you can created special effects with multi coloured resin by using a vacuum chamber as a "special mixer", now you do, some caster have discovered this and kept it a secret to avoid imitation/multiplication and have something different that is not their natural ability or skill to do it but, an accidental find...!

How it looks like...??? well, I just done a few knife handle blanks to go to Russia, made with Bottle Brush stabilized root with 2 ends and the resin in the middle, as requested. This was a 3 colour mix and the effects are made using the vacuum chamber for about 1 minute (reach full vacuum) and them put in a pressure pot at 80 to 100PSI...!

The effects inside are absolutely stunning, one of the blanks was requested to be sliced in half as 2 booked matched scales, unfortunately I don't have any pics of that, as I sliced the blanks just before I packed the box with all the blanks ordered and I forgot to take so pics, I only though of it the next day when I downloaded the pics I had in my camera...!

Anyway, I've got a pic with this batch, one of 6 batches, all with different woods colours and effects, only this one was done with the vacuum chamber,



I hope your learn something...!:wink::biggrin:

Good luck,
Cheers
George

 

[AngryRhino]

Great responses all, I'm learning a lot here.

The kind of blanks I'm looking to initially cast will be for kit pens w/ brass tubes. I'd like to dabble in not only casting multi colored blanks, but maybe even casting some easy things inside of the resin. (If there is such a thing.)

Would the PR still be a good option for these types of castings?

Also, I am trying to initially avoid the pressure pot. From what i've been reading, an ultrasonic cleaner is useful for removing the air bubbles w/ PR (as opposed to alumilite, in which a pressure pot is REQUIRED.)

Thoughts?

 

[Brooks803]

PR is good for casting objects to an extent. Alumilite is better suited for worthless wood type applications, but I've cast many different objects in PR with great success. However, when casting objects even with PR you still want to do so under pressure. Air can get trapped under objects and might not make it to the surface even with the ultrasonic cleaner. So it would leave a void in the resin and not just look bad if not repairable, but could lead to a failure of the blank while turning!

For colors...the cleaner would do just fine and no pressure pot needed.