Another casting failure - but by operator

[skiprat]

These are the results of my first casting with Alumilite in my new pressure pot. As you can see, the result is a failure but I learnt a lot, so not much loss. First, I copied Steve ( SteveJ72 ) by using a foil dish for the mold. That is an excellent idea Steve, as you can custom form your mold to suit the amount of blanks you do without unneccessary waste. Next was to measure and mix the two parts. I think I did ok with the measuring, but it was just a reasonable guestimate. I mixed the two together for what felt like ages as I was scared they would start to gel. The last two steps are probably the cause of my failure.
I just left the pot under pressure over night and was very pleased to see absolutely no bubbles when I tore the foil off. There was a tacky part to the surface in one area of the block. But the rest felt rock hard.
The things I learnt are;
1. I must measure much more accurately.
2. I must mix for longer
3. Sraypaint does not stick to CA, but seems to repel it.
4. For the effect of bringing the image to the surface, the resin needs to be a bit thinner than I could do with the items I chose to imbed.
5. For really clear resin, I need to make sure my work area is clean. See the dust spot above the skull.

I'm not sure if it was the short mixing time or in-accurate measuring that caused the soft spots. See the white marks on the wooden jigsaw attempt.

The pink one seemed ok till I over turned it and touched the edge of the flower and the butterfly.

Oh well[:I]

 

[Stevej72]

Hey Steve, I'm not sure if you can call it a failure if you learn something. My snake skin casting that I did yesterday didn't turn out, I'll have to post it. I started using the aluminum foil because I couldn't find a mold the size I wanted, these are easy to make and disposable. I really like the idea you are working on, can't wait to see it on you next cast.

 

[MesquiteMan]

Steven,

A couple of things to consider when using Alumilite...

-Buy yourself a cheap postal scale and use it to get accurate amounts of each part. I put my cup on the scale and zero it out. If I want 4 ounces of mixed resin I will pour in 2 ounces of A and then 2 ounces of B. If you do not know it, you will need .554 ounces of mixed resin for each cubic inch of mold space. (You will have to do the conversion yourself!)

-When mixing, be sure to scrape the sides of your mixing cup. This will help with making sure all the resin is thoroughly mixed. I buy cheap rubber spatulas for mixing and then rinse them in acetone when done.

-You can look into the cup while mixing and you will notice that when you first start, the resin will apear almost cloudy. Once you get it thouroughly mixed, it will return to completely clear. That is how I guage my mixing time. I usually mix for a minute or so.

-BE SURE to wear eye protection! I am $1,000 poorer because of my lack of eye protection. A small amount of resin splashed into my eye while mixing and I ended up in the ER. My deductable on insurance had not been met so I had to pay the entire bill of $1,000!

Another good way to make a mold that is a little less flimsy than the foil is to make it out of cardboard and tape. Then once the blank has been cast you simply cut the cardboard off with a bandsaw or turn it off on the lathe. Here is a picture of one I did:

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Of course then there is the re-useable molds I make from the white plastic cutting boards...

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[Ligget]

Great learning experience Steve!

 

[skiprat]

Many thanks for those tips Curtis. The foil is not the thin stuff you get on rolls, but little pie baking dishes and they are quite firm. I must say though that I really like your plastic ones. I did notice the cloudy swirls, but thought I had it pretty clear. I find myself rushing the mix to get it in the pot before it gells. My wife has just give me permission to 'borrow' her digital scale. I was going to get some of those clear disposable plastic cups for measuring, but I don't know if the resin will just desolve it.
I have had a closer look at the spot above the skull and I think it could be a short crack? Any idea's on that anyone?

Another thing I would like to ask is, has anyone double casted? What I mean is casting a finish piece in another layer. For eg, the pink one above, if I stuck a transparent label on it then re-cast it would it work?

 

[BRobbins629]

Steven - first of all, nice work. Double casting works fine. IMO it is the best way to get perfect lines on segments. You can also bring imbeded items closer to the surface by turning a cylander below the final pen diameter, either wood, plastic, or cast then glue the item to the cylander and cast clear (or color if it will be at the surface) around the object. Takes a little more time but can make some interesting background effects. Keep up the interesting work.

 

[MesquiteMan]

Steven,

Do a little experiment, if you will...mix up a small amount of Alumilite, say 2 ounces, and keep leave it in the mixing cup. Keep holding it until it starts to go off. This will give you a really good idea how long you really have to work with it. When I first started with it, I was just like you. I was pouring and pressuring my cactus blanks one at a time because I was afraid I would not have enough time to do more. I then did the little experiment I mentioned above and realized it had a lot more time than I realized. I now mix and pour 19 ounces at a time with no problems at all. Sometimes I have it all poured and realize my air hose is across the shop. I don't break my neck trying to get the hose. I just go get and it pressure the pot. I have not had one gel prematurely yet and I have mixed and poured over 20 gallons of the stuff!

I would certainly go with the scale. Mike, the VP at Alumilite, will tell you that it is really designed to be measured by weight rather than volume. Besides, you will get a much more accurate measurement that way. I have used the 12 oz. plastic cups from the grocery store and have not had any problems with Alumilite melting them. It might melt from the heat if you left it to cure but I do not believe Alumilite has anything in it that would dissolve plastic but I might be wrong.

As for the crack...can't help you there. I should not have happened during turning. In my experience, Alumilite blanks are nearly impossible to get to crack while turning. You should see some of the testing I have done with square blanks to try to get them to explode or crack! If it is indeed a crack it most likely has something to do with your inadequate mixing.

Double casting...can't help you there but it looks like Bruce already has anyway!

 

[stevers]

Hey Steven,
My first cast was a horrible failure. So you did good, slight imperfections and almost usable blanks? I should be so lucky. I'd like to see the final result of the pink one too. Keep us up to date. Neat idea on the jig saw pen too.