&%#$& Alumilite

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OKLAHOMAN

OKLAHOMAN

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Been casting with PR for a while now, have cast well over a few hundred prickly pear cactus with PR, I'll grant you a few were filed in file 13. But after talking to Curtis over the years I decided to try ^%#$@% Alumilite.
So yesterday I cut up my cactus ,put my molds in the toaster oven for an hour at 150 to make sure that they are dry ( I had cleaned them a few days ago) weighed part A 6.8 ounces weighed part B 6.8 ounces. Gently mixed parts A into part B, stirred gently for about 2 minutes, poured into my molds and placed into my pressure pot about 2 more minutes. Left in pressure pot for 2 hours. The results were not good. The blanks came out milky but had no bubbles........... had craters. This was all done outside the tempature was in the high 90's. Any advise from you Alumilite Guru's? What did I do wrong? I noticed when I mixed the two parts a little milkyness, my containers for the two parts were the 9 ounce plastic cocktaiglasses I always use for PR and were clean and dry, I mixed the parts in a quart ball canning jar that hasn't seen water in a while so no moisture. l'm well aware of the problem with moisture and &^%#^& Alumilite. Do you think mixing outside with humitdy of around 75% could cause that? All I know is I need a dozen cactus blanks by this week so I can restock for a show labor day week-end.
 
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Now I know probably less that you when it comes to alumilite, but the only thing that I could think of is maybe there was moisture in the cactus? I know there's a drying process that's a "need to know" type thing but it looks like you had all your other bases covered. Oh! Could there be any moisture in your air compressor line?
 
"milky" is usually not mixed well enough. when the two parts are mixed, they should be clear as water. Curtis is far more an expert but that is my experience. Only trouble I have ever had is humidity. (Moisture WILL make "foamy" bubbles) I suspect 90 degree temps might be involved but can't say, I don't usually cast when that hot.
 
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Brooks803 said:
Now I know probably less that you when it comes to alumilite, but the only thing that I could think of is maybe there was moisture in the cactus? I know there's a drying process that's a "need to know" type thing but it looks like you had all your other bases covered. Oh! Could there be any moisture in your air compressor line?
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I've had the cactus processed for well over a year so no moisture there but the compressor,Hmmm I'll have to check to make sure but I open the drain often.

hunter-27 said:
"milky" is usually not mixed well enough. when the two parts are mixed, they should be clear as water. Curtis is far more an expert but that is my experience. Only trouble I have ever had is humidity. (Moisture WILL make "foamy" bubbles) I suspect 90 degree temps might be involved but can't say, I don't usually cast when that hot.
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That's what I'm thinking, not mixed well and the temperature and the humidity just don't get the craters....er bubbles.
 
Roy,

When you pour the components together, they will be milky at first. Don't pussyfoot around when stirring. Stir the heck out of it, the bubbles that you create will go away with pressure. Don't whip it into a froth but make sure it is 100% clear with no streaks.

That said, I do not believe mixing was your problem. Improper mixing will not cause the craters, that is 100% guaranteed a moisture thing. Improper mixing will cause it to not polymerize properly, leaving uncured resin or stickiness. You say the cactus was dry. Are you 100% sure? Even high relative humidity will cause the cactus to pick up moisture.
 
MesquiteMan said:
Roy,

When you pour the components together, they will be milky at first. Don't pussyfoot around when stirring. Stir the heck out of it, the bubbles that you create will go away with pressure. Don't whip it into a froth but make sure it is 100% clear with no streaks.

That said, I do not believe mixing was your problem. Improper mixing will not cause the craters, that is 100% guaranteed a moisture thing. Improper mixing will cause it to not polymerize properly, leaving uncured resin or stickiness. You say the cactus was dry. Are you 100% sure? Even high relative humidity will cause the cactus to pick up moisture.
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Curtis, the cactus is stored in my shop and the shop is air conditioned so I do not think the cactus had any mositure but before casting the next batch in the AM I will place them in the molds and put into the toaster oven at 150 for about an hr. I will stir the crap out of it and we'll see how that goes. If not back to PR as I have to have some this week.
 
I'd be interested to hear your opinion on this Roy. I talked to Jeff Powell about this an hour ago. I've poured tons of PR but i'm thinking about making the switch.
 
i once used a water based mould release that screwed up my casting. when i took it out of the pressure pot it sounded like rice crispies.
 
I have had one cast that came out milky looking and my only thoughts on this is that I did not mix the Part A and Part B thoroughly. The mold is made of UHMW and the blanks were cooked for over 8 hours and checked with a moisture meter before casting. Shop temperature was 23 degrees C and the humidity was @ 32 % in the shop.

Dave
 
I used clear Alumilite for the first time this morning. I did add some tinting but no cloudiness and no bubbles (or craters). I was surprised at how quick it set up. I followed the directions, just as you described, using the pressure pot and all. The only difference is I did it in the basement (low humidity and temp around 77 degrees) and preheated the blank.

Hope your next batch comes out better.
 
Well, had a conversation with THE MAN last night, and just took out a small casting of 6 cactus blanks......PERFECT!!!!!!!!!!!!!!! Thanks to all for their input, between your input and Curtis's I just might become a .......boy this is hard for me to say, I might become ...........I might..........I might become a fa........... Oh hell just say it.. a fan of Alumilite. Don't tell Curtis I said that, I'll never hear the end of it.
 
OKLAHOMAN said:
Well, had a conversation with THE MAN last night, and just took out a small casting of 6 cactus blanks......PERFECT!!!!!!!!!!!!!!! Thanks to all for their input, between your input and Curtis's I just might become a .......boy this is hard for me to say, I might become ...........I might..........I might become a fa........... Oh hell just say it.. a fan of Alumilite. Don't tell Curtis I said that, I'll never hear the end of it.
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Just wait untill the day you can go out and cast blanks for hours then work in the shop all day WITHOUT being run out by the fumes and odors associated with polyester resins! THAT would make a convert out of anyone! :)
 
Landon, if you don't tell anyone............stir the hell out of the solutions when you mix A and B, don't worry about bubbles they will be taken care of in the pressure pot. Stir... not whip into a froth. Second if using a silicone mold make sure it is completely dry, moisture and alumilite don't mix. Today I cast in the air conditioned shop 72 Degrees, yesterday outside 95-100 and high humidty.
 
OKLAHOMAN said:
Landon, if you don't tell anyone............stir the hell out of the solutions when you mix A and B, don't worry about bubbles they will be taken care of in the pressure pot. Stir... not whip into a froth. Second if using a silicone mold make sure it is completely dry, moisture and alumilite don't mix. Today I cast in the air conditioned shop 72 Degrees, yesterday outside 95-100 and high humidty.
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I suspect here lies the difference, thanks. I have not casted a ton but have only had one failure, it was with pine cones. I rushed the job and suspect they were not as dry as I thought.
 
Yep..I use the large 3/4" popsicle sticks for stirring and I stir like a mad man. It doesn't whip into a froth, don't know if that's even possible, but don't worry about bubbles in the resin. I like to store and work around 70-72 degrees too. When the working environment is cooler, the resin doesn't kick off so fast. I do not bother heating up pine cones, which would be comparable to cactus. As long as the cones are dry, there good. If you heat them, they'll make the resin cure faster, but in the end it's the same. If you make thin pours, like worthless wood taking up most of the mold and your just pouring fractures and stuff, then heating is a must because now you don't have as much resin so it won't be able to generate as much heat. But..even then it will work out if you just leave your stuff in the pot 2-3 times longer. I like to leave things in the pot for 1 hr. Usually you can take it out sooner, but better safe than sorry, that resins not cheap.
 
OKLAHOMAN said:
Well, had a conversation with THE MAN last night, and just took out a small casting of 6 cactus blanks......PERFECT!!!!!!!!!!!!!!! Thanks to all for their input, between your input and Curtis's I just might become a .......boy this is hard for me to say, I might become ...........I might..........I might become a fa........... Oh hell just say it.. a fan of Alumilite. Don't tell Curtis I said that, I'll never hear the end of it.
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Hmmmmmm I'm not ready to switch yet. I wish they gave you a little more working time. I will wait a bit to see if you are really convinced that in the end Alum is better than PR

Roy another thought the compressor was mentioned just keeping the tank drained wont cut it you need an in-line filter water separator. like used with spray painting cheap and easy. You would be surprised when you blow a lot of air though it you can see the moisture on the side of the cup. Although I never had moisture problems with PR :rolleyes:

Good luck Roy check back in 2 or 3 weeks and let us know if your still a convert. :confused:

.
 
OKLAHOMAN said:
Neal, it better be fresh, I just got it last week:biggrin:.
wolftat said:
How old is the Alumilite?
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Probably fresh then, I was just trying to narrow down any possibilities. I had a problem with old Alumilite, foamed in the mixing cup , overflowing and making a real cool mess on the side of the building as I let it flow off the window sill and down the building for a laugh. It peeled off after a few weeks...LOL Looked like a rough night out.
 
I can get Aluminite with cactus perfect out of the mold, it is a chore to get a good shine but a dozen or so coats of CA will make anything shine. Then after a year the Aluminite shrinks away from the cactus. I've had multiple returns of cactus made with Aluminite because of the texture that develops over time.
 
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Gerry, are you saying that Alumilte shrinks or wears down? I've made hundreds of cactus pens from PR and never had a return because of texture, as a matter of fact I only remember 2 cactus returns and both were mechanical not aesthetics. This is my time using Alumilite., and this is the first time hearing this problem. I don't think a show has gone by where I haven't sold at least 2 Cactus pen's, I know Curtis is the Cactus man but it kinda has become my signature pen at shows, and that is a problem I don't need.

Chasper said:
I can get Aluminite with cactus perfect out of the mold, it is a chore to get a good shine but a dozen or so coats of CA will make anything shine. Then after a year the Aluminite shrinks away from the cactus. I've had multiple returns of cactus made with Aluminite because of the texture that develops over time.
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This is what makes casting so darn hard. There are so many variables and I don't think any one has the rite answer. Especially when you get into casting objects and organic ones non the less. Certainly not an exact science. I heard a lot of try this and that in fact I got a cabinet full $$$$ of that ... that didn't work for me.

Isn't pushing the envelope in casting fun :befuddled:

.
 
OKLAHOMAN said:
Gerry, are you saying that Alumilte shrinks or wears down? I've made hundreds of cactus pens from PR and never had a return because of texture, as a matter of fact I only remember 2 cactus returns and both were mechanical not aesthetics. This is my time using Alumilite., and this is the first time hearing this problem. I don't think a show has gone by where I haven't sold at least 2 Cactus pen's, I know Curtis is the Cactus man but it kinda has become my signature pen at shows, and that is a problem I don't need.

Chasper said:
I can get Aluminite with cactus perfect out of the mold, it is a chore to get a good shine but a dozen or so coats of CA will make anything shine. Then after a year the Aluminite shrinks away from the cactus. I've had multiple returns of cactus made with Aluminite because of the texture that develops over time.
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Either the Aluminite shrinks or the cactus grows. What I know is that when I made them the finish was smooth and flawless. I used several coats of CA. A year later, returns came back and there was a noticable texture. Same with the pens that were in my cases for a year without selling, they now have texture from the cactus. I believe the problem is limited to Aluminite, not Similar 41 castings.
 
Sorry to have to differ on this but Alumilite does not continue to shrink. Most likely, the cause was either the blank was turned too soon or too much heat was generated while sanding/turning. I have plenty of Cactus pens and not one has the problem mentioned above.
 
MesquiteMan said:
Sorry to have to differ on this but Alumilite does not continue to shrink. Most likely, the cause was either the blank was turned too soon or too much heat was generated while sanding/turning. I have plenty of Cactus pens and not one has the problem mentioned above.
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Turned too soon is not possible, but overheating during turning and sanding is a possibility. However, there was no texture a month after assembly, but there is texture now. Could the CA be too thin?
 
Chasper said:
MesquiteMan said:
Sorry to have to differ on this but Alumilite does not continue to shrink. Most likely, the cause was either the blank was turned too soon or too much heat was generated while sanding/turning. I have plenty of Cactus pens and not one has the problem mentioned above.
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Turned too soon is not possible, but overheating during turning and sanding is a possibility. However, there was no texture a month after assembly, but there is texture now. Could the CA be too thin?
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I have experienced similar in the past. I did a lot with Loofah and corn cob for example. I have noticed a texture a year latter like you are describing and this was with PR Silmar 41 and a coat of CA. What I think is happening is moisture is getting in somehow over time expanding and shrinking the media. Thus texture and possible cracks. I believed I have remedied it by applying a thicker CA coat and more importantly sealing the ends before assembly. After you square your ends before you mount the bushings seal the ends with CA a drop on a piece of plastic and dab the ends work good. I think that over time the moisture got in through the ends especially if you do outdoor shows.

Something to think about :confused:

.
 
Bruce has a good theory! I always put a thick coat of CA on everything I make and have not had a problem. The only time I have is when I turn a worthless wood blank before it has had adequate time to cure, like within hours of casting. Then I will get a difference between the wood and resin but that is the only time
 
By no means do I mean to cast doubt on the general durability of cactus blanks with either Aluminite or PR. All I can talk about is my own experience and that experience is that at least some of them developed a texture from either the resin shrinking or the cactus expanding.

I did not coat the ends of the finished turnings with CA. The texture developing pens that remained in my posession definitely had major exposure to heat. I've been to multiple outdoor shows this summer when the temp was in the 100 degree range. I also had the same problem with pens made with rice, and breakfast cereals. I have not had the problem with pens made from corn, bird seed, wheat, pine cones, acorns, coffee beans, oats, horse hair, dog hair, various types of pasta and assorted other organic materials.

I think that it is likely that heat and unsealed ends are the source of the problem.
 
Let me throw this one out there just for random info. If you are pressurizing your chamber with an air compressor (as I'm sure most do) remember, compressing air intrinsically causes moisture to condense out of it and collect in the tank. If you let it get full enough, not only will it eventually rust your tank out, but it will bleed over into your outgoing air line. A dryer attached in the main supply line from the compressor somewhere will help with this, but draining the tank occasionally is a good Idea.

PS water in the air supply is bad for tools too, especially nail guns
 
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