Alumilite Turned White After Pressure

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iWoodPen

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Mar 5, 2016
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Milford, Massachusetts
Trying to make a watch parts pen.

Poured alumilite clear - pressure 50psi. 2 hours.

then- i opened the pot and the mold is NOT clear- it is white.

I measured the amount of resin - part a and b by weight, not volume..

What gives? Anyone know?
 
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Some possibiities:

Measured wrong and used too much A?

Your scale isn't accurate enough for the amounts you are measuring and you ended up with too much A even though the scale said the weights were the same.

Didn't get all the B out of the measuring cup and ended up with too much A as a result?

Didn't mix it well enough?

Moisture? Introduced from the airline during pressurization? Too much humidity in your area has affected the resin?

Something else?

Ed
 
So too much a would cause the white to appear? Definitely not humidity, possible air in the line, buy i I don't think so. I'm leaning towards improper amounts. The scale I'm using should be good, but it's the first time I used it, so anything is possible. I'm going to try again tomorrow.
 
How many ounces was the Mix? in a 64 ounce mix if you are off by an ounce no big deal but if it's a small mix (under 10 ounces) then you have to be dead on. Also how long did you mix? Need to make sure you mix long enough to ensure A & B mix properly.
Eugene.
 
Did you measure the Alumilite resins in ounces or grams? My scale will do either and for small pours, I go with the much more sensitive grams.

If you measure Part A into one cup and Part B into another, then pour one into the other, you may end up not getting all of the one you're pouring from (at least make sure you have something to scrape inside that cup!)

How white did it turn? Cloudy or completely opaque? When I've had moisture problems with Alumilite, it shows up as bubbles (despite being under 70 psi) instead of cloudiness...
 
Man if alumilite is that sensitive I am so glad I do not use it for casting. That is a tough blank to lose. Not sure if you can save the pieces. Maybe you need to practice on some other less tedious blanks first. Get the exact formula and process down solid. Good luck.
 
jttheclockman said:
Man if alumilite is that sensitive I am so glad I do not use it for casting. That is a tough blank to lose. Not sure if you can save the pieces. Maybe you need to practice on some other less tedious blanks first. Get the exact formula and process down solid. Good luck.
Click to expand...

Fortunately, I used practice parts. This us the second go for me. Both times I've used parts that can be scrapped. But I have purchased a lot of Rolex and Franck and omega dials that would have been disastrous to lose. Thankfully, the first few are my learning blanks. Otherwise, I'd be freaking out.
 
Davidh14 said:
Very interesting subject here. What would one recommend to be the minimum amount to mix?
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I regularly do 50 gm batches , and have done half that successfully . Key is to have scale with 0.1 gm accuracy , don`t assume identical measuring containers will weigh the same , heat the B side to reduce the viscosity , have spatula to get nearly everything out of the containers , stir for 2 minutes . Doesn`t matter which side pigment is first added to .
 
iWoodPen said:
So too much a would cause the white to appear? Definitely not humidity, possible air in the line, buy i I don't think so. I'm leaning towards improper amounts. The scale I'm using should be good, but it's the first time I used it, so anything is possible. I'm going to try again tomorrow.
Click to expand...

Moisture in the air line is the most likely cause of your problem . It does not take very much . The amount of opacity will vary , depending on how close to set-up the mix is (close may cause white only on the top half of the pour) , whether the pressure forces the resin to flow into cavities (may cause white streaking) , the amount of moisture (a little may turn it white without any bubbles but a lot will make it frothy ) .
 
I have never tried a watch parts blank, but one thing nobody touched on is the adhesive used to glue the parts to the tube. What kind of glue? How long did it cure? If you used CA maybe it didn't cure enough to completely off gas. I use Allumilite and the only time I had a problem with it coming out cloudy was when I used acrylic paint by mistake. Hope this helps,

Bill
 
I've always kind of wondered how much room for error there is in terms of the A:B ratio when mixing Alumilite clear, so I've spent the last few hours performing an experiment.

I mixed approximately 40 gram batches of (probably near end-of-life)Alumilite Clear and varied the A side to B side ratios. At somewhere around 52 to 54 percent A side, the cured resin was turning white. Weighing was done with a digital kitchen scale set to weigh in grams.
I put a plastic cup on the scale, set the readout to zero and poured 20 or so grams of A side into the cup and recorded the weight of A. I then reset the zero and poured B side in varying amounts, also recording the amount.

At A:B=20g:19g the result was clear. This is about 51% A.
At A:B=20g:17g there were patches of white. This is about 54% A
At 57% A the cured resin was completely white.

These are pretty rough numbers given the 1 gram resolution of the scale. Next time I'll use a reloading scale with a .1 grain (about .006 gram) resolution.

Just for what it's worth.

The only suggestion that I would make is to use just one cup for weighing and mixing. That way you never have any residue left behind when you pour one part into the other.

Hope this helps,

Bill
 
bmachin said:
I've always kind of wondered how much...
The only suggestion that I would make is to use just one cup for weighing and mixing. That way you never have any residue left behind when you pour one part into the other.
Hope this helps,
Bill
Click to expand...
Bill has the right idea. I use one cup, zero(tare) the cup, pour in my amount, say 20 grams(my typical pour), usually "A" first, take it off the scale, add dye, pearl-x powders or what ever other mixer materials I am using, put it back on the scale and zero it again then pour in 20 grams of "B". So far I have never had a failure using the crystal clear Alumilite. However, I have had a similar failure using Alumilite black. It was a one time thing and I am not sure what happened but I got grey instead of black.
 
From what little I know about Alumilite, it might be that it didn't cure completely. Try baking it in a low oven for 10 mins and see if it clears up before tossing it out.
It just might work.

I do know that CA will turn milky if any moisture gets in it, but it can be baked out if you are careful doing it.

Hey, it's worth a shot, right?
 
Herb G said:
From what little I know about Alumilite, it might be that it didn't cure completely. Try baking it in a low oven for 10 mins and see if it clears up before tossing it out.
It just might work.

I do know that CA will turn milky if any moisture gets in it, but it can be baked out if you are careful doing it.

Hey, it's worth a shot, right?
Click to expand...

Once it's out, baking will help it get more solid, but will not alter (fix) the color.

All the above suggestions are worthy to check out.
 
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