Ultra Sonic cleaner?? is this one going to work

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LandfillLumber

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Hello,looking to get the bubbles out of my PR blanks.I want to start to make them and possibly even offer them for sale,so I will be prodution minded but not big time.I just want to add some new things to my sales to be able to keep people interested,and I have access to some much super worthless wood.My question will the cheap cleaner from HF do the job for doing small runs of blanks.Thank You,Victor

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=3305
 
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First, you have to determine if your molds will even fit into that one, which I doubt. Plus, the heat is very useful, although I haven't found it critical. But it is VERY useful. They have a bigger one for about 60-70 bucks. Get that one.

Dale
 
You will fry the ultrasonic transducers if the tank isn't kept at least 1/2 full of water, why not just get a jewelry investment vibrator they only used to be about 35.00 they are capable of vibrating air bubbles out of Silica Gypsum investment slury, Or Harbor Freight had a 2 CFM vacuum pump for 70.00 yesterday, hook that to a pressure pot or an old pressure cooker and for about 80.00 with a second hand pressure cooker you have an excellent way of degassing the air bubbles,
 
Glass Scratcher said:
You're putting your molds in the Ultra Sonic Cleaner??
Click to expand...

I take it I shouldn't? I've been putting solid resin (no aggregates) in the molds in there for 1 cycle, more to get the heat than the vibe. They've been coming out great. Is that too hot? I knew you guys used them for mixing, I guess I assumed you used them to put a mold into them too.

If it has any aggregate, I use pressure, after using the cleaner to warm and mix the resin.

Gimme the dope on this, Charles!!!

Dale
 
I pour the PR into jars and place the jar in the ultrasonic cleaner and run it for about 30 minutes while I get ready to cast. Add the catalyst and cast. The ultrasonic cleaner I have is the larger one (2.5 qts ??) and has the heater.
Do a good turn daily!
Don


Dale[/quote]
 
I looked at that one in the store. It was too small for me. Only big enough for one cup so if your trying to do any type of swirl pattern It would really slow you down.
 
Won't mixing the hardener introduce more bubbles,so the pressure takes care of those???I didn't think of multi-colors for swirl,I guess I do need a little bigger one.I do have a very good vacuum pump to use as well.Thanks everyone for the info. Victor
 
Yes, you can introduce more bubbles if you are overly aggressive in your mixing of the catalyst, but you can also add bubbles by overly aggressive mixing of your pigments or under mixing powder additives. Then there is also the issue of disolved O2 going in and out of solution, which Bruce Robbins is more qualified to discuss than I am.

If you are using Silmar 41 and mix your catalyst at the proper % in the working temperature range, and have not over pigmented your resin(whichever resin you use, each resin has differing ratios of loads they can carry, and different gel times) you have approx 20 minutes from catalyzation, to gel (unless you have added gel promotor, or are working with yellow or red liquid/paste pigments).

If you ultrasonic after pigmenting then again after catalyzing you should have plenty of time before gel starts.

I set my plastic mixing cups (RC5, Polypropylene) in my ultrasonic cleaner that has 1" to 2" of water in it. Remove them and wipe them dry before going near the molds.
 
But, if the heat function(on the jewelery cleaner) is used along with hot water, as I do, then the gel time is shortened. Sometimes it happens while I'm pouring, especially if I cast all three molds. I must hurry to get the last one filled.
Do a good turn daily!
Don

Glass Scratcher said:
If you are using Silmar 41 ... you have approx 20 minutes from catalyzation, to gel (unless you have added gel promotor, or are working with yellow or red liquid/paste pigments).
Click to expand...
 
its_virgil said:
But, if the heat function(on the jewelery cleaner) is used along with hot water, as I do, then the gel time is shortened. Sometimes it happens while I'm pouring, especially if I cast all three molds. I must hurry to get the last one filled.
Do a good turn daily!
Don
Click to expand...

That is one of the caveats one has to deal with. If the pigments or additives you are using are organic or inorganic then the addition of heat can seriously change the equation and the gel time. As with everything in casting, we need to record the materials and the processes, so we know what is happening and if possible build a process chart. The data can help us extrapolate a solution for timing, or help ask the experts at the manufacturers intelligent questions.
 
The heat is to help thin the PR. But, if memory serves Don is using a Swing resin, which is more viscous(thick) than Silmar 41.

Silmar 41, will thin under ultrasonic alone.

I'm sure I will be opening another can of worms but here are some additional notes.

Many red and yellow liquid/paste pigments accellerate the gel and cure time. It depends on whether they are manufactured with organic or inorganic components.

If I remember any chemistry from college, and Bruce may again be of help here... Adding heat to reactions involving organics, will accelerate the reaction. By reaction I am indicating the gel and cure of PR.

White pigments (and others) that contain TiO2 will inhibit gel and cure in Cobalt Promoted PRs. Silmar 41 is a Cobalt Promoted PR. The TiO2 binds to the Cobalt in the resin inhibiting the cure. Silmar 41 is promoted (according to Interplastics Co) at 3 parts per million.

The additon of gel promotor to compensate for a slow gel will provide many times the amount of Cobalt originally added by the manufacturer and will cause very sudden gelling of the resin.

MEKp has a specific gravity of 1.15g/cm^3.

MEKp should really be measured at 1% by weight against the weight of the quantity of resin to be catalysed. However since the specific gravity is close to 1 (1.15g/cm^3) at the volumes we are casting at we can just go by volume. I have been using 0.5% measured against metric ounces which are 30ml per ounce, I do this for simplicity. The actuall difference because of the SG becomes negligable at the volumes most of us cast at.
 
No pigments....just clear casting snakeskins and computer labels.

I really think that since I've been heating the resin that my castings are better...I think the warmed resin allows the air to more easily escape and also helps with bubbles introduced when pouring into the molds.

I cast both Silmar 41 and another PR called swing resin by Composites One...the swing resin is thicker and both Roy and I like it really well. But, I've been told that Composites One (in Ft. Worth, TX, at least) has changed to another polyester resin.

What about that Terry? Have you used the new resin from Composites One? How did you like it?

Do a good turn daily!
Don

Glass Scratcher said:
That is one of the caveats one has to deal with. If the pigments or additives you are using are organic or inorganic then the addition of heat can seriously change the equation and the gel time. As with everything in casting, we need to record the materials and the processes, so we know what is happening and if possible build a process chart. The data can help us extrapolate a solution for timing, or help ask the experts at the manufacturers intelligent questions.
Click to expand...
 
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