Bubbles in the Models!

[RileyS]

So my model and die tech has had problems with pouring bubbles. It's a roller coaster of good pours then bad pours.
We use Lean Rock. Impressions are lightly misted with de-bubb. Poured using a vibrator. tiny bubbles show up on margins or occlusal cusp areas of prep.
I've gone over some techniques a few times over the last 2-3 months. I'd like to hear any ideas as to what you all might think is occurring or just some basic principals to follow.

Thanks

 

[2thm8kr]

Have you checked to make sure the mixer is pulling full vacuum?

 

[H.Ross]

We use GC or Zhermack, we sterilise the impressions but we never keep them mist prior to pour. we never used mixers for stone (its better if we do). we use a vibrating machine and results been always good.

 

[ps2thtec]

I've been using this old broken hollenback. Rubberwheeled one end flat and the other to a point.
Carefully using it to flow stone around margins first. Especially on shoulders a bubble wants to appear.
By gently flowing with this your die problem should be solved.

Bubbles on cusp tips are from being sloppy not letting the stone flow though the imp.

I also do not spray imp wet after disinfecting.

 

[GarryB]

As said above, it sounds like a lack of vacuum when mixing.

 

[CoolHandLuke]

dont BLAST the impression with air to dry it, and don't let debubblizer pool in valleys. lightly blow to let residual debubblizer drain from the impression and pour straight away.

place the impression on the vibrator ensuring no squeezing, and ensuring the vibration is not so strong as to make stone fly all over the place. just enough vibration as to let the stone flow naturally.

ensure waterowder is the correct ratio (use a wasserman, people they arent expensive) and mix is air-free.

 

[RileyS]

Mixer vacuum is good. When I was pouring everything I always misted with de-bubb and never had bubbles. We'll try some today without today.
Thanks for all the ideas!

 

[rkm rdt]

Check and replace your o rings or you'll have

 

[charles007]

Bubbles probably came from pouring to fast, watch the stone flow to the bottom and up the walls of the prep/impression. Wet impression/debubblizer
can cause many problems including bubbles plus you will notice your die stone being softer.
Riley, I had that same bubble problem years ago when I used HS student pouring my models and delivering cases. This problem never went away
completely until I switched to FujiRock. For some reason FujiRock seems to be a smoother mix and we rarely see bubbles since switching.
fyi I originally changed to Fuji because of it being a low expansion die stone at that time. Once I switched I couldn't help but notice bubbles were rare to see.....
Riley, if you decide to try New FujiRock, order the smaller 3kg to see if it helps. I use Alabaster Ivory, regular set. Pastel Yellow is another pleasing color in the FJ Rock EP..

Edit: if you using the older model mixer replace o rings like rkm said and the veins.... what ever
there called in the unit...Quick and easy to replace and cheap to buy.. This will increase the vac

 

[Makes Dentures]

.... and get a good light so you can see what you are doing!!

 

[user name]

Its not the materials fault. Get his eyes checked and then start docking him per bubble.

 

[Affinity]

no debubblizer. Make sure disinfectant is thoroughly rinsed and air dried. Most diestones are thixotropic and dont need sprayed. Dont have that problem with zhermack or fuji.

 

[JKraver]

Tech may not care... It is probably too fast, or too lazy take your pick. If there are no bubbles in your vac mix then there shouldn't be bubbles in your pour. He may be letting water poor or over vibrating.

 

[Jenners]

Any time I've had to teach someone to pour, the biggest problems came from them dumping the stone in too fast. I always tell them to watch the stone flow from one end to the other.... if you don't see what's happening, then there's probably going to be an issue. I don't use debubblizer. After cleaning the impressions, I give them a good shake to remove pools of water and go from there.

 

[capickettcdt]

Most all of you are on the mark when it comes to general principles. Changing the stone to GC or Zhermack is not the answer as it is not the same type of stone. Notice they said LEAN Rock. This material has a technique to follow for multiple models. If you have not reviewed that technique with the technicians at Whip Mix and are pouring one model fully at a time, then the next and next... then you are going to have some issues. If you are using a de-bub then it should be dried before pouring regardless of any technicians success at not following the rules (the water in the mix re-constitutes the chemistry in the de-bub).
LEAN rock is a fast setting stone which can be pulled from the impression in 15 minutes and reaches 85% of its total expansion of 0.08 or 0.20 (two version) in one hour. Learning to work with it in a multiple pour setting can be difficult for some tech's who believe that "they know what they are doing"...it generally starts with "I've been doing this for....years" or "I know how it feels".
Rather than explain the technique here, give us a call and we'll tell you all about it. 800-626-5651