Boxed Vs Unboxed

[araucaria]

Is there a significant difference between boxed imp' models and unboxed imp' models ? Is anyone aware of worthwhile reading material on the subject ?
Is the technique just a throwback to the days before modern model trimmers, is it to allow unskilled operators to produce reliable working models, or is there some science to back up the claims that the technique is worth following?
Thoughts/opinions?
popcorn

 

[droberts]

Boxed impressions are more dense. Any air/water will raise to the top in the boxed impression not harming the pour / final cast. You'll have less chances of voids in the cast by boxing them. Some prefer to pour the impression and not flip it on to a heap of stone, then doing a second pour for the base. I prefer not to, due the cast at can separate from each other if heat is applied or getting duplicate cast as well. Cast look more professional in my opinion all of one pour.

 

[Paul Drufva]

I very seldom bother to box an impression. Some die stones are quite runny,fuji rock comes to mind, and if you are using a stone like that, I would sugest boxing the impression to prevent the stone from flowing where you do not need it. I use a stone that can be stacked, and if poured carefully can be poured into any impression without boxing. I find it much too tedious to box an impression. Always measure your powder and liquid and mix with a vacuum mixer. This will ensure a dense, strong cast with the correct expansion.

 

[CloudPeakDL]

Well I looked for my old thread about this subject and can't locate it.
Anyway and easy way to box and pour is to use alginate and those plastic ziplock/glad bowls, they come in many sizes so use the smallest the impression will fit in. Put the impression in the bowl supported with clay so its level - metal trays can be stuck through a slit in the side. mix alginate in a 2/1 water/powder ratio. pour in around the impression let it set up and use an instrament of choice to trim a land area as needed. The nice thing is the alginate will pull out of the impression if you make a mess. Mix up your stone and pour; do not go past the indent at the top of the bowl or you will have to cut the bowl to get it out. When the stone is set just push on the bottom of the bowl and the whole thing pops out, remove the alginate. No rope wax no fuss.

 

[paulg100]

"Some die stones are quite runny,fuji rock comes to mind"

You are not weighing and measuring your powder/water ratio if that is the case.

Use the correct ratios and it is very stakable stright after vacuume mixing. Its one of the reasons i use it. Fuji stones are the best on the market in my opinion.

The expection is the white colour which is runny for some reason.

100g powder : 20ml Water, mixed under vacuume 45 seconds





Then into a pressure vessel at 1bar to set, without slumping.

This is think enough for my needs.

 

[JohnWilson]

We use Fujirock exclusively in our fixed department and we don't think its runny at all. We use all whipmix foundation equipment that weighs and dispenses and mixes everything consistently EVERY TIME to proper ratio/spec

Its a fantastic product when used properly.

 

[kcdt]

Well I looked for my old thread about this subject and can't locate it.
Anyway and easy way to box and pour is to use alginate and those plastic ziplock/glad bowls, they come in many sizes so use the smallest the impression will fit in. Put the impression in the bowl supported with clay so its level - metal trays can be stuck through a slit in the side. mix alginate in a 2/1 water/powder ratio. pour in around the impression let it set up and use an instrament of choice to trim a land area as needed. The nice thing is the alginate will pull out of the impression if you make a mess. Mix up your stone and pour; do not go past the indent at the top of the bowl or you will have to cut the bowl to get it out. When the stone is set just push on the bottom of the bowl and the whole thing pops out, remove the alginate. No rope wax no fuss.

When you settle the impression in, if you pull some of the alginate up the side of the bowl, it will make it easier to just pop the model out.
Ziplock bowls are great- I also use them as cheap duplicating flasks...

 

[Paul Drufva]

I weigh my powder and measure my liquid. I Have not used fujirock in over ten years. As I recall it was quite runny. Perhaps I am mistaken. My point was that it is not necessary to box if your stone does not run all over the place. Anyone disagree?

 

[lcmlabforum]

Part of the advantage for boxing is having a predictable, strong 'land area' to wax the
border of a removable prosthesis to. This way you control the depth of the vestibule and can pack predictably the border molding your DDS took all the time to preserve.
I box as often as I can, using alginate (I know, it is expensive) or plaster and pumice mix.
LCM

 

[denturist-student]

When I make a model I place a small amount of sticky wax about 3 mils above the border on the impression....Then I will outline the impression with periphery wax and lute it too the impression...I vacuuspat and fill over the borders right onto the periphery wax bead...Then I place some nodules for retension on the vacuuspatted material....Then after drying for a bit invert and settle onto a patty of quickly setting gypsum..I think it is called a modified straight inversion.that saves a lot of time boxing and beading and I get good borders and a good landing area....Also advocate use of the model formers available for keeping the paddy upright...They are cheap and make a good clean base....I learned this recently in school....We don't box anything any more because of time constraints and the above technique produces good results.
Second option is to support the cast with some play dough and box around it after periphery wax....Easy to form and can pour in one pour and the playdough is reuseable. Don't really need periphery wax with playdough.... from a NEWBIE.

 

[denturist-student]

Another idea when vacuuspatting si to get one of the new rubber bowls from Whipmix...I purchased one of each...They have two sizes..Save time cleaning and don't make a mess...As well can focus on the impression model rather than cleaning the vaccuspat cyklinder before it sets up....only have to clean the paddles and then the bowls later....Taker care...from a NEWBIE