| |
Frequently Asked Questions about Alginate |
| |
|
| |
What is alginate? |
| |
What's the difference between dental alginate and prosthetic-grade alginate? |
| |
Why should I use Accu-Cast alginate over all the others? |
| |
What do the numbers in the names mean? |
| |
What's the best way to mix alginate? |
| |
Is alginate reusable? |
| |
Is alginate safe? |
| |
How can Accu-Cast sell alginate so inexpensively? |
| |
What countries can you ship to? |
| |
How do I get MSDS sheets for Accu-Cast alginates? |
| |
|
| |
Technical Articles |
| |
Why is setting time affected by water temperature? |
| |
|
| |
|
| |
|
| |
|
| |
Q: What is alginate?
|
| |
A: Alginate is a powder made of between 5 and 15 chemicals compounds, including "alginic acid". Alginic acid is a powder derived from seaweed that consists of long, chain-like molecules known as polymers. When water is added to the alginate powder and mixed, the result is a thick liquid. Depending on how much water is added, the consistency can range between the thickness of pancake batter and that of cream cheese. Certain applications require a thicker mix and some require a thinner one. |
| |
On the molecular level, calcium ions (individual atoms) are freed from the calcium donor, Calcium Sulfate, and they act like molecular glue. They glue the alginic acid polymers to each other in a three dimensional matrix similar to a sponge. The other chemicals in the mix affect mixing properties, setting time and final set properties. |
| |
This sponge-like structure can hold water for a time, but the water wil eventually dry out of the alginate matrix and it will shrink in direct proportion to the percentage of the initial water that has exited. |
| |
Back to Top |
| |
|
| |
Q. What's the difference between dental alginate and prosthetic-grade alginate?
|
| |
A. Dental alginate is designed to take a relatively small impression in a persons mouth within the confines of a fairly stiff container (the dental tray). Being in the mouth, the alginate should be fairly thick so it won't run down the patient's throat and gag them. It also needs to set pretty quickly because there will less time for the patient to gag. Being in the tray means that the alginate doesn't need to be that strong when set because it won't be subjected to great stress. Also, the inside of the mouth can usually tolerate cold water temperatures for a couple of minutes so warm water temperature isn't necessary. |
| |
Prosthetic-Grade alginate on the other hand often is mixed and used in large quantities so the stresses on it can be much greater. Accu-Cast prosthetic alginates use a higher percentage of alginic acid (the actual gelling agent) to make the final set material tougher. It is often used against a person's skin where cold water temperatures can be quite uncomfortable. Accu-Cast prosthetic alginates are formulated to be mixed with warmer water when necessary to make the subject more comfortable. Also, a quick setting time would be very inappropriate for large projects where it can take several minutes to mix and apply the alginate to the subject. Accu-Cast was a pioneer in the development of long setting alginates for prosthetic use. |
| |
Back to Top |
| |
|
| |
Q. Why should I use Accu-Cast Alginate over all the others?
|
| |
A. Glad you asked. There are many fine alginate products on the market today. |
| |
Dental alginates are designed to take very small impressions of teeth while being supported by a rigid dental tray. Dental alginates are designed to set very quickly to keep patients from gagging and to help the efficiency of the workflow of the dental office. Consequently, dental alginates are very poor at anything but the smallest lifecasting projects. |
| |
Several other companies make very good prosthetic grade alginates. Most companies make a regular set and a slow set. That's the choice they offer you. Accu-Cast makes a variety of alginate materials, each fine tuned for very specific applications. |
| |
Also, the Accu-Cast business model of selling product directly to our customers allows us to keep our prices very low. Alginate really doesn't cost very much to make. Most of the cost you pay goes to the distributor markup. If you need the convenience of a distributor, then that's a good tradeoff. If you don't, then its not. |
| |
Finally, Accu-Cast has been making prosthetic-grade alginates longer than almost everyone. We really know our subject and we strive to help our customers every step of the way. |
| |
Back to Top |
| |
|
| |
Q. What do the numbers in the names mean?
|
| |
A. The numerical component of the Accu-Cast product names refers to a setting time/water temperature ratio. For example, Accu-Cast 570-PGV sets in 5 minutes when mixed with 70°F water, 880 sets in 8 minutes with 80°F water. |
| |
Back to Top |
| |
|
| |
Q. What's the best way to mix alginate?
|
| |
A. Well, that really depends on how much you're mixing. See "Alginate Mixing" |
| |
For small quantities (up to 2 ounces), we recommend mixing with a small spatula in a bowl. The type of spatula we're talking about is a wide, flat bladed knife sort of like you'd use to put frosting on a cake. If you don't have one handy, a tongue depressor or even a popsicle stick will do. We have the bowls and spatulas for sale Here. |
| |
For quantities larger than 2 ounces but under about a pound and a half, a standard metal kitchen whisk is really great. A whisk is easier if you mix in a wide, round bottomed bowl. Put in your powder, then your water, stir for about 30 seconds, then whisk away. You'll see it smooth out pretty quickly. We have Whisks for sale Here. |
| |
For over about a pound, consider using a power mixer. This is an electic drill with a "paint-mixer" attachment on it. The paint mixer attachments are available at your local home improvement or hardware store. The one that looks like a little propellor with a ring around it works much better than the one that looks like a black plastic hamster wheel. Put your powder and water into a plastic bucket (1 or 5 gallon, depending on how much you're mixing), start off slowly and increase the drill speed when all the powder is wet. We have Jiffy Mixers for sale Here. |
| |
To avoid mixing in lots of bubbles, look at how the flow of the alginate mix is moving in the bucket. You DON"T want it being sucked down the shaft of the paint mixer attachment. If it is, then reverse your drill. This is a very fast and efficient way to mix alginate and can be done with very large quantities. |
| |
Back to Top |
| |
|
| |
Q. Is alginate reusable?
|
| |
A. Not for moldmaking. Alginate is an irreversible hydrocolloid. The irreversible reaction (the cross-linking of the polymer chains) cannot be undone. Used alginate isn't toxic and can be thrown into your normal garbage can legally and conscience free. |
| |
Most of the time, an alginate mold will have to be destroyed when unmolding your finished casting. In rare instances when the mold is still intact, it can be repoured, but the resulting cast will probably not be quite as big as the first one due to shrinkage (not the George Costanza type). |
| |
Back to Top |
| |
|
| |
Q. Is alginate safe?
|
| |
A. Yes. Alginate has been used in dental offices in people's mouths for over 50 years. The only problem with alginate has been the potential hazard of chronically (over years and years) breathing the dust of the dry powder. Accu-Cast has a "dustless" formula that virtually eliminates this hazard. Since its not a good idea to breath any kind of dust, we do recommend a "Nuisance Dust Mask" when mixing ours or anybody else's alginate. |
| |
That having been said, it is still not recommended to get alginate in people's eyes or to get large amounts on their clothes. When doing a face or head casting, it is important to watch the subject's nostrils to make sure that they have an unobstructed airway throughout the procedure. Even if it does get up their nose, they can still open their mouth to breath. It may ruin the mold, but nothing more serious than that. |
| |
Back to Top |
| |
|
| |
Q. How can Accu-Cast sell alginate so inexpensively?
|
| |
A. Most products are sold through suppliers or distributors. We have some distributors, but they sell our products because they provide a convenience for their local customers that they can't get from us. |
| |
Distributors are businesses that must make their living by marking up the prices of the products they sell. |
| |
Our business model is B to C (Business to Customer) which means that there isn't a markup in between. We sell alginate at the prices we do because we can. Don't worry about us, we're still making a few dollars, but you save some dollars purchasing from us as well. We think it works out pretty well. |
| |
Back to Top |
| |
|
| |
Q. What countries can you ship to?
|
| |
A. Most of our business is with customers in the US and Canada. We can ship to any country. The problem is shipping costs. We normally ship by UPS and sending 5 pounds to England or New Zealand is stupidly expensive and usually more than makes up for our inexpensive price. The US Postal Service will let us ship 5 pounds anywhere in the world for $39.50. We do have distributors abroad, but customers complain of their high prices. That's because THEY already paid shipping and customs charges into your country. Sorry, but until the cost of shipping goes down, these are the realities. |
| |
For larger orders, the "per pound" shipping cost can go down dramatically. For Ocean Freight, the cheapest method, the minimum space you pay for is one cubic meter. If you place an order that takes up a cubic meter, then the shipping will be pretty reasonable, but that's a lot of alginate. Maybe YOU'D like to become a distributor in your country!!! |
| |
Back to Top |
| |
|
| |
|
| |
|
