TIPS ON DISPENSING

[coffee joe]

I wasn't going to say anything myself Chip! But, I guess these younguns don't recall the days when frames were shipped as a front and temples and you had to mitre most of the temples when you assembled them.
Opticianry 101

i ain't old. i just like reading old text books with all the info that was omitted from the new ones because it was deemed obsolete.

[midohioeye]

That reminds me of the good old days when you hired someone new to the industry. That was part of their training, putting frames together and making sure they are bench aligned. After that task was completed we would send them across town for either the bucket of optical centers or the lens stretcher.
Ahh yes, the good old days. :cheers:

[kbfast]

most anything that is gold filled will have a quality mark on it ... 14k - 18k etc. If your stuff doesn't have any such markings I advise you to take it to a jeweler. A jeweler is going to have the solutions to be able to tell if it is plated. You could get the same solutions ... but why would you? (we are talking acids here)

[coffee joe]

(we are talking acids here)

ar stripper is acid. if you don't dilute it enough it'll take your skin right off.

[Chris Ryser]

ar stripper is acid. if you don't dilute it enough it'll take your skin right off.

Actually it is much worse. It is not just acid, it is hydrofluoric acid, the worst among acids. It actually travels through your skin anto the bones and starts some non reversible reactions.

Hydrofluoric acid is a solution of hydrogen fluoride in water. It is a weak acid. Hydrogen fluoride, often in the aqueous form as hydrofluoric acid, is a valued source of fluorine, being the precursor to numerous pharmaceuticals (e.g., Prozac), diverse polymers (e.g., Teflon), and most other synthetic materials that contain fluorine. Hydrofluoric acid is best known to the public for its ability to dissolve glass by reacting with SiO2, the major component of most glasses. This property has been known since the 17th century, even before hydrofluoric acid ...........................




Hydrofluoric acid is corrosive and a contact poison. It should be handled with extreme care, beyond that accorded to other mineral acids, in part because of its low dissociation constant, which allows HF to penetrate tissue more quickly. Symptoms of exposure to hydrofluoric acid may not be immediately evident. HF interferes with nerve function and burns may not initially be painful. Accidental exposures can go unnoticed, delaying treatment and increasing the extent and seriousness of the injury.[4] HF is known to etch bone, and since it penetrates the skin it can weaken bones without destroying the skin.[5]
HF chemical burns can be treated with a water wash and 2.5% calcium gluconate gel[6][7][8] or special rinsing solutions.[9][10]

If you use AR strippers look out for the safest possible versions on the market

[coffee joe]

also, it releases hydrogen on contact with most metals, potentially creating an explosion hazard. it can also scar you cornea on contact. and i bet most of you were just dipping your bare hands in your bpi ar dry thinking "this doesn't hurt." so since this is the tips thread, here's the tip; follow the safety precautions that come with it and be careful.

--edit--

btw, the reference to "weak acid" in the post above is a technical chemistry term, and doesn't exactly mean what it sounds like. don't let it lull you into a false since of security. improper handling of HF can lead to severe injury.

here is the msds

[Chris Ryser]

btw, the reference to "weak acid" in the post above is a technical chemistry term, and doesn't exactly mean what it sounds like. don't let it lull you into a false since of security. improper handling of HF can lead to severe injury.

Actually all those that purchase the dry powder, which is Hydrogen fluoride from suppliers end up with a solution of 100% HF acid upon adding water.

Hydrogen fluoride is generated upon combustion of many fluorine-containing compounds such as products containing Viton and Teflon parts
.
Hydrogen fluoride converts immediately to hydrofluoric acid upon contact with liquid water.

When you purchase a finished solution you will get the ingredients in measured parts mixed into the solution............therefore above statement is totally false and misleading.

Compared to the use of Hydrogen fluoride which becomes 100& % HF acid an AR stripper mix does contain a total of 9,5% of 2 acids by volume plus 20% of a solvent and the balance is water.

Therefore the use of a stripper which works as well or better with 10x less acids by volume, and for sure is a lot safer to use than mentioned in above post.

[coffee joe]

When you purchase a finished solution you will get the ingredients in measured parts mixed into the solution............therefore above statement is totally false and misleading.[/b]

the part of the post you quoted refers to the term 'weak acid'. i was simply pointing out that weak acid is chemistry jargon that can be misleading. some 'strong acids' aren't very corrosive while some 'weak acids' are very corrosive. 'weak' and 'strong' refers to the release of hydrogen in water. what about that is miss leading. HF acid is a 'weak' acid that is highly corrosive.

also the concentration of a chemical diluted in water would depend on the ratios used. it's not just 100% no mater how you mix it. i forget off the top of my head what the resultant concentration of HF acid is when mixed according to bpi's instructions but i have figured it up and have the notes in my lab and know it is not 100%. it's actually closer to something like 20% or so.

as far as i know nothing in my previous post was false, and if any of it was misleading, i can only hope to communicate more clearly in the future. what in particular is your point of contention?

-- edit --

from wikipedia:

A weak acid is an acid that does not completely donate all of its hydrogens when dissolved in water. These acids have higher pKa compared to strong acids, which release all of their hydrogens when dissolved in water.
While strong acids are generally assumed to be the most corrosive, this is not always true. The carborane superacid (H(CHB11Cl11), which is one million times stronger than sulfuric acid, is entirely non-corrosive, whereas the weak acid hydrofluoric acid (HF) is extremely corrosive and can dissolve, among other things, glass and all metals except iridium.

also from wikipedia:

Mass-volume percentage Mass-volume percentage, (sometimes referred to as weight-volume percentage or percent weight per volume and often abbreviated as % m/v or % w/v) describes the mass of the solute in g per 100 mL of the resulting solution. Mass-volume percentage is often used for solutions made from a solid solute dissolved in a liquid. For example, a 40% w/v sugar solution contains 40 g of sugar per 100 mL of resulting solution.

[pechsp]

For people that have problems working with nylon cord frames we have a an inexpensive tool that we use at our lab. When we get a box of paper that outside usually comes with the yellow "ribbons" wrapped around it. All we do is cut them in to about 4 inch pieces and cut one end at an angle. The angeled edge works great for getting in between the cord and the lens!

[For-Life]

For people that have problems working with nylon cord frames we have a an inexpensive tool that we use at our lab. When we get a box of paper that outside usually comes with the yellow "ribbons" wrapped around it. All we do is cut them in to about 4 inch pieces and cut one end at an angle. The angeled edge works great for getting in between the cord and the lens!

agreed

that is all I used to use

[kbfast]

Dr Laura is now the specialist who switched from the sex to the optical trade. Toilet bowl cleaner to work on lenses.

I bet you still tint your lenses in your kitchen with WRIT DYES for home fabric tinting in a saucepan on your kitchen stove.

:bbg: :D :bbg:

Naw ... I just stick a mason jar down into my salt pan :finger: ... (read sarcasm)

[kbfast]

[no text]

[Chris Ryser]

Where do you buy hot candle wax ? [no text]

What the heck you want to do with hot candle wax ????????

In all these years in the optical field I learned that you can remove hair with it. :hammer:

[kbfast]

Check the post I replied to ... just my strange sense of humor ... hot candle wax ... where do you buy it ... you don't you just light a candle ... anyway, I believe that the tip was you could use a drip of hot candle wax to expand the eyewire around a stubborn, broken screw to aid in its removal.

[chip anderson]

Today I had two jobs with the small reducing socket washers that go inside the temple before you can insert the temple screw. The ones you can't get replacement washers for and if assembled without same the temple will always have play. In the past I have lost a bunch of these, mangled a few more and wrestled with the infernal things endlessly trying to get all the pieces in place and hold them there while I got the screw in.

I just happend to have my paint out and coated (glued) the washers in the temple before attempting assembly. Worked like a charm and too seconds.. If you don't have any monomer~polymer mixture handy I suppose any glue or even grease would hold them in place just fine.

Chip

[Metronome]

Today I had two jobs with the small reducing socket washers that go inside the temple before you can insert the temple screw. The ones you can't get replacement washers for and if assembled without same the temple will always have play. In the past I have lost a bunch of these, mangled a few more and wrestled with the infernal things endlessly trying to get all the pieces in place and hold them there while I got the screw in.

I just happend to have my paint out and coated (glued) the washers in the temple before attempting assembly. Worked like a charm and too seconds.. If you don't have any monomer~polymer mixture handy I suppose any glue or even grease would hold them in place just fine.

Chip

Delete.

[Metronome]

Silhoutte are the easiest drill mounts, they usually take me less them 15 mins to get the whole thing done. Did any body ever worked with the Takumi (TO-9845) 3 pcs mount w/clip. They're turely nightmares for me.
:hammer:

Delete.

[Metronome]

Additon....................If working on polycarbonate lenses stay away from using solvents which promote crazing.

Delete.

[chip anderson]

Andro:

I had this explained to me by a rep: You can't have titanium to titanium bearing on itself in a moving surface. Hense the damn little washers. Would be less intolerable if they supplied us with about 50 washers now and then. But in anyevent and whether this is true or not (don't know if the hinges on other titanium products are titanium or not) this is why the washers are there.

Chip

[harry a saake]

quite often high cylinders will read as there off axis when they are not

one reason is there maybe too much pressure on the lens, especially with your wire frames, loosen the screw a few turns and take another look, if the lens now reads on axis, simply take a little off the size of the lens with a handstone.

other reason is the lens is not sitting in a proper position in your focimeter, any high cylinder(3 and above) are sensitive to the angle that the lens is sitting at due to the pressure from the lens stop. you can usually notice this by moving the lens table up and down. if you look at the lens from the side of the focimeter, you will quite often see that it may be sitting on an angle as much as 20 degrees. you need to look at the lens while in the focimeter while its on the same angle as worn by the patient

[harry a saake]

quite often i have noticed that screws come out of eyewires because of the type and length of the screw, even when it is the correct thread.

these replacement screws that have a long shank and maybe just the bottom 1 mm is threaded are great with big long barrels.

however when put into a frame with a smaller barrels, your not getting as much thread in the barrel as you could be. it will appear to hold at first, but usually does not last long.

solution, use a screw that is threaded all the way to the top, or use a snap and tap, PS, you can buy the ones that are threaded all the way to the top just as cheap as the ones that are only partially threaded.

If you are having a problem getting the screw into the first barrel, simply take a reamer or broach and make the hole slightly larger

[Miss Nancy]

I always specify 2mm min edge on plus (or lowwww minus) for grooved rimless. Don't have a problem with chipping during adjustment or the life of the lenses. If noticed, most patients don't have a problem when explained. Beats having to replace lenses repeatedly whenever an adjustment is required .

[stellarindia01]

It is really a great idea! One thing I have seen some new people fail to do when adjusting a frame with glass lenses is not loosen the eyewire screw.

Lisa11

[rdcoach5]

I believe it was Mike Disanto who gave us this approximation for edge thickness when choosing eyesize. For each size (2mm) bigger, the edge thickness increases by 8% plus 2x power.

[JerryR]

Temporary repair for broken spring hinges. Slip a piece of heat shrink tubing over the temple, bring the temple and endpiece together, slide the tubing over the temple and the endpiece and heat, the material shrinks around the temple and endpiece and holds the two together.