N.P. etching

[stt672]

I received a maryland bridge back for a re etch over the weekend. This had been in the mouth for 7 months. Wings had no cement or enamel attached to the wings at all. I usually give these a sandblast and acid etch of about 45 min with the ADS metal etching gel. I cleaned wings and gave them a etch of about 1 hour. The gel on the wings bubbled, turned green/black nothing unusual but after rinsing it looked as if it had not been etched at all. I used Talladium Star. What are you using to etch. I have used ADS for many years with good results, the kit I got expires 1-13. Totally stumped why I can't get an etch, other options other than ADS? They say if you do Maryland Bridges do about 100 then move a 1000 miles away, I'm thinking this might be a good idea. [ Yes I'm positive this is NP metal]
Thanks.

Scott

 

[Tom Moore]

Air dry the wings and put a small drop of water on the end of something with a sharp point like a BP #25. Touch the drop of water to edge of the wing. If the water wicks across the alloy wing and spreads its etched and if it stays in a ball its not. If you take a ruff diamond and lightly brush the surface of the area to be etched you put in some extra irregularities and it increases the etching surface a little. Then if it comes back with or without bonding material attached you can be sure the surface was contaminated in a place where you had no control.

 

[PDC]

Scott, a lot of times you have to take a pointed instrument and sort of stir the acid around on the wings after they turn that funky dark green color. The gas bubbles created from the etching process will cause the gel to sort of lift away and lose contact with the surface of the wings. Popping those little bubbles will put in back in contact with the surface. I usually etch the wings a couple of times. I place it in the ultrasonic in some distilled water after the first go-round and then add more acid gel. That should solve your problem.

 

[stt672]

Thanks Tom, PDC. But do guy's use the ADS gel or something else?

 

[TheLabGuy]

That's what I use

 

[PDC]

I use ADS gel, but only on Rex III. I haven't heard of that Talladium alloy.

 

[sidesh0wb0b]

i use TriDynamics etching gel. if im not mistaken it works faster than 45m-1hr. if i recall without seeing the bottle, 20-30min
and i agree with Tom on the steps to take above

also, RUNNNNNNNNNNN dont walk from maryland bridges haha

 

[hammerhead]

I received a maryland bridge back for a re etch over the weekend. This had been in the mouth for 7 months. Wings had no cement or enamel attached to the wings at all. I usually give these a sandblast and acid etch of about 45 min with the ADS metal etching gel. I cleaned wings and gave them a etch of about 1 hour. The gel on the wings bubbled, turned green/black nothing unusual but after rinsing it looked as if it had not been etched at all. I used Talladium Star. What are you using to etch. I have used ADS for many years with good results, the kit I got expires 1-13. Totally stumped why I can't get an etch, other options other than ADS? They say if you do Maryland Bridges do about 100 then move a 1000 miles away, I'm thinking this might be a good idea. [ Yes I'm positive this is NP metal]
Thanks.

Scott

Try cojet< it works great for those nasty things and any type of crown with a short vertical