No registration or passwords; no pop-up ads -- just aloha, fun, & answers.
(as an eBay Partner & Amazon Affiliate earns from qualifying purchases).
Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Advertise
 
Help
Wanted
Current
Q&A's
Site 🔍
Search
pub  Where the
world gathers for metal finishing
Q&As since 1989



-----

Chemically Polishing Fused Silica




Q. Hi Everyone,

This is my first post here. This actually has to do with glass finishing but when I use Google this site shows up a bunch (especially when it comes to the use of Ammonium Bi-fluoride). Hopefully this question is appropriate for the forum.

I am trying to not only etch but chemically polish fused silica with an ABF solution. The solution is saturated at 95 deg c and also has a small amount of surfactant added (FC-99). So far I can target my removal just fine but my results in terms of wanting a smooth finish are lacking. The surface is still fairly rough in the range of 30µ inch rms, where I want to be <5.

Here is the curious thing, If I let the solution evaporate a little I start to get a very strange effect. the edges of the part start to clear up dramatically (and measure ~3µ inch rms) but you get more than ~1.5 mm from any edge and there is a very cloudy surface left that is ~35µinch rms. The parts look horrible when this happens but there seems to be a glimmer of hope if I could just get the whole part to look like the edges!

Has anyone out there seen this before? Any suggestions would be greatly appreciated!

William Funk
Manufacturing engineer - Boulder, Colorado, USA
2007



2007

A. Chemical polishing solutions form a somewhat viscous surface layer that acts as a diffusion barrier between the substrate and the reactant. This limits the reaction more in low spots than in high. Add something to thicken the solution. Or perhaps add ABF to a pickling gel for stainless steel welds.

Ken Vlach [deceased]
- Goleta, California

contributor of the year Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.





(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact  -  Privacy Policy  -  ©1995-2024 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"