Chemically inert bonding of glass to glass? - Page 1
Forum section: electronics / general

author: ChristofferB
author_rank: Frequent Contributor
timestamp: June 12, 2018, 08:03:58 pm
content: So, this isn't really electronics related but i'm doing some projects with electronic detection in thin-layer chromatography. Anyone know a good way to bond sheets of glass together? It needs to be inert to solvents, so glues, resins and the like are a no-go. It also needs to be watertight.I'm thinking sodium silicate solution "water glass" - since it hardens into a cement of sorts, and is chemically similar to glass.I guess one could just clamp the sheets to be bonded and heat in a furnace until they sorta sinter together, but i don't have the setup for that.Anyone have any experience on the matter?thanks!

author: Kleinstein
author_rank: Super Contributor
timestamp: June 12, 2018, 08:24:50 pm
content: By itself sodium silicate will not bond or solidify. It still needs a way to get rid of the water. Usually glass does not absorb a lot of water.The trick with cement/concrete is that it is a kind of 2 (or 3) component mixture that will react without requiring water or something else to evaporate. Actually cement bonds really well to glass - so using a suitable mixture of cement maybe and water might be a possible way. Too much water would likely make is less water tight.

author: MadTux
author_rank: Frequent Contributor
timestamp: June 12, 2018, 08:41:33 pm
content: Lead glass, applyperhaps as powder/paste and then fuse in a furnace? As far as I know, some lead glasses soften at as low as 300°C.Was also used to bond ceramic packages (EPROM, early UV eraseable microcontrollers) together , the white stuff where the leads come out, between the top part with window and the bottom ceramic carrier.

author: Marco
author_rank: Super Contributor
timestamp: June 12, 2018, 09:06:39 pm
content: Isn't cement generally porous?You could try asking a company like Schott for a sample quantity of solder glass/frit and if they have some help for prototype fabrication with a torch or kiln.

author: langwadt
author_rank: Super Contributor
timestamp: June 12, 2018, 09:07:53 pm
content: Quote from: ChristofferB on June 12, 2018, 08:03:58 pmyou just need to bond them together at the edges?

author: ChristofferB
author_rank: Frequent Contributor
timestamp: June 12, 2018, 09:15:35 pm
content: Lead glass isn't really an option, unfortunately. Could one use sodium silicate and then bake it to cure? Else, is there a brand/recipe of/for cement that could work well?

author: mathsquid
author_rank: Frequent Contributor
timestamp: June 12, 2018, 09:34:02 pm
content: I think this is mainly used for optical-quality lenses, but there's a chance that this may be helpful:https://en.wikipedia.org/wiki/Optical_contact_bondingHere's a video showing someone doing it.https://youtu.be/se3K_MWR488

author: tpowell1830
author_rank: Frequent Contributor
timestamp: June 12, 2018, 09:48:37 pm
content: Quote from: mathsquid on June 12, 2018, 09:34:02 pmThe glass in the video is highly ground and polished for flatness. Real world panes of glass are not that flat. They will require grinding and polishing in special machines. The OP could go to a specialty glass company and possibly find a solution.Hope this helps...

author: ChristofferB
author_rank: Frequent Contributor
timestamp: June 12, 2018, 09:49:15 pm
content: Quote from: ChristofferB on June 12, 2018, 09:15:35 pmYep. just need to be able to make a sandwich of two square pieces of glass with two narrow strips as risers along the edges.

author: LaserSteve
author_rank: Super Contributor
timestamp: June 12, 2018, 11:45:01 pm
content: Anodic Bonding or Nanofoil Bonding are options and require less polishing then optical contacting.

author: LaserSteve
author_rank: Super Contributor
timestamp: June 12, 2018, 11:51:37 pm
content: Saueriesen, Aramco, and Zircar among others make fast, inert, water based cements. Considering I can Anodic bond or sometimes contact seal microscope slides out of the box with just a plasma cleaning, this is not that difficult. Although I really like laser initiated or electrically initiated nanofoils.Masterbond and dental suppliers make UV initiated glues that are inert, and Thorlabs and Edmund also sell UV initiated cements, some of which are based on fish proteins that can be very inert. Steve

author: rdl
author_rank: Super Contributor
timestamp: June 13, 2018, 03:04:13 am
content: What about the silicone glue that holds aquariums together? Once cured it's inert and relatively solvent resistant, though maybe out gas during cure is a problem. What type of solvents are you using? Otherwise I think the UV curable adhesives used for optical (or maybe dental) use are worth looking at.

author: David Hess
author_rank: Super Contributor
timestamp: June 13, 2018, 04:25:33 am
content: Solder glass:http://imajeenyus.com/workshop/20110321_solder_glass/index.shtml

author: calexanian
author_rank: Super Contributor
timestamp: June 13, 2018, 04:54:43 am
content: Quote from: David Hess on June 13, 2018, 04:25:33 amSolder glass is hard to get in small quantities, but would be a good option provided it has an appropriate CoE.Specifically what kind of glass are you wanting to bond? Pyrex/Duran, Soda Lime, Flint, quartz, etc.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 13, 2018, 05:18:10 am
content: @ChristofferAre you trying to make a chamber for development? Rectangular glass tubing is available. If you only want 3 sides, that can be cut from a tube (carefully). Here's one source of such tubing:https://www.vitrocom.com/categories/view/20/Rectangle-Glass-Tubing/I would look into how optical cuvettes are fused together.

author: langwadt
author_rank: Super Contributor
timestamp: June 13, 2018, 08:24:43 am
content: Quote from: ChristofferB on June 12, 2018, 09:49:15 pmhttp://randombytes.net/indium_seals.html

author: ChristofferB
author_rank: Frequent Contributor
timestamp: June 13, 2018, 07:28:23 pm
content: Quote from: jpanhalt on June 13, 2018, 05:18:10 amnow rectangular tubing IS interesting, but not exactly what I need: i need to bond two strips (2-3mm) of glass to two sides of plate, which can be placed onto a glass TLC plate, producing a VERY narrow chamber.Quote from: rdl on June 13, 2018, 03:04:13 amIt's going to have to withstand almost any imaginable solvent to be of any use; acetone, ethyl acetate, heptane, toluene, propanol, and xylenes at the very least, that's why i'm reluctant to try silicone based stuff. Since this is for analytical use, anything leeching out or dissolving will drastically raise the noise floor. Silicone cement might actually be fairly useful, worth a try atleast.I'd prefer to avoid exotic types of glass, as it'd be nice (and economic!) to be able to use standard window-pane glass.thanks all for the ideas!

author: jpanhalt
author_rank: Super Contributor
timestamp: June 13, 2018, 09:12:16 pm
content: Why do you come here and ask for help when you are not willing to describe what you want to do? I have done 1000's (no exaggeration) of TLC's since the early 1960's when the only source of plates was homemade until 2008 when I stopped teaching and doing research.You talk about a very thin chamber, presumably over the solid phase, but you won't even tell us that. Presumably, it will be exposed to vapor, not liquids. Again, no info. Why does it have to seal tight? Why won't strips of spongy Teflon held with clips work.It is frustrating to try to help someone who has no ideas himself, who shoots down every idea offered, and still won't reveal his top secret project.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: June 14, 2018, 12:06:47 am
content: Quote from: jpanhalt on June 13, 2018, 09:12:16 pmI'm pretty sure I did just that in my previous post? I kind of expected there to be a fairly standard way of doing what I asked about, and therefore i kept the question general, as i suspect TLC probably isn't going to catch that many people's attention in an electronics forum. I'm sorry if any of you feel that i'm ungrateful for your insight.The idea is indeed to raise a glass cover off of a glass TLC plate with glass strips along the side, it's a chamber invented by Egon Stahl in the 60's, but the patent documents doesn't seem to specify how the cover is made. Also, i don't read German.The entire 'sandwich' is going to be held together by binder clips, but it'd just be nice to have a way of attaching the glass spacers to the cover. I suppose the spacers could just as well be teflon or aluminum, too. The bottom of the cover will extend into the solvent reservoir, so whatever seals on the strips will be atleast partially immersed, and if the last ~5cm was left without sealant, the solvent could probably wick up the narrow gap anyway.Here's the patent application with drawings and all:https://depatisnet.dpma.de/DepatisNet/depatisnet?window=1&space=menu&content=treffer&action=pdf&docid=DE000001175013B&Cl=3&Bi=1&Ab=&De=1&Dr=5&Pts=&Pa=&We=&Sr=&Eam=2&Cor=&Aa=&so=asc&sf=vn&firstdoc=1&NrFaxPages=6&pdfpage=6&xxxfull=1

author: vindoline
author_rank: Unknown
timestamp: June 14, 2018, 12:18:15 am
content: Quote from: jpanhalt on June 13, 2018, 09:12:16 pmI agree. Without more info it's impossible to help. Frankly, there are many epoxies that will tolerate exposures to your list of solvents all day long. Should be fine for a prototype or proof of concept. For an actual product, just have it made from glass. I have to assume that you're going after a specialized market, as general TLC visualization is a solved problem. 99% of the time it's UV @ 254 nm