bond UHMW to SS

Call Locktite or 3M? Pretty sure they have a glue or tape that will do the job nicely. Can probably find all the selector info you need on their sites too. Heck, Woodcraft sells a thin UHMW adhesive backed tape for use on woodworking jigs and whatnot, perhaps you could just use that.

On Wed, 5 Sep 2007 20:59:02 -0500, with neither quill nor qualm, "Karl Townsend" quickly quoth:

Rivets!

=========================================================== Save the Endangered Bouillons from being cubed! ===========================================================

Best way is to buy a roll of self-adhesive UHMW tape - see McMaster p.3328

If that won't work for you, McMaster has epoxy meant for bonding difficult plastics on p.3295 - $55 for 1.7 ounces!

I've used the tape, it's cheap and works well, never tried the epoxy.

Proper thinking, Larry!

On Wed, 5 Sep 2007 22:49:01 -0700, with neither quill nor qualm, "Tom Gardner" quickly quoth:

Which, for the bouillons or the metal (and mettle) in my reply? At least the spamming Net Nazi won't get me for that post.

=========================================================== Save the Endangered Bouillons from being cubed! ===========================================================

There is another way (actually a couple).

A simple method is with a resiliant adhesive of the "pressure sensitive" variety -- rubbery acrylamide glue or double-stick foam tape come to mind. If there isn't much force in shear, foam tape works really well.

A "direct" bond can be made by surface etching the plastic. You can do it yourself with a nasty chemical brew (I can post a copy if you wish), or you can purchase polyethylene and teflon with a "treated surface" for bonding. McMaster and MSC sell treated teflon... I haven't bought any UHMW PE from them in that type, so I don't know what they have.

LLoyd

vhb tape

I wish.

The surface prep for the purported glues for PE are pretty ordinary solvents.

Bondable Teflon is a chemically converted layer, not just etched.

I wasn't aware that PE can be so converted. I thought the McMaster item just had a layer of pressure-sensitive adhesive applied to it.

There's always more to this question than one thinks of. Is it structural? What kind of tension or shear loads will it see? How thick is the bond line? What's the area/dimensions of the bond? Are the surfaces flat or shaped? Expected temperature range? Other environmental conditions? Will the joint have any kind of flex applied to it?

I've used all kinds of glues for things that work fine if the demands aren't high.

Richard J Kinch fired this volley in news:Xns99A3BD7BBC8ADsomeconundrum@216.196.97.131:

Richard, when I said "etched" that was inexact. The surface IS etched, but is also oxidized -- i.e. "converted". I have such a formula, and the process is do-able in the home shop.

LLoyd

On Sep 7, 12:25 pm, "Lloyd E. Sponenburgh"

You can also play a propane torch over the polyethylene and get the surface to oxidize. Not as controlled a process , but it will help in bonding to UHMW.

Dan

I'd like to see your etching recipe, Lloyd.

Don Foreman fired this volley in news: snipped-for-privacy@4ax.com:

This solution will work, albeit more slowly, on UHMW PE as well.

FWIW, I got this HERE from a past contributor.

It's nasty... use breathing protection or an exhaust hood, and work carefully. Hexavalent chromates and bi-chromates are potent corrosives and carcinogenic. And sulfuric acid ain't no warm puppy, either.

------------------

The solution of choice is a chromic/sulfuric acid solution: Parts By Weight H2SO4 (Sulfuric acid) 100 Na2Cr2O7 _2H2O (Sodium Dichromate) 5 H2O (Water) 8

The solution should be mixed with care as it is an extremely strong oxidizer. When fresh, it is dark brown, and gradually becomes dark green upon exposure to air and in use . a practical indicator that it should be replaced. The solution will naturally etch through a polyethylene container and should be stored in safetyglass bottles. Note that in past decades Emerson and Cuming manufactured .Ecoprime PP. as a recommended treatment for polyethylene prior to bonding. Though the solution is no longer available, it appears to be very similar to the mixture above as deduced from the Material Safety Data Sheets. The polyethylene sheets are cut from HDPE rod stock and turned on a vacuum chuck to approximately

20-mils thickness. They are then rubbed with an acetone-soaked Kimwipe to remove gross dirt and organics, then placed in the etching solution. The disks are etched for approximately 1 hour with intermittent stirring, then rinsed for 5 minutes under warm running water, and given a final rinse with distilled water. Baking is not recommended for the surface-treated polyethylene, nor is wiping the surface. Instead, the windows should be blown dry with clean nitrogen gas. If a bake is necessary to dry them, the temperature should be kept at approximately 50 C.

OK, that was my wish, that you post a copy.

But what concentration is this acid supposed to be?

That was the cleaning agent of last resort for any baked-on mystery crud on glassware back when I was a chemist, pre-EPA.

Coleman sold a patch kit containing an industrial adhesive that would stick to their polyethylene canoes.

jw

Thanks, Lloyd. Nasty stuff indeed, but archived for future reference. Given the 8 parts of H20, I assume that the H2SO4 is 98% or anhydrous? I don't know where I'd get that -- or the dichromate either.

Richard J Kinch fired this volley in news:Xns99A481D2D98F1someconundrum@216.196.97.131:

lacking any other information, I'd assume 9lb/gal.

LLoyd

Don Foreman fired this volley in news: snipped-for-privacy@4ax.com:

I'd have to ask more expert hands to do the calculations, but I think potassium dichromate would serve, and it is readily available. In this case, check out the several amateur pyrotechnic suppliers like Skylighter or Firefox.

LLoyd