This is NOT a coffee cup!

scruffy · Nov 7, 2000

I'll be darned, I never noticed that! I don't know about the rest of it Twink, I thought I would post until Muhammad gave me the boot! Hopefully, when things settle down, I will be buying another tractor to play with. Muhammad would be the authority on VA benefits!

WVBill · Nov 7, 2000

I wonder if Rick from R&BManufacturing (Tiltmeter fame) can shed any light on bonding plastics. According to his web page, the body of his tiltmeters are made of ABS plastic. I know that ain't polypropolene but maybe he did some research...

Rick... Do you read this boring thread???

Bill

RobertN · Nov 7, 2000

Harv,
Try Gorilla Snot. It will hold the magnets to the cup, no problem.

It's really a adhesive for trim and vinyl tops. I have heard lots of Mechanics refer to it as Gorilla Snot; when I was a kid and first saw it, that was more amusing /w3tcompact/icons/smile.gif I have used it in the past. It stick VERY WELL on irregular surfaces and plastics.

RobertN in Shingle Springs Calif

JerryG · Nov 7, 2000

Harv,
I hadn't thought of that (gorilla snot). It's really name is 3M Super Weather-strip adhesive (SUPER is the operative word). It WILL hold the magnets after it dries. The original color is yellow, but they now have black also.
JerryG

gordon · Nov 7, 2000

Ok here is a web link to not the KL-650 but the even better HV-350. The reason I ended up with a tube of this is because I bought the Tube-Grip for small caulk tubes 3.5 oz. in size. I will say this that the Tube-Grip is money well spent. I use mine almost daily at work and it sure does make life easier. http://www.valcocinconsumerprod.com/

Now Derek and a couple of others have brought up some good ideas on glues.

Right now at work I've got the 350 and the 3-m trim glue with a screw in the center of a dab of each on the bottom of a gallon plastic jug setting up to harden. Will post results tomorrow if anyone is really interested.

Gordon

Harv · Nov 7, 2000

Gordon -

Thanks for following through with the HV-350.

You, Derek, JerryG, RobertN and others have suggested some really fine adhesives, most of which I never heard of.

This has become an intriguing pursuit for me, since I am now learning way more than I ever knew about sticky stuff. But please keep in mind -- when it comes to plastics and adhesives, there seems to be two groups -- "most plastics" and "teflon, polypropylene and polyethylene". The latter is considered the "non-stick" group for which proper adhesives are scarce.

Having discovered that, I have read a number of labels on various glues I found in the local hardware store, and although many are pretty vague about which plastics they bond to, a number of them, including Goop and most epoxies, state specifically that they do not work well with polypropylene.

Now, since we know that Goop works "pretty well", my quest is to find one that is "guaranteed" to work on our cup. It's taking me a while to track down the specs on all these glues you're telling me about, but so far I've only found one or two which make that claim. One is a thin liquid that requires a "good fit" (not likely between our magnets and cup bottoms), and the other one I will have to mail order when/if I make up my mind to do so.

Your gallon plastic jug is "probably" polyethylene, so I'll be interested in your results.

gordon · Nov 8, 2000

I tested the pull power on the hv-350 today. I used a three inch screw and glued about and inch onto the bottom of the jug. With the screw flat on the bottom of the jug. I let this set up overnight. Glue wasn't set 100% but I tried it anyway.

I pulled on the free end of the screw it took alot of power to pull this apart but it did come apart at the gluebond to the jug.

Overall rating on the glue would be in my opinion fair to good holding power.
I should have let this set up for more time before doing the pull test. I also used no solvent and didn't rough up the bottom of the jug---just flat out glued it.
Gordon

Harv · Nov 9, 2000

Gordon -

Thanks for your test results. Sounds like your glue will ultimately perform as well as Goop, which ain't bad at all.

***** Beginning of extra boring dissertation *****

I decided to try out this product called "Nbond", which claims to actually bond to polypropylene, rather than "stick" to it. I believe the distinction here is that Goop-like glues form a "mechanical" connection to the polypropylene. That is, it interlocks with the molecular surface of the material without really interacting with it.

"Bonding", on the other hand, implies that the glue and the polypropylene actually intermingle on a molecular level -- virtually a "weld" of dissimilar materials. Intuitively you can see that this would be the stronger attachment.

I spoke to a tech-type at the Nbond company and he explained about high and low-energy plastics.

 If you didn't believe the first boring warning, this is your last chance.

"High energy" plastics, the most common type, contains a lot of electron activity which makes it quite willing to interact with other substances. "Low energy" materials, such as teflon, polypropylene and polyethylene, have little molecular activity going on and are therefore quite indifferent (inert, if you will) when brought into contact to dissimalar substances, such as glue.

The Nbond glue is formulated to actually "excite" the polypropylene molecules (foreplay?), thereby opening the door, so to speak, for a true reaction and genuine bonding.

Now here's the real sci-fi part (for those of you who are still awake) -- you can deepen the bond by raising the energy level of the polypropylene ahead of time by focusing the flame of a propane torch onto the target area for a short time. It's not just the heat, but the releasing of oxygen from within the material (I won't pretend to fully understand this part of his story). And catch this -- once this procedure has been applied, the molecular energy level of the plastic will remain elevated for more than 48 hours! No need to rush the glue job when your done with the torch.

The final result, after gluing and curing (48 hours), is a deep bonding, where the two materials have literally become one. (Kind of romantic, don't you think?)

Anyway, I've ordered the glue and will attempt the entire torching procedure as he described. My confidence level is sufficiently high that, well..., I might just pick up an extra cup at 7-Eleven, just in case. /w3tcompact/icons/crazy.gif

I intend to wind up with two completed Chalkley Cups -- one using Goop and the other Nbond. It will be interesting to see if either one ever comes apart.

***** End really boring dissertation ***** 

Those of you who read this far, please signify by raising your hand. /w3tcompact/icons/smile.gif

jimmoore · Nov 9, 2000

WOW. X rated glue. After reading that post, My keboard is sticking! jim

MChalkley · Nov 10, 2000

Harv - Absolutely riveting! No, wait, we already said rivets won't work, didn't we? At any rate, my eyes were absolutely glued to the screen as I read your narrative. I can see you're definitely in a sticky situation getting those high-powered magnets to stay on the bottom of the cup. Keep at it, though - I can see you're not stuck yet.

I can't wait 'til you get a chance to try this stuff. It certainly sounds like it should work. Keep us posted!

MarkC