Loctite wheel to shaft

Laugh you may but I have been sorely tempted! The only reason I havnt done this is that the weld will most likely pull the wheel off centre.

My reading of the guidance can be summed up in a few rules of thumb:

• Loctite's primary purpose is for bonding round shafts in circular holes.
• If the joint has some mechanical strength already (i.e. press fit) it will be stronger.
• Loctite will gap fill up to 0.3mm, but the joint gets stronger down to 0.005mm
• For optimal strength he joint gap should be no more than the thickness of a sheet of paper but it cannot be too small.
• For accurate alignment, an interference fit is best
• The joint surfaces should be abraded with emery to maximise adhesion and ensure adhesive is carried into the joint

This would suggest the 'cotton reel' is unnecessary, but if it reduces the force require or permits rotational adjustment before setting a shallow 'cotton reel' to allow hand assembly while maintaining alignment is a good idea.

Neil

Had to make some extended drills for working in deep holes. Drilled the end of a bar with an ordinary drill, turned it round and bonded the shank of the drill in the hole just cut with 601 (603 now). The drill would break before the joint, in fact removing the broken drill with heat would fire the shank out of the bore like a bullet.

In my experience, a decent running fit with all faces degreased will give a superb bond.

Trevor

On the assumption the key point has now been answered, may I distract the thread by asking, what's the best way to prepare bare steel for 2-part epoxy (specifically Araldite Metal 2K). I've tried milled and emery papered finishes and even cleaning with meths before applying still leaves the result prone to peeling. It's just a cosmetic patch, so the old 'superglue the epoxy patch in place' trick worked, but surely there must be a way to get this stuff to stick first time?

Araldite's consumer website says "Make sure surfaces are clean and free from dust, rust, dirt and grease. For best bonding, slightly roughen surfaces with sandpaper and degrease metals with a suitable solvent."

It doesn't even say what a 'suitable solvent' is.

Neil

I use acetone for degreasing, pure acetone, not the stuff your wife may use for her nails.

Works for me!

Bob

Hi Neil

Go to your local car paint suppliers and buy celli gun wash about £5 for 5lts will clean any grease and dust and dry out.

Stan

Neil, that's an interesting question. I think I have seen the solution in one of Dan Gelbart's Youtube videos. There should be 18 parts, but on the selection on the right I don't see all. Someone knows how to find all vids of a certain contributor? (end of OT interrupt). So I can't locate it at the moment.

Well what stayed in my memory is the following: whatever solvent you use, after it has dried off you still have a one atom (molecule) thick layer of organic matter on your material.This can be proofed by trying to net it; the water will build 'balls' and flow off. The only way to get rid of that is to treat the parts with a flame from your trusty propane burner. Maybe to around 150-200 deg.C, I'm not sure about that, but after this treatment the water will adhere to the surface and wet it. A surface like this will also be netted by your epoxy/acrylate or whatever adhesive you use!

If someone is able to find this video I would very much like to hear about it again.

Part one is here: Gelbart

Regards, HansR.

OK, addition to my poat above: I found it! The trick was to search for tha author's name.

It is in part 6, Coatings

He shows 3 methods best is sandblasting, second the heating (bluing he says, so a bit hotter than what I wrote), and the third cleaning with some abrasive kitchen cleaner.

Have a look at these vids, this man knows a lot and even I am able to understand his English very well (something that's not always the case, unfortunately...)

Regards, HansR.

the cotton reel method is very useful for locomotive wheelsets when setting up the second wheel on the wheelset in a quartering jig. the smaller the clearance for high strength loctite the quicker the glue becomes solid and grips tight! (i found this out the hard way when i first used loctite on wheelsets many years ago using a tight sliding fit and the first wheelset had the second wheel solidly glued before it was fully on the axle! i would guess this was after less than 10 seconds setting up the jig!)

cheers,

julian

Don't use nail polish remover, it usually contains an oil additive.

Ian S C

what is the cotton reel method?

Machine the central section of the axle spigot a thou or two smaller. Apply loctite to the spigot then when you press it into place the two full dia ends locate the wheel but the recess allows a space for the loctite. Also les sfriction so you can rotate wheel to right place

Edited By JasonB on 30/10/2014 20:53:28

Many years ago, too long to remember , I did a simple test on loctite retainer, two-part epoxy and soft solder. Used 3/8" bolts(plain shank) in 3/8" holes drilled in 1/2" black bar. Tested with a torque wrench, soft solder by far the best, followed by the 2 part epoxy. I must emphasise that this was not a proper scientific test! Sorry can not remember any figures. If I can find time I would like to repeat it, with a bit more control.

You need to optimise the bond-line thickness for the epoxy and loctite cases or the results are meaningless.