Help with Loctite 640

[ozzie46]

I used this product to quarter my loco wheels about 3 weeks ago. I thougbht I had them quartered right alas no joy. I decided to try and get them apart by whacking the end of the axle with the wheels supported close to the axle. I was afraid it wouldn't work because the I thought it was supposed to be permanent but it worked to easily actually.

On examination of the axles I discovered there was only about 1/4 in of residue on the axle and it felt slightly sticky. I had cleaned the axles and wheels with acetone before applying the locktite to stick them together. I applied a band of locktite around the axle and stuck them together. There was excess locktite on the outside of the wheel/axle and the inside that I had to clean off.before it set up.

This stuff is supposed to fill gaps up .007 and have shear strength of 3000 psi. Fit on my axle /wheel is less than .007, and is used for Bearings, bushes, anchoring studs, valve guides ect.

I used a 3lbs small sledge to whack the axle end with a steel punch. The hammer had a handle of about 14 in. No damage to axles or wheels.

Is this stuff unsuitable for this job or do you think I messed up some where along the line.

Ron

Edit; Only one axle had a 1/4 in band of residue. The other 2 had full coverage on the wheel land on the axle .

 

[mklotz]

What was the temperature when you glued the wheels? I'm far from an authority on the subject but I've had trouble with Loctite joints in the past if the parts were far from room temperature.

 

[mu38&Bg#]

I think that you'll find with large gaps you must use the activator.

http://www.all-spec.com/downloads/loctite/64031_120209s.pdf

 

[ozzie46]

Marv you may have hit on it. It was quite cold here about the time I did the quartering. I heat my shop during the day but at night the heat is off during the week and turned low at night on the weekends.

dieselpilot, The fit is just a slight shake fit. Nothing close to .0007. That activator might be a good idea anyway.


Thanks guys.

 

[Metal Butcher]

You should apply a coating of the Loctite to Both parts plus extra on the leading edge, and assemble the with a twisting motion in one direction only.

Unless there is aluminum or stainless steel in the assembly mix you shouldn't need the activator.

Assuming you thoroughly cleaned both surfaces you should have a full cure within 24 hours, it could be the low temp that slowed the set, but it also sounds like incomplete coverage.

I clean the surfaces at least twice using lacquer thinner and a fresh piece of non-printed (white) paper.

There's no way to take an assembly apart after its properly cured, with out using high heat and a whole lot of force.

It's either the low temperature, residual Acetone in the pores of the metal, or contaminated product that kept it from curing properly. Try a test piece using the same metals and Locktite before proceeding on your project.

-MB

 

[Metal Butcher]

I just realized that you mentioned that you used #640. Depending on your gap, this may be the wrong product to get a complete gap fill. If your gap is .005" or less you should be using # 609. The thicker 640 won't properly creep into the tighter gap.

-MB

 

[bearcar1]

This was posted a few days ago perhaps it will provide a bit more info to your application.

http://sds.loctite.com/us/content_data/166733_LT4985_Threadlocking_Guide_032010_Web.pdf


BC1
Jim

 

[ozzie46]

MB, My wheels are aluminum with steel tires, axles are steel. Does that mean I need an activator with aluminum?


Thanks Jim I'll do some studying.

Ron

 

[ozzie46]

According to info Jim pointed me to I need a primer and a different product. Probably 262 Instead of the 640 . Aluminum to steel fit.

Thanks guys.

Ron

 

[Metal Butcher]

According to info Jim pointed me to I need a primer and a different product. Probably 262 Instead of the 640 . Aluminum to steel fit.

Thanks guys.

Ron

Ron, With all due respect to you and Jim, Your both on the wrong track. (no pun intended).

#262 is a THREAD locking compound, and the info your referring to is for 'thread locking' a steel bolt in aluminum.

You need to use a RETAINING compound in the #600 series, ie- #609.

http://au.iloctite.com/en/loctite-641-660-635-638-680-620-668-603-609-648-retaining.


-MB

 

[Metal Butcher]

MB, My wheels are aluminum with steel tires, axles are steel. Does that mean I need an activator with aluminum?


Thanks Jim I'll do some studying.

Ron

Sorry I missed this post.

The iron in the steel axle will activate the Loctite and it will set up. It just takes a longer, or better yet use the activator. Just give it 24 hours for light handling and 48 or more for a better cure....and bring the assembly into a warm place, like 68F +.

-MB

 

[bearcar1]

MB is correct Ron, I apologize for sending you off in the wrong direction. :bow: I would look at one of the compounds that give you a bit of time after assembly before they begin to cure, it will allow you to do those finite adjustments to get everything 'just right; before setting it aside for the night.

BC1
Jim

 

[ozzie46]

I wondered why I couldn't find 640 in the info. No worries, it got sorted. Thanks again.

Well it looks like either 680 or 638 is what I need. Any recommendations between the two ?

Ron

 

[kvom]

I used 620 to quarter my wheels; followed the directions from loctite, which match what MB posted. I had to redo one wheel, and used a torch plus an arbor press to get the wheel off.

 

[steamer]

IIRC, 680 has a longer working time.
( takes longer to set up)

Dave

 

[ozzie46]

Thanks Kirk , Dave.

620 it is then. Now just have to see if anyone in town has it. May have to order off the web.

Ron