Loctite and quartering wheels

[Paul MParticipant @paulm98238]

I have just commenced quartering the wheels on my 3 ½" loco and successfully quartered two sets of wheels with a jig and using Loctite 638.

Unfortunately the third set of wheels proved a disaster. The Loctite grabbed within a few seconds and the result was a disaster. The Loctite is new and when I tested it on a mock up it didn't grab for about 20 seconds.

Two questions:

1) What is the best method to undo the joint (if at all possible)?

2) Is there an alternative Loctite that has a longer grab time than 638 suitable for fixing wheels to axles?

Apologies if this has been answered on a previous thread, I did have a look.

[Paul MParticipant @paulm98238]

It went pair shaped

[HopperParticipant @hopper]

Propane torch. The sooner the better.

Henkel data sheets give info on cure times for their various grades. The green stuff can be very quick to grab. I've been caught with it before. The red stuff seems more forgiving but may not be as strong in grip.

[WearyParticipant @weary]

Heating the joint (gently!) to a little over 250 degrees C will release the grip of the loctite. Any residue can be easily cleaned-off.

I would persevere with 638 as it is ideal for your intended use, and your first two attempts went well. Confidence and speed will win-out.

Regards,

Phil

('Hopper' types more quickly than I)

Edited By Weary on 28/04/2021 11:42:56

[Paul MParticipant @paulm98238]

Thank you for the advice. I have managed to release the wheel from the axle with heat. As you say speed and confidence will win-out. Maybe a second pair of hands as well!

[Dave HalfordParticipant @davehalford22513]

Posted by Paul M on 28/04/2021 11:30:38:

I have just commenced quartering the wheels on my 3 ½" loco and successfully quartered two sets of wheels with a jig and using Loctite 638.

Unfortunately the third set of wheels proved a disaster. The Loctite grabbed within a few seconds and the result was a disaster. The Loctite is new and when I tested it on a mock up it didn't grab for about 20 seconds.

That might just be down to tighter clearances on the 3rd set?

[Paul MParticipant @paulm98238]

Dave

As the axle is for the eccentric straps and the driving wheel I have a tighter clearance which, as you mention, may be the issue. Perhaps I should set the axle between centres and run a file over it to add a little more clearance. At present I would describe it as just about an interference fit. I have read that about 1 thou clearance is needed for Loctite 638.

[old martParticipant @oldmart]

I have had similar trouble with 638, it can be very fast setting. The solution found by studying the Loctite specs was to get some 620. This is similar in strength, but much slower curing. As long as you can hold the components in their positions then it is recommended.

[Martin KyteParticipant @martinkyte99762]

Looking at the graphs on the data sheets the curing time is longer at lower temperatures so by assumption the open time should be longer too. Maybe choose a nice cold morning and switch the workshop heating off overnight?

regards Martin

[duncan webster 1Participant @duncanwebster1]

Use nitromors paint stripper to eradicate all traces of the old stuff or it acts as an accelerant to the new stuff. This advice from Loctite many years ago

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