Another Way to Remove Wheel Inserts -- With a Warning

[HO RacePro]

Removing wheel inserts can be tricky. From what I hear even with the best methods it is common to damage them in the process of extraction. That got me thinking about another way to do the job.

I just removed four wheel inserts chilling them with MG Chemicals brand 'Super Cold' refrigerant (HFC 134a) before pressing them out of the wheel with an axle. Only a few seconds of spray were needed to break them loose and make them easy to remove.



Like it says on the can, the refrigerant spray chills to -51 degrees Celsius (-60 degrees Fahrenheit ) . That causes both the plastic and the aluminum to shrink due to thermal contraction. But plastic typically shrinks in the cold 10 times farther than aluminum, so the plastic inserts should come loose.

I see some evidence of an adhesive on the back of the wheel inserts I just removed. So it is possible those inserts were glued in place rather that pressed in. If that is the case chilling the adhesive may have made it brittle, and the differential shrinkage broke it. Different mechanism, same result.

Glued in, pressed in, maybe a bit of both. Whatever. My experiment with chilling the inserts shows once cold the inserts can be easily pressed out without damage. At least the inserts I experimented on, which were from Revoslot cars.

Don't stop reading now -- I need to warn you about that Super Cold spray...

That stuff is cold enough to give you INSTANT FROSTBITE. Dermatologists use it to remove skin tumors. A couple seconds of spray will KILL a patch of skin. BE REALLY, REALLY CAREFUL WITH THIS STUFF! Most especially DON'T SPRAY IT IN YOUR EYES! WEAR EYE PROTECTION!

I should also mention this stuff ain't cheap. A 14-ounce can (0.414 liters) costs about US$23. But it only takes three or four seconds of spray to loosen a wheel insert.

Please understand that I have only experimented with this refrigerant on one brand of slotcar wheel inserts. Your experience may dang well vary. It would be very useful to have some independent reporting using this technique on other inserts and by other people. Until we have some confirmation of my results don't assume this is a proven technique.Attached Files

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[Kevan]

Pipe freeze spray should work the same.

[Michael Squier]

I wonder if popping them in the freezer overnite would have the same result?

[Kevan]

I should imagine they ain't gonna get any colder after one hour.

[HO RacePro]

I tried re-installing those wheel inserts. They did not press-fit -- fell right out. Three tiny dabs of superglue worked.

So my guess is they were originally glued in. The cold made the glue brittle and the differential shrinkage broke it.

I don't know if other brands of wheel inserts press-fit. It would be interesting to find out, and to learn if chilling them will get them loose.

[Area 51 Raceway NC]

Errrr...... Well very interesting way of doing it I guess. It funny since I work with refrigerants at my job all day.

[Impulse-ive]

I like to put the wheels in water and then into my freezer so the expanding water breaks the glue seal. It usually works but it’s not 100%

[[email protected]]

I have never tried it but I have heard of some drivers freezing their silicone tires with cold sprays before they true them on a Hudy

[HO RacePro]

I bought my freeze spray to experiment with chilling soft rubber tires for truing -- to prevent them going gummy and shredding due to frictional heating. It didn't work very well.

What worked better was wet-sanding them in a bath of water and dishwashing detergent. Much, much better. The water kept the tires cool and the dishsoap/water solution lubricated them so they didn't stick/slip. Developed a very smooth and concentric surface.

I chucked an axle/wheel assembly into my benchtop mill, vertically. I used drywall abrasive sheet inside a square tub to do the sanding. The vertical spindle feed allowed me to shift the tire across the abrasive. The X-axis micrometer feed gave me fine control of the sanding process.

As good as that setup was I have gone to using a Professor Motor tire truing machine instead. Just easier to use.

It is nice to have a benchtop mill, but I wouldn't buy one just for tire truing. I've found it useful for a stack of other projects so I don't regret the high-dollar investment. The PMotor tire truing station was a lot cheaper, but still pricey. Even so it is an investment I highly recommend.