Repairing plastic with superglue and baking powder

[omni550]

I mentioned this on the 'broken cat water bowl' thread, but think it might have interest to a wider (frugal, DIY) audience, so I am posting this in a new thread.

With so many things these days having plastic components which can easily break and render that item useless, I was delighted to find an inexpensive and effective means by which to fix broken, cracked, and missing plastic. In fact, YouTube videos show the repaired areas becoming stronger than the original material.

I used this technique very successfully yesterday to repair a vintage sewing machine. The stitch-length is controlled/adjusted by the friction fit of a steel shaft that runs through a plastic tab. Over time, a crack developed in the plastic tab and the stitch length dial would, after the vibration generated by sewing a few stitches, move itself to the longest stitch length.

I had recently heard about this super glue liquid (aka cyanoacrylate) and baking soda method of repairing plastic and thought this might be a perfect application for it. I had nothing to lose, as the sewing machine is so old (1980s) that no parts are available for repairs. The super glue and baking soda repair worked like a dream (I pushed and held the crack together for a minute or two while it was 'setting up" to close the gap and reestablish a friction fit around the shaft.) As this repair was made inside the machine, I really did not care about the appearance, as I simply needed it to be strong.

This repair/reconstruction of missing material can be sanded, molded, etc, as well as painted, for appearance-critical repairs. It can be used on wood, plastics, metals. Apparently, hobbyists and musical instrument people have been using this for a long time.

BTW, dollar stores carry packages of 4 tiny tubes (0.01 oz. each) of superglue which are perfect for small projects, so you don't end up having a large tube/bottle of super glue dry out/harden from having been opened just for a small repair.

My repair cost was about 26 cents ($0.25 for one tiny tube of super glue and $0.01 for the miniscule amount (<1/2 teaspoon) of baking powder used.)

As someone who deplores waste, I'm overjoyed to find something so cheap, quick, and effective to fix useful items that might otherwise be discarded.

omni


Here are some YouTube videos:

https://www.youtube.com/watch?v=Sq5YJbZXaZk

https://www.youtube.com/watch?v=gME6bKbLymg&t=15s

https://www.youtube.com/watch?v=n1meoZaHYZo

https://www.youtube.com/watch?v=alyzGrgL6So

[youbet]

Thanks Omni...... I have a broken plastic motor mount in the Fantastic Fan (roof vent) of my camper. The motor mount isn't offered as a replacement part unless it's part of a motor/motor-mount/ fan blade assembly which is pricey. I'm going to try this method this afternoon!

[omni550]

Quote:

Originally Posted by youbet Thanks Omni...... I have a broken plastic motor mount in the Fantastic Fan (roof vent) of my camper. The motor mount isn't offered as a replacement part unless it's part of a motor/motor-mount/ fan blade assembly which is pricey. I'm going to try this method this afternoon!

Cool! Please report back with your results.

omni

[Walt34]

Oh yes, this is an old trick. Model airplane folks have been using it for field repairs since the mid 1970's that I'm aware of. It's generally not used for routine building because it's ugly and hard to sand down and finish well, but if you need it fixed NOW it's a great thing to have on hand.

[travelover]

I'm curious how this compares to JB Weld, which I find to be amazingly strong. It is my "go to" glue when I need a strong repair.

[zinger1457]

Quote:

Originally Posted by omni550 BTW, dollar stores carry packages of 4 tiny tubes (0.01 oz. each) of superglue which are perfect for small projects, so you don't end up having a large tube/bottle of super glue dry out/harden from having been opened just for a small repair.

I've had good luck reusing (multiple times) the Loctite super glue dispensers with the squeeze knobs on the side.

[kaneohe]

baking powder or baking soda? my impression was that they're not the same?

[omni550]

Quote:

Originally Posted by travelover I'm curious how this compares to JB Weld, which I find to be amazingly strong. It is my "go to" glue when I need a strong repair.

Dunno.

From several of the videos, this method also seems to yield an extremely strong repair.

Is JB Weld quick to cure and easily 'layered'? Those are 2 additional nice features of the super glue & baking soda method. Sets up in no time, and you can start with a thin application and keep adding more super glue and baking soda to build it up, or easily expand the area you want to reinforce.

omni

[travelover]

Quote:

Originally Posted by omni550 Dunno. From several of the videos, this method also seems to yield an extremely strong repair. Is JB Weld quick to cure and easily 'layered'? Those are 2 additional nice features of the super glue & baking soda method. Sets up in no time, and you can start with a thin application and keep adding more super glue and baking soda to build it up, or easily expand the area you want to reinforce. omni

Good point, the JB Weld takes a while to cure, though it can be layered.

[CRLLS]

I can't say anything specific about today's super glue. The original one, Eastman #910 (now called Permabond 910) once cured, was not strong in high humidity or heat environment. Strangely enough, moisture can accelerate the cure, among other things too. The baking soda is just one alternative method of initiating cure of the super glue. There are many other formulas since the original one. Some stronger than others.

Our granite countertop installers patch chips in the surface using some form of super glue and a spray accelerator.

[omni550]

Depending on your repair need, if you have one where appearances or clearances are important or where you might need a little "filler" to fill in a gap, this video shows a repair on a sewing machine's plastic fascia.

Andy pre-assembled his broken plastic parts. Then he applied a paste of baking soda and water...even using it to fill gaps. He let that dry thoroughly. ONLY THEN did he apply the super glue. He had a successful repair with a good appearance and without adding any bulk.

https://www.youtube.com/watch?v=NXx6JyP9d5U&t=794s

omni

[easysurfer]

I want to thank Omni again for this find. I'm kind of fascinated by the superglue/baking powder trick.

Found out, I got a broken piece of plastic in a GE washing machine timer. Broke in 3 places. The timer part I've seen at gouging prices about $280. A flimsy piece of plastic. What a racket, made to wear out and break.

So, I was thinking about doing the superglue/powder trick. Put the materials in my shopping cart. But couldn't pull the trigger.

I've never had much success with superglue in the past. I've had good success with JB Weld.

As I was about to, for the sake of science try the superglue/baking powder, I started having flashbacks of the movie Hoosiers where the coach played by Gene Hackman draws up a plan using Jimmy as decoy. Then I think of Jimmy Chitwood and JB Weld ... "I'll make it [the shot]".

For something else, another day, I'll try the superglue/baking powder trick. But this time around, I'm going to stick to what I feel less nervous more comfortable with.

Heck ... I'm in no rush to do a load of laundry.

[Gumby]

Quote:

Originally Posted by easysurfer I'm kind of fascinated by the superglue/baking powder trick.

It's baking SODA, which is pure sodium bicarbonate, not baking POWDER, which contains mono-calcium phosphate and cornstarch in addition to the baking soda. You may not achieve the same results as the video if you use the latter.

[easysurfer]

Quote:

Originally Posted by Gumby It's baking SODA, which is pure sodium bicarbonate, not baking POWDER, which contains mono-calcium phosphate and cornstarch in addition to the baking soda. You may not achieve the same results as the video if you use the latter.

Oh? I was going by the thread title of powder.

In the store, I was doing lots of second guessing like what if I used Krazy glue instead of Superglue or Loctite, or Gorilla glue?

That's when I went Jimmy Chitwood .