super glue and baking soda

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Submitted by Coronita on November 13, 2020 - 10:46am

Today's tech tip was from a friend that builds RC cars and model airplanes....

I was in the middle of replacing the airbag control module for one my older cars, and in the process of taking things out, I broke a lot of plastic clips panel fasteners (it's a 20 year old car and plastic is bound to get brittle and break easily)...I was figuring out a way to repair all the broken plastic tabs, when a friend of my suggested superglue and baking soda...

Apparently, super glue has excellent bonding characteristics, but does a pretty crappy job as a fillter, if the two broken pieces have a lot of gap in between. Baking soda apparently makes an excellent filler and accelerant for super glue and when dry, the bonding strength is excellent. So I tried, and apparently it works pretty well...

Never knew that..but apparently its an old trick among model kit builders...

sg1sg1

sg2sg2

Submitted by spdrun on November 13, 2020 - 1:50pm.

Quick-set epoxy also works nicely and is less brittle than superglue.

Submitted by XBoxBoy on November 13, 2020 - 3:17pm.

Do you mix the superglue and the backing soda before applying? If so, how long do you have from when you start mixing until it hardens?

Submitted by Coronita on November 13, 2020 - 4:30pm.

XBoxBoy wrote:
Do you mix the superglue and the backing soda before applying? If so, how long do you have from when you start mixing until it hardens?

For broken pieces, I put superglue in between, holding it slightly open, get a tiny spoon of baking soda and sprinkle it in between, then slam the two pieces together as fast as I can. then I take more superglue and drop some on the outside on one side sprinkle more baking soda and use a flat screwdriver to rub it... Flip it around and do the same thing... actually, youtube has lots of video about it.

https://www.youtube.com/watch?v=cARGGBa2...

Submitted by sdduuuude on November 17, 2020 - 3:45pm.

spdrun wrote:
Quick-set epoxy also works nicely and is less brittle than superglue.

You can also add fumed silica to epoxy to make it less runny, more like a paste.

Superglue and baking soda is much easier to deal with than mixing epoxy.

Submitted by svelte on November 17, 2020 - 6:50pm.

What's wrong with just using JB Weld?

When my son was in college and worked in a music hall setting up equipment for musicians, he said they used JB Weld all the time.

I didn't know about it until I was putting together a Cozy Coupe child's car and the parts were severely deformed. Instead of taking it back to the store, he whipped out some JB Weld and glued the top to the body. It held up all the years of use after that.

Submitted by Coronita on November 17, 2020 - 8:31pm.

svelte wrote:
What's wrong with just using JB Weld?

When my son was in college and worked in a music hall setting up equipment for musicians, he said they used JB Weld all the time.

I didn't know about it until I was putting together a Cozy Coupe child's car and the parts were severely deformed. Instead of taking it back to the store, he whipped out some JB Weld and glued the top to the body. It held up all the years of use after that.

Jb weld actually doesn't work that well. I don't think it causes a chemical reaction to bond with the plastic pieces. same with epoxy. Both of these get most of the strength from the glue itself, as it hardens. I think like a arm cast. Super glue actually reacts to plastic and the baking soda makes an excellent filler and excellerant. The only other thing I would trust is using a plastic welder, which basically melts the plastic with more melted plastic. but that's usually only works well with large areas like a broken / cracked bumper. trying to use my plastic welder on a small piece usually ends up melting and destroying the small piece.

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