The Home Scientist 009 - Forensic Fingerprinting III: Superglue

[pycastro]

Dear Mr. Robert! Thanks a lot for this great help. Your videos have helped amzingly we, csi´s of Brazil.

I would like to ask you if you have some book about the theme. Or planning to publicize some book?

I wait for reply.

Thank you!

Pablo

[michalchik]

Can you explain more about the role of NaOH, is it just generating heat by RXN that is causing the cyanoacrylate to vaporize?

[FishyAndTeamer]

How long would it take without the sodium hydroxide?

[sweetsensation115]

how do you make soot to reveal fingerprints on light objects?

[TheHomeScientist]

@sweetsensation115

Fill a beaker, test tube, or similar glass vessel with cold water. Light a candle, and use it to "smoke" the glass, depositing lampblack on the glass surface. You can also use soot from a fireplace or similar source.

[carlos10047275]

i am not a chemistry expert, could you please tell me how to prepare the accelerating NaOH solution?

[TheHomeScientist]

@carlos10047275

The concentration is not at all critical. Simply dissolve a small amount of sodium hydroxide in a small amount of water and use it to saturate the cotton. Be very careful with sodium hydroxide. Dissolving it generates a lot of heat, and both the solid and the solution are corrosive and extremely dangerous to your eyes.

[Stephencsi]

@carlos10047275 sodum hydroxide is costic soda you can get it from store

[carlos10047275]

what about a higher concentration of sodium hydroxide, perhaps 10%? Should it speed up the reaction?

[TheHomeScientist]

@carlos10047275

Maybe, but probably not. I haven't really looked into the details, but I believe the reaction is base-catalyzed, so any reasonable amount of hydroxide should have about the same effect.

[Sven2Perroy]

that i stole from my wife's make up supply

[y2nate]

you can also put cotton balls and baking soda in a bag and shake. when the super glue contacts the cotton ball it will also fume and get the same result

[TheHomeScientist]

I haven't tried that, but I believe you're correct. As I think I mentioned in response to another comment, you can also use sodium carbonate. I think just about any base would catalyze the reaction between super glue and cotton.

[jbohbot1]

can i substitute sodium hydroxide with potassium hydroxide?

[TheHomeScientist]

Probably. I think the reaction is base-catalyzed, so sodium carbonate or even sodium bicarbonate should also work.

[jbohbot1]

i tried and it worked. thx!

[TheHomeScientist]

The superglue I used was ethyl cyanoacrylate based, which is probably the most common in consumer brand superglues, but methyl cyanoacrylate, one of the other cyanoacrylates, or even methyl methacrylate super glues will work the same way.

[alexb12kt]

do makershed ship internationally ?

[TheHomeScientist]

Maker Shed ships lab gear internationally, but chemicals can be shipped only to the continental US.

[alexb12kt]

thank you :) do you know any good UK sources for chemicals ?

[Kizmox]

What type of superclue should be used?

Cyanoacrylate?