white skin chemical burn? - Page 1
Forum section: electronics / beginners

author: digitalnomadjc
author_rank: Contributor
timestamp: April 15, 2015, 09:18:39 am
content: Hi everyone,whilst handling my PCB after soldering my index finger went white and started to feel like it had pins and needles.I'm using resin core solder (lead/tin) and didn't feel a burning pain initially. For cleaning contacts i use isopropyl alcohol.That's it.Any ideas?

author: timb
author_rank: Super Contributor
timestamp: April 15, 2015, 09:26:15 am
content: Sounds unrelated. Unless you actually burnt your finger with the soldering iron?Iso can dry your skin out and make it flake off, which can appear as crumbly white spots. But it wouldn't make the entire finger turn white.Are we talking about the top side or bottom side?Sent from my Tablet

author: Zero999
author_rank: Super Contributor
timestamp: April 15, 2015, 09:30:51 am
content: Has it swollen up into a blister?What's your normal skin colour? I have light coloured skin and when I burn myself it looks lighter but not that much different.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 15, 2015, 11:04:04 am
content: Worth asking just in case.......Do you normally have sensation in that finger?Did you burn it with the iron, and not notice?Did you soak for an extended period of time (hours, days??) in the isopropyl?Tim

author: sacherjj
author_rank: Frequent Contributor
timestamp: April 15, 2015, 11:34:44 am
content: IPA Alcohol will give me a white region if I'm not careful. The alcohol mixes with the moisture on the top layers of the skin. Then they both evaporate rapidly.The same property is used to determine if your fuel is 100% gasoline (petrol) or included ethanol. (This is important when using automotive fuel for airplanes designed for 80 octane, but damaged by ethanol.) Add 10% water to the gas and the alcohol will combine with the water. Ethanol percentage is what separates minus the 10% from the water.

author: amyk
author_rank: Super Contributor
timestamp: April 15, 2015, 02:45:12 pm
content: Are you sure you're not just pricking yourself with fibreglass splinters?

author: free_electron
author_rank: Super Contributor
timestamp: April 15, 2015, 03:17:24 pm
content: some rosin solders are acidic and can cause skin reaction.

author: G7PSK
author_rank: Super Contributor
timestamp: April 15, 2015, 05:18:12 pm
content: Where in the world are you as it sounds like leprosy or white finger from vibration. Other than an actual burn from the iron the only other thing I can think of is contact with chromic acid which removes the calcium from the skin, but neither of those two thing will leave your fingers tingling.

author: Rick Law
author_rank: Super Contributor
timestamp: April 15, 2015, 08:54:58 pm
content: Sounds like you have some kind of allergy. You want to pay close attention to see if it leads to anything else, and also knows what to avoid.I used to have mysteries rashes on my arm occasionally. Worst is if I scratch it, it spreads and some times up the arm into my body. After paying more attention to it - I realize it was the paper shopping bag (in the USA, the kind you see at the grocery stores) and some card boards give me rashes if robbed against my skin.I also have some allergy with cats. After finding out what exactly I was allergic to (their saliva and their wet nose) I have cats most of my adult life.So knowing exactly what it ismaymake the problem immaterial.

author: The Electrician
author_rank: Frequent Contributor
timestamp: April 15, 2015, 09:59:39 pm
content: Quote from: digitalnomadjc on April 15, 2015, 09:18:39 amThis is exactly the effect that results from getting concentrated hydrogen peroxide on your skin. Are you etching your boards yourself with H2O2 containing etchant?One minute of exposure to 35% H2O2 is sufficient. I takes a few minutes for the effect to manifest itself. It's caused by small bubbles of oxygen being formed under the skin where the H2O2 has penetrated the skin. The effect will fade in a half hour or so. Exposure for several minutes can result in the formation of small oxygen containing blisters in the white area.Getting it in your eyes can cause blindness. The bubbles form in the cornea, and you can imagine why that wouldn't be good!

author: Nerull
author_rank: Frequent Contributor
timestamp: April 16, 2015, 01:30:06 am
content: Quote from: The Electrician on April 15, 2015, 09:59:39 pmI've seen whitening from 3%, which I didn't know could happen until it happened to me. It does go away after a while.

author: digitalnomadjc
author_rank: Contributor
timestamp: April 16, 2015, 03:55:54 am
content: Thanks everyone.I should have taken a photo - doh (I'll do that next time).In short washing my hands repeatedly made it go away but it came back when I started handling my PCB again (no iron - just cold). I want to use this board without a case so I'm going to have to clean it somehow. I notice that 'TTC Avionics' on YouTube use chemwipes when they clean with IPA.A general question - What do you use to remove the residue from PCBs?I also wanted to reply specifically to the great posts above:Nerull & The Electrician - I'm using single sided pre-fabricated boards designed for general use with a DIP package - No H2O2 that I can think ofRick - Could be, not sure what it was thoughG7PSK - South Australia, in my garage. Nothing too crazy other that what I buy from the local Aztronics store herefree_electron - I think you are onto something here. I will be consulting my MSDS.amyk - possibly but the board is pretty cleanT3sl4co1l & Hero999 - Short exposure, first time it has happened to me. I have dry skin and definately not an iron burn.Thanks

author: timb
author_rank: Super Contributor
timestamp: April 16, 2015, 09:55:48 pm
content: I clean my PCBs with 90+% Isopropyl and an anti-static scrub brush. Sometimes you may need to use a toothpick to breakup the buildup of flux in crevices (after letting the IPA soak in).For highly contaminated boards I've got a glass pan I soak the boards with IPA in. (You can funnel it back into a bottle for reuse afterwards.)Sent from my Smartphone

author: Unknown
author_rank: Unknown
timestamp: April 17, 2015, 02:55:00 am
content: I do know from experience, that strong hydrogen peroxide (>30%) will produce the same symptoms. Not sure about it leaving a residue though, and if so, why it would be used on a pcb.

author: con-f-use
author_rank: Unknown
timestamp: April 17, 2015, 07:26:07 am
content: It sounds more like a vascular Problem. Maybe you just blocked an artery by applying very odd pressure to your finger unwittingly. Was it could as well?

author: JoeN
author_rank: Frequent Contributor
timestamp: April 17, 2015, 01:42:55 pm
content: I've had the skin on my fingers turn white after using isopropyl alcohol. It's just the alcohol drying your skin out. You should wash your hands after using that stuff or use gloves. A very small amount of moisturizer helps too (just a fraction of a dab so you don't get your hands oily, just enough to replace skin oil and no more). Hopefully that is all it is.

author: G7PSK
author_rank: Super Contributor
timestamp: April 17, 2015, 05:18:54 pm
content: It is a good idea to use barrier cream before doing any work involving chemicals even if you wear gloves.

author: chibiace
author_rank: Regular Contributor
timestamp: April 17, 2015, 09:17:13 pm
content: turning white and stinging/pins feelings which fades away after awhile is what hydrogen peroxide does to your skin, get the occasional burn at work from 35% peroxide.