Paint on lacquer? - Page 1
Forum section: electronics / projects

author: oliver602
author_rank: Regular Contributor
timestamp: December 15, 2011, 06:49:21 pm
content: I've made a small LED blinker board which consists of a 2032 coin cell on one side of a 25x25mm double sided pcb and on the other side 2 LEDs, a PIC10F200, a tactile switch, 0805 resistors etc. I want something cheap and tidy that I can cover the circuit and components with to avoid short circuits. I have about 120 boards. I want to keep the pic ICSP pads clear(and LEDs/Switch). Tried a glue gun but it is too messy and hard to control.Any recommendations?Thanks

author: robrenz
author_rank: Super Contributor
timestamp: December 15, 2011, 07:00:58 pm
content: If the tactile switch is not a sealed unit, any liquid paint/sealant may wick into the internals and render it usless. A picture would help to see what you are trying to do. Mark up the pic with the areas you don't want covered.

author: oliver602
author_rank: Regular Contributor
timestamp: December 15, 2011, 10:42:49 pm
content: This is the circuit still on the pcb panel. (Seperated by the score marks).The 2 round pads on the left and the 3 on the right need to be kept uncovered for programming. Mostly concerned with shorts between the battery + at the top left and the switch or 0805 capacator killing the battery if they were thrown in a drawer etc.

author: Psi
author_rank: Super Contributor
timestamp: December 15, 2011, 10:57:48 pm
content: What about liquid insulation tapehttp://www.jaycar.co.nz/productView.asp?ID=NM2832&keywords=liquid&form=KEYWORDOr just some silicon rubber.or my favorite, glue gun

author: robrenz
author_rank: Super Contributor
timestamp: December 16, 2011, 12:48:55 am
content: In the US there is stuff called "GOOP" It is a tough translucent urethanelikematerial in a tube. It is thick like toothpaste and is somewhat self leveling depending on how fresh it is. It can be thinned with toluene (at your local paint store in the US) so you can remove it or thin it to whatever consistency you need. It shrinks in thickness quite a bit on drying so you don't want it too thin. If you have solder paste dispenser you could fill a syringe with it and put it exactly where needed and it would slump to a nice smooth finish. This stuff is very tough when dry so it would definitely prevent contact. the advantage of this over silicone is that you can adjust the viscosity with toluene and it is self leveling. If you try this use it as it comes from the tube first. It will probably be perfect viscosity. Once the tube has sat around a while it starts to get thicker and that is when the toluene comes in handy.

author: Joshua
author_rank: Regular Contributor
timestamp: December 16, 2011, 05:04:15 am
content: What about a wide piece of clear heat shrink. This is a popular method particularly in the rc airplane world. You could just drill or cut with a circle knife for your exposed pins. If you had a blade like a really small biscuit cutter, that would be ideal.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 16, 2011, 05:50:36 am
content: Here is few my suggestions (that i use)1. Spray it with clear lacquer (colorless) and protect the pins during the process2. Liquid tape works great3. There is a product used to protect motorcycle engines and wires from rain, salt and other things. When you spray it it smeels like diesel fuel but after few minuttes it will dry in clear coat. I use it for circuits exposed to sea water and it never failed.

author: Psi
author_rank: Super Contributor
timestamp: December 16, 2011, 07:19:30 am
content: You can also buy clear lacquer designed for circuit boards.http://www.jaycar.co.nz/productView.asp?ID=NA1002&keywords=circuit+board&form=KEYWORD

author: bfritz
author_rank: Regular Contributor
timestamp: December 18, 2011, 04:36:55 am
content: What you are looking for is commonly referred to in the electronics industry as "conformal coating".I did a quick search at google and found many different places.I can't tell where you are located, but here in the US, MG Chemical is readily available. They offer a variety of conformal coatings, with various characteristics. In addition, they offer a synthetic latex to use as a masking agent. You use the synthetic latex on connectors or pads you want protected from the conformal coating. You wait about an hour for the masking agent to dry. Then you spray with the conformal coating of your choice. Finally after the conformal coating has dried, you peel away the synthetic latex masking agent.The other possibility if you have to do this often, is to have synthetic preforms made for the locations you wish to mask. These are commonly manufactured for wave soldering to keep the wave away from connectors and specific pads.