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how to protect pads while applying solvent green mask? cure?

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#55095

how to protect pads while applying solvent green mask? cure? | 18 June, 2008

hi

i'm not experienced in creating pcbs but i have good background, and i have a bunch of questions.

i have no access to world wide known pcb chemicals but i managed to get a cramolin positiv spray and i don't know if it is still usable or not? (didn't use it yet)

i also got green/solder mask paste that the seller told me can dissolve in acetone, and has to be soluted, as it is thick in the paste form. it is packaged into a plastic jar, one like hair cream's or gel's package (and no tags what-so-ever).

i can go through all the steps of creating a pcb, from schematic design to etching, mounting and drilling and maybe tinning. but what i really don't know how to do is coating the pcb with solder mask without hiding the pads and holes? also i don't know which method is used for my type of solder mask to cure it, thermal, UV or what? my last is what quantity of acetone per unit mass is optimal for such mask to solute (any approximate values are welcome also).

i ask those questions although the material is not known to me as i know that whatever this compound was exotic or strange it will be categorized according to it's application which will pose some definitive knowledge about it or even just a plain idea.

the applications i might design a pcb for might require a smt/tht or hybrid product, so i need a method/methods that apply to both.

thanks all

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#55097

how to protect pads while applying solvent green mask? cure? | 18 June, 2008

Here is a link to a basic discussion of solder mask application methods: http://www.ami.ac.uk/courses/topics/0221_smp/index.html

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#55100

how to protect pads while applying solvent green mask? cure? | 18 June, 2008

thanks for the post...

but are you sure that the type of mask i mentioned is photoimageable and as i understood can be removed from desired places (pads/soldering areas) using uv and developer (which i don't know what material is it).

and also the article didn't mention how to cure the material discussed, although it gave me a good idea of how to apply a solder mask.

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#55118

how to protect pads while applying solvent green mask? cure? | 18 June, 2008

No, we not sure if your solder mask is LPI. The article we linked was aimed at solder mask application methods. LPI is the most common mask in use today. So, what kind is it?

Green tells you nothing. Solder mask can be a variety of colors.

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#55122

how to protect pads while applying solvent green mask? cure? | 19 June, 2008

actually this is my little problem, i don't know about the material except that it comes in a paste form and it has to be diluted with acetone and it has a green color. i wish that the compounds used to make a solder mask aren't that numerous to be difficult to identify or to consider it under certain criterion. all what i need to know is how to have pads after masking and how to cure the mask so it can withstand the environmental conditions that it will operate in.

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