At 01:01 PM 1/6/2006, you wrote:
>Even with no toner on the component pads, the nearby toner would
>melt?
>
>I'm not thinking of just a blanket coating of toner over everything,
>but of using a negative image of the soldermask layer to make the TT
>soldermask coating fit around all of the solder pads just like real
>soldermask.
>
>Mike
I see what you are trying to do.
Toner does melt pretty easily. It also blobs up a bit and traps flux.
I can see three reasons for a solder mask (I'm sure there are more).
1. Assist in soldering. Usually only necessary for wave soldering, hand
soldering fine pitch SMD, and /or using solder paste.
Wave soldering, hot air, hot plate, converted toaster oven, and
paste would melt all the toner. On hand soldering smd I've noticed I get
bridges between the actual part pins, not so much the pads, so I'm not sure
how much help this type of mask would be. If it's not an smd board I don't
see the need. If it is an smd board then alignment of the mask becomes a
real issue.
2. Protect the copper traces from corrosion / physical damage. Actually a
good use if you don't want to tin the board.
3. Esthetics. Mask does make a board look better, more professional.
So I can kind of see using a tt solder mask for 2&3, but not so much 1. I'm
not sure it's worth the effort for prototypes.
But hey, It's certainly easy enough to do some tests.
I do love the idea of using a color laser printer and TT to do a
silkscreen replacement. The toner is pretty tough, and you can always
overcoat with letraset or equiv,. to protect it.
just my .02
carl
--------------------------------------------------------
Henry Carl Ott N2RVQ
http://users.rcn.com/carlott/--------------------------------------------------------