Pre-Blotter test questions

[97tbird]

I'm planning to do a blotter test, too.
..and have a few "?"s:

1) How long should I wait to take the pic after blotting?

1a) How much oil (how many drops) should I put on the media?

2) If I don't have a white business card, what's the next best paper?
--Can I use real white filter paper from the chemistry lab?
--Do the printed stuff on the back of a buisness card matter?
--What kind of paper should be avoided?

3) How "good" are the blotter tests? I mean: Can I really base the oil-life left on the results?

Thanks a lot.

 

[Schmoe]

I just use a clean tissue. If the drop starts to spread out, oil is still good. This is just a general "feeling." Nothing scientific about it, period. I use on engines that I don't use regularly like my truck.

 

[TallPaul]

I use white file cards cut in half and store them in trading card pages (9 per page) from centuryphoto.com. Usually two drops of oil is plenty or (three if it is off the same stick dip as the drops get smaller). Carefully support it horizontally (I use a fat rubber band on its side) with the blot area not touching a surface. I usually check periodically in case they are leaning and the blot wants to creep before it dries.

After 24 hours I put the blot in the trading card holders. Holding the blot (once totally soaked in) to a light for back lighting is another way to view them, but the file cards may have a pattern in their paper that you don't want to attribute to the blot. Perhaps filter paper would be better?

Type of paper is perhaps not as important as consistently using the same paper over time, but as noted above, a more uniform paper may be better. No harm to try the lab filter paper.

For your third question, "Can I really base the oil-life left on the results?" I would say yes and no. Yes if you are not trying to push the limit of usability. I would guess that we need to establish a library of blotters, especially when a blotter has a corresponding UOA. The UOA data would help us establish what to look for in a blotter.