Mei Klaf/Spray Klaf: A Visit with Rav Friedlander shlit"a

HaRav Michael Tzadok Elkohen and i visited with R' Friedlander shlit"a at the beis hora'ah in jerusalem today. armed with a bottle of mei klaf, a can of spray klaf, a mezuzah psulah that had been treated with spray klaf and a copy of the ishur for spray klaf from HaRav Yaakov Meir Shtern shlit"a (thank you, R' Alberto).

1. the bottle of spray klaf was presented along with the ishur. it was pointed out by Rav Friedlander first and foremost that the ishur listed on the can of spray klaf (by Rav MOSHE Shtern) is from two different rabbanim (printed ishur provided by R' Alberto in a previous post was given by Rav YAAKOV MEIR Shtern).

2. the mezuzah that had been treated with spray klaf was shown to R' Friedlander along with with a hands-on demonstration of how easily the otiyot were smudged from a simple negiya with a finger (the original tish-tush of otiyot happened simply from rolling the mezuzah). Rav Friedlander and those present were visibly dismayed. Rav Michael Tzadok next sprayed an index card with the spray klaf. after it had dried R' Friedlander rubbed his finger over the treated area and mentioned that it felt like wax and that there was obviously an issue of chatziza present.

3. Rav Friedlander said that Rav Yaakov Meir Shtern (from the ishur posted by R' Alberto) should be notified about this issue

4. i presented a bottle of mei klaf  produced by the Dyo Nahari company (clear plastic bottle with a blue brand label), asking about the issue of chatzitza with this version of the product. R' Friedlander said that there is absolutely no problem with mei klaf and that there is no issue with chatzitza whatsoever since the liquid is totally absorbed into the klaf.

In summary according to Rav Friedlander's psak:
A) SPRAY KLAF poses a concrete issue of chatzitza and Rav Yaakov Meir Shtern must be contacted

B) MEI KLAF is mutar for use; no issue of chatzitza at all.

i would like to thank R' Michael Tzadok Elkohen for accompanying me to visit Rav Friedlander and may the oilam of the heilige STAM FORUM and all sofrim mus'machim abroad find yishuv hadaas and mishivas nafesh on this issue. sh'koiyach.


  1. Just as a side note, Rav Friedlander said that Rav Eliashiv had told him that mei klaf was fine except for one brand that came in a dark/black bottle. He said that he didn't remember the name of the brand, but that if it was left on the shelf for anytime, a solid ring would from about the liquid line of the mei klaf.

  2. Good work, shkoyach.
    This is really what the forum is all about...

  3. Nice. Now that HaRav Friedlander resolved the doubts with respect to spray-klaf, let's do the same experiment with mei-klaf, also using an index card like R' Tzadok did.

    1. Anyone who has mei-klaf in his possession, please use a paint brush and paint mei-klaf on the entire surface of an index card. After it dries, run you finger on it and tell us what the surface feels like. Same as untreated card? Wax? Rubber?

    2. Now do it again and brush a second coat on the same card. After it dries, run you finger on it and tell us what the surface feels like. Same as untreated card? Wax? Rubber?

    1. Are you saying that when Rav Friedlander said that there are no problems with using Mei Klaf he was wrong?

      The reason we used the index card was so that he could see what a minimal amount did. He asked me to spray the index card the same way that I did the mezzuzah, and was shocked by how little Spray Klaf I used and how clearly it felt like wax.

      However he reiterated at least 5 times that for many many years Mei Klaf has been in use, and that there are no problems with using it.

      So forgive me for being blunt, but are you saying you have a better understanding of this inyan than Rav Friedlander and Rav Eliashiv?

    2. I just did your experiment by the ways, using the פאר brand of mei klaf. I put down four layers and the paper still felt like untreated paper. I decided to stop wasting Mei Klaf then. If anyone in Jerusalem would like to come to my house and see said demonstration I would be happy to host them.

    3. Please don't let imagination run too far. Who talks about being wrong? Who talks about better understanding? The only thing we are looking for are the experimental facts. When we want to compare products we make the same experiment on both. We don't make an experiment on one and use "words" for the other.

      Thanks for doing the experiment. Now we know that פאר brand of mei-klaf does not leave a wax/rubber layer on the card. Good.

      I think we should also do the same experiment on other brands of mei-klaf.

    4. r' zvi, it's really simple. HaRav Michael Tzadok and i heard it directly from HaRav Friedlander.

      After tdiscussing "spray klaf" i presented a bottle of nahari 'mei klaf' (nahari as in the same company that produces nahari dyo). it's a clear plastic bottle with a blue brand label. HaRav Friedlander stated that MEI KLAF does not pose any issue of chatzitza (i specifically made sure that he would directly verify and confirm that MEI KLAF in the LIQUID FORM was KOSHER FOR USE and that there were NO ISSUES OF CHATZITZA).

      As HaRav Michael Tzadok mentioned, HaRav Friedlander said (also in the name of HaRav Eliyashiv, zt"l) that all forms of mei klaf were 100% kosher for use, except for ONE brand that was packaged in a black bottle that if left sitting formed a solid ring around the inside of bottle. Other than that one form of mei klaf, the others had been verified as mutar for use

      If you need further clarification, i strongly suggest you call HaRav Friedlander directly at: 057.317.5788
      if calling from outside of israel, that number is: 011.972.57.317.5788
      he can also be reached at home: 02.571.5707
      outside of israel that number is 011.972.2.571.5707

      if you wish to contact the va'ad mishmeret sta"m of bnei brak, they can be reached at 03.579.1616 or outside of israel: 011.972.3.579.1616

      HaRav Moshe Flumenbaum, who also distinctly said that there was no issue with chatzitza with mei klaf because it is "nivla (absorbed) into the klaf" can be reached for furthering questioning at his store: 02.538.3701 or outside of israel at 011.972.2.538.3701

    5. I don't need further clarification. I believe you. I just want to see experimental comparisons of various brands of mei-klaf because they are not all the same. If I had access to mei-klaf I would do the experiments myself.

      Let's not forget what a vary experienced sofer published elsewhere in September 2011:

      לא מזמן הייתי בבנק מסויים ובדקתי שם כ-150 מזוזות שהוחלפו לפני כשנה. להפתעתי שחרות הדיו בהמון מקומות נמרח בכל נגיעה עברה ליד מיד. לא הכרתי את התופעה, התקשרתי לסוחר שמכר להם את המזוזות. אחרי בירור קצת התברר שהסופר השתמש בדיו רגיל אבל מרח את המזוזות במי קלף בכמות נכבדת. י

      So, מי-קלף can cause the same problem as spray-klaf. The only difference being that it was discovered a year later.

      Now we need to know which brands are good and which brands are not good.

    6. By the way, I have a liquid that works exactly like mei-klaf. It makes the writing easy and beautiful. It leaves absolutely nothing visible on the klaf (not visible even under 400 times magnification with a microscope). When you touch the klaf or an index-card coated with this liquid you feel absolutely no difference. This liquid would easily gain approval by all the Rabbanim.

      Only one problem. A few days or weeks after writing on klaf treated with this liquid, the writing easily rubs off, just like the writing on klaf treated with spray-klaf.

      Conclusion: There can be hidden/invisible dangers lurking. Mei-klaf must be well tested for a long period of time to make sure it does not cause damage to the writing.

    7. So again you are essentially saying that Rav Friedlander doesn't know what he is talking about.

    8. Where did you get this negative attitude and frame of mind?

      There are materials which are good and there are materials which can cause future problems. And we all need to know which is which.

      Did you tell Rabbi Friedlander what I posted here about 2 weeks ago about the 150 mezuzot where the ink smeared after being written on one type of mei-klaf? If not, then, how is he going to know about it? He does not read internet postings...

      It looks like Rabbi Yaakov Meir Shtern too did not know about the reliability problems with spray-klaf. That's why Rabbi Friedlander recommended informing him about it.

      We are already past the point of worrying about חציצה . The more important issue is long-term reliability.

      Being an aerospace engineering scientist, long-term reliability happens to be one of my specialties. How would you like to fly in an airplane where none of its components or engines were tested for their reliability?

    9. When we started to tell him about reported problems, he waved it off and said that they were lies and rumors that had been around since Mei Klaf first came out.

      He went on to say that he and other Rabbanim have thoroughly checked Mei Klaf, and have never found problems.

      Where did you get this negative attitude and frame of mind?
      Your continued baseless attacks on Mei Klaf. Despite having two people on this forum go to Rav Friedlander and ask him directly, and being offered contact information so that you can clarify anything you want with him, you continue to make baseless attacks, centered around anonymous postings of supposedly expert sofrim.

      Rav Friedlander said that they had done extensive research into Mei Klaf, and aside from the one brand, they have found no problems.

  4. As one further point of clarification, when I pressed Rav Friedlander for a psak on the permissibility of using Spray Klaf he declined to give one.

    He said that it would require extensive research. All that we presented directly in front of him were one sample of writing, of one maker's klaf and one brand of ink. He said he could not issue a psak based on such limited information, because, "Writing is like a chulent and it depends on the ingredients." He said maybe with a different ink or a different brand of klaf things would be different.

    He then again insisted that we contact Rav Shtern and inform him of the problems that he might do the necessary research.


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