Salt Test Problems

[BrianEE93-cl]

I wanted to see if I am alone in having problems with the salt test. I have a Staebell Aristrocrat and I had the Set-n-Forget recently recalibrated so I know it is very accurate to within NIST standards. Whenever I have this done, I put my other digital hydrometers next to the the meter in the cabinet for at least 2 hours and then check them. My main portable digital hygrometer reads 7-8% high. I keep my cabinet somewhere around the mid 60's depending on the season/house temperature. When I did a salt test on this same hygrometer, it was only 2% high. I figure the problem is that the salt test produces 75%RH compared to the 65% of the cabinet. Either my hygrometers are not very accurate over a range of humidity or the salt test is a little flawed. The digital hygrometers I have are kind of cheap but not too bad. I have had them for over 8 years and they are very repeatable when compared to the cabinet calibration.

I would like to get a big jar and do a salt test with my Set-n-Forget. I would have to run wires through the lid for power but I could use plumbers putty to seal it up good.

What do you guys think?

[jam]

I just did it make sure you dont use alot of salt and a few sprays with distilled water and put in a mason jar and no less then 8 to 10 hours , first time i put to much salt and to much water it was all over the place now its perfect

Good luck

[Sea Jay]

Brian - I have had the same problems. I found that my air temp was too low...raised it to 68-70 and have had better readings.

Have you contacted Bob Staebell? He is great to work with.

[tobacmon]

I did just the opposite--It said somewhere I read that the chemical test are done with 1/2 - 1 cup of salt--wow--I just filled a cap (soda) and dampen,"its enough water if you see it almost puddle-if to much water drain off the top", and my test came out correctly--I also put in Tupperware with it inside a sealed baggie---Try this and see---

[BrianEE93-cl]

Originally Posted by Sea Jay

Brian - I have had the same problems. I found that my air temp was too low...raised it to 68-70 and have had better readings.

Have you contacted Bob Staebell? He is great to work with.

It's not a Set-n-Forget problem. I trust that the calibration is very accurate on it after sending it to CMT. I was just curious and ran the salt test on the same small digital hygrometer I had tested in the cabinet and didn't get the same results.

[Paesano]

I would do the same thing you are. I just have to be sure. In this day and time knowing people the way we do it could have been a bad calibration on the setnforget. I have HUGE swings using the salt test when the temp swings. You could try a boveta pac to be sure. The temp still swings way off even with those I have tested. Good luck man.T

[FoZzMaN-cl]

Originally Posted by BrianEE93

It's not a Set-n-Forget problem. I trust that the calibration is very accurate on it after sending it to CMT. I was just curious and ran the salt test on the same small digital hygrometer I had tested in the cabinet and didn't get the same results.

My $.02 - 2 hours isn't enough time for it to stabilize...

[iloveclmore]

Yeah usually the rule of thumb is at least 8 hours.

[BrianEE93-cl]

Originally Posted by FoZzMaN

My $.02 - 2 hours isn't enough time for it to stabilize...

That was actually 2 hours in my cabinet. When I did the salt test I left it for at least 8 hours.

[full count]

My .02, Boveda calibration kit. It is dead on and can be used quite a few times.

[iloveclmore]

Originally Posted by full count

My .02, Boveda calibration kit. It is dead on and can be used quite a few times.

How long do they last between uses?

[foolwithnohair]

Originally Posted by Paesano

I would do the same thing you are. I just have to be sure. In this day and time knowing people the way we do it could have been a bad calibration on the setnforget. I have HUGE swings using the salt test when the temp swings. You could try a boveta pac to be sure. The temp still swings way off even with those I have tested. Good luck man.T

The RH of Sodium Chloride (not table salt, pure NaCl) is 75.30% at 25 degrees Celsius (77 degrees F). It is different at other temps, but 25 degrees is the reference standard. Do your calibration at 25 degrees C with pure NaCl and you're now NIST-traceable! (Yup, that's all that means ... )

I assume that the Boveda calibration kit uses Sodium Chloride. Table salt can be a reasonable substitute, but is often iodized and may have stuff coating it to keep it free-flowing in high humidity. If you're cheap (or just inquisitive like me), you can purify table salt somewhat by washing it a few times.

[BrianEE93-cl]

Originally Posted by baldheadracing

The RH of Sodium Chloride (not table salt, pure NaCl) is 75.30% at 25 degrees Celsius (77 degrees F). It is different at other temps, but 25 degrees is the reference standard. Do your calibration at 25 degrees C with pure NaCl and you're now NIST-traceable! (Yup, that's all that means ... )

I assume that the Boveda calibration kit uses Sodium Chloride. Table salt can be a reasonable substitute, but is often iodized and may have stuff coating it to keep it free-flowing in high humidity. If you're cheap (or just inquisitive like me), you can purify table salt somewhat by washing it a few times.

I actually did the test with non-iodized salt. I guess it would probably still have the non caking agent.

[CHRIS7891011]

Originally Posted by BrianEE93

I wanted to see if I am alone in having problems with the salt test. I have a Staebell Aristrocrat and I had the Set-n-Forget recently recalibrated so I know it is very accurate to within NIST standards. Whenever I have this done, I put my other digital hydrometers next to the the meter in the cabinet for at least 2 hours and then check them. My main portable digital hygrometer reads 7-8% high. I keep my cabinet somewhere around the mid 60's depending on the season/house temperature. When I did a salt test on this same hygrometer, it was only 2% high. I figure the problem is that the salt test produces 75%RH compared to the 65% of the cabinet. Either my hygrometers are not very accurate over a range of humidity or the salt test is a little flawed. The digital hygrometers I have are kind of cheap but not too bad. I have had them for over 8 years and they are very repeatable when compared to the cabinet calibration.

I would like to get a big jar and do a salt test with my Set-n-Forget. I would have to run wires through the lid for power but I could use plumbers putty to seal it up good.

What do you guys think?

Were you doing the salt test in the cabinet? I'm a bit confused on that. If so that's probably your problem.

If not I'd agree with everyone else and say that 2 hours is not nearly enough to regulate the RH.

Hope that helps. Shoot me a PM with any other questions.

[foolwithnohair]

Originally Posted by BrianEE93

I actually did the test with non-iodized salt. I guess it would probably still have the non caking agent.

Well, I'm going to find out if it makes a measurable difference, as I got a Boveda pack with my Heartfelt Hydrometer. I'm guessing no ...