Leave them at a specific range for an extended period of time. Beads are all the same. I won't get into it but there is no little man in each bead regulating humidity. The all start off the same and are placed into a 60,65,70 percent enviroment for at least two weeks or so and that conditions them to that humidity. So if your humi has been reading low for a year they have some how conditioned themselves to that enviroment.
Shooter, I'm not sure that's true. This is how "Kittly Litter" beads work but it was my understanding that the RH control beads Viper (and other) sell have a slight difference in their chemistry that results in the difference in humidity. For example, viper's beads can be "dried out" when they become saturated and will regulate to their specific humidity once again. I'd think if they became conditioned to their environment, that wouldn't be the case.
As I said, I'm not 100% sure. I'll do some more research but maybe Viper or the good professor Wilkey will check in on the subject.
To the OP, it sure sounds like you have a leaky humi, or maybe it's just never gotten conditioned correctly. I've found a shot glass full of distilled water placed inside the humidor does wonders.
Cheers, gents - B.B.S.
5. METHODS FOR RECONDITIONING SILICA GEL
5.1 CONDITIONING SILICA GEL OUTSIDE THE EXHIBIT CASE
5.1.A REMOVING MOISTURE
The most efficient method of removing moisture is with heat. Although silica gel has a very high melting temperature (1600º C), it will lose its chemically bound water and hygroscopic properties if heated above 300º C. In addition, there is a new class of indicator gels, incorporating organic dyes that are heat sensitive and their color indicating dye will be effected above 125-150º C (Goldberg and Weintraub 2001). Therefore, it is not recommended that indicating silica gel be heated above 120º C and regular gel be heated above 200º C. The principle impact of a lower heat of regeneration is that a longer time is required to dry the gel and there is less potential for the degradation of silica gel properties.
In a conventional oven, the time of regeneration varies from minutes to hours, depending on temperature and the thickness of the gel. Although silica gel can be dried in a microwave oven, it is difficult to determine the temperature inside the gel. Also, since metal cannot be used in a microwave oven, only glass, ceramic or microwave safe plastic with a high melting temperature should be used to hold the gel, since the individual beads can become very hot.
5.1.B ADDING MOISTURE
The simplest method for conditioning silica gel is to place it in a room or environmental chamber set to the desired RH level. The best method of confirming that the silica gel is at the correct RH is by measuring the RH of a sample batch of gel. This is done by placing the sample gel in a sealed container or plastic bag with a hygrometer (use a large amount of gel relative to the surrounding air), and allow a day for the RH within the bag to stabilize with the gel mixture. Although an approximate RH value can be calculated based on weight, this method is not recommended because of its margin of error.
- • Methods of speeding up conditioning time:
[*]o Spread the gel as thin as possible.
[*]o Use a fan to circulate air around the gel.
[*]o Periodically mix the gel layers to improve uniformity.
[*]• For a single layer of bead, allow at least 4 days if the gel is initially dry, and longer if spread as a thicker layer.
[*]• Silica gel can be conditioned to a higher RH than the desired level, either to speed up the conditioning process or because of the inability to control RH. If so, it is important to allow 2-3 day for the moisture to equilibrate within and between the gel beads, especially if beads with different moisture contents are mixed together.
[*]• The direct addition of water through mist spraying or immersion is not recommended, since the high heat of decrepitation causes silica gel beads to crack and fragment. Although silica gel retains its hygroscopic properties, the overall response time of silica gel in a tray will slow down because of denser packing from the mix of large beads and smaller fragments.
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- 5.2 METHODS FOR CONDITIONING SILICA GEL WITHOUT REMOVING IT FROM THE EXHIBIT CASE or humi (i added)
Silica gel in cases can be reconditioned by adding water or appropriately conditioned silica gel to the case. This method is very effective if the silica gel is spread into a very thin layer, or has a very fast response time, such as is achieved with Rhapid Gel. Otherwise, only the upper layer of silica gel will be conditioned and there is a risk that the RH within the case will rise or fall too quickly, without adequately conditioning the full bulk of silica gel.
Increasing or decreasing surface area can control the rate of water evaporation. If there is concern about placing water directly in a case, or if a fast rate of evaporation is desired, a saturated humidifier wicking pad, preferably one treated with an antimicrobial agent, can be used. Generally, water will evaporate more rapidly in this manner because of the extended surface area of the wicking pad compared to a dish of water.
The initial speed at which dry gel removes excess moisture is very fast. It is important to limit the surface area of dry gel to prevent the case RH from dropping too quickly. This is because the speed at which dry gel adsorbs moisture is faster than the rate at which silica gel desorbs moisture.
If silica gel is conditioned in place, the rate at which the RH rises or falls within the case must be carefully monitored in order to determine if the rate is acceptable and when the water or dry gel that was placed in the case to condition the main supply of silica gel must be removed.
It is possible to calculate how much moisture must be added or removed to recondition silica gel in place (Lafontaine 1984, Weintraub 1991). It is important to take into account the impact of other hygroscopic materials inside the case. With experience, adjusting the amount of water or dry gel required may be required to compensate for other hygroscopic materials.
5.2.A CALCULATE THE AMOUNT OF WATER REQUIRED TO INCREASE RH:
Multiply the % increase in RH required, the M[sub]H value of the silica gel, and the weight of silica gel within the case.
For example, if the goal is to raise RH from 45% to 55% in a case containing 2 kilograms of silica gel with an MH of 9, 180 grams of water is required:
10% RH x 9 (MH) x 2 kg = 180 grams of water
5.2.B CALCULATE THE AMOUNT OF DRY SILICA GEL REQUIRED TO DECREASE
RH:
- • Step 1 - Determine how much moisture must be removed by multiplying the % decrease in RH required by the MH value of the silica and the total amount of silica gel within the case.
[*]• Step 2 - Establish the EMC adsorption value for the dry gel at the desired RH set-point and multiply this value by 10, to convert the value to the amount of moisture that can be removed per kilogram of dry gel.
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[*]• Step 3 - Divide the amount of water to be removed (Step 1) by the amount of water that can be removed by a kilogram of dry gel (Step 2). The result is the total amount required to recondition the silica gel in place.
For example, the goal is to lower RH from 55% to 45% in a case containing 2 kilograms of Rhapid Gel (M[sub]H = 9). If the dry gel is a regular density silica gel (EMC = 25% at 45% RH), the amount of dry gel required is 0.72 kilograms:
1) 10% RH x 9 (MH) x 2 kg = 180 grams of water
2) 25% EMC x 10 = 250 g of moisture per kg of silica gel at 45% RH
3) 180g/250 g = 0.72 kilograms
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for all 24 pages of the document.
LINK
Conditioning of ART SORB
Usually, ART SORB is delivered pre-conditioned at 50% RH ±3% RH.
Any other value is available for a moderate supplement.
In order to avoid any damage to your art work (or cigars) you should always control the conditioning of your ART SORB before use.
(A.K.A buying them from someone who has preconditioned them for you) To determine the actual conditioning of the ART SORB material please use a hygrometer which is known to be well calibrated and precise. We consider the
Testo 645 with high precision probe best for this purpose and use it for our regular controls. You can use it for readjustment of your hygrothermographs as well.
Measure:
If you wish to measure the actual conditioning of your ART SORB material enclose it together with your hygrometer in a non-permable bag, keep it in a room with constant temperature and read after 24 h.
If the set point of your ART SORB proves to be too low or to high for your application it will have to be re-conditioned. The rules below will help you and will guarantee a long lifespan to your ART SORB.
- The thinner the layer of beads (where applicable) the faster and accurate the re-conditioning.
- After re-conditioning it is advised to stir the ART SORB (cassettes can be turned around slowly) and place it in a non–permable bag for a few days to allow stabilization of moisture.
- Water should be applied in a purified form.
- All re-conditioning should be verified for accuracy with the use or a calibrated hygrometer. If cassettes are used it might be sufficient to bring them back to their initial weight printed on the cassette.
Increasing the RH Set Point
1) The simpliest method (but time-consuming) is to put the ART SORB into a room which is known to have the desired relative humidity and let it reach equilibrium. A humidity chamber (sounds like a humidor to me) is perfect, too.
2) Sponge method: (sound familiar) by placing a moist sponge with ART SORB in a sealed case, water can be adsorbed and the weight checked or continuosly monitored until appropriate weight is reached.
3) Direct application of water by misting or a spoon. Dry beads may crack during this process, but this does not change ART SORB's adsorption capacity. Cracking is negligible above a set value of 40-50% RH. (sounds even more familiar)
4) Or "Hey my humidity just shot up after I added a few boxes of smokes" WET SMOKES= an addition of water.
Bead type: a cycle of misting and stirring the beads to promote adsorption should be employed.
Cassette type: care must be taken not to moisten the cardboard. The best method is to humidify a small spot on the PE/PP-mebrane with very little alcohol or isopropanol by means of a slightly ‚wet' kleenex. Then the distilled water passes through the membrane easily. Applied with a spoon the water normally doesn't even touch the cardboard.
Sheet type: a misting and a waiting period should be used to allow adsorption followed by checking with a hygrometer.
Decreasing the RH Set Point
1) Again, a room with the desired relative humidity or a humidity chamber is a simple but time-consuming method.
2) ART SORB can also be dried directly in an oven, but care must be taken not to exceed 65°C. This method won't be quicker than the desiccant-bags following up.
3) The best method is to place ART SORB in a non-permeable bag and to add dry desiccant bags. It is very time-effective and works well for beads and for cassettes. A dry 250 g desiccant bag takes up about 48g of moisture between 0% RH and 40% RH. The desiccant bags can be dried in an oven at 130°C (see page "
silica gels...").
4) What do we do, just leave the lid open for awhile and allow the water vapor to escape, ever done that???? I know I have after adding wet smokes and my humidity rises.
In some cases it may be possible to leave ART SORB in the showcase and to correct the RH-value of the showcase simply by adding small amounts of desiccant bags - the easiest and least time consuming procedure.
Precautions
ART SORB contains silica gel and lithium chloride.
(the lithium chloride, is the only difference bwtween beads and kittly litter, the latter being straight silica gel) It is harmful if swallowed and irritates skin and eyes. Don't inhale eventual dusts. Further informations see
Material Safety Data Sheet..
The water adsorbed by ART SORB is present in a liquid phase on the surface of the particles. Direct contact with metals like iron, zinc and aluminium may cause oxydation. Therefore ART SORB should not be in direct contact with art objects, especially since the liquid is containing chloride ions. The same characteristics apply to dusts. Try to avoid dusting by careful handling and keep them away from your art objects. Don't touch ART SORB and art objects in turns in order not to transfer dusts to them. ART SORB should not be used in an environment with rapid air movements (>1m/s).
MORE INFO
click on ART SORB 60-80% then read that page. Near the end click on "How to use ART SORB for the Preservation of Art" under precautions. This should answer any questions.
Everything in
blue was added by me except any links that were already in the document.
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