Safe handling of fumed silica (and fumed alumina)

[Photopathe]

Hi! I am interested in trying this technique to enhace my prints, but would like to know more about how to handle it safely. I do not find much on this specific topic on the net. I am fine with wearing a mask while using it but what about the particules that inevitably became airborne. I suppose they settle down in the room and become airborne again when the coating or printing session is over as soon as one enters the room and walks around. Must be very difficult to tack down and remove all of it. Maybe best to use the wet application? Do the wet mix outside the appartment and only do the wet coating inside? But it doesn't seem as convenient and easy. I suppose fumed alumina is even more worrysome.
Thanks!

 

[Photopathe]

No one to chime in?

 

[pentaxuser]

It might help if you describe what your process will be and what this does for prints. I have been around this forum for a number of years and cannot recall seeing any posts about this process for prints.

pentaxuser

 

[cowanw]

Fumed silica had a mild web popularity for alternate processes, specifically platinum/palladium about 8 years ago.
There is an excellent summary here
https://www.bostick-sullivan.com/cart/1253.html

 

[Photopathe]

According to some side by side comparisons (with and without fumed silica sizing) I have seen, including in Christopher James Book of alternative processes, it seems well worth the trouble with several processes. I was just concerned with handling the product safely and was wondering if someone who has experience with fumed silica could give it’s input.

 

[Photopathe]

Bostick and Sullivan doesn’t adress all the concerns (see my initial post).

 

[Donald Qualls]

Fumed silica is very finely divided silica, near the particle size of smoke -- and I presume fumed alumina is the same with aluminum oxide. Number one precaution is to avoid inhaling the fine particulates; lungs and very fine silica are a very bad combination (especially over the long term exposure a photographer working a particular technique might see). A dust mask is a good start, but may not be fine enough to stop particles as small as smoke; there are specific filter mask cartridges that will protect against sub-micron particulates, but expect to spend some money (and follow their expiration and usage time limits -- more money for regular replacements).

The second line of defense is aggressive exhaust ventilation. If you have ventilation that exhausts the air to outdoors (where the dust will be diluted in enough ambient air to be harmless, barring intentional dispersal) and changes the air in the work area every few minutes, any material that becomes airborne ought to be expelled before it can settle on equipment or surfaces. Change and launder your working clothes after each session to control carry-out (equivalent to third-hand smoke from a tobacco addict), and ensure that containers of the materials are tightly closed when not in use, and you should be reasonably well covered.

 

[Photopathe]

Thanks!
And what about the option of using the wet application? Prepare the wet mix outside the appartment and only do the wet coating inside?

 

[Donald Qualls]

Thanks!
And what about the option of using the wet application? Prepare the wet mix outside the appartment and only do the wet coating inside?

That should take care of deposition and ventilation, as long as you don't let the wet mixture dry out inside. I'd still suggest wearing a mask for the actual mixing; turbulence around your body can keep fine particulates close enough to inhale even in a fair breeze.

 

[Photopathe]

Thanks a lot Donald!
Any specific recommendations as for the mask/respirator? Models and source? I also have an interest in wet plate so something that would kill two birds with one stone...

 

[Dirb9]

I worked with fumed silica frequently with epoxy resin, a half or full face respirator with interchangeable filters rated at N95 or N100 should be fine, I use a 3m 7502 with 2297 filters, see the niosh info here: https://www.cdc.gov/niosh/npg/npgd0684.htm Right now you might have trouble getting the filters and masks due to the Covid19 stuff. For wet plate, if you're concerned about fumes, you'll need a vapor rated cartridge, which one will depend on the specific chemicals. While working outside is a good practice, it's best to be in an area slightly sheltered from the wind, a small breeze will send dust everywhere. In addition, I've found most vacuums won't filter fine enough, they'll spew the silica dust right out the exhaust.

 

[Donald Qualls]

If you can't get an N95 or N100 mask/filter, another short term option for dust only is a multilayer mask of heavy T-shirt knit (four layers minimum), kept damp so dust that contacts the fibers will stick. Doesn't need to be drippy wet, but don't let it dry out.

This is absolutely not a substitute for the correct filter -- but it's much better than nothing.

 

[nmp]

But then if you are daring like Dick Sullivan, you won't worry about all of that (not my recommendation):