New Fume Box Design

[TyG]

Thanks to the help and various images and design ideas sent to me via the forum and email; I have come up with a fuming box design that I think may work well. I use the screw concept from the strike through style, but made two separate slides to shrink the overall footprint and size of the thing for use with fume hoods and storage.

More info. can be found on my site Just follow the link “Fume Box for Dags”

Alan and Andy, would you mind copying the images of my box and put them into the resources section? Also, if I should have posted this elsewhere; feel free to move it if needed.

Thank you Andy, Alan, Jason, Michael, Walter, and everyone who posted replies on my questions post.

If I am new to some of you, I build cameras for wet plate and dag photography.

[Andy Stockton]

Looks like a very fine piece, just like your cameras. The offset finger cutouts for the sliding covers are a nice touch. It is great that you are making these available.

[jdanforth]

Beautiful! Well done. The through-dovetails are a nice touch. Is there a reason that you opted to use hardware to affix the screw plate instead of the sliding dovetail method?

[CasedImage]

Brilliant original design! I too like the offset finger cutouts, also the breadboarding of the cover plate (and coincidentally harks to the wooden construction of 19th dag and ambro cases). Well done!

www.CasedImage.com

[TyG]

Jonathan, I opted to veer away from the sliding dovetail because of the strength factor. There is a weak point at the points of the cutout that can break easily if dropped or just hit wrong. It may be plenty strong if using plywood, but I use solid hardwood. Also, it is just one more “moving part” to deal with. The dish can still come completely out with my design. I got the idea for the fixed bar from one of Walter Johnson’s strike through boxes.

This design is definitely a culmination of the good points of each design out there.

[photolytic]

What prevents the slide from being pulled out all the way when it is withdrawn?

I don’t see a stop at the far end.

Also the slide plus drawer design requires 4 steps for each plate fuming operation instead of two.

The first one to push the drawer in, the second one to pull the slide out, the third to push the slide in again and the forth to pull the drawer out.

Uniform fuming requires rotation of the plate between fuming operations so the drawer must be pushed in and out and the slide must be pushed in and out for each fuming operation.

As many as 10 fuming operations may be required for each plate, so this adds a lot of extra manipulations to the fuming process.

[CasedImage]

I guess a tweak to the design if there is no stop is to have the coverglass to be oversized to the dish enough to have stops at the corners, that would pass on the outside of the dish.

I don’t see the extra manipulations as a serious downside. If you had one strikethrough fuming box and and one of this design then yes it might get confusing but having two the same and you would fall into the rhythm of it. I’ve had two sets of the european style and the only thing that bothered me was a less than optimum seal. I think this is a good design and as a first model out of the workshop I think it bodes very well for genre which has too few suppliers of quality equipment.

www.CasedImage.com

[Andy Stockton]

What makes this design interesting to me is that it is a thoughtful hybrid of the strike-through and European styles. I don’t personally like the strike-through because it takes a lot of room to store and operate. The European style tends more toward leaks and the plate is still is being fumed somewhat even when the glass slide is closed – rendering fuming precision very difficult. This design takes 1/3 less space to operate and store and it eliminates the “fuming by leakage” problem of the European design. To me these advantages outweigh the additional movements required. After all, it’s not like anyone is making hundreds of plates a day. The need to add a stop to the glass plate seems a valid criticism, but can be taken care of a number of different ways.

[photolytic]

The strike-through design does not leak at all when not in use and almost none when it is in use. It does emit a very faint odor of bromine as the drawer is withdrawn and hence should not be placed in the same hood with your mercury box. Even a faint exposure to halogen fumes will destroy or weaken the latent image before the mercury has a chance to do its job. I9th Century literature recommends this to correct for accidental overexposure. I always keep the fuming boxes in a separate room from my mercury developing apparatus to prevent such an occurrence.

If you can’t accommodate a fume hood large enough for a strike-through fuming box, I suggest performing the fuming operation without a fuming hood as I have done for 13 years.

After you have raised 3 kids using cloth diapers, which have to be soaked in Clorox, the fuming box odor is very faint by comparison.

Eliminating the need for an extra 10 box manipulations per fumed plate has saved me 35 thousand extra steps during the fuming of over 35 hundred plates during my Daguerreian carrier. Remembering to perform that extra step of withdrawing the slide is sort of like remembering to remove the lens cap on your 35mm camera. An occurrence that happens to me all too frequently on my rangefinder camera.

[TyG]

I am a bit confused about the manipulations comment of being 10 steps…

No, I did not put a stop for the holder. It will slide all the way out and the cover lid goes down onto the ground glass. You can tighten that down or not, then put the plate holder in and simply lift the cover lid about 1/2″ and slide in the holder; then, yes slide out the ground glass, and the holder and lid drop to the dish and can be tightened down if desired.

What I did was try to take the better seal from one design and the compactness of another and combine them.

Also, the concept of the two separate slides on top of each other as I have comes from a handout from a Jerry S. workshop (if I remember correctly there). I was told that he said he liked that design.

Another thing that may not be clear is that the holder slide can be pulled out without moving the glass slide.

Also, I made it so that, unlike the other European designs I’ve seen; all pieces “float” so when you pull out the glass slide, the holder drops onto the dish with the lid still on top and can be tightened down during the fuming to help with escaping fumes during this stage.

[photolytic]

In the multiple fuming process, the plate is first fumed over iodine, preferably in 3 to 4 stages so the color change can be visually monitored. Each stage requires 2 steps (in and out again) for the slide-through design and 2 more if the box is equipped with a glass slide for a total of 4 operations per fuming stage. For 4 iodine fuming stages this amounts to 16 operations for the first iodine fuming alone.

Then the plate must be fumed in the bromine box in 3 to 4 stages for a total of 6 to 8 stages until the desired color is obtained. This adds as many as 16 more operations for a total of 32.

Finally the plate must be returned to the iodine box for 2 more stages, one in white light and the second under a safelight for a total of 8 to 10 stages per plate. This adds another 8 operations to the total fuming process for a grand total of 40 operations per plate.

My comment was about the glass slide not having a stop. I didn’t realize that the plate holder had no stop either. Both should be equipped with stops to prevent them from being pulled completely out of the box.

[CasedImage]

I really don’t see how the “operations” thing is such a issue, you put the plate in, you expose it to the halogens. Each “operation” takes a second, yes its an extra second or two but so what. The benefits are its compact nature whilst maintaining a good seal. Agreed adding stops would be prudent but its a small tweak to be made.

www.CasedImage.com

[TyG]

If I had a stop to keep the glass from coming out, then the holder slide would not seal against the dish.

It really does seem to be pretty smooth in operation. When you slide the holder out with a loaded plate, it can just stay out until the next plate is ready to go in.

[photolytic]

To construct stops for the glass slide you could add wood strips along each side of the glass plate with a downward protruding ridge at the end which would catch on the wooden front of the box thus preventing complete withdrawal unless the screw mechanism on the top is removed first.

The side wooden strips would also add extra strength to glass slide so it would not break if it was inadvertently pushed down too hard. Alternately you could glue small Plexiglas blocks to the underside at the far corners of the glass plate

If you leave the slide out between plate fuming steps you save operations and time but there will be no seal to prevent fumes from escaping the box during this period. As a result you will need to wait between fuming cycles for the fume concentration at the top of the box to be restored.

If you do push the slide back in after each fuming cycle, which typically last only 4 seconds per cycle, the plate will continue to react with the fumes trapped between the slide and the drawer until the drawer is withdrawn. Even if this operation takes only an extra 2 seconds, the plate exposure to the fumes could be increased by as much as 50% per cycle. Depending on the overall fuming time, a 50% fuming increase can have a significant effect on plate sensitivity, image contrast and highlight solarization.

Because the density of iodine fumes is 8.8 times that of air, the concentration of iodine fumes at the top of a Galasso slide though box, which is approximately 8 cm above the iodine is only 0.00001m/l or 1/1000 of the concentration the fumes on the iodine surface, which is approximately 0.01 m/l at 20C. Adding extra distance between the top of the glass tray and the plate drawer will further reduce the concentration of the iodine fumes reacting with the plate. Thus it is important that the top of the glass slide be very close if not flush with the bottom of the plate drawer.

[TyG]

John, where were you when I was asking for opinions and help with design ideas and what people like/dislike in each design? Kinda like a fair-weather fan.

Simple enough fix; if someone needs a box and does not feel the above design fits their needs, a strike through can easily be made as well.

[photolytic]

TY,

Sorry, but I didn’t need new boxes and didn’t want to spend another $1000 for a second pair.

Many on this site like your design and you should make and sell a lot of them to this market.

Many don’t consider extra time or manipulation a problem. Maybe after making thousands of dags for a decade or so and developing arthritis in their old age they will. I only wanted to point out what I have found to be beneficial in the slide through design. As a chemical engineer I’m a big proponent of the total confinement of polluting chemicals approach as opposed to the “blow it up the stack” approach and the strike though design comes closest to this goal.

I think what is really needed is a box with a glass liner for plate sizes larger the wholeplate. Any plans?

[CasedImage]

John, I don’t see how this design doesn’t provide total confinement of chemicals as with a strike through design.

www.CasedImage.com

[TyG]

John,

I do have a design for a strike through and will be able to provide that as a second option.

Two options is always a good thing.

Although, I don’t have plans for a box larger than whole plate at the moment.

[photolytic]

With the strike through design the glass tray is covered 100% of the time either by the back end of the drawer, which is glass, or by the front end of the drawer which is wood and a plastic insert which holds the silver Dag plate.

With the slide construction there is an interval, however short, when the slide is withdrawn, leaving a gap between the glass tray and the drawer through which fumes may escape from the tray. Leaving the slide withdrawn for the entire fuming cycle only makes this situation worse.

[TyG]

I don’t want this to get negative, just understood correctly all the way around. With the posted design, when the glass is pulled out, the holder slide drops onto the glass with the wood lid over it. True, not as airtight as the glass slide, yet no open cracks either. Basically just the same as the strike through; wood slide touching glass, and lid touching holder slide. You do have the brief second to lift the holder slide a tiny bit to get the glass slide to go in under it.

I do not take your advice lightly, I will have both designs available for make. Images of the strike through will be up in a couple months.

The first design comes from a Jerry S. workshop handout, with a slight variation in the screw. I have also had someone email me today saying the have one made very similar to the posted one and it has worked fine for 5 years.

[jgmotamedi]

I have been using a pair of boxes of a very similar design for many years also based on Jerry Spagnoli’s drawings. While I can understand the criticism voiced above, I have found this to be a excellent design, with the only flaw that it does tend to leak a bit when the holder is removed. But then again my strike-through box isn’t any better, as iodine accumulates on the slide and leaks when it is shifted.

My solution to the leak is to have a sheet of teflon resting on top of the plate holder. When I pull out the plate holder the teflon sheet slips down to cover the box. I suppose you could do this with the glass also. I wonder about rabeting a track for the plate holder and the glass slide. The glass slide could be partially pulled out (maybe include some sort of stop?) to expose the plate but keeping the fumes in. Then it could be simply slid back in. Or perhaps this is what you intended?

[CasedImage]

Here is cropped view showing the plate holder and its recess that allows the plate holder to drop down into place over the glass dish.

 

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[photolytic]

Regarding the statement above:

“But then again my strike-through box isn’t any better, as iodine accumulates on the slide and leaks when it is shifted.”

It is physically impossible for solid iodine to deposit of the underside of the tray of the slide-through fuming box, or any other box design for that matter.

Due to the high density of the iodine fumes and the absence of any stirring, the actual measured concentration of the iodine fumes, 8 cm above the crystals (0.00001m/1), is one thousand times lower than the concentration necessary for any iodine to sublime onto any surface which is 0.01m/l at 20C. (International Critical Tables) Any iodine solid there would have to be the result of the box having been inverted or violently shaken before fuming.

As to escape of iodine fumes, the space between the bottom of the Galasso box Tray which is in contact with the glass tray, and the bottom of the plate holder tray is only 3mm, making the volume of iodine fumes trapped there only 107cc, which at a concentration of 0.00001 m/l, contains less than 0.00027 grams of iodine, most of which is still reacting with the silver plate until it is removed from the tray.

Bravo!

The drop down design of the tray when the glass slide is removed, which was mentioned above would greatly mitigate any fume looses. I am a bit concerned that the shock of the drop might damage the lip of the glass tray and the force of the air pushed into the top of the tray might cause eddy currents in the iodine fumes which would take a while to die down. If the bottom of the tray were lined with some inert cushioning material like Teflon, that would eliminate the shock problem and make sliding easier.

[TyG]

Hello, Sorry to bring up an old thread; but, I am not longer able to make any fuming boxes.
Take care, Ty

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