Hello all,

I'm new to the APUG but have been shooting/developing/printing B&W for a few years now.

In my previous darkroom I used trays too process my prints but now I've moved house and building my new darkroom (in the loft) I was interested in finding out more about vertical slot processors.

Trouble is they are so expensive. I have to admit that I've not searched for secondhand items yet but I have started to think about how hard it would be to make my own slot processor for basic B&W printing?

As the title says, am I mad to be thinking this or has anyone else managed it and to what degree of success?

Thanks for any opinions,
Anthony

Polycarbonate sheets can be bought from the places that sells window glass, screwed together with a sealant in between. Maybe a siphon to empty it. Just ideas.
/matti

"Building my own slot processor - am I mad? "

Yes.

Welcome to the asylum.

Polycarbonate sheets can be bought from the places that sells window glass, screwed together with a sealant in between. Maybe a siphon to empty it. Just ideas.
/matti

I was originally thinking of using glass but poly sheets are a much better idea, thanks.

"Building my own slot processor - am I mad? "
Yes.
Welcome to the asylum.

Hmmm... I thought as much ;)

Yes, depending on definition you might be mad… But, well, in that case so am I. If your initial impression is “how hard can it be?” - I definitely think that you should try to build your own vertical slot print processor.

Welcome to APUG

Claes

Anthony In recent weeks a 4 slot Nova with thermostatic control went for just over £50 on e-bay and it looked OK from the picture. OK most will go for more and certainly Nova itself or Secondhand Darkroom Supplies will charge more as is to be expected. Given the difficulties of producing one yourself, especially a heated version and the longevity of the professional models, I know which I'd opt for - even if it meant persisting with trays while I saved the money needed for purchase.

pentaxuser

I'm using 1/4" thick black ABS. It'll be capable of 20x24" prints. The sheets are ripped. When it get's a little warmer, I'll crosscut them and glue them up.

I built one out of 1/4" acrylic bonded with an acrylic solvent and reinforced with epoxy.
Before i put the sides together, i used my table saw to cut half the 1/4" width into the side.
I think its called a daito or a rabid....I have to brush up on my This Old House for the correct terminology.

Anyway, the processor worked great until i loaned it to a friend and never saw it again.
I purchased a 4x8' sheet of acrylic online, it was about $100. IIRC, I was able to get 3 11x14 slots out of it with plenty left over.
Its a fun project to take on. My only recommendation is a very sharp table saw blade. If its not, you will chip the acrylic.

No! If you build any processor, the slot processor is probably easiest to build and judging by the price of these things it does make sense.

I think its called a daito or a rabid....I have to brush up on my This Old House for the correct terminology.

dado and rabbet

My only recommendation is a very sharp table saw blade. If its not, you will chip the acrylic.

Good advice for any material. :)

I am also about to do this.

One thing I have found is that it is a lot cheaper to buy acrylic clip frames than it is to have the acrylic sheets cut to size. If you can find clip frames of the right size for you that is.

Thanks David for the correct spelling.

The homemade unit will give you grief in use because the surfaces
are smooth and the paper will want to stick to it when immersed in
the developer and fixer. The big advantage of the Nova is its use
of textured walls to prevent this from happening. By all means give
it a try if you have the time and skills and inclination, but you may
find that a homemade unit with smooth walls causes you enough
trouble to drive you back to trays, or to Nova.

RFXB

The homemade unit will give you grief in use because the surfaces
are smooth and the paper will want to stick to it when immersed in
the developer and fixer. The big advantage of the Nova is its use
of textured walls to prevent this from happening.

I was contemplating that myself. (I have no experience with either a "real" Nova slot processor or a home-made equivalent.) Perhaps adding some small ridges or bumps to the dividing walls would help minimize these problems. You'd need to use some sort of glue that'd stay put in photo processing liquids. I'm sure a browse through a hardware store would turn up something that'd be suitable for this purpose.

I was contemplating that myself. (I have no experience with either a "real" Nova slot processor or a home-made equivalent.) Perhaps adding some small ridges or bumps to the dividing walls would help minimize these problems. You'd need to use some sort of glue that'd stay put in photo processing liquids. I'm sure a browse through a hardware store would turn up something that'd be suitable for this purpose.

There is a similar problem with the Paterson Orbital in that you have to "roughen" the surface by use of a Dremel (or similar tool) or some have used spots of glue. I'd advise searching APUG for "Orbital" to get the best info.

The homemade unit will give you grief in use because the surfaces
are smooth and the paper will want to stick to it when immersed in
the developer and fixer.

RFXB

That's simply false. My "homemade" ABS unit has wall that are textured on the inside and smooth on the outside. Furthermore, with FB I plan on using a holding sheet, ala the Nova FB processor.

I built one out of 1/4" acrylic bonded with an acrylic solvent and reinforced with epoxy.
Before i put the sides together, i used my table saw to cut half the 1/4" width into the side.
I think its called a daito or a rabid....I have to brush up on my This Old House for the correct terminology.

Anyway, the processor worked great until i loaned it to a friend and never saw it again.
I purchased a 4x8' sheet of acrylic online, it was about $100. IIRC, I was able to get 3 11x14 slots out of it with plenty left over.
Its a fun project to take on. My only recommendation is a very sharp table saw blade. If its not, you will chip the acrylic.

It may be possible to cut a dado or a rabbet with your DAITO??

If you use silicone like that for aquariums for gluing, maybe just adding strings of that to the inside will be the simplest way to make the ridges.
/matti

Here's some inspiration:

http://www.paladix.cz/clanky/procesor-pro-vyvolavani-papiru.html

The homemade unit will give you grief in use because the surfaces
are smooth and the paper will want to stick to it when immersed in
the developer and fixer. The big advantage of the Nova is its use
of textured walls to prevent this from happening. By all means give
it a try if you have the time and skills and inclination, but you may
find that a homemade unit with smooth walls causes you enough
trouble to drive you back to trays, or to Nova.

RFXB

That's an interesting point I hadn't thought of. You can buy frosted acrylic sheets so maybe this is the way to go... But then the cost of building the thing approaches the price of a used unit.:o

About 20 years ago I looked into building my own slot processor, at the time I was manufacturing machines for precious metal recovery so had all the relevant equipment & skills. However the time to design and then build a one off was disproportionally high.

When I decided to start colour printing again about 8 years ago the market was flooded with second-hand Nova processors, so I bought a 12"x16" for about $100/£50. It would be hard to build anything similar with such good temperature control for the prices they are selling for now.

Ian

One thing I have found is that it is a lot cheaper to buy acrylic clip frames than it is to have the acrylic sheets cut to size. If you can find clip frames of the right size for you that is.

Interesting idea, maybe I'll have a go at building a smaller one first before trying to take on 20x16 monster project. :)

I should be able to find smaller frames more easily.

The homemade unit will give you grief in use because the surfaces
are smooth and the paper will want to stick to it when immersed in
the developer and fixer.
RFXB

Interesting point, I'd not thought of that; thanks for the tip.
It may well be the time restriction which prevents me from building one, but I'm yet to make a decision either way...

Maybe I'll have a look on ebay first :)

Interesting idea, maybe I'll have a go at building a smaller one first before trying to take on 20x16 monster project. :)

I should be able to find smaller frames more easily.

On ebay you can get quite big frames. I recently saw 5 12x16s for £15 including postage. The same supplier had bigger sizes, but this was the size I was going for.