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Making a replica of Durst RCP 20

arturo_rs

Member
Allowing Ads
Joined
May 4, 2022
Messages
140
Location
Spain
Format
35mm
Hello everyone, I need your help.


I’m planning to build a functional replica of a Durst RCP20.


The starting point, I want to reproduce the gears that drive the rollers, since this seems to be the most complex part.


Based on the photos I have, I can identify at least four different types of gears (possibly five or six), but I’m missing key dimensions to move forward.


Also, I would need:

  • The outer diameter of the gears
  • The number of teeth

If anyone has access to a machine and could take these measurements, or provide any additional technical information, it would be extremely helpful.


Any advice or insights are also very welcome.


Thank you.





I am going to print with a 3d printer. The material of the gears will be PETG.

I also have the other materials planned.
 
The rollers will be made of stainless steel 304 or 316, also acrylic tube and FKM or PTFE in contact with the chemicals.
 
Why would you want to replicate it exactly? Do you have a donor machine to use as a basis, is that it?

What are you going to use for the rollers?

Perhaps somewhere over the weekend I can send you the numbers you're looking for.
 
koraks said:
Why would you want to replicate it exactly? Do you have a donor machine to use as a basis, is that it?

What are you going to use for the rollers?

Perhaps somewhere over the weekend I can send you the numbers you're looking for.
Click to expand...
I’m tired of developing RA-4 paper using my Jobo tank—sheet by sheet. I’ve been thinking about starting this project for a long time, but I never quite committed to it.


A few months ago I saw that a fellow forum member, @elgatosuizo, was making a replica of the Durst Printo, and that got me interested.


I don’t have anything yet—just photos and videos taken from different angles that I found online. From my point of view, it’s simpler than the Printo.


The first hurdle is the gears—their dimensions.


I’m planning to use PETG for the gears. Although it has decent chemical resistance, I know I’ll eventually have to replace them. That’s not an issue.


Then there are the rollers. They’re built in layers:


  1. Base – A 6 to 10 mm rod made of 316 stainless steel
  2. Intermediate – An acrylic tube to increase the diameter, bonded to the metal rod with epoxy
  3. Outer layer (in contact with the chemicals) – Latex rubber becomes sticky over time. I’m considering NBR, EPDM, or PTFE tubing—the last one is the most chemically resistant

I should be able to reach a final diameter of 16 to 20 mm.


After that, I’ll move on to the bushings and the springs that apply pressure to the rollers
 
Honestly, if you're starting from scratch, I'd not try to replicate an RCP20. Where will you get the housing? The shape of the baths is essential to its 'fuel economy' so to speak. That's not something I'd suggest printing, either.

Given the massive amount of time you'll end up spending on this project, I honestly think the most sane approach would be to actively search for an existing machine. They're around; it takes time to find one, but sooner of later you'll likely get lucky.
 
You need to get a couple 1 gallon SS tanks and print baskets or 8x10 film hangers. Two 8x10 sheets back to in a hanger 3 hangers at a time. Six prints. Develop, stop, blix in 2 minutes wash for a minute or so.
I have a RCP-20, I use it more for black and white snapshot/postcards. It's great for printing smaller prints when you're trying to determine exposures etc.

I always allow for 45 minutes to clean up. You cannot leave chemistry in these overnight
 
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