PCB Prototyping Unit Conversion Chart                          
Data based on Kepro's chemical supplies, DRY FILM PROCESS                          
Developer DFD-12G   Sodium Carbonate   Water     Sq Ft of Board Developed            
250 mL 2.3 grams 250 mL   0.7 sq ft          
500 mL 4.6 grams 500 mL   1.3 sq ft          
1000 mL 9.2 grams 1000 mL   2.7 sq ft          
1500 mL 13.7 grams 1500 mL   4.0 sq ft          
2000 mL 18.3 grams 2000 mL   5.4 sq ft          
3000 mL 27.5 grams 3000 mL   8.1 sq ft          
3875 mL 35.5 grams 3875 mL   10.4 sq ft          
Mix at Temperature 32-38 deg C (90-100 deg F)                          
Develop at temperature 38-43 deg C (100-110 deg F)                          
Etchant SP-1G w CAT1G   Sodium Persulfate   Water     Catalyst   Catalyst Maintenance   Copper Capability    
        every (1-2hours etch)   Sq Ft (1oz) Sq Ft (2oz) Sq Ft (4oz)
250 mL 58.5 grams 213 mL   1.9 mL 0.13 mL      
500 mL 117 grams 426 mL   3.81 mL 0.26 mL      
1000 mL 234 grams 852 mL   7.61 mL 0.52 mL      
1500 mL 351 grams 1277 mL   11.4 mL 0.77 mL      
2000 mL 468 grams 1703 mL   15.2 mL 1.03 mL      
3000 mL 702 grams 2555 mL   22.8 mL 1.55 mL      
3875 mL 907 grams 3300 mL   29.5 mL 2.00 mL      
Bath Temperature 38-43 deg C (100-110 deg F)                 Note: Copper Capacity is per sq ft of copper single sided        
Copper Capacity 4-5oz/gallon                          
Note( If you expect to run more than just a few boards, the SP12G or SP20G is                          
much more economical due to the Hazmat fees. The etchant has very long shelf life                          
until mixed, then it is only 3 weeks.                          
Premix the etchant 24 hours prior to use to allow the PH to stabilize. You can                          
accelerate PH stabilization by shocking the solution by adding some spent                          
Sodium Persulfate solution see www.kepro.com for details                          
Exposure Times                          
BTX-200A   30-45 seconds                      
PE-2 Photoflood   4-6 minutes at 10-12 inches                      
BX-101 or GE FT15-BL single   2-3 minutes at 10-12 inches                      
BX-101 or GE FT15-BL double   1-2 minutes at 10-12 inches                      
I have a BTX-200A, so I can't validate the other numbers and they are from Kepro                          
Be sure to let the exposed pcb sit for 15 minutes after exposure to allow the phototesist to harden properly                          
Develop time is 45-60 seconds up to 90 seconds                          
Etching time depends on a lot of issues, see www.kepro.com for details                          
Dispose of used solution safely, follow your venues recommendations, do not put in household drain                          
Precipitation and Evaporation are 2 methods.                          
If you want a more environmentally sound procedure, see Think and Tinkers greencircuit.com                          
Copyright Ron Amundson KB0PAX 2002                          

Last Updated on 7/29/02
By Ron Amundson
Email: kb0pax@qsl.net