Wire speed control - exponential!

[Robert Weaver]

The current pot is linear, and the board is converting this to a log-ish response, what about fitting a log pot with the wiring reversed, so the taper is bottom biased?

https://learnabout-electronics.org/Resistors/resistors_09a.php

 

[HughF]

Given that the wire feed speed increases with the power steps automatically, you probably don’t even need to adjust the wire speed that much.

Every compact mig that has this wire feed power tapped off the main transformer has worked in this semi synergic fashion.

 

[RogerT]

Thanks Eddie, that’s a great explanation. I’ve decided to start with the lowest tech solution, (and the cheapest!), and I’ll work up from there. The aim, as for most of us I suspect, is to get better welds, and my investigation started with looking at recommendations for wire speed and welding voltages for different thicknesses of steel. For my project that’s between 0.8 and 4mm depending on whether it is original panel, or chassis, and I tend to use 1.6 for a lot of my fabricated stuff simply for easier welding.

As I have said I was finding it hard to get the right wire speed, so I’ve made this..

…from old Meccano, and I’ll calibrate a scale onto the white paint for wire speeds that I’ll be using. Together With a cheat sheet for recommended settings, that should allow for easier setup and fewer errors when welding.

If I still have problems, I’ll move onto other suggestions.

Thanks all for your time, patience and expertise.

 

[Farside]

You could also fit a Jackson slow-motion dial, which will give you sensitive movements (ooh matron).

 

[Epace]

It might be a good idea to fit a pot like this: