Building a HF start box

Metalworking Technology Workshop

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.

View more articles by Gareth Branwyn

@garethb2

January 20th, 2009August 31st, 2015 2

A high-frequency (HF) start box is a device used in AC arc welding that allows you to start an arc welder without having to “scratch-start” the arc. You used to be able to buy such an add-on device; apparently, they’re now hard to find. William F. Dudley Jr. decided to build his own and shares the details on his project page.

[As with all high-voltage projects, the usual warnings apply (as in: don’t try this at home unless you’re familiar with HF and know what you’re doing).]

High-Frequency Start Box

2 thoughts on “Building a HF start box”

Tom says:

January 21st, 2009 at 12:18 am

Is the 3ÂµF 400V optimised for 240V 50Hz or 120V 60Hz operation of the ignition coil?

The capacitive reactance at 50Hz would be a bit over 1K Ohm giving about 230mA into the coil. Too high?

I would have asked the project designer but couldn’t find any contact details on his pages.

Comments are closed.

Discuss this article with the rest of the community on our Discord server!

Tagged welding

Building a HF start box

By Gareth Branwyn