| Electronics > Beginners |
| Homebrew soldering iron. |
| << < (3/8) > >> |
| vk6zgo:
People used copper tips for decades before the plated ones appeared. Yes, they do eventually deteriorate, but they can be "redressed" with a fine file. Unless they are abused, or are very poor quality to begin with, they won't normally have "a large hole in the tip after a few days use", but they definitely do have significantly shorter lifetimes than plated tips. I had a very small soldering iron made by "Fairey" (not sure if it was the same company that made aircraft), when I was a teenager. It was quite usable off a 6.3 volt "filament" transformer, but definitely lacked "grunt" when it came to large joints. I never took the time to measure its element resistance, but my guess is, it would have been quite a bit higher than the OP's one. The tip sat around the shaft of the iron, so it had a bit of mass to heat up, but also it didn't just lose heat when applied to the solder joint. Nevertheless, it was a bit limited, so my next one was a thing called a "Scope" iron, which supplied a lot of current to a carbon rod which contacted the back of the tip when a control ring around the iron handle was pushed. These were used for just about any conceivable job, with larger or smaller tips & manually controlled "on" time, depending on the job. There are still some godawful things masquerading as soldering irons. Foremost among these are the allegedly adjustable ones which just have a mains operated iron fed through what is basically a "light dimmer", using an SCR or TRIAC. You wind the pot up, & they become too hot. Wind it down, & they become too cold. The tips have a very short life. After my Weller WTCP croaked, I picked one of these things up from Jaycar to "get me out of trouble" till I fixed it. Well, it was a nightmare to use, but I did do a few joints OK, after I developed the right technique. Wondering why it was so lousy, as the base seemed quite heavy, as if it had a reasonable transformer, I opened it up, & was confronted by the previously mentioned "light dimmer". The reason it was heavy was a weight glued to the inside bottom of the case. :palm: To the OP, I would suggest picking up a secondhand WTCP, as it will do most of the work you need to do. You are then free to experiment with homemade irons without needing them to be useable in the short term. By the way, you mentioned using a small iron with a spirit lamp. Have you thought of trying a gas soldering iron? They will work outdoors, & are reasonably economical, probably better than your spirit lamp setup. They would certainly be more convenient. |
| joeqsmith:
--- Quote from: registereduser on January 17, 2019, 07:01:23 pm ---I'm asking for help on how to build a soldering iron, not how to buy one. ..... My end goal is to build an iron for smaller/general work and a gun for stripping parts from junk and heavy assembly. I don't by into the exotic tip hype after my success with the alcohol burner iron. --- End quote --- Let's say I wanted to make an iron to work on what I would consider smaller general work. I will want something that can reach around 620 F. I want enough heater to to keep up with a somewhat large load, say maybe 40 Watts. I started by selecting a decent tip. Of course, I went with Pace. I want to keep the heat in the tip and use some ceramic to insulate the tip from the handle. I cut the tip and thread it into the ceramic with a bit of Kapton to help prevent it from chipping. Kapton is good for over 700F. |
| joeqsmith:
Next we need some sort of heater. I will use some NI80/CR20 28AWG. This is spec'ed at 4.094 ohms/ft. I want to be able to run it from a 24V source. I spool off a bit over a foot and measure 4.9 ohms. V^2/R or 24*24/4.9 = 117Watts. I will never run it up this high but should give me plenty of heat to ramp it up fairly fast. I need some sort of a temperature feedback and I also want the tip grounded. Time to kill two birds with one stone and add a K-type. Wires used to power the heater will need to handle a bit of heat and are Teflon jacketed. |
| joeqsmith:
A layer of Pyropel is then placed over the heater. I'm ready to see how fast it ramps and lay it on a brick for testing... |
| joeqsmith:
After a bit of testing with the bench supply, it looks pretty good. I let it cook for a while at 630F. This is a bit higher than Pyropel is rated for. I let it cool and then wrap a second layer of Pyropel over the entire assembly and tape it up with some 3M aluminum foil. Time to give it the hand test... Now the people that seem to make these crude tools always seem to use some POS handle. Many seem to be proud they have used an old pencil. I think I want something a bit nicer. |
| Navigation |
| Message Index |
| Next page |
| Previous page |