Soldering Iron Wattage - Page 1
Forum section: electronics / general

author: xrunner
author_rank: Super Contributor
timestamp: July 08, 2013, 01:55:22 am
content: I had to solder a PL-259 connector onto a rather large size of coax - looks like this -and I needed more thermal mass (not higher temps) than the irons I had so I ordered what I thought would help me - an 80W iron. Unfortunately it turned out to be a complete piece of crap and I ended up throwing it away.I did plug it in once (after I replaced the plug) but the handle got so hot I could not even hold it. Not even kidding. But I have a question I hadn't thought of before, as far as non-controlled soldering irons go. Of course I know that the higher wattage means it consumes more power, but what I want to know is, does the higher power mean it effectively stores more heat (have more thermal mass) at "normal" soldering temps (say 650 - 750F) or does it mean it will have a higher temperature and no more thermal mass than other lower wattage irons?In other words, what does the wattage rating really tell in terms of thermal mass or tip temp on non-controlled irons when no tip temp is stated in the specs?

author: Psi
author_rank: Super Contributor
timestamp: July 08, 2013, 02:51:41 am
content: I've never found anything my generic 30W soldering station can't solder with a 5mm chisel tip on it.

author: David_AVD
author_rank: Super Contributor
timestamp: July 08, 2013, 02:51:53 am
content: I would have thought a higher wattage (temperature controlled) iron would have better thermal recovery than a small one. How that works with uncontrolled irons I don't know - probably not very well.

author: robrenz
author_rank: Super Contributor
timestamp: July 08, 2013, 03:11:46 am
content: IMO Thermal mass is equal to the actual metallic mass of the tip/heater. Large amount of tip heater mass compared to what you are trying to heat means therateof tip temperature droop will be slower. But this is a dynamic thing and if you hold that tip on a joint for a long time or do a lot of joints in rapid succession the temperature will drop to whatever the heater wattage can maintain. That mass will also slow the recovery of the temperature when the tip is unloaded. That is why an unregulated temperature iron is really bad. it gets too hot when idling for a long time and has no reserve power when heavily loaded. This is why the high performance soldering stations typically have very low mass tips that allow the applied wattage to be very quickly adjusted to match the load. As an example a JBC station will use up to 130W to maintain temperature yet not over heat a small tip. The wattage is quickly conducted to the load because there is very little tip mass to slow the thermal recovery.

author: neslekkim
author_rank: Super Contributor
timestamp: July 08, 2013, 11:44:51 am
content: experienced this myself when soldering an heatsink to an pcb, found it difficult to use my hakko 888d, might be that the tips I use are clones(or, I belive so), but using the jbc was totally different, heated up the piece very fast so I could solder nicely without melting everyting else on the pcb. Not only are the jbc tips small, but i guess the pid-feedback-loop (or what one can call it) really also does matter here. The Hakko should also manage this, but I guess it's way slower due to its construction?

author: SeanB
author_rank: Super Contributor
timestamp: July 08, 2013, 06:47:02 pm
content: Normally for those I pull out the Black and Dacker soldering gun. It will solder them quite quick, and as the tip actually will glow cherry red if it is not in contact with a sink the 300W is definitely enough. If something is too big for that I pull out a MAPP torch, and if that does not do it ( 5/8 copper pipe or bigger) I pull out the acetylene torch which will do it.

author: xrunner
author_rank: Super Contributor
timestamp: July 08, 2013, 06:55:25 pm
content: Quote from: Psi on July 08, 2013, 02:51:41 amWell try a PL-259 and LMR-400 coax (which is the bigger kind not the smaller size ) with your 30W iron. It sucks the heat faster than the iron can produce it. I've tried a 35W iron and it just can't put out the heat fast enough.Quote from: SeanB on July 08, 2013, 06:47:02 pmThat's what I ended up using - my Weller soldering gun, but even that takes a while. The PL-259 on large coax is basically a great heatsink.

author: robrenz
author_rank: Super Contributor
timestamp: July 08, 2013, 07:15:38 pm
content: An overall warm up with a hot air gun to as high a temp possible that won't melt any plastic will help also regardless the iron used.

author: Rory
author_rank: Frequent Contributor
timestamp: July 09, 2013, 06:11:04 pm
content: I use a Weller #4033-S chisel tip 45W. Lots of thermal mass.Here's a pic. Needs a handle to go with it.There are cooler ones than this but a light dimmer in a quad outlet box with a duplex outlet works pretty well as temperature control.This will get red hot if you let it sit too long. Use LOTS OF FLUX and keep it clean or they erode quickly.

author: xrunner
author_rank: Super Contributor
timestamp: July 09, 2013, 06:33:09 pm
content: Quote from: Rory on July 09, 2013, 06:11:04 pmWow really? I've never seen a soldering iron tip that got red hot. Gulp.

author: edavid
author_rank: Super Contributor
timestamp: July 09, 2013, 06:56:47 pm
content: Quote from: xrunner on July 08, 2013, 01:55:22 amClassic uncontrolled soldering irons have a larger tip mass to go along with the larger heater. Check garage sales (or even antique stores) for a good old 100W-200W iron in the $1-10 range.Here's an example, but don't pay that much:http://www.amazon.com/American-Beauty-Soldering-Iron-Model/dp/B000EJ1BV4

author: Rory
author_rank: Frequent Contributor
timestamp: July 09, 2013, 07:03:18 pm
content: Quote from: xrunner on July 09, 2013, 06:33:09 pmWeller specs them at 1000F for the 45w iron. 800F for the 27W. And as uncontrolled iron, it has no thermostat so can get hotter than the working temperature if it's not being used.

author: WarSim
author_rank: Frequent Contributor
timestamp: July 09, 2013, 07:20:27 pm
content: Nobody even mentioned the tool intended for the job? Contact tweezers.I advise against the heat gun or a high temp low thermal mass heat source. It will likely mess up the gap (the impedance matching mechanism), or any of the numerous name for it. Not to mention the insulator.Alas if you have no choice be sure to sweep the cable after to see if you have to try again.Contact tweezers can be had for a <$300 which could be the cost of 3 re-terminations, depending on cable and connector cost.BTW I am not talking about thermal tweezers they are comparatively more expensive and the wrong tool.

author: ddavidebor
author_rank: Super Contributor
timestamp: July 09, 2013, 07:30:42 pm
content: Quote from: xrunner on July 08, 2013, 01:55:22 amLook at the first 3 video of paceworldwide on youtube, it's all there

author: nctnico
author_rank: Super Contributor
timestamp: July 09, 2013, 07:48:59 pm
content: Usually 80W should get most electronics jobs done but you need to use the biggest tip possible.

author: G7PSK
author_rank: Super Contributor
timestamp: July 09, 2013, 08:48:31 pm
content: I always solder PL259's with a 25 watt Antex soldering iron, I have found it plenty man enough for the job even the braid through the hole.

author: xrunner
author_rank: Super Contributor
timestamp: July 09, 2013, 09:32:05 pm
content: Quote from: G7PSK on July 09, 2013, 08:48:31 pmWell we got ourselves a mystery then, because as I said my 35W can't manage it.

author: nukie
author_rank: Frequent Contributor
timestamp: July 09, 2013, 10:34:33 pm
content: Some iron are more efficient than others. Some have really good coupling between the tip and the heater. The worst are those firesticks which clamps the tip with a screw at the end of the heater.Next, the internet is filled with nonsense or technique which doesn't work as well for soldering a huge load like this. Most instructions start off with heating the pad with the iron then poke the solder on the pad. This is good a good way to avoid cold joints for newbie because it ensures high percentage of success.The right way for efficient heat transfer is to wet the tip with small amount of solder to help with heat transfer. Once the pad is hot, poke the solder wire at the tip where it touches the pad. So your solder wire should be 50% on the pad, 50% on the tip. Add solder slowly it should melt and flow nicely if the pad is at the right temperature.

author: xrunner
author_rank: Super Contributor
timestamp: July 09, 2013, 11:03:35 pm
content: Quote from: nukie on July 09, 2013, 10:34:33 pmAgreed - solid advice. Prolly what is going on is that the specs on the little irons aren't worth spit. What I ought to do is look into the largest tip available for my Hakko and see if cranking it up will do the job. The only tip I have is way too small for this job at any temp.

author: ColinA
author_rank: Contributor
timestamp: July 11, 2013, 07:14:30 pm
content: Hit the shack and pick up one of these.http://www.radioshack.com/product/index.jsp?productId=2062752Had mine for 20+ years and only comes out to solder the big stuff. Used it on plenty of 259's over the years.

author: dfmischler
author_rank: Frequent Contributor
timestamp: July 11, 2013, 08:27:20 pm
content: I have occasionally soldered large wires/connectors/random pieces of metal with thetorchI use for sweating copper pipes (not the same solder or flux. though).

author: xrunner
author_rank: Super Contributor
timestamp: July 11, 2013, 11:18:25 pm
content: Quote from: ColinA on July 11, 2013, 07:14:30 pmOh yea I got an old Weller. I used it on the 259s. Worked reasonably well. Maybe I'll start using crimp connectors.