Re: Success using Press-n-Peel and H202 HCL etch
2006-02-28 by Richard
Thanks for the good report. As others mentioned, you might try thermal-relief pad styles. And get a higher-power iron with internal temp feedback. It is a common fallacy, which you see all the time, that you can damage parts by using "too big an iron", or "too hot an iron". That's generally baloney. You damage a part by getting it too hot....and you get it too hot by the integral of temp and TIME. And when you use too small an iron for the job, you have to leave it on there near -forever-, to get the joint up to temp. By the time the joint's up to temp, the whole damn -part- is up to 500+ degrees. Not good. The -right- way is to use a powerful enough iron that you get the -joint- up to temp -instantly-, and get the heck -off- it; before the heat has even had a chance to flow up the leads into the part. The Pace stations I've used for years now have 70+ watt irons. No bigger physically than the usual "25w"; but ever so much quicker at soldering. The design of the tips is also slick...with a very thick section inside the barrel; so that the thermal-path is very low resistance to the tip; and so that there is great thermal-mass storing heat behind that path. Even with a typical .062" tip, it will properly flow a joint on a ground plane almost instantly...1-2 seconds at most. I do quite a bit of RF work myself; along with a lot of power-electronics; so I face the ground-plane thing a lot. I should add that these irons are also temp-controlled. Not with just a "dimmer" type of variable power-input; but with an actual temp-sense right up in the barrel; and a feedback servo control in the power-supply. You set the temp at 650-700 with the knob, and it will stay right there, whether you're soldering joint after joint with it; or letting it sit on the stand. Very very nice units. I've seen them go on ePay for a hundred bucks....which is an -excellent- bargain if they're in good working order. (they cost $700-1000 new). By the way, I'm not talking about just an iron here....I'm talking about the DEsoldering station with the vacuum handpiece too. One of these is a DREAM to have on your bench. I couldn't live without it. Once you're skilled with it, you can suck a 40p DIP out of a 4-layer board in literally only 90 seconds....and it comes out cleanly; without destroying the PTH's. About the only thing that goes wrong with these units is that the little vane-pumps for the vacuum do wear out. But Pace sells a rebuild-kit for not too dear....about 30 bucks if I recall. I've had my current one (an MBT model Sensa-Temp unit bought new) for about 10 yrs now; and have yet to even notice degradation in the vacuum. It still works like new. (I do not use it 'production', i.e. 8 hrs a day....if you do, you'll of course have to rebuild the pump every few years). ps; these Pace stations are also setup to blow hot-air for reflowing, to mount desoldering-tips for IC's (i.e. melt all leads at once), and also to use the vacuum to pick up parts for SMT assy. Anyway, if you see one of these in working-order for 100 bucks, snap that puppy up... Richard -- ============================ Please do NOT add or "subscribe" my name to ANY lists/databases.