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I used the search bar but couldn't find too much on the following..... Whats a best practice for removing these chips off the boards? Should i just go with a smash technique or what im also thinking is to grind off the connectors and the solder with a rotary tool or something....
if they're pressed in just push a small screwdriver under it and pry up. If they're soldered I think it best to just leave them on, unless you're scrapping the board.
There's three ways to remove the soldered on chips. Desolder, heat gun, or grind them off. The beat-it-to death-with-a-hammer routine won't do you much good in this case. I don't know how to desolder, and my attempt to use a heat gun only blew up a neighboring capacitor. So I use a Dremel tool with a cut-off wheel. Wear safety glasses and a dust mask if you go that route. And don't purchase a cheap Harbor Freight Chicago brand knock-off rotary tool. They don't last. I found that out the hard way.
The ones that are soldered on the same side where the chip is can be removed with a wood chisel. Make sure you know where both hands are or you can wind up with stitches or scraped knuckles.
I only do this on low grade boards. Removing them from higher grade boards will devalue the boards
Quote:
Originally Posted by PattyScrap
I found this video on stripping IC Chips.
http://youtu.be/L8GTW_7GHc0
It depends on the board, if it's a low grade board then I use a 4 1/2" angle grinder and grind the solder on the back of the board. Some people take the IC chips off the green boards or the higher grade boards if they are the type that plug into a socket, my buyer says leave those chips on the board or it will be down graded, but he also pays very well for green boards. I think it will be up to your buyer weather or not to take the IC chips off of high grade boards. Hope this helps.
What ever you do to get the pins off once you have removed the chip, don't do this...
It may look easy to just hold the chip vertical on its edge, then use a boxcutter knife to cut the pins off one edge, then turn it around 90deg& do the next edge.
Whats going to happen, after a few edges the knife will get blunter, it'll take a bit more energy to cut the pins, then you have to wiggle the knife a little so it cuts thru the first few pins & then it cuts down thru the rest of the pins.
After a few more, it'll grab one of the pins instead of cutting thru it, because you use more force, it'll rotate the chip 90deg.
That'll pull your fingers around the chip (to your right hand side) a bit.
Then with that amount of force, it'll slide down & slice the end off your finger & thumb.
http://1.bp.blogspot.com/-Wyine2mkG5...Kinkade.sm.JPG
I use a box cutter to remove the chips, I put the board down flat & for every chip I slice one side of pins off the shortest edges (both sides)
Then I turn the board 90deg & scrape a slice down one edge, I don't cut right thru it, just enough that I might cut thru a few pins but scrape all of that edge. ( I do it that way so theres something still attaching the chip to the board when I do the next cut, and it weakens that edge of the chip)
I then turn the board 180deg & then slice thru the pins on their right edge. Sometimes the chip comes off. Most of the time they stay there sqewed around a bit.
Then I go thru & lift the chips 90deg to the board with a screwdriver, still stuck on by the weakened pins.
Then I go thru with pliers or by hand & rip the chips off.
Who said anything about cutting the legs off? Never heard of it.
all this over a $4 a pound(=about 500 times) chip???
(when the board is bringing almost that anyway?)
Bear, that's why I said I only take them off low grade boards. My yard only pays 8 cents a pound for them. So anything worth more than that comes off the boards.
Yup, Billy is right only low grade boards, thats what I said in the above post. Why would anybody take the legs off the chips? I've been getting 5.00 per pound for the chips.
maybe post #2 shoulda mentioned the good ol hammer and chisel tecnique ; )
frankly i don't feel smashing a hundred chips for 4 or 5 bux are worth the time or trouble
smashing is fun
If I can pry them off low grade boards easily with a screwdriver then they come off. If the first one is difficult then I stop trying with the rest. You'll notice that is the case. Some ics are easy and others are not.
only profitable if chips are goldQuote:
Originally Posted by Bear
Heck, I'd rather smash for 4-5 bucks than wrestle with those PITA aluminum heatsinks for 40-45 cents.Quote:
Originally Posted by Bear
haha, i'm not sure which ones you're talking about, but i do know some of those tiny ones, i just leave on there ; )Quote:
Originally Posted by billygoat
maybe you missed this one too ; )Quote:
Originally Posted by Bear
i pull cpu heatsinks on the way to the cpu , haha ; )
Theres no places close to me that buys the chips or boards. There is a escrap place but thats too far away & their prices are rubbish anyway.Quote:
Originally Posted by billygoat
By removing the copper legs it makes it easyer to process.
Oh, & if posting that info saves a few people from cutting the end of their fingers off.... Safety first.
I will use a small belt sander to remove the legs.
I just found out that you can reclaim 10gms of gold from 7Kg of flatpacks.
Pliers work very well.Just grab and twist.Done
Yeah, I am that guy who did that experiment. :)Quote:
Originally Posted by eesakiwi
A little clarification is due - I processed whole mix of IC chips in that experiment (s/n bridges, ram chips, eprom like chips, ...... practically whatever size black plastic IC from electronics)
Since then (august 2011) I did many another batches but this time I separated chips to different types and sizes.
Gold yield is then different. South/North bridge - the ones with black plastic cap and green fiber bottom yield 5g+ of gold from one kilogram. I consider them as the best from IC comonly found in modern electronics. There are certain Russian made IC chips which are like gold mine but it is increasingly hard to find them and soon they may have bigger value as collector items.
I try to separate or categorize IC chips in few types:
1. s/n bridge - high grade
2. ram chips - medium to high grade
3. all other thin IC - medium grade
4. thick two sided eprom like IC - low grade
I buy IC chips or I toll refine them but this is little bit out of question for most of members as I am located in Ireland and shipping, insuring and custom charges makes them more expensive in larger quantities. However we can talk about that and we may find some way.
Pat.
For better understanding of my classification of IC chips as in previous thread
s/n bridge
http://www.goldrefiningforum.com/php...e.php?id=17461
ram chips
http://www.goldrefiningforum.com/php...e.php?id=17462
mixed but thin chips
http://www.goldrefiningforum.com/php...e.php?id=17460
eprom like chips
http://www.goldrefiningforum.com/php...e.php?id=17459
The two methods I have used are to encourage the components to come off, or to force them with brute force to break off.
First method I like the most...
I found an iron wok at a salvation army store. I then purchased kiddy play sand.
I fill the wok with the same, then put the wok on heat. I do this outside because of the poisonous noxious fumes that solder and PC boards give off when heated.
If you place the PC board on the sand, solder side down, it will heat the solder to melting point and it will be drawn away by the sand. Then later you can simply pluck the components off the board without any issues.
The other method requires a press and two pieces of case hardened steel. You simply clamp off the steel blocks so that the space between barely allows for the PC board to fit in the slot, then you load the board so that it's up and down, end to end. You place something between the press and the board so it doesn't just break the PC board, and then lower your press so that the board goes through the gape, shearing the components off. This will fling components all over the place, what I did was use a drop cloth in a funnel shape all around the press that caught the components and let them fall into a bucket.
Heat guns work also, but you should use a respirator or some sort of breathing mask so you don't breathe in any of the fumes, again they are toxic and can cause neurological damage. In other words if your face starts twitching after a few times doing this, you are affecting yourself in a negative way.
Traditional desoldering works, but it's a pain...
You can dissolve the solder with acids, and then pluck out the components, but this generates NOx gases again, and can be harmful
You can cut them off, but that is time consuming
There are many other ways, each with their merits and issues. Hope this helps some.
Scott
Welcome Pat and I recognize you from The GRF forum, it's good to have some experts stopping by here. With over 11,000 members and hundreds of guests stopping by on a daily basis, we have quite a few members from all over across the pond.
Nah... It is flattering but expert sounds more than I regard myself to be. Lets agree that every day I know more than previous one and that we all learn from each other.