Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Whitney Trepel

#9041

Recycling Solder Paste? | 11 October, 1999

We have three buckets filled with leftover solder paste from our screen printing process. Kester has informed me that they no longer take paste, but only dross and pot dumpings. Does anyone know if there's someplace I can recycle this, or am I going to have to dispose of it as hazardous waste?

Thanks for any suggestions, Whitney Trepel whitneyt@amc.com

reply »

#9042

Re: Recycling Solder Paste? | 11 October, 1999

| We have three buckets filled with leftover solder paste from our screen printing process. Kester has informed me that they no longer take paste, but only dross and pot dumpings. Does anyone know if there's someplace I can recycle this, or am I going to have to dispose of it as hazardous waste? | | Thanks for any suggestions, | Whitney Trepel | whitneyt@amc.com | | We use Alpha for recycling and they are fine with paste. What ever you do don't dump it into your wavesolder pot. John Thorup

reply »

Scott Davies

#9043

Re: Recycling Solder Paste? | 12 October, 1999

| | We have three buckets filled with leftover solder paste from our screen printing process. Kester has informed me that they no longer take paste, but only dross and pot dumpings. Does anyone know if there's someplace I can recycle this, or am I going to have to dispose of it as hazardous waste? | | | | Thanks for any suggestions, | | Whitney Trepel | | whitneyt@amc.com | | | | We use Alpha for recycling and they are fine with paste. What ever you do don't dump it into your wavesolder pot. | John Thorup | | I've had conflicting advice in the past about dumping left-over solder paste into a wavesolder pot. Commonsense would tell me it's not good practice, bit I've been told that occassional, small quantities of paste would not cause any real problems. Anybody have any comments and/or experiences?

Regards Scott

reply »

Brian

#9044

Re: Recycling Solder Paste? | 12 October, 1999

| We have three buckets filled with leftover solder paste from our screen printing process. Kester has informed me that they no longer take paste, but only dross and pot dumpings. Does anyone know if there's someplace I can recycle this, or am I going to have to dispose of it as hazardous waste? | | Thanks for any suggestions, | Whitney Trepel | whitneyt@amc.com | | A bit of a bind, but you could melt it and treat it as waste solder, adding it to your dross (the chances are it will be quite drossy, anyway). I know one guy who does this by placing about 5 kg at a time in a small stainless saucepan (type with metal handle) and heating it with a propane torch, outdoors, of course: this burns off most of the chemistry, at the same time.

Better still, change your supplier to one who is more environmentally conscious.

Do Kester say why they no longer take it back?

Brian

reply »

Brian

#9045

Re: Recycling Solder Paste? | 12 October, 1999

| | | We have three buckets filled with leftover solder paste from our screen printing process. Kester has informed me that they no longer take paste, but only dross and pot dumpings. Does anyone know if there's someplace I can recycle this, or am I going to have to dispose of it as hazardous waste? | | | | | | Thanks for any suggestions, | | | Whitney Trepel | | | whitneyt@amc.com | | | | | | We use Alpha for recycling and they are fine with paste. What ever you do don't dump it into your wavesolder pot. | | John Thorup | | | | | I've had conflicting advice in the past about dumping left-over solder paste into a wavesolder pot. Commonsense would tell me it's not good practice, bit I've been told that occassional, small quantities of paste would not cause any real problems. Anybody have any comments and/or experiences? | | Regards | Scott | Scott

Solder paste, especially used stuff, has its metal coated with a neat, thin coat of metallic oxides/carbonates, as all solder exposed to the elements. The surface area to mass ratio of a paste is humengous, compared to a bar, so putting it in the solder wave will generate large amounts of dross, which can seed the future dross formation rate to above acceptable levels. I therefore concur with John: never do it.

Brian

reply »

Jeff Sanchez

#9046

Re: Recycling Solder Paste? | 12 October, 1999

| | | | We have three buckets filled with leftover solder paste from our screen printing process. Kester has informed me that they no longer take paste, but only dross and pot dumpings. Does anyone know if there's someplace I can recycle this, or am I going to have to dispose of it as hazardous waste? | | | | | | | | Thanks for any suggestions, | | | | Whitney Trepel | | | | whitneyt@amc.com | | | | | | | | We use Alpha for recycling and they are fine with paste. What ever you do don't dump it into your wavesolder pot. | | | John Thorup | | | | | | | | I've had conflicting advice in the past about dumping left-over solder paste into a wavesolder pot. Commonsense would tell me it's not good practice, bit I've been told that occassional, small quantities of paste would not cause any real problems. Anybody have any comments and/or experiences? | | | | Regards | | Scott | | | Scott | | Solder paste, especially used stuff, has its metal coated with a neat, thin coat of metallic oxides/carbonates, as all solder exposed to the elements. The surface area to mass ratio of a paste is humengous, compared to a bar, so putting it in the solder wave will generate large amounts of dross, which can seed the future dross formation rate to above acceptable levels. I therefore concur with John: never do it. | | Brian | I have a small shop so it looks to me like melting the paste down in a small solder pot and scraping the dross then putting the melted solder in the wave would be cost effective for our use.Provided it's the same alloy? If you have a large shop I wouldn't know how cost effective it is. So feel free to send me your unwanted buckets of paste and I will be happy to convert it into $$$$......lol I have some customers who could care less about what the alloy mix is! Come to think of it, You could all send me your wasted paste! Then I could separate it by alloy and save big bucks. NOT KIDDING PEOPLE! Contact info is on my mini page..........Jeff Sanchez

reply »

#9047

Re: Recycling Solder Paste? | 13 October, 1999

Jeff In my experiance the main problem is the flux content of the paste (up to 50%). throwing it in the wave pot results in a big stickey ring around the pot, a lot of smoke and, as Brian says, a lot of dross. A fire is not that unlikely! I tried melting it in a seperate pot and making ingots to add to the wave but it was not really worth the trouble. I did get a good doorstop however. After the pot caught fire I decided not to do it anymore. John Thorup

reply »

Jeff Sanchez

#9048

Re: Recycling Solder Paste? | 13 October, 1999

John, I'm sure your right! Cause my partner is laughing at me over the idea. "How often do we want HazMat at our door" "Do we really want to be friends with them on a first name bases" " Do we want to make friends with their friends,OSHA" I still think that there might be a way of doing it. I will play with some low temp that might work? That last thing I need is another door stop. I got lots of old equipment for that. Thanks, I will keep you posted..........Jeff Sanchez

reply »

soldering station

SMT Custom Nozzles