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Why isn't my solder sticking?


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I'm somewhat of a soldering newbie with a few projects under my belt with few issues outside of my novice abilities.  

 

I'm trying to solder some large pieces of Eduard brass (1/72 MOAB.  A must if you're building an MC-130 like me).  I'm not getting any solder flow and all I get are a few globs of solder goo stuck to a part I don't want it to.  

 

The flux I'm using has zinc chloride in it and the solder is Radio Shack (RIP) "silver bearing" type. 

 

My guess is that I'm not using the correct solder.  Eduard brass is only brass on the outside because is silvers up when sanded.  (Does Eduard use brass plates nickel?)

 

Thats all I've got. 

 

Thanks. 

 

Chris

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1 hour ago, swimmer25k said:

I'm trying to solder some large pieces of ...

"large pieces" ... hmm ...Even before getting to the flux and solder types question there is the question of heat and whether enough heat is applied at solder point; I don't know how large 'large' is, will have to look up Eduard's website, but large can radiate heat away from soldering point. 

Edited by southwestforests
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A question, what diameter is the solder, spaghetti noodle? Soda straw? 

If it is larger it would again be a heat question.

 

Now, I've not soldered photoetch parts but have soldered solid brass parts for trains, so whether it is a chemical compatibility with the photoetch question is beyond my knowledge.

 

Any chance this might shed any light on the situation?
http://store.curiousinventor.com/guides/how_to_solder/kind_of_solder

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1 hour ago, swimmer25k said:

... and all I get are a few globs of solder goo stuck to a part I don't want it to..

Could this be a factor?

Quote

 

"One Other Thing

Clean your soldering iron tip before putting it away. How?
While still hot, dip it in the flux, then apply some solder in
a uniform coat around the tip. Then unplug it and let it
cool. This prevents the tip from oxidizing (rusting), which
would cause the solder to roll off in hot blobs of liquid
trouble! Trust me on this. You can also sand the tip so it's
bright and shiny when you begin another session"

 

 
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I solder the rails on my model railway so that's my only experience with soldering. I may not be of help here but here's my suggestions. You said you've used flux, and flux is essential to get a good solder flow. Don't spare the flux! Another thing that I find works is tinning the tip of the soldering iron...have you tinned yours? The next is heat. Without enough heat the solder will only ball up and not run. It only gets worse if you continue to force it! Let your iron get good and hot before using it. If you have a heat setting on yours set it up to the high range.

 

Good luck with your project!

HTH...

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Ah, another train person! 

Oh, something else, when soldering something where small parts are attached close together to a large metal part, there are issues with the part adjacent to the one you are trying to attach ending up getting hot enough to melt the solder and the part comes loose.

I haven't done that situation but people who have report using different solders with different melting points and start with the highest first then work to lower melting points.

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One consideration may be your "silver bearing" solder. As a general rule, silver type solders require a  higher temp and result in very strong joints. Hence, your heat may not be high enough at the site or the joint may not have sufficient heat distribution to allow melt and flow. All the above points are great too, flux, tinning your iron AND both pieces to be joined, enough heat, clean metal, and good physical contact ensure a good joint. Perhaps you might consider a lower temp solder and flux? If your soldering an adjacent piece, you can prevent that one from loosening by applying tissue soaked in water to prevent melting of the previous solder joint. Regardless, i admire your patience. I'm sure your have a nice piece (and strong), when done!

Best of luck,

 afoxbat

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Full silver solder needs very high heat for its higher melting point, but produces a much stronger though more brittle bond. Silver bearing means you'll get some of those qualities.  Also brass is a good heat sink.

 

Lead-based solder has a lower melting point, needing lower heat, while providing lower strength but higher ductility. Personally, I think this is better suited to the stated task. But, lead-based solder isn't used anymore for good reasons!

 

You might try a tin-copper solder instead of silver-bearing solder.

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5 hours ago, dnl42 said:

Lead-based solder has a lower melting point, needing lower heat, while providing lower strength but higher ductility. Personally, I think this is better suited to the stated task. But, lead-based solder isn't used anymore for good reasons!

True, but when the RoHS compliant solder became available, many electronic companies were faced with the problem of the solder not sticking to the printed circuit boards and the components. But I think this has been solved by now. So I guess it is a temperature problem.

Edited by Lancer512
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22 hours ago, afoxbat said:

Please tell us how you make out. That kit is cool (and pricey). I'm sure you'll prevail but tell us what worked for you. 

Best of luck,

afoxbat

 

 

Thanks Fox,

 

Im a sucker for interesting subjects and kits.  

 

I bought the Italeri MC-130E a few months back and started scribing it right away.  I got sidetracked and switched to an Academy F-4.  

 

Even though I was working on a different build I went ahead and bought a few resin and PE sets for it.  I had zero intent to do any work on the cargo hold, but then AIM came out with their MOAB.  So, more money out the door.  AIM makes a nice weapon, however, you're on your own for the cradle.  When Eduard announced their kit I quickly knew I had to have it (along with their PE cargo bay parts.  

 

I'll post some pictures along the way.  Right after I finish the Academy F-4.....

 

chris 

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Good show, Chris! Looking forward to the pics too! Yes, that Academy F-4 can be most distracting- rates up there with the Zoukei-Mura, Phantom, but more affordable. Am a real Phantophile as well. 

Best Regards,

afoxbat

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