A little more on extruding solder...

Some of this might be of use in Adrian's Wood's Metal work, so I'm passing it along.

I sloped on down to the hardware store this morning with my calipers. Standard American plumber's and electrician's solder comes in a nominal 1/8 inch diameter. In reality this solder is 0.12 inches in diameter (3.048 mm). You can fit it in the 5/32 diameter hard copper tube of my low thermal inertia extruder with a tiny bit of leeway. You have to be very careful when you cut it and straighten it, however.

I bought a roll of the acid core and made a few quick tests with it. Using pliers I was able to get it into the test barrel and extrude a bit of it. After a while, however, I was unable to pump it. It appears what happens is that at the top of the melt zone in the extruder barrel the solder and the copper barrel make a tight bond which basically locks up the barrel Making the barrel hotter just moves the melt zone up the barrel a ways and keeps the lock.

This seems to suggest that the extruder barrel needs to be made of some metal which the solder will not easily wet. Nichrome 80 comes immediately to mind, but I am sure that there are many others that would fill the bill. The wetting might be a aggrevated by the acid core solder, but I suspect not.

Given that Wood's Metal also has a high lead/tin content you might be facing the same situation there. It will be interesting to see.

I somehow managed to cramp a muscle in my lower back, so I may not be on-line for a while till it unkinks.




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This is all very useful. Presumably the locking up problem would go
away if the whole barrel were above the melting point?

Sorry to hear about your back - get well soon! (And again to Simon if
his leg's still a bit dodgy.)

Yours

Adrian

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Quoting Forrest Higgs :

> Some of this might be of use in Adrian's Wood's Metal work, so I'm
> passing it along.
>
> I sloped on down to the hardware store this morning with my calipers.
> Standard American plumber's and electrician's solder comes in a
> nominal 1/8 inch diameter. In reality this solder is 0.12 inches in
> diameter (3.048 mm). You can fit it in the 5/32 diameter hard copper
> tube of my low thermal inertia extruder with a tiny bit of leeway.
> You have to be very careful when you cut it and straighten it,
> however.
>
> I bought a roll of the acid core and made a few quick tests with it.
> Using pliers I was able to get it into the test barrel and extrude a
> bit of it. After a while, however, I was unable to pump it. It
> appears what happens is that at the top of the melt zone in the
> extruder barrel the solder and the copper barrel make a tight bond
> which basically locks up the barrel Making the barrel hotter just
> moves the melt zone up the barrel a ways and keeps the lock.
>
> This seems to suggest that the extruder barrel needs to be made of
> some metal which the solder will not easily wet. Nichrome 80 comes
> immediately to mind, but I am sure that there are many others that
> would fill the bill. The wetting might be a aggrevated by the acid
> core solder, but I suspect not.
>
> Given that Wood's Metal also has a high lead/tin content you might be
> facing the same situation there. It will be interesting to see.
>
> I somehow managed to cramp a muscle in my lower back, so I may not be
> on-line for a while till it unkinks.
>
>
>
>
> ____________________________________________________________________________________
> Sucker-punch spam with award-winning protection.
> Try the free Yahoo! Mail Beta.
> [advision.webevents.yahoo.com]
> _______________________________________________
> Developers mailing list
> Developers@reprap.org
> [reprap.org]
>


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On Mon, 2007-02-26 at 19:08 +0000, Adrian Bowyer wrote:
> This is all very useful. Presumably the locking up problem would go
> away if the whole barrel were above the melting point?

Make barrel from aluminium?

Vik ;v)

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***Make barrel from aluminium?***

I think that that's my next move. The hardware store has 5/32 inch tube in aluminum and I've been interested in trying out an aluminum extruder barrel in any case.

I've also thought of using a 3/32 inch tube in that it will hold the 1.27 mm fine solder pretty well. The only problem with that is that solder at that thickness is about as stiff as cooked spaghetti. Mind, some of the bismuth-based no lead solders are pretty stiff.

----- Original Message ----
From: Vik Olliver
To: developers@reprap.org
Sent: Monday, February 26, 2007 11:21:37 AM
Subject: Re: A little more on extruding solder...

On Mon, 2007-02-26 at 19:08 +0000, Adrian Bowyer wrote:
> This is all very useful. Presumably the locking up problem would go
> away if the whole barrel were above the melting point?

Make barrel from aluminium?

Vik ;v)

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