What happened to my flux?

[500cadillac]

I'm new to casting. The first few times I fluxed with wood shavings they just turned into white ash.

Then I added tin for making HP bullets and this is what formed on top.

Is it the tin oxidizing?

[454PB]

Looks more like dirt. Was the tin reclaimed?

[500cadillac]

It is pure tin bars.

[500cadillac]

I guess I should say that the rest of the alloy is clean WW

[geargnasher]

That's strange, never experienced that one before. I'll bet it isn't the sawdust causing that.

Gear

[lwknight]

Did you by chance use saw dust from treated lumber?
If so that could be arsenic and or salt left over.

[RP]

Looks like he used treated wood and if not maybe the added tin helped remove more crud that was stuck on sides of pot and in the lead its self.

[cbrick]

Looks quite odd to me. Logic would say it's something that was in the alloy/wood shavings.

Bottom line is: How does the alloy cast now?

Better? Worse? The same?

Sawdust is quite good at removing unwanted things while reducing both tin and antimony back into the melt so . . . How does the alloy cast?

Rick

[500cadillac]

Wood shavings are choke cherry that I cut myself.

The alloy casts fine I think. Before I added the tin the boolits were too small. Pics of boolits here http://castboolits.gunloads.com/showthread.php?t=92674

"the added tin helped remove more crud that was stuck on sides of pot and in the lead its self."
This kind of makes sense because I could sometimes feel grit on the sides of the pot. Also I used up a bunch of lead before I saw this stuff on top so maybe as the level went down the junk came to the top.

I was worried about this stuff being my tin because I was casting with my 4-20 pot maxed out and I read that the hotter it is the faster it oxidizes.

[jsizemore]

I got the same thing on the top of my melt when I was using a Lee 4-20 pot run hot. I used some heart pine to stir and flux. I left it on top of the melt to limit oxidation with all the added pewter,2-5%, to get good fillout of buck shot.

Since I've dropped my casting temp there is less of this on the surface. Never hindered good boolits or shot produced.

The heart pine I use has a lot of resin. Could be a result of 'green' wood sawdust and most of the cherry in my area will run sap when cut.

[fryboy]

hmmmm.... heavy ? crumbly ? some say that the tannin/oils in pine/cedar is best [shrugz] my guess would be a combination of perhaps still some impurities in the alloy and those impurities reacting to the choke cherry , choke cherry is much like treated wood in some ways it has it''s own poison tho and didnt need it pressure treated ( tho that part mite help the longevity of it lolz )

" The bark of chokecherry root was once made into an asperous-tasting concoction used to ward off or treat colds, fever and stomach maladies by native Americans[9] The chokecherry fruit can be used to make a tasty jam, jelly, or syrup, but the bitter nature of the fruit means you need a lot of sugar to sweeten the preserves.
Chokecherry is toxic to horses, especially after the leaves have wilted (such as after a frost or after branches have been broken) because wilting releases cyanide and makes the plant sweet. About 5-10 kg of foliage can be fatal. Symptoms of a horse that has been poisoned include heavy breathing, agitation, and weakness. The leaves of the chokecherry serve as food for caterpillars of various Lepidoptera. See List of Lepidoptera which feed on Prunus. " etc

http://en.wikipedia.org/wiki/Prunus_virginiana

btw ? dont take the poison too seriously unless u consume in mass quantities , note that a diluted dose was administered for meds , as noted above the proof's in the ummm pouring ;) try it next time with a different wood [shrugz] i had one batch of alloy that seemed to take several fluxings to get all the sand (?) out

[oneokie]

Leave a good layer of sawdust/ash on top of the melt in the pot while casting. Prevents oxidation and helps keep the pot walls clean.

[500cadillac]

jsizemore: Yep, green sawdust.

fryboy: Yes it is heavy and crumbly.

oneokie: Yep I was leaving a good layer of sawdust on top, but this last time it didn't turn into fluffy ash.

I have some dried spruce-pine shavings that came in a big brick. I will use that next.

Thanks everyone.

[lylejb]

I've had smaller amounts of that stuff when using green pine shavings.

I don't get it when using parafin wax.

No, it's not tin

I think it's some kind of minerals from the sap, but not really sure.

never worried about it, just scooped it off with the other junk.

hasn't been a problem.

[fryboy]

if it's real heavy u mite try adding it to ur next smelt but if it weighs about the same as a comparable spoon of dirt eh .... toss it

[454PB]

Yes, it looks like the junk that collects on the interior of my Lee melters. Apparently that sawdust flux does a really good job.