I was filing a casting when....

[Cory Joe Stewart]

I was working on cleaning up a trigger guard today.  There was a divit in the front bow from the casting process that I was trying to file out, I almost had it gone when all of the sudden it got bigger and seemed to be filled with white powder or dust.  I worked at it more but have already altered the shape of the guard more than I wanted to, and have created a weak spot.  What causes this??

Coryjoe

[davec2]

If the casting was an investment type, it was some loose investment that became entrained in the pour and trapped in the metal.  It is an occupational hazard for castings.  In the aerospace world, we X-ray castings (and welds) to find such flaws and either fix them or scrap the part before we invest more time in it.  You can clean up the cavity and fill it with braze or scrap the guard and get another one.  Sorry, but this is not unlike finding a crack or a flaw in a stock as it is worked down to final shape.  You can either patch it or start again.

[Cory Joe Stewart]

Makes sense.  I have contacted teh guy I got it from to see what they suggest.  It may be scraped because I do not think I can file the divit out. Thanks for the information.

Coryjoe

[b bogart]

Cory can you drill a hole where it is and fill it with brass rod.  Countersink both sides. cut the rod a bit longer than the hole and peen it into the countersinks?? Or thread it for a brass screw and run it in and file the head down to the level of the tang. Then maybe solder it in. File down the other side?
All this if the supplier won't replace.
Just my .02$

[longcruise]

Cory, I had a similar exp with a sand cast tg that had voids in it.  One at the front of the bow and one a bit back from the rear.  Since it was an unconventional "no-school" conglomeration of parts, I decided to put mounting screws through both of the void points.  It worked in the front but the back was so weak that the tg cracked in half.

Long story short (too late for that<g>) I soldered a strip of brass to the underside of the broken tg and then filed it into shape.  Had it not cracked in half, Bogie's idea with the screw would have been the ideal fix.  Wish I'd thought of it!

[Pete G.]

Some of the old original castings have what appears to be some sort of solder filling voids. Give that a try before scrapping the whole thing.

[Long John]

Cory,

I find that 1 out of every 3 or 4 cast parts has a flaw of some sort in it.  I always buy two of what I need at the outset.  You will be able to pick up a bunch of parts real cheap when I kick-off.  Think of how much time you are going to spend building this thing and whether you will really care if you spent and extra $25 dollars on it the first time you drop a nice buck with it.

Build it with the best parts you can find!  the cost of the parts will be irrelevant a year from now.

Long John

[Cory Joe Stewart]

Long John, I hope your extra parts do not come available anytime soon. 

I contacted the company it came from and their suggestion was to replace it.  Which we are in the process of doing right now.

Coryjoe