H anchor casting

SCOTT SALZER

SCOTT SALZER

Active member
A friend milled me a mold for H style decoy anchors out of billet aluminum. I tried casting a few yesterday but it was a pain in the a$$ to get the anchors out of the mold. I tried re-heating the mold, putting wax in the mold and it didn't help much. Any suggestions?
 
Scott, I have a mold as well. My method is to preheat the mold on a propane camp stove, while I heat the lead in the Lee pot. Keeping the mold hot makes a better pour, and once you start molding it will stay hot! What I do is pour, watch it set up, color change, wait no more than a minute or so, and then slap the mold upside down on a piece of plywood. Try to keep it close to horizontal, only slightly tilted. Sometimes they we ill crack or break, but they just get tossed back into the pot. I think the smoking will help as Tod suggests. I will try that next time I make some more this Summer.
 
Scott,

Was your mold milled with enough "draft" on the sidewalls? If not, it needs remilled. If it has the proper draft, the anchors should pop right out. Also the surface of the mold should be smooth and free from any machining marks.

You could also ask your friend to add ejector pins to your mold.
 
Last edited:
I am with Dave on this you might need to get a chamfer tool in the same diameter you milled the slots. 82 degree chamfer the profile around the tool. File any sharp edges. Also you might want to consider using QC-10 Alloy. It is a better aluminum material that will withstand any torsional heat response. About $80 for a 6"W x 6"L x 1" Thk plate.

Regards,
Kristan
 
I have had good success making them with oak on a router table. Obviously after a while they split, but I get a couple seasons out of a mold then just make new ones from scrap, cheap and easy.
 
Yes, what Tod said. Use a candle to coat the mold with carbon. Also, once you get the mold hot, it will start popping them out quicker.



Nate
 
Scott,

If you find that there is no draft (or taper) and you're friend re-cuts your mold, 5-8 degrees per side should give you enough draft. You could always go more than that if you wish but anything over about 12 degrees (per side) is overkill for this application.
 
Last edited:
Ok, I see. There is no draft. It is cut 90 degrees, he did it on the sly at work so I don't think I can have him re-do it for me. I will try other methods of heating the mold and the candle carbon trick. Thanks all for your help.
 
If you know any old telephone guys, ask for styrene candle [used like a flux on lead cable splices]. I use it on my weights and sinkers [smokes a little when applied to the hot mold]. I put a little in the lead pot also, it flows cleaner.
 
This is really a question for Dave McCann

Could he use a carbide chamfer bit (if he could find one narrow enough, I know they make them to 15 degrees and with a bearing) to cut the "draft" in the aluminum mold? I've seen folks use carbide woodworking tools to cut aluminum.
 
[font=Verdana,Arial,Helvetica]
Could he use a carbide chamfer bit (if he could find one narrow enough, I know they make them to 15 degrees and with a bearing) to cut the "draft" in the aluminum mold? I've seen folks use carbide woodworking tools to cut aluminum.
Click to expand...

Brad,

I assume you are referring to a carbide router bit? I would not attempt to do it. For me, the risks involved would out weigh the benefits. That plus the fact that the router bit (because of the guide bearing) would not be able to cut the draft all the way to bottom of the mold.


I myself have cut aluminum sheet stock on a table saw, but even that operation, is not particularly a safe endeavor.
[/font]
 
I agree with Dave totally on this, not enough draft. My bro in law has done several molds for me over the years (owns a fab shop) and now that he is aware of this issue, he no longer does them at 90 degrees.

that said, on the old mold, I just used a file, first rubbed the file with chalk, (think kids sidewalk chalk) then slowly filed the sides just slightly. I then would clean out the file after about 50 strokes or so with a brass wire brush, re load chalk (trying to keep the soft alum from filling/cloggin the file) Took a bit to put a bit of chamfer on the sides, but not bad. About 2 beers worth. I would also say 5 degrees is really more than plenty, mine have about 2-3 degrees at the most and have no issues. I have never had to "smoke" the molds, but I have heard that helps as well. I would not try to get a router running, unless you really know how to use one, and have the proper hold downs available, that said, it woudl work but very risky. VERY light passes to just shave off material. file is safer and actually quicker with less set up time.

filing will keep your buddy out of trouble too!!

best of luck with any method
 
You must log in or register to reply here.
Back
Top