Did I warp that MOLD??

[hoppy]

Hi All,
I am new to the form and to casting and I think I may have stepped in it. I have a Buffalo Arms mold and to preheat the mold I use a blow torch. I try to heat it up evenly around the outside and the inside, I have used it twice. The first time when the mold is closed I could not see any light through the halves. After the second use I can see a thin line of light in the nose of the cavity when the mold is closed and the sprue plate is open while I hold it up to the light. On some of the boolits there is a very fine line on the side of the boolit, not where the light is showing. I looked at the inside of the mold and it is clean along with the guide pins. Finally, my question is: did I warp the mold by heating it in this fashion? Will this line on the side affect the boolits flight? Any suggestions/opinions are appreciated. Thanks.

[M4bushy]

I doubt you warped it, check for any traces of lead on the mold faces, lube the pins and spruce plate.



Ron

[leadman]

Check for lead on the mating surfaces and lube the pins as mentioned. Then buy a hotplate or just cast some bullets to preheat the mold.

[stubshaft]

I doubt that you warped the mold. Pics of the boolits would help in assessing whether the flashing on the seam line is excessive or normal.

[.22-10-45]

Hello, hoppy. While I think a blowtorch for pre-heat is a bit much..I doubt very much you warped anything..you see, I too have a BACO mould..a .40.
With all new moulds, I always run a hard arkansas stone over face & use a med. stone to lightly chamfer outside edges of blocks. For the top mating edges..I VERY lightly stone..just enough to see a "white" line thru the oxide..this provides aditional air escape..but can easily be overdone..with fins resulting on bullet base!
Anyway, as I was doing this, I happened to see light between blocks at nose, as you did..I had not yet used this mould. Doesn't seem to show on cast bullet.

[hoppy]

Thanks guys. I will try and post a picture today.

[MT Gianni]

I consider a blowtorch to be gasoline fuelled, with a pump on the side of the fuel tank for air, and a round handle that turns for the fuel adjustment? Is that what you used? You may get it hot enough to warp if so, you probably will not with a propane torch and you can warp one with a oxy-acetlene torch.

[1Shirt]

For many years I have only dipped the mold into the melt for a period of time. For alum molds about 12-15 seconds is usually adequate to start casting. For iron/brass molds, about 30 seconds us usually adequate, The bigger the mold, (2 or more cavs)the longer in the melt. I use an RCBS furnace turned up as hot as it will run. This method requires no additional gear i.e. torch, hotplate, etc.. Good luck!
1Shirt!

[madsenshooter]

I've seen light through a few of mine, but when you have pressure on the handles, as you would in casting, it squeezes shut. If you got it too hot before your first cast, as in it too a long time for the alloy to cool, some of you alloy may have seeped outside the cavity an is now blocking complete closure.

[runfiverun]

i would look at the mold off the handles.
you may just need to knock one or both alignment pins back into the mold block

[hoppy]

Thanks guys for the advice. I tried to get some pics but the camera wouldn't focus that close. As mentioned above I did not use a blow torch but it was a benzomatic supplied torch. I think it is okay as some, not all, the boolits have a very fine line. I did see some lead, very small amount, on the edge of the mold, the inside edge that forms the boolit, and I brass wooled that off. I guess I'll have to make some more and see how they fly. Thanks again.

[mooman76]

I'm no expert when it comes to digital cameras but I found on the ones that don't take close ups too well, it's best to back away and then zoom in as much as you can.

[hoppy]

Well I finally realized MY error When I was loading the boolits I realized that as they fell out of the mold they were hitting the other half of the mold as they fell or the half that they fell from. That is why the lines are not in the same place as the line of light mentioned in my first post. I was reading a Paul Mathews article and he was able to see a thin line of light on some of his molds but they still cast very precise and accurate boolits. I believe I did warp the mold but it dosen't seem to affect the boolits. At any rate I will heat up the mold from now on by casting a dozen or so vs using the torch.

[Bullet Caster]

Welcome to CastBoolits, hoppy. We all began where you are now. I don't think you really warped the mould but you did find your mistake. I start heating my mould by casting several boolits and then return them to the pot when I return the sprues to the pot. This has always worked for me but others use hotplates to heat up their moulds. I don't think I'd use a Bernzamatic torch for heating up any moulds, though. Just cast a few and when they start falling like good boolits return the first casts to the pot and go from there. I've checked all my moulds for light entering through the nose cavities and could find none. You have to lube your mould before any attempt at casting so the mould will preform at it's optimum. Glad you're into casting and have fun. I've found that casting boolits is the most fun part of the whole reloading scene. It's nice to see your hard work come into fruition. BC