Trouble keeping tape on mould to gain diameter

[Rex]

The metallic tape lasts about 20 bullets then falls off. This is on a Lyman iron mould 358429.
The tape is fairly old so maybe that is the problem. The tape says good for 600 deg and I usually run the melt 700 or a bit higher, maybe that's too high.
Anyone else have this problem and what did you do?
Thanks a Million
Rex

[elmacgyver0]

Tape to gain diameter?
I must be living in a closet, never heard of this.
Wouldn't the tape make the boolits out of round?

[Hossfly]

I’ve never tried the aluminum tape but have done the bullet spin with valve compound and drill. Works but its more permanent fix. Just go slow and test often, you may get bigger cavity than you wanted.

[beagle]

Should not be happening. I've run 5-600 and it was still good.

Check your PMs./beagle

[Dusty Bannister]

What exactly is the type of high temperature tape you are using? The mold should be in the range of 400 degrees. Perhaps you have something coating the surface of the mold faces that is preventing the tape to stick? Are you cutting very small strips, or large enough to cover the mold face but not intrude into the mold cavity? "Beagling" is a common temporary method of increasing the diameter of a cast bullet.

[lar45]

I use the aluminum ductwork tape and cut thin strips for both sides. Apply to a clean mold and it should stay in place for awhile. After you cast for a bit the tape will compress some. Maybe it's the glue that cooks out?
Yes the boolits can be slightly out of round, but generally doesn't cause any problems. If you want a round boolit run it through a sixer to clean things up.

[Rex]

Beagle, I think I have a reply going to you, if not let me know. My tape is pretty old so that maybe the problem. I do pre heat the mould on a hotplate while the lead melts and comes up to temp.

[Billwnr]

how big of a bullet do you need? I'm getting around .360 from my mould.

[Rex]

my Lyman drops close to .358 if I'm careful. My 686 Smith doesn't lead when I get to .3585.
Yes, LAR, I used aluminum duct tape and my mould may need better cleaning. The tape strips were put on one half of the blocks and after a few bullets the tape may be on the other mould half. Tape is old and I'll blame that until I know better.

[Maven]

If you extend the tape to and around the bottom and sides of the mould you'll find it remains in place better.

[Rex]

Mavin, thank you I'll try that

[elmacgyver0]

I may have to give it a try sometime.

[Dusty Bannister]

Is there a difference between aluminum duct tape and high temperature flue tape? All I see discussed in this thread is aluminum duct tape and no mention of high temperature applications.

[Rex]

I'm going to take a wild guess that they are the same Dusty.

[onelight]

I have not tried this but this Flue tape is rated to 600* https://www.amazon.com/3M-High-Tempe...216689&sr=8-14

[abunaitoo]

Tape is to old.
Had the same thing happen to me.
Also clean clean clean.
Depending on the brand, vent lines sometimes hard to clean.

[RU shooter]

An option to tape is feeler gauge material use whatever thickness you need and a small amount to high temp rtv sealant did this to a old 1 hole Lee mould years ago thousands of pours later still there .

[beagle]

Just sent him a strip of what I use. Should get him on the right track. Has worked on every mould I've tried except one obstinate .41 Mag mould and that may have been my fault./beagle

[fredj338]

The metallic tape lasts about 20 bullets then falls off. This is on a Lyman iron mould 358429.
The tape is fairly old so maybe that is the problem. The tape says good for 600 deg and I usually run the melt 700 or a bit higher, maybe that's too high.
Anyone else have this problem and what did you do?
Thanks a Million
Rex

The mold never gets quite as hot as the melt. If it did the bullets would never setup. The tap is likely old. Make sure you degrease BEFORE applying the tap & then be careful about oiling the molds again.

[Billwnr]

how big of a bullet do you need? I'm getting around .360 from my mould.

Rex, I mis-spoke earlier when I said I was getting a bigger bullet. Had a casting session this morning and while letting the sprue harden and the mould to cool down a bit, I measured a cast bullet and a sized bullet. Cast came out .358 and sized came out .367. I had made an assumption based on resistance I was getting sizing the bullets and the fact the sizing die was marked .358 that I had a larger diameter bullet. Next trip out I will measure a bit more carefully with more light to see if my measurements were accurate.