Tumble coated needs time to harden?

[dahermit]

Is it my imagination, or does Harbor Freight Red need time to harden after leaving the oven and cooling off before sizing? (did I use enough question marks?) Even when using the powder coating gun, the "flash" (excess coating that sticks to the base of the bullet), seems rubbery at first...despite being cool, util about a hour when it then becomes quite brittle.

When I tumble coated some 9mm round nose bullets today, I noticed that sizing them just when they were fully cool, some small amount of cured powder coating was rubbing off in the Lyman size/lube die and could be scratched off with a finger nail. I let them sit about an hour and the coating seemed to be more resistant to scraping off.

Is this a Harbor Freight Red thing, or are there some other powders that exhibit the same just-after-cooling, need-time-to-age property?

[chutesnreloads]

Never tried sizing so soon after baking.What's the hurry?

[Taylor]

I haven't noticed this.I will size soon as they are cool enough to handle.But I do,most of the time,leave them on the bench for a couple of hours.Or just depending on what else I have to do.Sometimes they lay there over night.

[waksupi]

Pretty much any type of paint or coating can benefit by being allowed to sit and harden for a day or so.

[Taylor]

I agree with Waksupi.If you read the instructions,one will find a curing time is required.Be it paint or glue.

[dahermit]

I agree with Waksupi.If you read the instructions,one will find a curing time is required.Be it paint or glue.That really sounds logical. However, when I just read the instructions on the Harbor Freight Red container, it says nothing about any curing time save for the time required at 400 degrees. No cigar for you.

[MrWolf]

You are dealing with Harbor Freight so lack of instructions are right up their alley :wink:

[fredj338]

Agree, why the rush? I size after the bullets are cool, several hours min, often days.

[popper]

HF is epoxy coating with heat as the catalyst. First heat melts the powder, it flows and begins polymerization. That is not finished for a while. Can be handled as soon as cool but wait a day for final cure. Even lead takes a while to stabilize after cooled.

[Tenbender]

HF is epoxy coating with heat as the catalyst. First heat melts the powder, it flows and begins polymerization. That is not finished for a while. Can be handled as soon as cool but wait a day for final cure. Even lead takes a while to stabilize after cooled.

Found that out the hard way. I would size soon as cooled enough to handle. I would wind up with a undersize boolit. If I wait for 24 hours or more my size would be right. Sometimes experience is the best teacher.