simple Hi-Tek coating

[HI-TEK]

My next testing will be with liquid coating.
I have coated some of the same bullets with a 5-1-7 mix of Brick red coating. these will get baked tomorrow for 20 minutes with the same bullet selection process.

I am also going to try some that are baked at 220Deg C for 6 minutes to see if that works.
If it does, I'll go to 250 DEG C for 4 minutes.
Why???
Just for schits N Giggles to see what happens.

Good ideas.
I go have some concerns about some ovens not being able to get to those temperatures, especially the hobbyist type ovens.

With heat testing,
there is another parameter that is not known.
When uncoated alloy is placed into the oven, it should absorb heat quickly.
As coatings reflect heat, at same settings and metal loads, the heat going into alloy should be absorbed at a slower rate.
Obviously, two or 3 coats will also reduce heat absorption at increased levels.

What would be great, if we could monitor in real time, and plot a graph, the temperature of oven versus temperature of alloy internally, without and with coatings.

That way we can determine, say at 200C, non coated alloy at 10 minutes, will get to a specific temperature inside, possibly to 200C, and then repeat same test with one coat, and then two coats at same loads and settings.

I am guessing, but I think, that there may be a significant difference with heat transfer rates with non coated alloy as compared to coated alloys.
I also think, that two and three coated alloys may not get to the 200C after ten minutes.

This then may explain, why some have problems with coating "not working" as it should.

Any one with ideas???

[Ausglock]

one temp probe in the oven and a second probe drilled into the core of a bullet should display any temp differential.

[220]

Can you please advise what alloy you used?
It may shed some light on why there may be long term loss of adhesion of coating.

The gold was on range salvaged lead, should be very close to commercial alloys as I sort pulling out the swaged HBWC and round balls. What is left would be nearly all commercial cast from HR and Westcast as they seem to be the most popular brands used by club members.
Blue/green was on a mix of straight COWW and 50/50COWW/pure lead.
I do recall a similar post earlier in this thread but cant recall if the cause was discovered, I'll work my way back through all the old posts and see.

[HI-TEK]

The gold was on range salvaged lead, should be very close to commercial alloys as I sort pulling out the swaged HBWC and round balls. What is left would be nearly all commercial cast from HR and Westcast as they seem to be the most popular brands used by club members.
Blue/green was on a mix of straight COWW and 50/50COWW/pure lead.
I do recall a similar post earlier in this thread but cant recall if the cause was discovered, I'll work my way back through all the old posts and see.

Previous such results, as you seem to have experienced, were found to be from alloys containing Zinc and Cadmium.
Initially, coating bonded well, and with time, it simply lets go.

I am not sure what each manufacturer uses as alloys, so I cant comment.

I question that any range, in the majority would have alloys from only two manufacturers.

Range Scrap, is not all "correct" alloys, as people use whatever Lead is available including wheel weights, and it is very difficult to separate and identify composition of shot projectiles by simply looking at them.

To determine composition, you would have to have alloy tested by Atomic absorption.

What happens with Zinc and Cadmium type contaminants in Lead alloys is, that they seem to produce a white powdery Oxidation on alloy surface with time.
This Oxidation is then becomes the film between coatings and alloys which then seems to affect long term adhesion.

This powdery film, reminds me to salt coming out of stone and drying on the surface.

Coatings cannot cope with such a problem.

Usually, metals are acid pickled/etched to remove surface reactive metals that may produce such corrosion problems and where good bonding is required.

My initial suspicion is, that alloy composition is not up to scratch.

[prickett]

Again apology for long reply.

No apology needed. It's a very interesting history. Thank you for explaining.

Extended cooking is good news as we can ensure the product is fully cured and also so we don't have to be so careful about pulling out our trays after exactly 12 minutes.

[Rompin Ruger]

I've read thru all this from the beginning and talked (email) with one US supplier at length.

One thing puzzles me in advance of actually getting set up to try all this.

I keep reading about so many pounds of this or that bullet and how long to bake... 9mm, 10mm, 45 acp, etc.

How can bake times be consistent with larger, heavier caliber bullets as smaller lighter ones? I mean, it seems to my fragile mind that a 45 Colt 280 gr. bullet is going to take a good bit longer to come to an even internal temperature than an equal total poundage of .45 or 9mm bullets?! Being far larger, heavier, denser, the 45 colt is going to take longer to reach internal temps. Did I miss something? I read every new post that comes along, but that fact seems to be lost with the semi shooters being the majority of users.

I'm not going to invest in probes and drilling bullets to see when the internal temp of heavy slugs reaches "cook temp" but it does seem to be a variable...same total poundage of bullets that are 25% heavier seemingly would take longer to reach "temp"?

NO?

[HI-TEK]

I've read thru all this from the beginning and talked (email) with one US supplier at length.

One thing puzzles me in advance of actually getting set up to try all this.

I keep reading about so many pounds of this or that bullet and how long to bake... 9mm, 10mm, 45 acp, etc.

How can bake times be consistent with larger, heavier caliber bullets as smaller lighter ones? I mean, it seems to my fragile mind that a 45 Colt 280 gr. bullet is going to take a good bit longer to come to an even internal temperature than an equal total poundage of .45 or 9mm bullets?! Being far larger, heavier, denser, the 45 colt is going to take longer to reach internal temps. Did I miss something? I read every new post that comes along, but that fact seems to be lost with the semi shooters being the majority of users.

I'm not going to invest in probes and drilling bullets to see when the internal temp of heavy slugs reaches "cook temp" but it does seem to be a variable...same total poundage of bullets that are 25% heavier seemingly would take longer to reach "temp"?

NO?

The answers are simple.
Get a good oven with Cyclone air circulation and adequate heating recovery capability, and with a good quality thermostat.
Use weight of projectiles instead of number of projectiles, and dont overload..
Consistent weight loads into the oven, will be equal time for all calibers at set temperature.
My reference to measuring internal and external temperatures was to actually measure what happens to heat transfer rates when coating is applied.
I never expected the home user to carry out such tests as it really has no meaning for the average person.
It is a technical detail that can explain results with heat transfer rate changes.

[runfiverun]

it would also be real helpful when water dropping, for a consistent bhn from batch to batch.

[Ausglock]

Core temp testing is for my info only. You only need the bullet to reach 180Deg C, not the core. The surface is what is in contact with the coating.
Fired the 20 minute bake bullets today. Fired fine. Accurate and barrel is clean. No difference to the normal 12 minute bake bullets with the same coating and bullet.

[220]

I question that any range, in the majority would have alloys from only two manufacturers.

Small club with less than 40 members, only about 50% shoot centre fires, Im the only one who casts apart from a few of the BP shooters who cast round ball.
May be a small percentage that isn't from the manufacturers mentioned but shooting with them every week I know what everyone is using.

Could be some contamination in the COWW or pure lead, I guess I will have to smelt it all again and see if it cleans up.
Mould fill out was good so didn't think zinc would be an issue. I guess I will leave a few uncoated from each session and see if I get any oxidation on them with time.

So the next question, If I cast and leave them 3 months before coating am I going to run into any trouble apart from contaminate oxidation. I guess it should be visable by this time but is there anything else that will effect the bond if they are left for this amount of time?

[Ausglock]

I have had 45 pills cast from range reclaim and left to sit for a few months prior to coating. No problems.
Check your process.

[Love Life]

I just fired some 45 acps that were coated over 7 months ago. No leading or any other issues.

[runfiverun]

calcium would probably also cause the coating issue...
zinc could easily be in a ww alloy you wouldn't even notice it until it got over about 2% except that the boolits would be a bit harder than normal.

[kentuckycajun]

Took the plunge and bought some red copper (liquid) from Donnie at Bayou Bullets. After reading through about 1500 *whew* of the 3540 posts here, I'm sure I have the process down before trying this - just can't wait to finish reading the other 2000+ posts


I have a nice convection oven and a DVOM with K type thermocouple. I placed a tray of uncoated boolits, about 200 158g RFP, to see how the oven would respond. It took about 5 minutes for the oven to come back up to 375. Should this be counted as cook time, or does time start when oven has come back up to the 375 deg temp? It regulated well between 370-380 through the cycles.

Will post back with pics after my first batch...

[Ausglock]

Cajun.
Turn oven on.
Set at 200 Deg C.
Let heat up until the thermostat turns the heating off when temp is reached.
Insert Tray of bullets and set the timer for 12 Minutes at this time.
At the 6 minute mark, you can open the oven, take the tray of bullets out and shake them and replace back into the oven.
Leave until the timer turn the oven off.
Remove tray of baked bullets.
Let bullets cool and repeat.

[leadman]

Since you will be opening the oven and placing boolits in it each time you will want to include the time it takes to recover up to temperature. Have you placed a brick or stones in your oven to help stabilize the temperature?
Donnie is great to deal with so if you have any start-up issues give him a call.
With the Red Copper make sure the coating is mixed well as the solids like to gather at the bottom of the container. I use a clear container so it is easier to see if the coating is mixed well. Go light on the first coat.

[HI-TEK]

one temp probe in the oven and a second probe drilled into the core of a bullet should display any temp differential.

That would be great to do.
However, it would be much better if we could then plot the readings on a graph continuously, against time.

I wonder who would have such equipment, even if we need to hire it, to do the tests.
It would really provide some interesting results.

[kweidner]

I have a probe I might try this with this afternoon as I coat the ones cast before vacation. I only use one rack in my ovens currently but am trying to source a commercial convection. I got about 10k to cast and catch up but the new bullet master has allowed me to focus on baking while casting. Ausglock if you find 6 minutes acceptable for new powder I will be doing the happy dance. I still use three coats for cosmetic reasons and that would cut bake time significantly at 10000 a day! I am moving to the "new" gold for the resin properties.

[HI-TEK]

I have a probe I might try this with this afternoon as I coat the ones cast before vacation. I only use one rack in my ovens currently but am trying to source a commercial convection. I got about 10k to cast and catch up but the new bullet master has allowed me to focus on baking while casting. Ausglock if you find 6 minutes acceptable for new powder I will be doing the happy dance. I still use three coats for cosmetic reasons and that would cut bake time significantly at 10000 a day! I am moving to the "new" gold for the resin properties.

Not so fast gungadin....lol ( I will need a video of your happy dance)

The secret of speeding up of cooking, is to have a cyclone air circulation inside your oven.
And I mean a cyclone, not just air circulation.

Air is a very poor conductor heat transfer medium.

You need to have the heated air, touch the projectiles as many times as possible to transfer contained heat to the alloy.

The faster air is circulated, the faster the heat will get transferred into coated alloys and more even bake.
Simply increasing temperature is not the complete answer, you may achieve reduction of cook times by simply an increase air circulation rate.

Combining air cyclone and higher temperatures is ideal set up..

Downside of higher temperatures is that in a static oven system, from batch to batch, you may get variations with colour and cure, and it will occur much quicker.

Flow though ovens, (mainly for commercial suppliers), have better possibility to control exposures to heat more accurately.

I am hoping that Ausglocks tests work out OK, but only time will tell.

I have some reservations about a few colours, and especially a few liquid versions, coping with longer cure time at set temperatures, and in fact may fail at elevated temperatures, or fail when cooked at longer times as same temperatures.

Again test will reveal all.

[kentuckycajun]

Cajun.
Turn oven on.
Set at 200 Deg C.
Let heat up until the thermostat turns the heating off when temp is reached.
Insert Tray of bullets and set the timer for 12 Minutes at this time.
At the 6 minute mark, you can open the oven, take the tray of bullets out and shake them and replace back into the oven.
Leave until the timer turn the oven off.
Remove tray of baked bullets.
Let bullets cool and repeat.

Therein lies my question: Being it takes my oven 5 minutes to come back up to temp, they would have only been exposed to 200 deg for about 1 min when I open the door to shake them around (at the 6 min mark). When I replace them after shaking, I'm sure it will come back up to temp faster (as the boolits are already hot), though I haven't timed the second temp recovery.
If it takes 2-3 minutes to come back to temp the second time (just a guess), them that only exposes them to 200 deg for another 3-4 minutes. Will this be enough to properly cure the coating?