simple Hi-Tek coating

[HI-TEK]

Guess what colour combination?

My colour mix guess is
First picture is TRUBLU plus TMG Gold
Second picture is TRUBLU plus Modified TMG Gold.

[HI-TEK]

My bismuth here is 20 BHN and brittle.

I wanted to try Hi Tek coating bismuth before ordering alloy from Rotometals... their 10% tin alloy melts a bit low,too,let's see.

At least I can make lead-free pistol ammo now,fwiw.

I know that Lead alloy with more than 20BHN hardness was coated and used successfully in Rifle ammo.
If Bismuth/alloy, hold up the high energy deformation, it also may work with Rifle, but not sure, and be very careful about such use.

[Tazza]

I wonder if the biggest issue with using it in rifles could be the melting point. It melts lower than lead alloys do, wonder if that could be an issue? Unless you can alloy it with other metals to get the melting point closer to lead.

[HI-TEK]

I wonder if the biggest issue with using it in rifles could be the melting point. It melts lower than lead alloys do, wonder if that could be an issue? Unless you can alloy it with other metals to get the melting point closer to lead.

You may be correct with low melt point of Bismuth to be a major question factor.
Even with Lead alloys, gas checks were used, as the heat from powders affected base area and resulted in gas bypass cuts and Leading.
I don't know for sure, but it seemed from various feed backs, that applying two or three coats of Hi-Tek, removed the need for Gas Checks, and no Leading or gas cutting was evident.
Because of the high insulating property of Hi-Tek, the only way to determine suitability is to try it with Bismuth or its alloys.

[Tazza]

I wonder just how much melting of the base actually occurs, causing leading. The amount of time the projectile is subject to the heat of burning powder would be in the milliseconds. Surely not enough time for it to melt? I always thought of a gas check being a good solid base for the gas from the burning powder to push on, creating a tight seal in the bore. I'd like to think the bulk of the heat in the actual projectile is friction between it and the barrel.

With the layer of hi-tek, it means it needs a lot of heat and pressure to get to the lead under it, i have run coated "soft" lead in my race gun without leading issues, soft as in wheel weight hardness. I do get carbon build up in the compensator (good 'ol AP100), but a soak in hoppes no9 gets rid of that easily. The barrel was only ever cleaned with a plastic brush and a wet patch.

I know i can get away with 2 coats, but i do 3 just so they look "pretty"

[Stephen Cohen]

I wonder just how much melting of the base actually occurs, causing leading. The amount of time the projectile is subject to the heat of burning powder would be in the milliseconds. Surely not enough time for it to melt? I always thought of a gas check being a good solid base for the gas from the burning powder to push on, creating a tight seal in the bore. I'd like to think the bulk of the heat in the actual projectile is friction between it and the barrel.

With the layer of hi-tek, it means it needs a lot of heat and pressure to get to the lead under it, i have run coated "soft" lead in my race gun without leading issues, soft as in wheel weight hardness. I do get carbon build up in the compensator (good 'ol AP100), but a soak in hoppes no9 gets rid of that easily. The barrel was only ever cleaned with a plastic brush and a wet patch.

I know i can get away with 2 coats, but i do 3 just so they look "pretty"

I tend to agree with you Tazza, back in the dark ages of wax lube I tried cardboard gas checks which were just discs punched from primer boxes, I used these in my 9mm auto to try and stop leading, it did not work. I found that there was no burning of the discs and in fact one could still read the writing on them, I have to say I no longer believe that the heat generated by powder flame has any effect on cast bullet bases, it is as you stated such a short duration to have any effect. I have never seen or know of anyone who has seen a cast bullet base melted by firing. In the case of Bismuth I would not bet my life or the safety of my firearm on it. Regards Stephen

[HI-TEK]

I tend to agree with you Tazza, back in the dark ages of wax lube I tried cardboard gas checks which were just discs punched from primer boxes, I used these in my 9mm auto to try and stop leading, it did not work. I found that there was no burning of the discs and in fact one could still read the writing on them, I have to say I no longer believe that the heat generated by powder flame has any effect on cast bullet bases, it is as you stated such a short duration to have any effect. I have never seen or know of anyone who has seen a cast bullet base melted by firing. In the case of Bismuth I would not bet my life or the safety of my firearm on it. Regards Stephen

Stephen
You are correct with heat affecting base of cast.
My explanation was not adequately clear when I referred to heat and gas cutting.
If we examine gas cutting, there is a tapering melting starting from edge of base and the melting of alloy travels along bearing surfaces. The widest melt is near the edge of the base, and the travel of gas cutting, tapers off as gasses travel towards to pointed end of cast.
I was really trying to refer to this phenomena. The gasses travelling/bypassing alloy simply is hot enough to melt that alloy.
If Cast correctly sized for bore, hot gasses are prevented in majority to do damage like gas cutting. The heat behind well sealing alloy, should not damage alloy due to short resident time of that alloy after firing.
I agree also with Tazza, that friction heat by Lead and bore causes damage to cast.

[Petander]

My colour mix guess is
First picture is TRUBLU plus TMG Gold
Second picture is TRUBLU plus Modified TMG Gold.

Spot on,Sir!

The mix was done in the bowl,2 ml TruBlu and 3 ml Gold. 5 lbs Bullets were "pre-wetted" with ~2 ml of metho for a slightly longer swirl time. Very low humidity here now. Surface temp was max 185°C at the end of bake for max 30 sec,bullet core being 180-182°C for the last 2.15 min.

Smashing felt like 15 BHN after setting overnight.

[Stephen Cohen]

Joe, I fully understood what you were trying to put forward in your first post, and I certainly did not mean to assert you were wrong in what you were trying to convey as I agree with all you said. I am certain a properly sized and Hi-Tek coated cast bullet will never suffer any gas cutting. Sorry for the misunderstanding. I actually considered the post by Tazza to be a look at things from a different angle, especially his mentioning about a coat of Hi-Tek allowing the use of soft lead alloys in many cases. Regards Stephen

[Petander]

[HI-TEK]

How pretty are they...…
Purple ???? how did you get that colour?

[slide]

Joe, I can't figure out a way to get a bhn on hi-tek. I am going to take a break from it and maybe try it again later.

[HI-TEK]

Joe, I can't figure out a way to get a bhn on hi-tek. I am going to take a break from it and maybe try it again later.

Thanks Slide,
I had always had suspicions that it was not going to be an easy task. You had a go, and that is what counts.
I have had another thought when you feel like having another play.
I am wondering, if you use a piece of sheet Lead, (roofing Lead) scuff it up on one side, to remove surface oxidation, and coat that side with HI-TEK.
It may be easier to simply brush on some powder onto scuffed side because the Lead sheet is laying flat.
May be do a couple or 3 coats. Bake all layers well and don't worry about colour.
Then, when cool, do a hardness test on coated side, then do a hardness test on opposite (uncoated) side.
I think, (my theory, and don't know if it will work or not), that a flat sheet Lead may be easier to coat evenly and do measurements on, than a cast alloy.

[slide]

I"ll give a go when ready. Good idea!

[Ausglock]

Joe..
Whay not take a large bullet, say a 230gn 45 and machine a flat on one side.
coat it, bake it x2 then machine a flat on the other side to remove coating. that way you have a bullet that has been through the same process. 1 side coated and the other uncoated. hardness test both sides.

[Petander]

How pretty are they...…
Purple ???? how did you get that colour?

That's a Mystery Mix with Candy Apple Red and some other colours which I don't remember...

Blue is shooting fine,I was clinging an A4 -size plate @ 75 m pretty good with 38 Special wadcutters.

This target is typical 25 m.

[slide]

Ausglock, I will try your idea too!

[Petander]

My tester reads a little higher BHN with Hi Tek coating.

Like the coated bullet here reads 12 BHN but the scratched reads 10. 10 is correct for the lead.

I have no idea of the actual hardness of Hi Tek costing though, if that's what you folks are talking about.

[slide]

We are trying to determine if hi-tek does have bhn. I am beginning to wonder why,this one is a doozy!

[HI-TEK]

My tester reads a little higher BHN with Hi Tek coating.

Like the coated bullet here reads 12 BHN but the scratched reads 10. 10 is correct for the lead.

I have no idea of the actual hardness of Hi Tek costing though, if that's what you folks are talking about.

Petander
A question was asked as to actual hardness of cured HI-TEK.
Various methods were tried, without success.
From your results, it seems that the HI-TEK actually offers 2 BHN surface hardness to cast alloys. I don't know what a 2 BHN number increase relates to alloy that is 10BHN.
I would think, that the 2 BHN increase would be beneficial.