Heat treating freeze plugs

[fivefivesixphoto]

I keep seeing people talking about heat treating and hardening the zinc freeze plugs but I can't seem to find a "how to." Any chance someone can fill me in on this process? Are heat treated plugs hard enough to be used with 5.56? I was just planning on doing a .22, but I figured if I'm gonna do this form 1 suppressor thing, might as well make it multi caliber if I can.

[FarmDadCO]

You can't heat treat freeze plugs . There is simply not enough carbon in them for that to work . About all you can do is burn the zink coating off and give yourself a fine headache if you get in the fumes .

[mr fixit]

Mild steel is exactly what it says, mild. Mild steel is the softest of steels, and is made up of remelting and reusing every kind of steel scrap that comes back to the mill. The bar for quality of mild steel is very low compared to other alloys of steel, and for that reason the quality of any batch only has to meet the minimum standards. There can be large differences in hardness and quality between batches of mild steel. As another point, even using a specific grade of steel such as 4130 for a tube is a step up in quality from the mild steel used in the freeze plugs.

If you want or need to use freeze plugs, I might suggest at least using Stainless steel freeze plugs. They can't be hardened but at least they start of generally harder than the mild steel would, and have more resistance to wear.

[c5_nc]

Discussion of the suitability of freeze plugs as baffles usually creates a debate. I posted an article on forming them and got a lot of correspondence as a result. The people that tried to heat treat them reported they could not notice a difference. The plugs are a really soft cold rolled steel that is very easy to stamp. As you imagine if they are retailing for $.39-.69 they need to be made for $.10-.15 each. The exterior is commonly referenced as Zinc but it is actually Zincalume (55% aluminum, 43.5% zinc, 1.5% silicon). There are "carbonizing powders" and you can get more information and tutorials on by visiting Knife/Blade forums, but it not so clear how you would do this given the actual composition of the plugs. When you are getting to the parts produced in China the line between steel and pot metal is blurred further. There are some "old Stock" Ford OEM plugs that are 1.375" (measure 1.375-1.390 taper) if you are building a 1.375" ID tube you may want to use. They appear to be like real metal and would be more difficult to form. You may want to spend some time looking through the Seastrom Manufacturing catalog, they have interesting plugs, including ones that already have holes, countersink washers that are suitable sizes, etc. They are USA and listing grades in metals in some cases, I think it is likely they can be trusted more than some other brands, they are more pricey though.

[fivefivesixphoto]

Discussion of the suitability of freeze plugs as baffles usually creates a debate. I posted an article on forming them and got a lot of correspondence as a result. The people that tried to heat treat them reported they could not notice a difference. The plugs are a really soft cold rolled steel that is very easy to stamp. As you imagine if they are retailing for $.39-.69 they need to be made for $.10-.15 each. The exterior is commonly referenced as Zinc but it is actually Zincalume (55% aluminum, 43.5% zinc, 1.5% silicon). There are "carbonizing powders" and you can get more information and tutorials on by visiting Knife/Blade forums, but it not so clear how you would do this given the actual composition of the plugs. When you are getting to the parts produced in China the line between steel and pot metal is blurred further. There are some "old Stock" Ford OEM plugs that are 1.375" (measure 1.375-1.390 taper) if you are building a 1.375" ID tube you may want to use. They appear to be like real metal and would be more difficult to form. You may want to spend some time looking through the Seastrom Manufacturing catalog, they have interesting plugs, including ones that already have holes, countersink washers that are suitable sizes, etc. They are USA and listing grades in metals in some cases, I think it is likely they can be trusted more than some other brands, they are more pricey though.

I have zero access to any machining. So, I have to pretty much use all parts I can get from SDTA. More specifically, the tube and end caps. So unfortunately I'm stuck using the 34.3mm plugs and they don't come in stainless, at least none that I could find. It seems all the stainless ones are as you said and are a hair too big to use with the pre made tube and end cap options out there.

[T-Rex]

Do you have a drill press and vise or press available?
You're going to need them to make the FPs.
Why not get the larger SS FPs, make a mandrel to fit in drill press and spin the FPs in that.
You could then turn down the OD with sand paper, file, etc.

[fivefivesixphoto]

Do you have a drill press and vise or press available?
You're going to need them to make the FPs.
Why not get the larger SS FPs, make a mandrel to fit in drill press and spin the FPs in that.
You could then turn down the OD with sand paper, file, etc.

I do have those tools. And I thought about trying to do that but was a little worried I would end up making the side walls of the plugs too thin.

[T-Rex]

Just go a scoche at a time and try the tube. Hit it again and try the tube. Even if it took you 3 min per FP, you'd have SS fitted baffles.

Challenging yourself is a good thing.

[armalite_ar50]

Another forum I'm a member of.
This will give you some insight to treating metal with heat.

http://www.iforgeiron.com/forum/68-heat ... iscussion/

Rich

[fivefivesixphoto]

Just go a scoche at a time and try the tube. Hit it again and try the tube. Even if it took you 3 min per FP, you'd have SS fitted baffles.

Challenging yourself is a good thing.

Sounds like a plan. Now I just need to find the SS 1.375 plugs.

[T-Rex]

Just go a scoche at a time and try the tube. Hit it again and try the tube. Even if it took you 3 min per FP, you'd have SS fitted baffles.

Challenging yourself is a good thing.

Sounds like a plan. Now I just need to find the SS 1.375 plugs.

I ordered SS freeze plugs direct from Freeze Plug Factory. Napa shows they have them on line, but they couldn't even order them when I went in.

Freeze Plug Factory will sell in multiples of 10, 25, 50, or 100. Be prepared though, they are about $2 each plus change depending on what size you order. I would suggest that you order twice as many as you plan on using, you will press some off center or press too far and tear them if you use a 12Ton+ press.

Its kind of a weird system, but the way it works with freeze plug factory is this;
1. go to the website and click on the contact tab.
2. ask for a price on the size and number and material you want
3. after you get the email with the quote, go back to the site and click on the store tab.
4. under that tab choose the option 'pay by pay pal'
5. make a payment in the amount of the quote you received via email.
6. in a few days you will get another email with tracking info for your order.

It's kind of a strange way, but it is what it is, and worked for me.

[c5_nc]

Just go a scoche at a time and try the tube. Hit it again and try the tube. Even if it took you 3 min per FP, you'd have SS fitted baffles.

Challenging yourself is a good thing.

Sounds like a plan. Now I just need to find the SS 1.375 plugs.

Freeze plug factory sells that size.

Another option is to just buy a solvent trap that is already a 1.375" ID (1 3/8), that way you can use the 1.375 Tubing, valve retainers, or spacers that are easier to fit. The other option is opening up the ID of the of the solvent trap that is undersized by boring the ID at a machine shop. Turning down Titantium or SS 1 3/8 Tubing to fit inside the smaller tube is a massive undertaking on a belt sander. When you are going to reduce the Freeze Plugs it is not an easy as it may seem. The forming process dictates that you start off with a small 1/8" hole get a cone before the bore expands past the finished bore size. The problem is that if you are chucking this up to sand it down there is wear on the bore hole. I know some people have built a form 1 with the freeze plug method, and after going through this on the first one, on the next one they ordered a solvent trap that had a ID to match what they were getting on the formed freeze plugs, so they would just drop in.

[fivefivesixphoto]

Just go a scoche at a time and try the tube. Hit it again and try the tube. Even if it took you 3 min per FP, you'd have SS fitted baffles.

Challenging yourself is a good thing.

Sounds like a plan. Now I just need to find the SS 1.375 plugs.

Freeze plug factory sells that size.

Another option is to just buy a solvent trap that is already a 1.375" ID (1 3/8), that way you can use the 1.375 Tubing, valve retainers, or spacers that are easier to fit. The other option is opening up the ID of the of the solvent trap that is undersized by boring the ID at a machine shop. Turning down Titantium or SS 1 3/8 Tubing to fit inside the smaller tube is a massive undertaking on a belt sander. When you are going to reduce the Freeze Plugs it is not an easy as it may seem. The forming process dictates that you start off with a small 1/8" hole get a cone before the bore expands past the finished bore size. The problem is that if you are chucking this up to sand it down there is wear on the bore hole. I know some people have built a form 1 with the freeze plug method, and after going through this on the first one, on the next one they ordered a solvent trap that had a ID to match what they were getting on the formed freeze plugs, so they would just drop in.

That's pretty much what I planned on doing. I don't have access to any machine so I was going to do the solvent trap method with a tube and end caps from SDTA.

[mr fixit]

T-rex beat me to it, thanks.


A couple of thoughts:

IF you are forced to use freeze plugs as the baffles
and
IF you have the ability to buy a tube that they will fit inside of without modifications

then by all means take that option.

[fivefivesixphoto]

T-rex beat me to it, thanks.


A couple of thoughts:

IF you are forced to use freeze plugs as the baffles
and
IF you have the ability to buy a tube that they will fit inside of without modifications

then by all means take that option.

With all the new info I'm getting, it seems that is getting to be harder than it sounds. The biggest reason I was going to use everything from SDTA is they have the pre threaded tubes with end caps and have USA made freeze plugs that fit. If I order SS freeze plugs form FP Factory then I'll need to find a tube that will fit them. Then I'll need to have it threaded and have caps made to fit. Or am I not understanding the process and making this harder on myself than I should be?

[c5_nc]

T-rex beat me to it, thanks.


A couple of thoughts:

IF you are forced to use freeze plugs as the baffles
and
IF you have the ability to buy a tube that they will fit inside of without modifications

then by all means take that option.

With all the new info I'm getting, it seems that is getting to be harder than it sounds. The biggest reason I was going to use everything from SDTA is they have the pre threaded tubes with end caps and have USA made freeze plugs that fit. If I order SS freeze plugs form FP Factory then I'll need to find a tube that will fit them. Then I'll need to have it threaded and have caps made to fit. Or am I not understanding the process and making this harder on myself than I should be?

There is a little more to it than that. You should not discount the process of forming the freeze plugs. You are needing to be really careful on the forming and make sure your holes are perfectly centered. Variations can really effect accuracy. Buying the forming jib and shop press makes it easier, but then you have put to much money into it. But to answer your Question you have:

1.350" ID Tubes from Apogee and SDTA in Steel
-The Napa 381-3179 Plugs when formed come out about 1.353", so you have a grind on them for a bit to make them fit
-Turn down 1.375" Valve Retainers as baffles
- The SDTA has spacer material that is 1.328" or so, so it is loose fitting in the tube. You would want to have 1.375 turned down or make compression fittings out of 1.375" tube.


1.360" ID Tubes from Apogee and SDTA in Ti
-The Napa 381-3179 Plugs form about 1.353" still, so they are too loose. I think if you skeleton the sides prior to forming they may expand more. I've heard of people actually running them this loose in the tube.
-Same deal as above on the spacers

1.375" ID Tubes from Diversified Machine (SS and Ti)
- Maker sells tube that is a direct fit, .035" Ti and freeze plugs that are a direct fit.
- Valve retainers that already 1.375 drop in
- Some 1.375 Tubing drops in for spacers, some is oversized and requires sanding
- Freeze plugs that are made for 1.375 are typically oversized so you can sand them or press them in.
- The ID on this tube is bored to 1.375" so you can request to be a certain size, for example I have one that is 1.381

1.486" ID Ti tube from DM
- Maker sells tube that is a direct fit, .035" Ti and freeze plugs that are a direct fit.
- 1.5 Valve retainers are easy to reduce or you can machine your own baffle solution
- Buy 1.5" tubing and sand it down or turn it down
- Have the tube bored to 1.5" to use 1.5" components.

I've done some of the above and having the ID of the tube made to the ID I wanted was certainly the easiest. The next would have been starting with the 1.375" ID tube.

[fivefivesixphoto]

T-rex beat me to it, thanks.


A couple of thoughts:

IF you are forced to use freeze plugs as the baffles
and
IF you have the ability to buy a tube that they will fit inside of without modifications

then by all means take that option.

With all the new info I'm getting, it seems that is getting to be harder than it sounds. The biggest reason I was going to use everything from SDTA is they have the pre threaded tubes with end caps and have USA made freeze plugs that fit. If I order SS freeze plugs form FP Factory then I'll need to find a tube that will fit them. Then I'll need to have it threaded and have caps made to fit. Or am I not understanding the process and making this harder on myself than I should be?

There is a little more to it than that. You should not discount the process of forming the freeze plugs. You are needing to be really careful on the forming and make sure your holes are perfectly centered. Variations can really effect accuracy. Buying the forming jib and shop press makes it easier, but then you have put to much money into it. But to answer your Question you have:

1.350" ID Tubes from Apogee and SDTA in Steel
-The Napa 381-3179 Plugs when formed come out about 1.353", so you have a grind on them for a bit to make them fit
-Downsize 1.375" Valve Retainers as baffles
- The SDTA has spacer material that is 1.328" or so, so it is loose fitting in the tube. You would want to have 1.375 turned down or make compression fittings out of 1.375" tube.


1.360" ID Tubes from Apogee and SDTA in Ti
-The Napa 381-3179 Plugs form about 1.353" still, so they are too loose. I think if you skeleton the sides prior to forming they may expand more. I've heard of people actually running them this loose in the tube.
-Same deal as above on the spacers

1.375" ID Tubes from Diversified Machine (SS and Ti)
- Valve retainers that already 1.375 drop in
- Some 1.375 Tubing drops in for spacers, some is oversized and requires sanding
- Freeze plugs that are made for 1.375 are typically oversized so you can sand them or press them in.
- The ID on this tube is bored to 1.375" so you can request to be a certain size, for example I have one that is 1.381

1.486" ID Ti tube from DM
- 1.5 Valve retainers are easy to reduce or you can machine your own baffle solution
- DM sells correct fit tubing for spacers
- Buy 1.5" tubing and sand it down or turn it down
- Have the tube bored to 1.5" to use 1.5" components.

I've done some of the above and having the ID of the tube made to the ID I wanted was certainly the easiest. The next would have been starting with the 1.375" ID tube.

I've heard a bit about the valve retainers but that they don't baffle as well as formed freeze plugs. Is there any merit to that? I planned on actually buying the forming tool. I know I'm going to make a few of these as will my brother so we'll probably split the cost of the forming tool.

[c5_nc]

I've heard a bit about the valve retainers but that they don't baffle as well as formed freeze plugs. Is there any merit to that? I planned on actually buying the forming tool. I know I'm going to make a few of these as will my brother so we'll probably split the cost of the forming tool.

That would be not accurate based on the ones I have tested or seen other videos of.

The ones I have tested on video have never been the exact same configuration, meaning the same bore and length. The two Valve Retainers cans I have tested were quiet for their configuration. I recommended a certain configuration of the VR discussed in my thread here:

Lil' Chubby 5.75" AL can with video:
viewtopic.php?f=10&t=132654

I have not go around to posting thread on my other VR can, but it was with a 8.375" Tube for a OAL of 8.9". I did shoot it against a AAC SDN6 (which is shorter) and the VR can was quieter on 5.56, 300blk, and 300blk subsonic. I did post several other videos of that can. This can is a 308 can it was a little quieter than a 7" FP can that had a .27" bore.

That can on 300blk subsonic
https://www.youtube.com/watch?v=CccZObvE3VM

A FP 5.56 can vs VR 30cal can tested with 5.56
https://www.youtube.com/watch?v=3vcML6kXUSo