spacer thickness

[mr fixit]

I know this has been asked, but I can't find the thread where it was answered.

I plan to build a suppressor for 5.56, roughly 12-14" overall, with 6" reflex, to go on 16" barrel. Stainless outer tube and caps, hoping for titanium baffles and spacers. OD of spacers needs to be 1.625" .

What thickness of titanium tube do I need for spacers?

[Samson104]

Minimal , .025".
personally id use aluminum , its WAY cheaper , and its lighter.
you really don't need any mechanical strength for pressure reason.

[mr fixit]

will the aluminum hold up to temperatures of a center fire rifle? I thought aluminum is a no no in a rifle can

[Samson104]

It will be in a position where the direct blast won't be eroding it away , in all honesty I think you can use 7075-7068 aluminum for the 3 baffel back with little worry that its gonna see the extreme temp that will cause significant wear to them. I've seen a few 308 can with 7075 outer tubes.
granted I wouldn't advise doing mag dumps through it.

[mr fixit]

It will be in a position where the direct blast won't be eroding it away , in all honesty I think you can use 7075-7068 aluminum for the 3 baffel back with little worry that its gonna see the extreme temp that will cause significant wear to them. I've seen a few 308 can with 7075 outer tubes.
granted I wouldn't advise doing mag dumps through it.

Not sure I completely understand. Do you mean AL should be ok from the 3rd baffle to the end (exit)? I think I need to line the reflex chamber area to help take the blast from the brake. But AL would help keep the weight down.

[Samson104]

yes you definatly want the area around the brake to be more heat resistant that aluminum , i didn't take that into consideration

[c5_nc]

1.625 is a off the shelf size for Ti tubing so the spacers would be easy to do, I would use Ti. I've used or fitted .028, .035, .036, .040", and .045. The 1.625 comes in .035 and .050, I would use the .035 it is a lot cheaper, this is still really thin and your baffles have to be a perfect tight fit to the tube in order to use something this thin. I staked the edges of the spacers on mine to give it more bite.

[mr fixit]

I found Ti tube online but it was only .020 wall. I thought that seemed awfully thin, maybe not.

[CMV]

.020" is too thin. Take 5-6 sheets of paper out of your printer - that's how thick 20 thou is.

I would use some flavor of steel (other than mild) for your .223 can & guts. You won't go wrong with alloy or stainless steels commonly used by others here. Mine is 4130 tube & spacers, 4140 end caps, & 416 baffles. Plenty strong.

I stole this idea from Kyle and really like it. Don't know if it's 'right', but is how I make my spacers after seeing his. Instead of just facing them square, I taper the end that meets the cone. Gives the cone more bearing surface to ride on. Do have to make a slight adjustment in spacer length to compensate, but in the [crudely drawn] illustration below you can see how I picture a square cut spacer and cone sitting together and a tapered spacer and cone (with some distance between them for illustration).

[mr fixit]

thanks, .020 sounded very iffy to me.

I am corresponding with Capt. Link in regard to my build plan. Right now I am hoping for titanium slant baffles. Picture YHM's Phantom, but instead of a monocore, individual baffles and spacers. Tube will be stainless.

looks like I can find .053 wall Ti tube. That should do wouldn't it?

[Capt. Link.]

thanks, .020 sounded very iffy to me.

I am corresponding with Capt. Link in regard to my build plan. Right now I am hoping for titanium slant baffles. Picture YHM's Phantom, but instead of a monocore, individual baffles and spacers. Tube will be stainless.

looks like I can find .053 wall Ti tube. That should do wouldn't it?

That should be perfect I don't like the idea of a thin shoulder for a baffle to sit upon.The reason aluminum is not popular is it will be eaten by the residual nitric acid and is subject to erosion.The 5.56 has lots of pressure to cut lesser metals.The best way in my opinion is to dispense with the spacers and plug weld the baffles.This will save you money in materials plus it solves baffle rotation and orientation.You can use a thin spacer .020 but then it should be tack welded to the baffles.

[mr fixit]

That should be perfect I don't like the idea of a thin shoulder for a baffle to sit upon.The reason aluminum is not popular is it will be eaten by the residual nitric acid and is subject to erosion.The 5.56 has lots of pressure to cut lesser metals.The best way in my opinion is to dispense with the spacers and plug weld the baffles.This will save you money in materials plus it solves baffle rotation and orientation.You can use a thin spacer .020 but then it should be tack welded to the baffles.

Titanium baffles and a stainless tube is a no go for welding, at least welding together.

Hmmmm.........

a stainless outer tube......stainless tubing of say .125 wall to match the ID of the outer tube, cut at the same angle as a baffle, but only about .125 long plug welded to the outer tube to serve as a shoulder for the baffle to rest against...............????

still thinking this on through

[Mongo]

I would stay away from aluminum for spacers in a centerfire rifle suppressor. Another issue that you need to account for when designing a suppressor is thermal expansion. If you are using a stainless steel outer tube and aluminum tubing spacers the spacers will grow in length more rapidly than the stainless steel outer tube. This will cause the baffle stack to be in compression and you will get buckling of the spacers causing them to collapse. The coefficient of thermal expansion for aluminum is approximately twice that of stainless or carbon steel. The interior of the suppressor will also reach higher temperatures before the outer tube. Both of these factors will result in your internals becoming longer than your external tube. This will drive stresses in the suppressor up and typically as temperature increases buckling (inner spacers) is much easier than tensile failure (outer tube). Also at the temperature of the inside of a centerfire suppressor can reach high enough that the strength of the aluminum becomes insignificant from a mechanical design perspective.