SpudFiles

i heard somewhere that you can seal breaches on breach loading launchers with this, is it true and does it work? if it does how would you use it.

You mean seal the part that slides over the open breach yea? It'll work better as a lubricant for an o-ring. Cut a small groove on either side of the opening and put in an o-ring, then use the grease as a lube.

would the groove be alright in sch 40 pvc, and how would i be able to cut it with no specialized tools.

Well, you may be able to seal it just with the grease come to think of it. Just depends on the viscocity of the stuff. If it's good and thick, you can probably just use that. But you'll have to replace it every now and then, some will get into the barrel every time you slide the cover and get shot out along with your projectile. As long as your outer cover that you're sliding over the hole fits pretty good, the grease should be fine. I should have said that earlier.

If you do decide to cut the groove, you don't really need special tools, just a steady hand. And you don't cut it very deep at all, just deep enough for the o-ring to sit and not move.

what would i use to cut it? and if i wanted to seal a 3/4" pipe to a 3/4" pipe inside a 1" pipe would the silicone work?

Hi,

I had lots of success with cutting O-ring grooves with a Dremel, mounted to the Dremel mill table. It´s not all that expensive, and very useful.

A circle saw set VERY shallow could also be used. Ideally, a lathe.

But for the breech loader, consider to cut (file) one side off one 3/4" pipe. Look around everywhere you go for a pipe that fits really tight over the 3/4" pipe; like it´s made for that. You will find something eventually.

Grease will not seal other than quite small gaps, and not where there is pressure for an extended period o time - the pressure will simply push out the grease.

Regards
Soren

i am planning on using 1" pipe over the 3/4" so grease could probably seal that gap.

also what size of o-ring would i need to seal it ( the o-ring would be in 1" pipe) and would it just seal by being pushed through the o-ring.

sorry forgot to add this in my last post, do you put the o ring on the outside of the 3/4" i am assuming yes because you said a circular saw could be used to cut a groove.

There are a couple other ways to cut grooves for O-rings.

A V-shaped router router bit on a router table or mounted in a drill press works well. A fence parallel to the pipe to push the pipe against and another fence, perpendicular to the first, to push the end of the pipe against, keeps the groove square to the pipe axis and a uniform distance from the end of the pipe.

Or, a triangular file and a steady hand, like paaiyan said.