Hollow Underribs

[RAT]

When using hollow underribs, how do folks here do the solder fill?

My understanding is that traditionally the hollow rib is attached to the barrel with screws, but the hollow is filled with soft solder. The rib is not actually soldered to the barrel.

[Scota4570]

Don't fill it with solder.  That would make it heavy.  Might as well use a solid rib if you do that.

Tin the barrel with solder.  Tin the rib.  Jig them up.  Heat.  Add solder to the joints to fill them.  Let it cool. 

I never use screws or rivets.  Soldering is easy and there is no chance of messing up screw holes. 

[rich pierce]

Original Hawken rifles show a filled soldered end on the hollow under rib. To simulate this many use a solid rib riveted or screwed to the barrel, and file a bit St the end to give a spot to melt some solder into.

If I was simulating the same look with a hollow rib I’d jam a piece of patching in the hollow end leaving 1/4” gap, flux it, and pour melted solder into it.

[Daryl]

Good idea with the patch, Rich. A piece of wood would also work.

[Scota4570]

Maybe a little ball of aluminum foil?

[rich pierce]

Maybe a little ball of aluminum foil?

What? No smoke? Where’s the fun in that?

Actually good idea!

[msellers]

Maybe a little ball of aluminum foil?

What? No smoke? Where’s the fun in that?

Actually good idea!

Find a shop that supplies stuff for model rocketry,  they sell a fire resistant stuff for wading onto of the engine. It is used to keep the parachute from burning up when that stage fires. Looks like thick toliet paper,  but won't burn. A pack would serve as a lifetime supply, cutting pieces off of the squares it comes in.
https://estesrockets.com/product/002274-recovery-wadding/
Mike

[alacran]

Taylor Sapergia's tutorial covers how to use rivets to attach hollow under ribs. Also he shows how to prep them before attachment. Last one I did had to be soldered because of barrel thickness. I used an aluminium plug to fill the end cap.

[D. Taylor Sapergia]

I have a huge block of asbestos filled grease that is used in lumber mills in the casting of babbit bearings.  It does not melt or burn.  I apply some of this to a small bit of steel wool and shove that into the cavity about 1/4", then flux and fill with solder.  Only the last 1/4" gets filled, not the entire rib.

[jerrywh]

When I used a hollow rib I just stuffed the end with a small piece of steel wool and then filled with solder. I soldered the rib on with paste solder.

[RAT]

I've been without an internet connection since the governor ordered lock-down. Bars opened yesterday. Without access to get these suggestions... I came up with pretty much the same thing on my own.

I filled the ends of the rib with modelling clay, but left 1" at each end empty. I wrapped the barrel with foil, clamped the rib to the barrel, melted the solder in a cast iron ladle, and poured the molten solder into each end. It worked great. The foil kept the rib from attaching to the barrel. I then drilled the rib and barrel separately, put them together, screwed in some #5-40 screws, cut off the heads and peened the end into a counter sink in the rib. It looks pretty good.

I still want to know how the originals were done.

[FALout]

The last few rifles I’ve built with hollow ribs, I riveted them on, very easy to do and have yet to have one pull apart.  Like Jerry, I just shove a piece of steel wool in the end and melt some solder.