How to Install Tromix weld on rail and H&K sights

[RXtacy 1]

This thread is meant to detail how I installed the Tromix weld on picatinny rail w/ H&K rear sight base, as well as the CSS weld on front H&K sight. This is simply how I chose to do it, if you have another method you used feel free to post it up. I chose to plug weld both the rail, and front sight for the cleanest install I could think of. It keeps the welds hidden, and once ground/refinished they should be invisible.

 

We'll start with the pieces laid out. The rail from Tromix is a very nice piece.

 

 

First thing you need to do is align the rail on the dust cover, and trace out the location. This step is VERY important, and you need to make sure the rail is straight while the cover is installed on the gun. Double and triple check yourself before performing any welding. I used a combination of digital level, caliper measurements, and visual references to ensure the rail was on straight when installed. Once I had the rail positioned properly I traced out the outline.

 

 

Once you have the outline traced remove the rail. I then flipped the cover over and center punched where I wanted my plug welds.

 

 

Here you can see the indentations from the center punch. Place the rail section back on the dust cover to ensure your plug locations make contact with the rail. Especially important at the rear sight base where there is a relief in the rail.

 

 

Next you need to drill out the locations for the plug welds. Remove the rail section and flip the dust cover over. Drill from the inside out using the center punches as guides. I used a 5/32" drill bit. Size doesn't really matter, but I wanted to make sure I had a good amount of weld contact without making it difficult to fill. Once drilled it will look something like this.

 

 

All you need for this is a hand drill, center punch, and I used a deburring tool to clean the holes up so the rail sat flat.

 

 

Once you have your holes drilled wipe everything down with Acetone, You may also want to remove the factory finish around the weld area to make welding easier. I didn't and it went fine, but YMMV. Once both pieces are clean reinstall the rail, and again triple check alignment. I can not stress how important it is to take your time and make sure everything is plumb. It will be a real b**** to remove once welded. I used masking tape to secure the rail while welding. I would imagine there are clamps that would work well also, vice clamps for instance.

 

 

Here it is positioned and ready to weld. I did a small tack weld on one of the plugs and rechecked the alignment on the gun. Luckily it was still properly positioned, but at this point would be easy to break the tack and reposition if necessary. After the sanity check I continued to finish the plug welds. I started from the rear of the dust conver, then went to the front, then second up from the rear etc. This ensured the heat was evenly distributed to eliminate any warping. I started from the rear as there is the most structure there to reduce warping.

 

Once done it will look something like this.

 

 

I used a Tig machine at about 50 amps with 316 filler rod. Most of the heat was directed at the much thicker rail section. This worked pretty well, and there was no noticeable warpage. This piece is rock solid after welding. The dust cover will bend way before this piece comes off.

 

 

 

 

Once the welds are finished it's time to grind them flat. A simple die grinder or dremel with a stone or sandpaper roll will work well for this.

 

 

After grinding.

 

 

I have not refinished it yet, but next would be to paint/durakote/cerakote etc the inside and at least the rail section on the outside.

 

Then give yourself a pat on the back and grab a beer the rail section is done.

Edited March 3, 2014 by RXtacy

[RXtacy 1]

Now it's time to move on to the front sight. I again chose to plug weld, as I don't like the look of the external fillet welds, and that introduces more heat to the gas block. To much heat can lead to warping which can mar the plug threads, or freeze the gas puck neither of which are good things.

 

First I center punched both "legs" of the front sight.

 

 

Then again drilled them with a 5/32" drill bit.

 

 

It is again imperative to make sure you have it located properly. A laser bore sight is a good way to ensure the POA is correct. Triple check yourself here again, then tack the sight in place and check again. Once you are positive it's aligned properly finish the plug weld. I used a little more current here so I could get the gas block material to puddle quickly and get the sight base/filler rod to flow into it.

 

 

 

Once you're done welding grind and refinish, and you'll never know the weld is even there.

 

That's all folks. Pretty straight forward job if you have the tools and you take your time. I still need to do the refinishing, but here are some overall pics.

 

 

 

 

Thanks for reading

 

 

[Maxwelhse 1,285]

Nice set of first 2 posts!

 

Looks like everything came out very nice!

[RXtacy 1]

Nice set of first 2 posts!

 

Looks like everything came out very nice!

I've been lurking for a while, didn't realize I had never posted before though lol.

 

Thanks!

[Maxwelhse 1,285]

 

Nice set of first 2 posts!

 

Looks like everything came out very nice!

I've been lurking for a while, didn't realize I had never posted before though lol.

 

Thanks!

 

 

Yeah, you didn't even say Hi, just "look at all this great work I did on my gun!"

 

Hope you continue to enjoy the forum!

[RXtacy 1]

I picked up a can of Rust-Oleum textured black paint to finish the job. The finish was incredibly close to the factory finish, and virtually indistinguishable.

 

 

 

 

 

[6500rpm 670]

Nice welds Bro, you also made a wise decision mounting the front sight at the rear of the block away from the threads.

[RXtacy 1]

Nice welds Bro, you also made a wise decision mounting the front sight at the rear of the block away from the threads.

Thanks man. There's been too many posts about messed up gas blocks of late