Solder a Guard

David Loukides

David Loukides

Joined
Mar 17, 2006
Messages
1,363

This process works for me and I am sure there is room for improvement.

To Get a Clean look and a good seal I solder my guards.

To explain it right I need to start with fitting the guard correctly.

Start off point.
Blade is hand sanded to 1000grit recoso is belt sanded to 400 grit.
I leave the recoso at 400grit and will hand sand it later.

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Layout where you want the guard to stop.

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Put it into your filing jig up to your line.

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Measure the thickness that I blacked out and write it down (.130) Then write down the thickness - .005. or .125
Sorry for the blured picture I have a few of them in this how too.
Notice the guard I premachined on a mill is .108

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File and sand first side till you have removed .005

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Next
Flip your filing block over and write down your thickness. mine is .125.
write down the thickness - .005 or in my case .120
File and sand till you measure .120

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I use a micrometer out of habit for this.

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Next turn the spine up and file a radius where the tang meets the recoso.

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Same side now using a smaller file.

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File and sand to blend.Then flip over and start the other side.

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When you finish put the tang straight up so you can see you work. You should have a continues line around the recoso.
Drag a pin around it to see that there is no major steps. If so file and sand untill you are satisfied.

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Remove the jig and inspect your work.

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Sand the recoso, spine and area under the recoso. to 1000grit.
Why I do it now is it removes the burr I pushed up when filing.
Why I like 1000grit or higher it make the clean up easier later.

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Cut tang to length. In this case 4"

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Blacken the shank with a marker and slide the guard on till it stops.
Note where it marks.

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Time to fit the guard,
File the guard where it marks the tang.

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Keep on working the guard till it approaches the fit area.
I mark the guard so I do not get it turned around.

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If you wish to skip this next step its OK. go to the push tool
I use a hammer and a piece of aluminium tubing to try to drive the guard partway on,
I trust my blade to stand up to the abuse.

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After getting the fit close file and sand the high spots using the push tool to get it even closer.
I use a spacer so the push screws do not dig up the guard.

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Now layout the guard shape.

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Rough Grind the guards profile and install usin the push tool Check for gaps.

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Getting ready to solder.
I use stay-brite solder and liquid flux.
Solder pieces no longer than 1/8" make a extra or two. Put in a lid with a a little flux.
Q-tips to apply the flux to the guard and fitted area.
Dykem cleaner
Brass rods with various points on them to scrap the extra solder off.

Clean the guard and the fitted area with some sort of industrial cleaning agent. ie Dykem cleaner.
Using magnification of some sort and a Q-tip with no cotton on the end, put a LIGHT coat of flux on the contact areas of the guard and blade.

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Push together with the push screws and using the protective spacer.
Take off push tool to remove the protective spacer.
Reinstall the push tool only lightly pushing the screws onto the guard.

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Put Stay-brite pieces one on each side.

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The Torch is next.
Using a torch, heat the solder till it beads up and sticks. Aim on the solder side not the blade side.

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Now hold the tang in the vice.
You can see how the flux is working only in the area that I applied it.

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Apply heat toward the guard aiming at the spine. This will pull the solder up thru the fitting.
Using a sharp probe run it along the contact area. This will help you see that the solder flowed all the way around.


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Side note.
Keep your cutting edge cool. If it gets to hot you will lose some hardness.
I us a damp wash cloth. To wet and the water will make it to the guard and cool it also.

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Once the joint is soldered let cool and then spray with Windex to start to neutralize the acid flux.

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Spray and wipe a few times then inspect the joint for flaws.

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The Solder is only where I wanted it and will clean up nicely.

Using the brass rods as scrapers remove excess solder. Note the little solder scrapping at the spine.

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Spray again with windex, dry, Dowse with neutralite, baking soda or any thing that neutralizes acid.
Then Wash with hot soap and water, windex again.
This step of cleaning is very important. If the acid remains it will at least discolour the blade, at worst rust will form.
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Now clean and oil the blade with a good penetrating fluid.

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Sand the guard and mask.

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Sand the blade.

I will be refinishing every surface after assembly.

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With practice Makes almost Perfect!!!!!!!
 
PLEASE ASK QUESTION's
I am not a really good writer and just because I understand what I wrote doesn't mean I got all my points across.
Sincerely,
Dave
 
David - Thank you so much for taking the time to create and post this. I've been interested in this process for quite some time.

Question - How do you manage to not create little fish hooks and stop/start sanding marks on the already soldered guard face.... especially near the spine? Or, is this taken care of during refinishing after final fit up of the handle?

Again, THANK YOU!!

Peter
 
Hi Wloch248,
I start scrapping while it is still warm, solder not liquid. The windex is wiped off at this point.
Soft solder scrapes easily but you will have to sand to get it all off.
Any tool harder than brass I find risks marking the guard or blade.
 
Hi Peter,
I redo the blade and the guard again after the handle is finished.
The "Tricks" I use are,
I only use the silicon carbide Sand paper with the paper backing.
While sanding the guard it won't scratch the blade.
Use strips of the paper under a strip of brass shim stock. Use finger pressure of one hand while dragging it in one direction with the other hand.
The little areas under the recoso and over the spine I use hard wood with a chisel edge ground on it. Its width is no wider than the thickness of the blade. I then cut the paper in narrow strips to use under it.
Hope this helps out,
Sincerely
 
Wow. I just did this for the first time Sunday, man I wish I would have seen this. What a great thread, thanks for taking the time to post. I'm interested in that push tool, is that your design, what thickness is the base plate for it?

Earlier this week I thought "press fit" meant whack it with a hammer, I bent my guard and had to straighten it back out. I ended up ripping a scrap 2x4 and placing it on each side of the guard and hammering that. If I can't figure out how to make the push tool I will at least use the tubing idea. Thanks again, I'm going to print this one.
 
Great thread. I too like your push tool. I read somewhere that using a valve spring over the tang and pressing against the guard works well also. Just hold in place in a vise clamped on the tang. The spring provides constant tension against the guard. Over time, you will lose the spring as the soldering process will take the temper out of the spring, so you could treat it as another consumable.

I had a neighbor (fireman) give me a whole bunch of broken hickory ax handles. I drilled out one so that it would slip over the tang of the knife and used another as a hammer to "persuade" the guard into place. After filing, fitting sanding and fitting some more, of course. The wood is hard enough to do the job and yet left no scratches.

Just another couple of ideas..

Bob
 
Hi S2f,
I made my push tool after I saw one like this. http://www.riversidemachine.net/item608238.ctlg
It is 1/2" thick
The protector I made out if a spacer that was made for a Bowie that didn't work out.
The spacer you use needs to have one side that is kept smooth. That side goes towards the guard the screws will dig up the other side.
The tube I use is thick wall aluminium pipe. But other types of pipe will work if you have something protecting the guard from getting damaged.
 
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