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-   -   Rust under those vintage Micarta scales? (http://www.knifenetwork.com/forum/showthread.php?t=68057)

samg 02-28-2018 01:52 PM

Rust under those vintage Micarta scales?
 
I recently purchased a vintage Brown Micarta Astro, and the first thing that I did was carefully take the Micarta scales off to check the condition of the tang.
**Take care to use the correct size screwdriver, so as not to strip the slot in the bolt.**

http://fs1.directupload.net/images/180228/tq45qij5.jpg

As I observed when taking the scales off another brown Micarta astro, there was rust. The red type that will eat away at metal if left unchecked.
So I pulled the scales off this one too, and there was rust. Natural for any kind of carbon steel.
The rust was on the Micarta when I separated them too.


http://fs1.directupload.net/images/180228/lbkbo7ls.jpg

Rust on the micarta


http://fs5.directupload.net/images/180228/xxi3p2up.jpg

I picked up some 1000 grit aluminum oxide sandpaper made for steel and carefully removed the red rust till all that was left was the black.

**Another method suggested in a post below...
For future reference use Birchwood Casey Blue and Rust Remover and you will get the rust off even down in the pit holes where the sandpaper doesn't reach. Most sporting goods stores should have it. Be careful when you apply it as it will turn the edges grey as it is caustic and etches into the metal, but it gets rid of 100% of the rust. I use a Q-tip to apply it near edges if I don't want to have to rebuff them.**


http://fs5.directupload.net/images/180228/vmmc6myq.jpg

Red rust removed.


http://fs5.directupload.net/images/180228/paqyi3la.jpg

When sanding was complete, I used some light oil to coat the steel.

** It has been noted to take care using oil or any penetrating oils, as they may stain the Micarta.***


http://fs1.directupload.net/images/180228/pogyklsm.jpg

I also used the sandpaper to remove the rust from the Micarta scales.


http://fs5.directupload.net/images/180228/2ze4wghz.jpg

Cleaned and ready to reassemble


http://fs5.directupload.net/images/180228/2mxwb9en.jpg

I put the sandpaper down on a hard surface, then put scales flat on sandpaper. I feel it best to do it this way. If you hold in hand and sand freehand, take care not to allow sandpaper to go off edge of scales and sand finish off edge of scales.


http://fs5.directupload.net/images/180228/z9jh5547.jpg

Reassemble, and good to go for a few more years.
When removing the bolts, make it a point to keep the nut oriented to the same bolt for reassembly. Also note each scale and reassemble on same side of tang it was removed from.


http://fs5.directupload.net/images/180228/ih6duw28.jpg

I haven't had any problem removing bolts. You shouldn't have to apply much torque to remove, just make sure to use a correct sized screwdriver so you don't strip the slot.
After removing the scales on the first Astro knife that I owned and found significant rust, it has been my habit since.
Perhaps someone else who has done this has some tips?

Regards, Sam

samg 02-28-2018 02:04 PM

This is another brown Micarta astro that I removed the scales for inspection a few years ago.

http://fs5.directupload.net/images/180228/s43oo39u.jpg

On this Astro I just received, it has some kind of dark discoloration on the scales. Anyone know if this can be removed? Is it just a discoloration in the original finish? If it's natural, I'll leave alone.

http://fs5.directupload.net/images/180228/zy8g552i.jpg

I'm usually of a mind to leave a vintage Randall alone, especially patina, but I don't know if this is patina. I don't know the aging characteristics of Micarta.
Any suggestions?

Thanks, Sam

cut_n_run 02-28-2018 08:21 PM

I was concerned about damaging the Astro's screw-slots with an undersized screwdriver, so I made an exact-fitting one out of an old brass freezer key--filed it down to a precise fit.

https://www.dropbox.com/s/iqvcjfvpfv...es%20.jpg?dl=0
https://www.dropbox.com/s/iqvcjfvpfv...es%20.jpg?dl=0

-Steve

samg 02-28-2018 09:00 PM

Thanks Steve.
Were the bolts easy to remove without much torque?
Regards, Sam

crutchtip 02-28-2018 10:21 PM

Not an "aging characteristic". Generally, it is chemical based staining i.e. oil.

Don't use oil on the bolts. It will stain the micarta.

jimmontg 02-28-2018 11:48 PM

For future reference use Birchwood Casey Blue and Rust Remover and you will get the rust off even down in the pit holes where the sandpaper doesn't reach. Most sporting goods stores should have it. Be careful when you apply it as it will turn the edges grey as it is caustic and etches into the metal, but it gets rid of 100% of the rust. I use a Q-tip to apply it near edges if I don't want to have to rebuff them.

samg 03-01-2018 12:27 AM

Quote:

Originally Posted by crutchtip (Post 496276)
Not an "aging characteristic". Generally, it is chemical based staining i.e. oil.

Don't use oil on the bolts. It will stain the micarta.

Thanks Joe. The bolts were in great shape, so no lubricant/oil was required to break them loose.. Are you saying that if lubricant is used to break loose the bolts, say wd40, it could stain the Micarta?
Any idea how the shop prepared the Micarta slabs? I assume they used 1/4" sheets of Micarta and cut it to shape. Judging the color of the storage recesses in the scales being light in color, the top/bottom of the sheets were factory stained at Westinghouse or wherever it came from? Then when Randall cut to shape they had factory stain to match the factory color?
So do you think I should leave this discoloration alone, that I could actually make it worse if I used any type of cleaning agent on it?

http://fs5.directupload.net/images/180301/gmzh55ku.jpg

I will have to do some research on Micarta.
Thanks Joe, Sam

samg 03-01-2018 12:28 AM

Quote:

Originally Posted by jimmontg (Post 496278)
For future reference use Birchwood Casey Blue and Rust Remover and you will get the rust off even down in the pit holes where the sandpaper doesn't reach. Most sporting goods stores should have it. Be careful when you apply it as it will turn the edges grey as it is caustic and etches into the metal, but it gets rid of 100% of the rust. I use a Q-tip to apply it near edges if I don't want to have to rebuff them.


Thanks for that suggestion.

crutchtip 03-01-2018 06:17 AM

The bolts are stainless steel, they should not require lubrication.

Yes, lubricants can stain the micarta, particularly if allowed to "sit" without being wiped off.

When the handle is prepared for the bolts, it exposes the linen or canvas making "lighter" in appearance. Not unlike the counter sink for an unlined thong hole.

The handles are buffed only at the shop. No "treatment" is used.

cut_n_run 03-01-2018 07:29 AM

Quote:

Originally Posted by samg (Post 496275)
Thanks Steve.
Were the bolts easy to remove without much torque?
Regards, Sam

Yes--no difficulty
-Steve

samg 03-01-2018 07:45 AM

Quote:

Originally Posted by crutchtip (Post 496284)
The bolts are stainless steel, they should not require lubrication.

Yes, lubricants can stain the micarta, particularly if allowed to "sit" without being wiped off.

When the handle is prepared for the bolts, it exposes the linen or canvas making "lighter" in appearance. Not unlike the counter sink for an unlined thong hole.

The handles are buffed only at the shop. No "treatment" is used.


Joe, just as drilling bolt holes expose the "bare" Micarta, doesn't the "bare" Micarta get exposed when the scales are cut to size? Requiring the edges to be restained? I thought the Micarta was impregnated with the stain when manufactured, the color being part of the batch, through out.
I guess what I am getting at is that if the color is surface, and if enough cleaner/ pressure is used, it could lighten/remove color?

I have read that Dawn detergent and a toothbrush can clean whatever surface stain or grime that is on the scales.

Thanks, Sam

crutchtip 03-01-2018 08:36 AM

The fibers being exposed by drilling/sanding will make it appear lighter

The color of the micarta is a dye used in the resin, not added after the fact.

Many folks make the mistake of seeing the yellowing of the linen or canvas in a black micarta handle and think it is brown. This is where the "veined green" material Bo mentions comes from. Again, the resin denotes the color of the micarta.

As with most materials there is some porosity. So I presume if you get something in the fibers, it could wick through the fibers to some degree thus staining it.

Again, the micarta is buffed on a wheel as are all handle materials including leather.

samg 03-01-2018 12:06 PM

So if the dye is in the resin, in the case of this scale cavity cutout, it's very light in color as a result of routing the cavity out. When the scale over all handle shape is done, assuming that process would leave it lighter in color as well, like the routed cavity. So if dye isn't added, the original color after routing/cutting comes back with enough buffing? If left unbuffed, it remains the color of the cavity?

Thanks Joe, Sam

http://fs1.directupload.net/images/180301/9kqk2xad.jpg

http://fs5.directupload.net/images/180301/w2ah7uog.jpg

crutchtip 03-01-2018 12:53 PM

Yup, not exposed to anything including the elements.

samg 03-01-2018 01:17 PM

By the way Joe, while inspecting this astro, I noticed a very small number "2" centered under the Randall stamp. Any idea what that would be for? The number font is a different size than the one used for the Merchant Marine Z number on the engraving.
The knife has an engraved name on the other side, so ownership was already established.
Maybe just a mystery...

http://fs1.directupload.net/images/180301/unwogk24.jpg

Also, see the wavy look of the metal under the letters USMMD? Is there a chance this knife at one time could have been plated? I'm not sure, there are indicators that make me think possibly, but the blade illustrates carbon discoloring. Do you see that with plating?

I know it's hard to tell by photos...

Thanks Joe, Sam

http://fs5.directupload.net/images/180301/ciuhkhiq.jpg

http://fs5.directupload.net/images/180301/4mkdgfeq.jpg

http://fs5.directupload.net/images/180301/dr5fst2k.jpg


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