Surface prep prior to hardchrome

[RippinSVT]

Hey guys, just finishing up a 1911 build in carbon steel.  I'm sending the pistol to Metaloy for hardchroming and they mentioned that they'll give the parts a quick glass bead blasting but not polishing, etc.  My question for those who have done it, is what level of prep so you send your gun in?  The frame has faint tool marks from the machining process, and I don't know if the bead blasting will take care of that.  I'd like a satin finish on the majority of the gun, with the flats coming in a bit brighter like a brushed stainless look (400 grit polish, ish).  I suppose I should just polish the flats down to 400-600 prior to sending the gun, and let them bead blast the contours?  Also, I am TIG welding the dustcover extension and surface grinding back to flush, so if the surface is prepped adequately and evenly, aside from discoloration from heat...will anything show through the chrome or will it appear seamless?  I have dumped a lot of time, money, and effort into building a really truly custom pistol, and I don't want to be disappointed after the final plating. Thanks!

 

Kyle

[IronicTwitch]

If you have a slide already fit, send that along with the frame.  Ideally you'd fit the slide after the frame chroming.  I think they bead blast the sharp edges so the chrome sticks better.  

 

Plating is pretty thick so I'm assuming it'd cover minor tooling marks.  I've only had them hard chrome a cast steel CZ frame for me, matte finish, and it's holding up very well.

[RippinSVT]

The entire gun is effectively complete already. The slide/frame fit is very good, but not so tight that .0005" of plate will impede movement.  I took that into account when I lapped the slide/frame and actually went a little further than normal to give only the faintest amount of movement.  I like tight guns.  I've done a bit of reading that says the weld on the dustcover can be nearly hidden if the surface is prepped thoroughly, but that blasting the weld will yield a slightly different finish due to metal hardness and thus show through.  Which brings me full-circle to having to polish the flats so I don't have a big stripe down the front of the gun as viewed from the side.

[zzt]

Rip, good chrome plating adds .0006" to all surfaces.  That's .0012" added for mating surfaces. If you send in a tight slide to frame fit, one of two things will happen.  Either you get a very thin, worthless coating of chrome, or they open up the dimensions so there will be no binding after chroming.  Different firms handle it different ways.  You should check first.

 

When I inquired about having my build chromed, I told them I had sanded the flats down to 1200 grit and polished, because I was originally going to have the gun blued.  I was using APC Chrome.  They told me they were going to bead blast whatever I sent down, then they would buff the flats to 400 grit Satin (which I asked for) and Matte the rounds.  So all the work I did on the flats was wasted.  They no longer do mirror finishes.

[Dan Sierpina]

I've sent tight guns to Metaloy in the past. Just work the slide and frame with only oil upon return.

The tool marks will show even when bead blasted. If you welded on chrome moly, and didn't draw it back, the weld will show as the hardness is different where the weld is than the rest of the metal. It showed on guns in the old days when tig welding the front sight slot on 1911's.

[RIIID]

When you send it in mark where the welds are, Metaloy is the only one who can blend the two different hardness of metal when they bead blast it if they know where they are. It will still be slightly noticeable to you because you know where it is at. If you don't want machine marks noticeable remove them yourself or pay them to remove them. I have always sent guns in for hard chrome tight.

Rich

[RippinSVT]

Thanks so much guys.  I will prep the entire gun to a 220-400grit finish and remove all the tool marks, then mark the weld and notify Metaloy about it so they can work their magic with the blaster.  I don't care if it's really faint and I have to point it out for people to notice, I just don't want it to stand out like a sore thumb.  The gun is a competition gun first and foremost, but it's very unique and I'd like it to look nice and last a long time. I'll post pics later, it's a bit different than most.

[Powder Finger]

+1 to take care of tool marks yourself. also I don't know if it's still offered but Metaloy used to do "starburst" chrome finish which if I remember was a little more aggressive bead blast.

I've got a few with starburst and it looks very nice. BTW after dealing with some other chrome shops Metaloy is the only one I use now.

[RippinSVT]

Anybody got a pic of the starburst look?

[Powder Finger]

I had a gun on Brian's site but can't find it

but on Metaloy's site in the gallery

these have that finish

1st gun upper left w/ red back ground

Vic Tribbets gun

guncrafters 50GI

us shooting academy

it ends up a non shine satin finish

[RippinSVT]

Thanks!