# 1st time working with aluminum core



## Albinogek (Jun 16, 2015)

Have a question & hoping someone can assist me on how to go about sanding the aluminum core. Should I sand down the sides of the aluminum prior to gluing it to the wood, just to take out the scratches caused by the file? And if so what type of sand paper should I use? (Grit) & up to what number? Any suggestions would be greatly appreciated.












































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## Albinogek (Jun 16, 2015)

Have already epoxied the wood to the aluminum core. Working on Micarta Palm swell next!























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## chacal (Jan 15, 2016)

nice! very very nice!

How cast the aluminium ? lost wax? or its cut from a aluminium block


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## Albinogek (Jun 16, 2015)

It's cut from 1/4" 6061 aluminum plate. Thanks for the response!

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## honorary pie (Feb 12, 2015)

Looking good sir. I'd recommend pinning it or using mechanical fasteners, as it looks like you have no relief cuts or variations on the surface of the aluminum to create a strong bond.. as far as sanding, it can look good sanded up to 220 or 300, but the REAL magic happens at subsequent higher grits.. an oil or CA finish will probably be your best best. That wood look awesome and deserves some love.


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## you'llshootyereyeout (Apr 5, 2014)

The real trouble you'll find will be the aluminum dust getting into the pores of the wood. Some have tried to put blue painters tape over the wood. Sand along the core and keep the paper clean.


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## Albinogek (Jun 16, 2015)

Appreciate the feedback honorary pie & you'llshootyereyeout

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## Albinogek (Jun 16, 2015)

I did score the aluminum & the inside of the wood before gluing them. I am however planning on pinning it. Plan on using a mosaic pin along with some brazing brass pins. I am in the process of making some Micarta for the palm swell & plan on using expoxy to glue it as well. Should I place the pins after that & then start sanding? Just not sure if the pins would be easy to sand, as I said before, this is my 1st, any insight is greatly appreciated

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## you'llshootyereyeout (Apr 5, 2014)

I would drill the holes for the pins while the slingshot is still flat


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## Chuck Daehler (Mar 17, 2015)

Brass is pretty easy to sand and equalize to hard wood, you'll have to use a hard sanding block instead of a foam or soft one...to make sure the brass equalizes to the wood flush.

Matt brings up a good point about getting black aluminum dust into the pores of wood resulting in discoloring of the wood. Metro issued a post on how not to let that happen... Since I don't make al core SSs I didn't bookmark it...but it's on the forum...perhaps Erik can post it again for you. I think he used linseed oil somehow...I forget. Getting the aluminum flush with the wood will be tricky since they have dissimilar hardnesses and properties just as brass and wood do. Plenty of course succeed at perfect flush joints. Also, polishing the aluminum without blackening the wood...there's methods posted. When you polish any metal you create nano particles of that metal which show up black since they absorb all visible light frequencies and reflect none. Some fellas just leave the aluminum brush finished and be done with it.

I had some fairly disappointing bouts with bonding with 30 minute epoxy, came apart. I had all surfaces absolutely clean too and scored. Solution... You can drill small partial sort of shallow holes in both the Al and the wood well away from edges that will be rounded later, and fill them meticulously with epoxy..both sides, keeping away from edges that will be later filed or radiused down, using a pin or wire to make sure they're filled all the way, and clamp the parts together. The holes form little epoxy rivets which mechanically bond the two parts. When I do that I get no separations. The long cure epoxy seems to bond better than the 5 minute or 30 minute epoxy..dunno why, just seems to work better.


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## Albinogek (Jun 16, 2015)

Will take both of y'alls advice on the next step to take. Do y'all know the grit of sandpaper to use on the brass pins?

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## Chuck Daehler (Mar 17, 2015)

As in sanding the whole frame, just use the same grit in each step. Most fabricators of such frames go to 800 or even 1000 grit for wood, plastic and metals. For aluminum since it's so soft you might consider up to 1500 then a metal polish. Metal polish as warned above will blacken as it removes metal in the polishing process...so if it gets into the pores of wood it will stain it black.

I believe Metro (AKA Erick) used linseed oil to apply to the work while sanding so the metal particles would be floated away, wiping frequently with a clean cloth. If you sand in line with the metal lamination/core, it's less likely you would cross contaminate the wood with metal particles and discolor it.

I hope this advice helps, I encourage others who have made metal core/wood frame laminates to edit or correct this post and/or my previous post so you are not lead astray. It would be sad if after all the work you did that you end up with stained wood or other errant results.

Another issue is any finish compound you apply...I don't think it should cover the aluminum...so the question is, how do you apply it and still get a flushness of all laminations including the aluminum core? I can't answer this having not made one metal core frame with wood overlay...I'm merely giving some thought out loud for this since others have not had time to respond.

Matt's response to drill holes for pins while the frame is still flat prevents the drill from misregistering in the correct position, it can slide and wander a bit on a radiused edge. Also if it's flat, it sits on the drill press table perpendicular to the drill axis assuring a straight hole. If the hole is not perpendicular to the frame, it will result in an oval hole and a pin that's offset on one side as in uncentered, which will show up pretty obviously in the finished product. So get your profile exactly (as in exactly) how you want it first, drill the holes, and if it were me I'd then epoxy install the pins, THEN after the epoxy has cured fully after a day or to just to be sure it's really cured 100%, then radius and sand/finish.

Make sure the pins protrude a little from the wood so you are assured of a flush finish instead of an indented pin. You then use a metal file and carefully without wobbling the file off kilter, file them down flush with the wood, sand and finish. I've done similar work on knife handles using brass brazing rod for pins, procured from a welding supply shop.

If you can, make the hole a snug fit to the pin so you have to gently tap it into place. If it's the slightest bit loose, with slap, the finished product will exhibit an epoxy halo around part or all of the pin making an unsightly go at pinning.

Make a small bevel on the leading end of the pin, not a point, just a slight bevel which would protrude from the wood when in place. This helps prevent a lift up of fiber from the wood as the pin emerges out the other side. Unsupported fibres as Metro explained in a post a while back when pressure is applied to an edge, unsupported fiberous material splinters or lifts.

The epoxy acts as a lubricant as well, helping a snug pin through the hole. The pin should not be driven as a nail through the hole lest it splinters the wood as it emerges from the other side.

This is why Metro and others have gone to hex screws and threaded holes in the core to secure laminated frames. They are a bit "equipmenty" looking but sometimes that's appealing to some. But it eliminates the problems with flush pins.


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## Albinogek (Jun 16, 2015)

Thanks for the info Chuck! Really appreciate all your "know how", as I am still a newbie. I really enjoy reading all of your comments in other posts!

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## Chuck Daehler (Mar 17, 2015)

You are quite welcome Albi, a lot of what I know about making slingshots I LEARNED RIGHT HERE, and when you have some experience in this hobby you also can give advice to newer slingshoteers too. One hand washes the other in this world. There are a number of folks here who not only are enthusiasts but also make slingshots for a living, THEY are a bottomless pit of informational resource into which to tap...and they often give pointers on this valuable forum. You can dig into the archives and read for months about all sorts of things from making to shooting slingshots, sling bows, sling rifles, there are even offshoot links of this forum which deal with walking sticks, cutlery, blow guns and more...just poke around this website for a virtual encyclopedia of knowledge. Tournaments put on my members also welcome anyone who wants the benefits and can contribute to the social aspect of the sport. Many of our members are fervid fire arms enthusiasts as well as fire arms hunters and ammo reloaders, using a myriad of weapon types including slingshots and sling bows for competition and bringing home a little supper once in a while.

Vendor and manufacturer/inventor with a number of patents Bill Hays of www. pocektpredator.com is also a Texan as well as a number of members, I encourage you to look them up. You'll find for the most part the slingshot community has a wide variety of folks.


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## Albinogek (Jun 16, 2015)

Going to the next phase...paper Micarta for the Palm swell.

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## Albinogek (Jun 16, 2015)

Well on the way making Micarta for my palm swell.

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## Albinogek (Jun 16, 2015)

Fixing to cut out my palm swell.

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## Albinogek (Jun 16, 2015)

Scored both sides. Getting ready to epoxy the palm swell to the slingshot.

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## Albinogek (Jun 16, 2015)

Epoxied the palm swell to the slingshot. Next step will be to add mosaic & brass pins.

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## Albinogek (Jun 16, 2015)

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## Albinogek (Jun 16, 2015)

Drilled my holes, fixing to epoxy pins!

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## Albinogek (Jun 16, 2015)

Put my brass & Mosaic pins in

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## Albinogek (Jun 16, 2015)

Fixing to give her a BLO bath!

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## Albinogek (Jun 16, 2015)

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## Albinogek (Jun 16, 2015)

Just out of the oil bath, next after a few days beeswax.

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## Albinogek (Jun 16, 2015)

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## honorary pie (Feb 12, 2015)

Right on! That's a thick mama...looks great man, have you seen it in action yet?


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## Albinogek (Jun 16, 2015)

No, not yet. Still need to finish it & make some bands as well...can't wait! Thanks for the comment!

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## Chuck Daehler (Mar 17, 2015)

That's a masterpiece. I would have rounded/radiused the handle more but that's just me. Your build along is really appreciated and interesting.

I found that ordinary linseed oil cures pretty well, it does take a month to polymerize fully aided by my sunroom's warmth of course. Afterward I PU'd it several coats just to make a hard finish...fine steel wooled it and shezam, it's done...shot it today (posted much earlier on Susi gallery, board cuts).

I see more fat handled frames now days... to me at least that's good. There is of course much merit in pocketable frames but for comfort shooting you can't beat a fat frame.

The mosaic pins and paper micarta add a touch of class too, and the wood you chose is tops.

With such narrow and shallow forks, I hope you know how to shoot a semi pickle fork before you take this out to the range and shoot.

Great work, keep 'em coming!


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## Albinogek (Jun 16, 2015)

Thanks Chuck! Really appreciate it

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## alfshooter (May 11, 2011)

:wub: :wub: Excellent work !!!!


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## Albinogek (Jun 16, 2015)

Thanks alfshooter for you kind words! Really appreciate it

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