Acraglas Gel with fine Aluminum powder

[khadre]

Guys,
has anyone of you ever repair a hole or fill in a hole using Brownell's Acraglas Gel w/ one of their Atomized Metals (fine powder), specifically the aluminum powder?

How strong is the stuff?

My situations:

First finished AR forged receiver (finished shot approx. 1000rds, no issue other than below)
1. I am also planning on filling an area (bottom of fire control pocket, front of the trigger - drop-in hole) on another forged receiver that I had also milled way too deep (right thru...lol). The old JB Weld a friend repaired with, had cracked and fallen out, opening a hole about 1" x 2". Back then, I was too wet behind the ear and didn't take it slow during my milling process. Of course, I will clean and prep and remove the old JB to bare aluminum before refilling / patching.


80% AR receiver (not yet finished, just trigger hole enlarged a little on one side):
2. I am repairing a trigger pin hole in an forged-aluminum AR receiver that a drill bit had wondered off and enlarged the trigger pin hole a little bit more than I needed. I am thinking refilling that trigger pin hole w/ the acraglas and aluminum powder and redrill that one hole on that one side.

.154" is mil-spec, the trigger pin hole in question was enlarged to .163" and I do not want to use the Colt .170" trigger group if I can help it.



Edited for clarity in situations.

 

[HSMITH]

A much better alternative will be Plastic Steel or a similar product made by Devcon. It is machinable and durable, it has very similar coefficient of expansion to the base material too if you select the right product. Devcon makes the only epoxy based metal repair products with a Mil Spec that I am aware of, it is also approved for repair of aluminum parts by Caterpillar, Cummins and Navistar.

 

[DnPRK]

Aluminum filled epoxy likely won't withstand the shock of dropping the hammer repeatedly. I'd use an aluminum bushing and KNS anti-rotation pin kit.

 

[dfaugh]

Don't know about the Accra-Glass never used it. But I used Devson for years when working on cars, including race cars, and it pretty amazing stuff. My Dad, who was a machinist, got me using it, as they often used it to fill mis-drilled holes and such. In both instances, we used it in some pretty high-stress situations and it worked out quite well.

 

[JackOfAllTradesMasterAtNone]

I've used AcraGlass in several situations, and not being an AR expert, I don't think I'd use AcraGlass in this situation. Not knowing more about the repair, I can only say that there's no substitute for welding and re-milling for what sounds to be a stressed piece.

-Steve

 

[khadre]

keep the ideas coming....thnx.

Thanks guys for the ideas, keep them coming.

HSMITH or dfaugh,
I like the idea of the Devcon plastic steel in Putty version. Is it actually steel in there or another metal?

Can Devcon handle being anodized with the forged aluminum when I am done? (I do not know what all Devcon contains).

I could use Devcon after anodizing but BEFORE refinishing if it doesn't handle anodizing well if that's the case.


DnPRK,
where would one find the aluminum bushing, for use in the trigger hole of my situations?

 

[asknight]

I'm in the camp with the guys who vote to drill it out and use a bushing and KNS kit.

 

[HSMITH]

Devcon has a lot of metal in it, and what that metal is depends on the version used.

It won't anodize, but it will paint easily. If you anodize I would do that first, then grind or blast out the area to be repaired. Repair it, and paint with a good bake-on finish.

Sounds like you are working on 80% recievers, if so just finish this one enough to try it, get it running without anodizing etc and learn from your mistakes. Then crank up another one to be finished out 100%.

 

[khadre]

I've edited my situations up above to be more clear.

1) finished and functional AR receiver with fire control pocket in front of trigger milled too deep.

2) 2nd 80% being worked on has the enlarged hole on one side

HS,
that is correct; these are all 80% forged receiver. Trying to salvage the 1st finished receiver since it's functioned safely (approx. 1000rds) other than the bottom of the fire control, in front of trigger had gave way. So I 'sometime' have to reset the trigger myself. The trigger spring dangles out from above...lol

Devcon does make an Aluminum putty so I am researching more on it.

I do have a KNS kit in my other AR and will be using them in all my AR receiver. I just need to fix these minor problems first.

 

[mrmeval]

3M Scotch weld would work
http://solutions.3m.com/wps/portal/...try_portal&PC_7_0_2JA2_command=AbcPageHandler

These need baking at the right temp.

You can contact them and ask for engineering support, tell them what you're doing.
http://solutions.3m.com/wps/portal/3M/en_US/Manufacturing/Industry/Contact-Us/eMail/


This looks reasonable
http://solutions.3m.com/wps/portal/...try_portal&PC_7_0_2JA2_command=AbcPageHandler
A 350 degree F curing epoxy for metal to metal bonding provides exceptionally high strength, impact resistant bonds. Meets requirements of MMM-A-134 Type III.

If it's a load bearing area you may need to fabricate just that area and bond it in. In the case of that hole you'd bond in a piece of aluminum and redrill.

The MMM-A-134 Type III is a milspec, I've worked with that and it's machinable when cured. It must be duracoated or painted as it will not anodize.

 

[dfaugh]

Dunno about anodizing the Dezcon stuff, never tried it, but my gut tells me, that it probably won't work...Or really that it won't color the same as the main piece.

 

[gamachinist]

If you are planning on reandonizing the finished one with the booboo,I'd vote for welding and remachining.
Same for the oversize hole,either weld and recut or install the oversize bushing and the antirotating pin set.

An oversize bushing can be made on the lathe,but a weld would probably be easier to deal with in the long run.

Make sure the welder is using the tig process,not mig or wire welding as you will probably find voids in the weld that don't look nice when you machine the side of the receiver.

Most any epoxy type repair isn't likely to work well on the trigger hole unless you enlarge it to give the epoxy room to have a thicker ammount of hardened epoxy.

Just my opinions based on my experiences,your experiences may vary.