Nitric Acid or ALUM

[claymen]

Anyone know a good source for ALUM or even better Nitric Acid?

I know there are places like sigma chemicals but hoping for something I can source this weekend.

In the past ALUM used to be available at chemists but no one seems to stock it anymore.

For reference its to remove a broken tap in an aluminium piece. ALUM and Nitric Acid can be used to dissolve out the part without damaging the rest of the part.

[TurboR1]

If you find a supplier... I *ahem... also need to remove a broken tap in an aluminium piece... *wink.

[claymen]

Pharmacy 777 can get ALUM in but it's not kept in stock.

[Nine]

Nitric acid is a main ingredient in some quality explosives (or is in meth) and is probably the reason it's hard to find. It's also used in processing film photographs so try a photographer supplies place maybe. Good luck though.

[Rorschach]

Nitric Acid or ALUM

I have a bit of Nitric at work...
What's it for?

[claymen]

Cheers for the info. Worst comes to worst if I cant sort something by tomorrow I'll leave the prick in there.

It's to secure a baffle into an aluminium valve cover. There are 5 other bolts that'll hold it in place but would have liked to extract this one to keep it nice and clean.

[Sookie]

find some coded welders, they will have a small quantity

[g0zer]

you want to dissolve a carbon steel bolt thats broken off inside an aluminimum thread? whats the purpose of the alum? i wouldnt have thought thats something that would happen quickly anyway depends on how long the bolt is but im thinking if you need to dissolve it its going to take weeks.

[claymen]

you want to dissolve a carbon steel bolt thats broken off inside an aluminimum thread? whats the purpose of the alum? i wouldnt have thought thats something that would happen quickly anyway depends on how long the bolt is but im thinking if you need to dissolve it its going to take weeks.

I've seen different reports. Some saying anything from a few hours to a few days. One claims 3 hours using ALUM in a hot solution.

It's not for a bolt but the tap I was using to put in new threads. Basically from stock the baffle is held in by nobs in the casting which are smashed flat to secure the baffle. The baffle was removed to be sand blasted/powdercoated and relocate a pickup. So I am drilling out a hole and tapping a new thread to reattach the baffle. I've got most of it done, although to finish I also need a new M4 tap. But ideally would have liked to remove this tap, but to be honest if it aint coming out now it probably aint coming out ever so doubt it's going to back out and fall into the head.

[g0zer]

oic

Use of Alum to dissolve screws [Archive] - National Association of Watch and Clock Collectors Message Board

they are talking about using ALUM to dissolve screws in that thread but its in a watch repair context, very small screws. for an M4 tap you might be waiting a while.. it raises the question how the hell did you break an M4 carbon steel bit in aluminium?

[claymen]

oic

Use of Alum to dissolve screws [Archive] - National Association of Watch and Clock Collectors Message Board

they are talking about using ALUM to dissolve screws in that thread but its in a watch repair context, very small screws. for an M4 tap you might be waiting a while.. it raises the question how the hell did you break an M4 carbon steel bit in aluminium?

No idea, cheap tap maybe, screwed bit. Pre-drilled the holes out to 3.3mm, screwing down and the bastard snapped off.

[Captain Starfish]

how the hell did you break an M4 carbon steel bit in aluminium?

Super fucking easily, I would imagine - I've lost several over the years. M4 in aluminium seems to be a somewhat magical combination of wide enough to still need torque to cut threads, thin enough in the shank to succumb to torsion shear very easily, and soft grabby metal doesn't help.

Every time I've been careful, I've loobed up, I've gone slowly. Every time it's coming along swimmingly and then there's just the tiniest bit of stickiness. Every time I succumb to the temptation to push through it and >BANG< there goes Mr Tappy.

[keys]

Use Kerosine as a tapping lube in alum no idea why it works but it does

[Captain Starfish]

WD-40 is a beautiful machining lube for aluminium in general and yes, it's mostly kero.