Polishing Aluminium (Merlin) Parts.

Hi folks,

Sorry for my delayed appearance – have had problems with my internet access the last couple of days.

I have attached 2 shots of the piece I originally posted about.

Many thanks,
TEC

I’d go either plastic then baking soda route, or the vapour blasting if there’s someone nearby who does it.

However, having said that & loooking at the size I’d first try the homemade soda blaster I linked to earlier…

The great thing about using baking soda is the local authorities really like people using it & hosing it down the drains as it neutalizes all the nasties that other people throw in the drains.
Shouldn’t cost more than a fiver to put together & the soda will (or should) take off the corrosion. If it was mine I’d probably glassbead blast it because I like the finish it leaves.

Given all the hullabaloo about cad & the fact I live in the land of wacko environazis it’s a bit odd that the place I use to get my cad plating done is smack in the middle of a residential neighbourhood…

When I fire up the blasting cabinet I open the door next to it, lift the vacuum outside & then put a hose from the vacuum exhaust port around the corner into an adjacent shrubbery…… which is where my neighbours retarded cat sits 🙂

I bet its IQ used to be a lot higher :p

It’s getting hard to find places that do cad plating in the UK as well. How about zinc chromate dust? Surely not healthy to breathe that in either. I was told it’s more dangerous in aerosol form… Anyone from the industry care to comment?

Hi folks,

Sorry for my delayed appearance – have had problems with my internet access the last couple of days.

I have attached 2 shots of the piece I originally posted about.

Many thanks,
TEC

Given all the hullabaloo about cad & the fact I live in the land of wacko environazis it’s a bit odd that the place I use to get my cad plating done is smack in the middle of a residential neighbourhood…

When I fire up the blasting cabinet I open the door next to it, lift the vacuum outside & then put a hose from the vacuum exhaust port around the corner into an adjacent shrubbery…… which is where my neighbours retarded cat sits 🙂

Hi Ross,

Try Tasman Aviation Enterprises at RAAF Base Amberley on phone no. (07) 32829911
or
Jet Turbine Services in Melbourne on phone no. (03) 8346-2130

I think the one at Amberley may be no more – I heard a whisper about some issue with the permits. Besides from the few people I know who used them, the cost was a major driver in looking elsewhere. Mind you they did a great job. I have hundreds of bits all blasted and soaking in oil awaiting a desision on where I can get them plated.

I will give both a call and see what happens.

The issue about bead blasting and cad plating in the dust is a very good point and will cause me to take action over the dust comming out of my cabinet.

cheers

Back to Cadmium, the metal bands on the old issue Amplivox Ear Defenders were cad plated and one of the entry routes for cad poisoning is through cuts. Most if not all Hunter Lineys had a cut on the top of their heads from forgetting the centring spike in the wheel bay dragging the fuel hose in. So obviously the pain in my kidneys most mornings was cad poisoning not the gallon of McEwans Export from the night before!

Almost correct the Gallon of Alcohol trick is well known for neutralising the effects of Cad poisoning and I have been immunizing myself for years with the stuff, just to be on the safe side. :rolleyes:

Without wishing to create panic among the horses and not really applicable to Merlin bits; but there can be fairly significant amounts of beryllium in aircraft built from around the mid 1950’s onward and that can present quite a health problem if inhaled when blasting etc.

Notable uses are drive shafts, some relays and as a soldering/brazing medium. I am sure that a good outlet blasting cabinet filter and ori-nasal mask will take care of the nasty’s though.

Back to Cadmium, the metal bands on the old issue Amplivox Ear Defenders were cad plated and one of the entry routes for cad poisoning is through cuts. Most if not all Hunter Lineys had a cut on the top of their heads from forgetting the centring spike in the wheel bay dragging the fuel hose in. So obviously the pain in my kidneys most mornings was cad poisoning not the gallon of McEwans Export from the night before!

Gooday All

A discussion about bead plating isn’t complete without mentioning cadmium plating.

Here in Australia it is difficult to find a plating shop that does it (heavy metal).

What are the alternatives? Zinc?

cheers

Hi Ross,

Try Tasman Aviation Enterprises at RAAF Base Amberley on phone no. (07) 32829911
or
Jet Turbine Services in Melbourne on phone no. (03) 8346-2130

The amount you would have breathed in isn’t gonna make you drop over night….I have been working with Cad plated items in the as an Aircraft Engineer for some 35 years and I am still he…………………………………………………..

re :p

After all, the alluminium dust will give you Alzheimer’s disease, so you probably won’t remember what caused the problems in the first place :p

If it’s old & either silver or gold, it’s probably Cad…

So that’s what that soft shiny non-corroding plating is!

I’m worried now that sometimes I’ve gone at this stuff with a wire brush or grinder and breathed in the dust. 😮

From Wikipedia:

Inhaling cadmium-laden dust quickly leads to respiratory tract and kidney problems which can be fatal (often from renal failure). Ingestion of any significant amount of cadmium causes immediate poisoning and damage to the liver and the kidneys. The kidneys lose their function to remove acids from the blood in proximal renal tubular dysfunction. The kidney damage inflicted by cadmium poisoning is irreversible.

Where might you find cadmium plating on an aircraft and how do you identify (and avoid) it?

If it’s old & either silver or gold, it’s probably Cad.. Cad #1 is silver, Cad #2 is gold… there’s also an OD Green version. Pretty much all AN/MS/NAS hardware is cad plated.
Don’t gnaw on the bolts etc 😉

With cad plated stuff I just dip it in muratic acid for a few seconds, takes it right off…

Your mention of cadmium-plating and bead-blasting has got me worried; isn’t cadmium (especially dust) highly toxic?

Where might you find cadmium plating on an aircraft and how do you identify (and avoid) it?

Gooday All

A discussion about bead plasting isn’t complete without mentioning cadimum plating.

Here in Australia it is difficult to find a plating shop that does it (heavy metal).

What are the alternatives? Zinc?

cheers

We stiill haven’t found out what the actual Merlin parts are that the OP refered to….

Incidently, came across this page about buffing:

http://www.caswellplating.com/buffs/buffman.htm

Thanks very useful.

The section regarding safe directions to attack the wheel with your parts is worthy of study to those of you who have never tried a polishing wheel before. I have personally launched a small thin alloy plate about 50′ across a factory floor before, narrowly missing my face……..:eek:

Incidently, came across this page about buffing:

http://www.caswellplating.com/buffs/buffman.htm

(I recall that soda blasting requries parts to be very carefuly washed prior to coating/painting if applicable)

IIRC There was an interesting thread on here some time back regarding how the RAF discovered that beed blasting alone of alloy could peen over the edges of corrosion pits and whilst leaving the surface appearing corrosion free, entrapping corrosion underneath. There was even a link to a report provided. Worth a read if you’ve never seen it before.

A good wash with hot soapy water will suffice after soda blasting to take care of that issue. Then just prep as you normally would for paint.

I read the RAF report about that issue, I wasn’t convinced.

ZRX61
what a good idea with the ouly scotchbrite I will have to do that as I have fine white powder over everything.

That’s on the atmospheric port, not the vac port 😉
You can also tape used automotive air filters over the hole. Lots of cars use ones that are about 1.5-2in thick. The one my Chevy S10 uses looks to be about perfect. It has the advantage of having a rubber seal on one side that will seal against the cabinet 😎

Lots of good stuff at that TP Tools site 🙂

Vapor blasting IMHO opinion provides a much better almost factory finish.

http://www.tsrvapourblasting.co.uk/What_is_Vapour_Blasting.html

(I recall that soda blasting requries parts to be very carefuly washed prior to coating/painting if applicable)

IIRC There was an interesting thread on here some time back regarding how the RAF discovered that beed blasting alone of alloy could peen over the edges of corrosion pits and whilst leaving the surface appearing corrosion free, entrapping corrosion underneath. There was even a link to a report provided. Worth a read if you’ve never seen it before.