Does anyone know what kind of aluminium the lower intake is made from?

I'm thinking of getting the intake plated, so it would be preferable to have as much information as possible while getting quotations from the shops in the area.

The plating shop will probably use an autocatalytic (electroless) copper for the initial deposit, followed by Electroplating metals.
Alloy information is not that critical.

I was thinking of going with electroless nickel (though I'm not sure what would be best). In that case, is the alloy information as non-critical as with electroless copper?

I want to protect the IAC passage from corrosion, as I plan on using it as a water/methanol distribution manifold.

I'm skeptical about any kind of electrolytic methods; the shop would need to insert an electrode down the center of the IAC passage to get plating inside of it... which seems like it could be tricky/costly to set up.

I just spoke to my dad, and he suggested looking into the paint-type fuel tank sealers. POR-15 makes a tank sealer that you pour in, slosh around, and pour out. There also seem to be some tank sealers intended for aircraft tanks (which I guess are aluminium).

If I choose paint, I will sandblast the inside of the IAC passage to help clean/etch the surface. To blast deep inside the passage, my plan is to weld a steel pipe to one of our old worn-out sandblasting nozzles.

I know that sandblasting is good for pre-painting preparation; is sandblasting also good to do before plating?

So far, the manifold cleaning regimen has consisted of a few rounds of caustic oven cleaner, scrubbing with an SOS pad, and a shotgun bore brush in the IAC passage.

EDIT:
I just found:
https://www.caswellplating.com

They seem to sell plating kits geared to the DIYer.

A good Plan B in case I get quoted out the wazoo because I'm an unprofitable one-off walk-in customer.

[This message has been edited by pmbrunelle (edited 05-31-2018).]

Electoless plating coats all surfaces that are chemically activated, a big plus over electroplating where current density determines plating thickness.
E-nickel would be a good choice for the IAC passage.
Mechanical finishing is not necessary for what you are doing, the chemical processes will clean and prepare the surface.

Sounds like either you're in the plating business, or you've had experience as a customer of plating shops!

Thanks for the tips.

[This message has been edited by pmbrunelle (edited 06-02-2018).]

Tell the plating shop the thread dimensions need to be maintained, they will provide proper plugging for the holes.

An update, since this project is still alive. The intake manifold is now back from the machine shop.
The six outlets have been drilled and tapped to 1/8 NPT:



There is also clearance for a thin-wall 7/16" hex socket; needed for screwing in the nozzles:


So far, I've done a two week long soak test of items known to be e-nickel plated, and they've held up to windshield washer fluid. Furthermore, my online searches have found that the water/meth distributors use nickel plating on the fittings they sell for water/meth use. So, e-nickel it is!

Since I didn't know where to begin with specifying e-nickel plating, I referred to the ASTM B733-15 standard on the subject.

Apparently, thicker = more corrosion resistance, so I asked for SC4 = 0.003" thickness. With this plating thickness, the straight threaded holes will no longer fit the bolts correctly, so I have requested that they be left unplated.

I want the NPT threads to be plated, especially those for water/alcohol connections. Anyway, with a tapered thread, all that's going to happen is that the fittings will just sit slightly higher above the surface.

I asked for high phosphorus, since that seems to be good for corrosion resistance (but I'm guessing). The plating shop I am in communication with can only do 5 - 9% phosphorus, but that's good enough I suppose?

Not that I have much choice, the other two shops I've contacted have ignored my RFQs...

I'll be bringing the intake next week to the shop that has communicated with me, for face-to-face discussions on how to proceed.

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In ASTM B733-15, there is a mention of a post-plating baking for enhanced adhesion of the plating on aluminium.

The recommended bake temperature for age-hardening aluminium alloys is less than the suggested temperature for non-age-hardening aluminium alloys.

I interpret that to mean that the higher temperature baking makes the plating stick better, but it will over-age aluminium, if it's the kind that age-hardens.

If I have no information, I will err on the side of not damaging the aluminium, at the risk of an inferior plating adhesion.

So, if a Fiero historian does know that the intake is made of, I'd like to know too!

Would you mind posting a picture from the top side? I can't quite envision where/how the nozzles are going to thread in ...

Top of the manifold:


The old IAC / 7th injector passage is repurposed to carry water/meth. The old IAC outlets (plain holes in a stock Fiero) have been machined to accept screw-in nozzles.


My ECU won't need the 7th injector, and the IAC flow has been re-directed to just downstream of the butterfly:
https://www.fiero.nl/forum/F.../HTML/141063.html#p5

In order to change the nozzles, the intake must be removed from the heads. The nozzles can be screwed / unscrewed though the ports of the manifold, using the special thin-wall socket.

The nozzles look like this:


They contain the actual nozzle, an anti-drip check valve, and a filter.

I'm about to place my order for these.