Clear coating engine aluminium parts

[rutger kohler]

Hi, I am going to get various aluminium engine  parts bead blasted  and would like to know what sort of clear coat I should put over them afterwards.  The larger parts include the rocker or tappet cover, intake manifold and about 6 other parts.  I don't think a gloss finish is right?  Have seen a VHT product that is gloss and needs to be cured.  Also Por15 have a product that is gloss only.  What is the group collective wisdom on this plse?

[Garry]

I have used a clear coat in semi gloss that was suitable for engine temps after peening my rocker cover with a walnut media.  I have also used it on some of the other items in the engine bay area and not had any problems. It did not need anything more that the application and drying.  The can recommended driving for 30 minutes to get the engine up to temperature to assist with curing.

[rutger kohler]

Hi Garry, looks good, what was the brand and type of clear coat plse?

[66andBlue]

Rutger,
I have used VHT clear coat SP115 SATIN - do not use "gloss' since the valve cover should not be too shiny. Not more than two coats because even "satin" will become "glossy" after several coats.
I have also used it on the intake and exhaust manifolds as a final coat after first using SP117 (flat aluminum) and they still look good 5 years later.  But in this case - especially for the exhaust manifold - you need to cure the paint in stages as described on the can.  Use the car engine or put the parts into a gas grill and heat up to the desired temperature.
http://www.vhtpaint.com/products/flameproof/

[Garry]

Rutger,

Like Alfred,  I have used VHT paint. see photo of what I used.  I assume given that it is USA and in Aust it is probably available in NZ

Garry

[rutger kohler]

Hi, thanks for that, I looked at the VHT products but didn't reralise they have a clear satin finish, definitely don't want a shiny finish.  Looking at the spec sheet you sent I see they have a prep coat too,  is this necessary as the parts will be fresh from bead blasting?  I could put the non exhaust parts in a big hooded barbecue I have, with a temperature gauge on it. Do you think the exhaust gas off the barbecue would affect the coating?

cheers

Rutger K

[66andBlue]

I did not use a prep coat for the manifolds or the valve cover and I used the aluminum paint only on the manifolds, not the cover. However, all parts were thoroughly degreased before painting or coating.
I did not polish the cover since I wanted to preserve the somewhat "unfinished" original look. It was only solvent cleaned with a stiff brush (plastic bristles) followed by a very mild swipe with very fine (0000) steel wool.
The clear coat helps to wash of grime and dirt and the aluminum doesn't oxidize as quickly.

[Garry]

I cleaned off the parts with a white spirit (Mentholated Spirits) prior to spraying even the rocker cover that had been peened after washing it with soapy water to get any left over peening material off the cover.
I agree with Alfred, it certainly makes it much easier to keep the items clean once coated

[mdsalemi]

Rutger,

There are many ways to achieve what you are looking for.

One thing to consider is chemical cleaning; do an internet search for "aluminum cleaner" or "aluminum brightener"; these are products that chemically clean the surface of aluminum and bring back that "fresh cast" look.  In the USA there are many of these products available.

Be very, very careful using any kind of bead blasting--the media selection is critical and so is the handling of the piece.  It is very easy to change the surface texture.

Professional powder coating is less costly than many people think in areas where it is available; the one I use has all manner of clear powders to use to maintain a fresh-cast look and provide longer lasting protection than paint.  In addition there are all kinds of "aluminum" colored powders as well.  All depends on what you want.

My guess is the local firm I use would charge about $75 or so for a valve cover.

Attached is a "before" photo of my valve cover "in situ"; also is the valve cover on the engine after a chemical cleaning with that "fresh cast look".  Other aluminum components on the engine were painted aluminum color.  The photos are not the best "apples to apples" comparison, but they are what I had available.  The original valve cover had "greyed" over the years, and also showed some elements of the white powder corrosion in places and typical grease/dirt/oil spots and marks.  After chemical cleaning w/o any media, the cover became what is shown in the second photo which truly looked "freshly cast".

Alas, today the valve cover, while mostly clean, looks somewhere in between the two...

[stickandrudderman]

Aluminium brightener is good but DO NOT USE IT IN SITU! It will damage any plated surface that it contacts.