Aluminum Threshold Plate Restore

[New-to-240z]

Hey guys! I'm finally get the Z painted and I'm doing some things in the meantime. I was hoping someone might be able to point me in the right direction on how to refinish/restore the aluminum kick/threshold plate for my 73' 240Z. This is the plate that is at the bottom of the door on both sides and says "Datsun". I don't have any bench tools or anything, so simple would be best

I have tried simple green and a scotch bright pad with no luck. I would REALLY like them to shine tho, so if I can't do that with simple tools, does anyone know a place that could do it for me on the cheap? I'm in Orange County, CA :-)

Much appreciated!

[tlorber]

I hit mine with a buffing wheel. For all the grooves I used Mothers and a toothbrush. That part took a lot of scrubbing.

[esmit208]

DITTO TLORBER. But if you use the car often the finish will have to have constant attention to keep the appearance. I am working on a few paint schemes for mine. A misaligned door will never let them be pristine.

[EScanlon]

The original finish wasn't shiny polish, it was more of a high luster SATIN finish.

You can go ahead and polish them, but as mentioned they will show any scrapes from your shoes, butt, or mis-aligned door.

Once you have them cleaned up and polished or buffed to whatever finish you decide you DO want to coat them with something, aluminum tends to "gray" out exposed to the air. You could use a clear paint, but the problem with that is that the paint dries hard and can eventually chip, crack and allow the corrosion to begin in the cracks.

POR sells a product called GLISTEN PC which is essentially a type of CLEAR POR (not the Clear POR they also sell), but specifically made for application on polished metal as opposed to the regular POR which requires an etched or "toothy" surface.

I used this on my Roadster which has not only the sill plate, but also the lower edge of the inner door panel and the door weatherstrip welting overlays in ribbed aluminum. They were polished and treated with Glisten PC about 5 years ago and still shine like the day they were mounted on the car. It's not cheap, but the end result is far better than any clear paint would have given. It does take patience though, you'll apply it and have to wait about 4-5 days depending on temperature and humidity.

FWIW

E

[Carl Beck]

..... does anyone know a place that could do it for me on the cheap? I'm in Orange County, CA :-)

With the cost of living in California - I don't see how or why anyone would do it on the cheap. I had a set done by a person that specializes in that type of work here in Florida - Very Presentable but not "perfect" - they were $80.00 each. "Perfect" was $160.00 each. When they were done - his "Very Presentable" looked near perfect to me...heck, they weren't "perfect" when new.

I have a couple of used sets that need to be refreshed - I think I'll try boiling them in Lemon Juice to see how they clean up.

Now these are parts that should be economical to reproduce... especially in SEA..

FWIW,

Carl B.

The last NOS set that I saw on EBay went for about $110.00 each.

Edited November 29, 2012 by Carl Beck

[9teen7t240z]

If I'm not mistaken, I believe that these sills were originally made using an anodized aluminum coating. In order to get a high quality shine, it is necessary to first remove the anodized coating. That can be done by intensive buffing with alot of elbow grease, or can be done chemically using any number of "home remedies" such as bathing in Drano, etc. Carl's idea of boiling in lemon juice may work as well for removing the coating. After which, you would buff and polish to achieve the level of shine that you desire. (I'd try the lemon juice first, as it is more environmentally friendly and can be re-used to marinate your trout or salmon) .....just kidding....don't recommend re-using it.

If you don't want to hassle with it, I do offer a service for chrome plating and polishing of aluminum and stainless steel parts. It can be a viable and cost-effective solution, but it is not very quick as I have the parts refurbished by a facility in southeast Asia. As a rough estimate, I would guess the cost of polishing your sills to be around $30. each, but would need to allow 4-6 weeks for the turnaround time. If you want more information on that service, feel free to send me a PM.

To Carl's point, I think that I'll check with my SEA sources to check on the feasability of having these sills reproduced there.

Good luck with your project!

Mike

[Mikes Z car]

I didn't know about these options when I cleaned up the ones I got from the JY for my car. I used a wire wheel on them as they were really dirty looking and then waxed them with ordinary car wax. I probably removed some aluminum with the brutal wire wheel but they look ok to me though not satin I would say.

[240260280z]

Carl,

WRT lemon juice, I have read mixed results. I think a crucial part of the process is to use an inert glass or enamel coated container so that pot metal (literally) does not become part of the reaction.

It would be interesting to boil two carb domes, one in glass and one in aluminum to see if my hunch is correct...maybe a third in stainless for completeness.

[SteveJ]

Carl,

WRT lemon juice, I have read mixed results. I think a crucial part of the process is to use an inert glass or enamel coated container so that pot metal (literally) does not become part of the reaction.

It would be interesting to boil two carb domes, one in glass and one in aluminum to see if my hunch is correct...maybe a third in stainless for completeness.

To expand upon your idea, Phil, how about a 5 gallon bucket and an immersion water heater? Worried about volume? Add a couple of bricks to take up space in the bucket.

[Kurbycar32]

I used a regular buffing wheel on a handheld drill as already suggested. For the little "valleys" I used a tiny brass brush on a dremel after the nylon one didnt cut it. The brass brush is great for cleaning but you then have to polish the area, a soft buffing wheel will get inside the valleys enough for polishing. The polish I used also has a sealer that needs to be reapplied yearly. Its been over a year and still looks good and I think its because the part is rarely exposed to sunlight. At least with the sealer I wont have to remove a faded clear coat in the future.

[EuroDat]

We use water blasting to polish SS parts. I used then to do the outside of my 71C transmission. Could be an option for the threshold plates too. The water treatment is not so harsh as grit blasting etc. They can also do satin finish.

http://www.innomet.nl/docs/WATER%20BLASTING%20rev%203.pdf

[LBO730]

I used "chrome" powder coating after a thorough cleaning on a set a few days ago and they turned out really good. They had that sort of satin finish like EScanlon was describing.