Brushed finish problem- can you advise?

Superarnie · #1 (**permalink**) 05-20-2009, 11:44 AM

Hi folks, I thought I would post a thread in your Kirkham forum as I believe you're the guys that can help me.

I have an aluminum bodied genuine AC. In fact it is an AC Superblower- it's a follow on to the 1960's cars. It was made by AC Cars in Brooklands in 2001 before they hit financial troubles (again). However the car was never finished by AC and I have the task of completing the build. My question to you all is this;

I have decided to go for the brushed aluminum finish with polished stripes as many of you guys have done. I think your cars look awesome with that finish! I am using a DA sander and have sanded it down to a 400 grit finish and then Scotchbriting the grained look, but what I am finding is that the soldered body joints are visible. As you'll be aware the car bodies are made in many sections and soldered/fused together. I am finding that on each of those joints the welds are visible. Have you guys experienced the same problem and if so how did you deal with it. I'm wondering if I'm going too smooth with the grit and maybe if I finished with a rougher grade I wouldn't see the joints?

Many thanks for your help/advise
regards

Gary

Kit Cars Mexico · #2 (**permalink**) 05-20-2009, 01:41 PM

In some cars you can see the weld more than others, you can try with different grits and see witch one is better for your aluminum.
We use in our Kirkhams 120 grit to give the final finish.

Alfredo Canalizo
www.kitcarsmexico.com

xlr8or · #3 (**permalink**) 05-20-2009, 01:45 PM

Yep you went too fine on the finish... Go back to a 120 or so and scuff the car with that and the welds should mostly disappear. They showed up on mine with 320 grit and remained visible until I got to the polish stage.

Hexnut72 · #4 (**permalink**) 05-20-2009, 01:49 PM

The Kirkham cars are welded using the parent material as rod. This means that other than impurities in the weld, you get the same metal used for both the panels and the filler.

I wonder if AC used some other type of rod when they were welding them? Could you see the difference as you sanded through the various grits? If so you may not be able to get rid of it as it is a different material. Just something to look for.

Superarnie · #5 (**permalink**) 05-20-2009, 01:51 PM

Thanks fellas, I'll drop back to 120 grit and see how I get on.

kindest regards

Gary

Superarnie · #6 (**permalink**) 05-20-2009, 01:54 PM

Thanks Hexnut, I do seem to recall that the welds became more apparent the smoother i went. I initially started on a 120 grit to remove the initial scarring. I then moved onto 240 and finished on 400. After that I used the 3M's maroon scotchbrite pads and the welds became more and more aparent as I went along. I'm wondering though if the 120 grit is too rough? I think AC Cars welded with the same parent material, but I can't be sure.

HI Cobra · #7 (**permalink**) 05-20-2009, 03:06 PM

120 is the smallest used typically on the sanded finish. I can barely see
some of the joints on mine - I look at it as patina.

big-boss · #8 (**permalink**) 05-20-2009, 04:08 PM

I went to the 120 then kissed it with 500 to knock the sharp stuff off. Stays cleaner (as clean as it gets) and is easier on rags and staining. Lets see some pictures if we can- sounds like artwork to me. Thanks

franklin · #9 (**permalink**) 05-20-2009, 04:19 PM

If you do end up going to 400 you may want to use 320 between the 220 & 400.

Superarnie · #10 (**permalink**) 05-21-2009, 09:17 AM

Thanks you all for your input

Franklin- I've already done the 400 grit stage and scotchbrited the car. Unfortunately the welding/joint lines are quite clear to see. It may be that I'll go back to the rougher finish and see if it hides the joints. I'll try to upload a couple of images to let you see the problem- I'm not too good with these computer things though!!

Regards

Gary