How to get internal crevices?

[cruizer]

Hi all, new this particualr forum, but been with the powdercoating forum for over a year now.

I've ben dabbeling in the art of metal polishing for the last couple of month. What I have found is that simple external stuff is fairly easy to do. What I have a problem with, though, is smaller internal crevices.

I am currently working on my engine for my VW Corrado. I had decided to port and polish the throttle body intake. Porting it wasn't that hard, as a simple flapper sanding wheel was used. And when it was worn down enough I was able to get to the smaller areas and crevices. I could only find flapper wheels down to 180 grit though.

So from that point I hand sanded with 220, and then 320. This is where I started running into problems. Even with hand sanding, I could barely get the crevices. no matter how hard I worked, I was sanding away other areas trying to sand the crevices, which was not good. I didn't want to sand those areas more, there are some areas with tolerences I can't pass (example, where the throttle plate is. That area was never sanded to begin with, it was only going to be polished).

Then came the buffing wheels. While the open barrel areas were relatively easy, the buffin wheel would get caught on something inside, and slam the part into the machine, causing gouges and cratches, which required me to sand again. Then trying to get to the crevices was next to impossible. The little arbor I had was the kind where the small buff would literally screw onto it, and the end stuck out too far. I ended up chopping that end off with a grinder. Then the little buffing wheels would just fall apart after a few minutes.

I pretty much gave up after the black emery. Mostly smooth is pretty good. but the more I worked at it, the more the piece was getting damaged, adn I didn't want it damaged anymore.

I initially started out with the EW manifold polishing kit. I have since bought a few other buffs. But I literally cannot find any place in my area that sells buffing supplies. So everyhting I want I have to order online and then wait like a week for them.

I also wanted to say the work I see you guys do is amazing, and I hope it is not under-appreciated!

[cruizer]

Wow! What did I do to **** off you guys?

Well i tried it again myself tonight. It's shiny, but looks like ****. you can see all the sanding marks. I remember reading somewhere that many people stop sanding at 320 grit, then go to black emery. perhaps I am wrong. Or perhaps it's because the tapered roll was skipping on the part as I was sanding. Even with grinderd grease. Even with much force. I dunno.

Ruined like 6 buffs too. Turns out NO ONE on this side of the country seems to sell buffs. I have to order everything. That totally blows. I need more buffs, and now I have to wait a week to get them.

[cruizer]

Not bad in my opinion. Although it's hard to see the polish because I can't take pics.

[cruizer]

And what's left of my buffs. Although these weren't big to begin with.

[cruizer]

And what's left of my buffs. Although these weren't big to begin with.

[jrow]

cruizer,

You can use these to get into the internal crevasses http://www.cratex.com/
I would also suggest that you go to a VW forum and see what grit the intake manifold should be polished to. Remember the air has got to tumble through the manifold. I know there is a recommended grit finish for carbureted engines but I can't find anything in fuel injected engines.
You can check out this site also http://www.sa-motorsports.com/do-it-yourself.aspx

John

[cruizer]

The people I talk to on my VW forums say that a polished intake is just fine, as the gas is mixed with the air in the head. So the more laminar the flow getting to the head, the better.

Thanks for that other link! That is exactly what i needed to see as I am porting the head this weekend (I think).

[grommit]

hello Cruizer, i had a nightmare just like you with crevices,really done my head in and i got the same advice with cratex, i thought these were the top dogs! but i did find that they did wear down very quickly.
a novel way is making sanding heads for my dremel with the desired sandpaper the right size for the crevice,but ya have to make sure the sandpaper is attached tightly or they will be heading off over your garage at mach3 or at u at worse.have you researched GREASELESS? using that on your mini bobs can be the answer.
take care
Grommit

[cruizer]

Thanks for the help guys! The next venture I take should be much easier!