How can I avoid flat spots when sanding?

Hi all,

A couple of nights ago, I sanded off the seam on my Phantom’s centerline fuel tank. The night before, I glued the tank together with liquid glue and let the gooey, liquidized plastic ooze out of the seam. That way, I could sand the dried ooze down and make the seam disappear. This is nothing new; I’ve read that tip so often that I’m convinced that’s how liquid glue is supposed to work.

Generally this technique works pretty well for me, but the fuel tank is small and has a much smaller circumference than, for example, the fuselage. So, while sanding just the seam on the bottom, I managed to create a bit of a flat spot.

I’m using Testors sanding films, and they’re pretty flexible, so for the top of the tank, I tried to wrap the sand paper around the tank more. I ended up sanding more of the tank on either side of the seam, but the seam wasn’t as flat as on the bottom.

It there a technique that makes this easier?

Regards,

Drew back up your sand paper with something that has a similar contour to what you’re looking for. It should also be slighty soft-kinda like a sponge sander. I also trim first with a knife to eliminate high spots and keep sanding to a minimum.

Drew, Micromark also has that tool called a Flex-I-File, that curves naturally around compound curves. It is $25.00 at www.micromark.com I don’t have one yet, but It is on my wish list, and I have heard it mentioned numerous times in FSM.

Flex-i-files are the greatest thing going for ovoid shapes. Sanding “belts” are plastic backed and come in coarse, medium, and fine grits, and can be used wet or dry. At my LHS, Flex-i-file has a set of sanding sticks and the flex-i-file system in one blister pack.

Gip Winecoff

Thanks, guys. I’ll need to look into those. I did a search for Flex-I-File and got this review:

http://www.s96920072.onlinehome.us/tnt1/001-100/TNT011_Flexi-file/TnT011.htm

It’s actually from the Aircraft Resource Center web site.

The review doesn’t say much more than you guys have, but it has pictures. That way I know what I’m looking for when I go to my LHS. [:D]

Regards,

Those are interesting, I haven’t seen them before. I do basically the same thing, just by a more “Manual” means.

I open the jaws of my bench vice enough to give the part something to sit down in. I don’t clamp it, just give it a groove to sit in. When the part is somewhat stable on the vice I sand the joints with thin strips of sandpaper held between both hands.

I like the Flex-i-files though since it leaves a hand free to hold the part. I’ll have to look for some of them.

I love the Flex-I-Files too. I have four of them with different grits in each one.
You can also take scissors or an X-acto and a straight-edge and cut the sanding strips lengthwise to allow them to fit small areas such as between machine guns on wings, etc. I have some strips that are only 1/16" wide for this purpose and it’s great.

Mike