On Sat, 19 Apr 2014 18:38:35 +0700, John B.
wrote:

On Fri, 18 Apr 2014 20:00:16 -0700, SteveB wrote:

I need to make a gasket. It will be about 2 x 3 inches. Pretty simple
stuff. I made one before for my welder carburetor. IIRC, I laid a
piece of paper on it, and rubbed it with dirty fingers until I got a
pattern, then carefully cut it out. It lasted a long time, and would
have lasted longer, but I left it full of gas, and it varnished.

I have cleaned the carb really well, and blown out all the channels and
chased them with pipe cleaners.

I figure to use the piece of white paper again. There are only four
bolt holes, and they have a lot of room for error. I figure this time,
I'll use an X-Acto knife to cut out a lot of the bigger pieces, and a
improvised punch to get the bolt holes.

Any tricks to gasket making? I have enough material to make about four
in case I mess up. Just go slow and easy, I guess. I was going to use
a tiny ball peen to cut off at the outside edges, but decided to leave
about 1/8+" sticking out so I don't have to worry about having too close
tolerances, and having a potential leaking spot. I can just cut outside
the line with scissors, and get it pretty close.

I thought of taking a digital picture, and enlarging it to exact
duplicate scale, and then using that for a template to cut the gasket on
a flat piece of plywood. Might take a little time, but I think I can do
it easily, just include a tape in the pic, and keep adjusting and
printing until it prints dead on.

What would you do?

Steve

For years people have been laying the gasket material on the part and
carefully tapping with a small ball peen hammer to emboss the outline
on the gasket material. In some cases like the outside edges you can
actually cut the gasket to size with the hammer but in more delicate
locations it is usually more practical to cut to the embossed line
with a knife of scissors. I usually punch bolt holes with a hole
punch.

As I'm sure you know, real gasket material beats everything else for
long life and sealing.
Another simple method of transferring the pattern is to oil or
lighly grease the flange, then press it onto the gasket material. For
other castings I've done it with paint too. Light shot of spay fast
drying laquer, plop it on the gasket material, press hard and remove.
Perfect print.