On Sat, 19 Apr 2014 00:50:47 -0500, Tim Wescott
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.

Except for the paper, good. I've used cardboard from a cereal box
before, but that was because I couldn't find gasket material at my
local auto parts stores. Tim has the right idea. DO get the proper
material. It comes by the foot (historically) or in several foot
rolls (more recently).


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've made them with a ball peen hammer myself, but I've also seen
fellow students (Universal Technical Institute, 1972) CRACK and/or
dent carb bodies doing that. I recommend against it.

No, better is to measure and cut off a piece gasket material which
will be large enough to do the job. Lay that out on the bench, lay the
carb body on it, trace around the outside, and cut that line with an
exacto or scissors. If there is linkage in the way, guess on the wide
side and trim later. Then draw a parallel line around the inside so
it is just a bit wider than needed, increasing it to a larger diameter
where the screw holes will be. Carefully use the exacto to cut that
outline. Now use a hollow punch to cut the screw holes. HF has a set
for $6, if you don't already have a set.


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.

No, I think printing would only increase parallax errors.


What would you do?

Once you have a good gasket, make a few more, keep them in a baggie
(backed by a little piece of cardboard to keep them from betting bent)
and save them with your welder manual. Staple it to one of the
sillier warning pages at the front.


I'd start by going to a decent auto parts store and getting some 1/32"
thick gasket material.

You'll know it's a decent auto parts store if you say "do you have 1/32"
thick gasket material?" and they say "yes".

Ayup, I heartily second that, Tim. 1/32" at minimum. I used to use
long-fiber wheel bearing grease on that material to give it a longer
life. They dry out terribly without it. Goop up the cut gasket, let
it sit for half an hour to soak in, then carefully wipe off the
excess. Gas will eat away any grease within the carb body, but the
grease will keep the gasket from sticking to the carb (or, worse, a
timing chain cover), so it is easier the next time you rebuild. I'm
so VERY glad that automotive technology moved to EFI and I don't have
to rebuild carbs any more. g

--
Stoop and you'll be stepped on;
stand tall and you'll be shot at.
-- Carlos A. Urbizo