Making a part out of rubber

DOH here's the link

if this is what I think it is, you might consider using urethane adhesive, like the one 3M makes - you put a bead of it in place and then just put the parts together -

I don't have the specific reference, but casting-grade polyurethane rubber for making gaskets and such is, or was, available in three different durometers that correspond to a wide range of gasket types. I can be cast in Plaster of Paris, so it's very easy to work with. It's been used for decades to make reproduction parts for old cars.

Maybe someone else can help you with a link.

-- Ed Huntress

Thanks Ed, that's exactly the direction I was trying to go. It looks like

This is not a replay to the OP, but a request for WHAT IS THE DUROMETER for rubber grommets. I need to make one for a antique Lauson engine. So it needs to be flexible enough to push into a .25 hole, .1 thick groove, and .5 od. All square edges. I tried off the shelf, but nothing I found fit this. I would not suspect anyone would figure out a radius-ed version, but if I have to make one, I'll try exact replacement copy. This is for a ignition wire feed through from the magneto coil. And next would this be a castable material (flexible enough to insert into hole) that is procurable.

ignator

You could probably coat it with a butyl rubber or Marine aluminum compatible silicone caulk and fix it that way. But you could also contact a couple of outboard / outdrive shops and see if it is in old stock or is also used on outdrives.

The stuff I was trying to think of is Devcon Flexane. I don't know if it's still available.

Using it is covered in a good little book that I have around here somewhere, _How to Cast Small Metal and Rubber Parts_, by William Cannon. If you're patient, you can read it for free on Amazon. d8-)

According to the book, a car-door weatherstrip is around Shore A 30. A car tire is around 50 - 60, and the cover of a golf ball is approximately 95. Flexane is available (or was) in Shore A 80 and 94, with an additive that will let you mix any *softer* degree of hardness.

I hope it's still available. It's great stuff. I've used it, but not for 20 years or so.

-- Ed Huntress

I have a book from TAB books on how to reproduce rubber parts, mostly for old car restoration. It gave sources and how-to tips. Not sure it's still in print, though, it's been at least 20 years since I got it. MSC used to have both castable urethane and silicone, kind of steep.

"How to Cast Small Metal and Rubber Parts" by William Cannon, hah, Amazon still has it and on sale yet!

Stan

Take a look at How to Cast Small Metal and Rubber Parts on Amazon. The book lists the durometers of various car parts, so you may be able to figure out what's equivalent.

-- Ed Huntress

Evening Ed Is this the stuff you're referring to?

Bob rgentry at oz dot net

Aha. That's close. That's the trowelable putty. It's also available as a liquid for casting.

I went to Devcon's site and I see they still make the liquid. This looks like the one I used 20 years ago:

-- Ed Huntress

here are two hints

1. Lynn Steele rubber makes a wide range of repro rubber parts (not particularly cheap) for old cars - I've used a lot of their stuff, generally it is well done and fits

1. Skinned Knuckles Press publishes a book on casting small rubber parts

Ed Huntress wrote: (...)

Indeed it is.

It's good, and cheap:

I had a spare Flexane kit in a cabinet for at least 10 years. Finally needed it to create a seal for a custom vacuum. The stuff worked perfectly.

--Winston

Bill Cannon must have passed on by now, but he was the editor of a car restoration magazine called Skinned Knuckles - I published a number of articles in it a long time ago - Last I heard, I think his son was running the magazine - my articles are on my web page (at least some of them) - it was a really good magazine

Ed's idea it great, but there is an alternative that I have used in the past. If the shape can be acheived by a lathe or mill, you can place a rubber blank in liquid nitrogen and then turn it, occasionally pouring more nitrogen on it as you go. Steve

Part of it's on Google Books

I worked at an opthalmic research co, this technique was used on a special purpose micro lathe for machining research contact lenses from a gel material. A cool idea!

Go to freeman manufacturing on line.They have every rubber and plastic thig known to man and downloadable videos. They have urathane for molds as well as silicones.They have a nearlt 90 min dvd for

It is absolutely not available anywhere. I belong to a saildrive group and this part has been discontinued for at least 20 years