Making a part out of rubber

I need to make a part out of rubber. The part is obsolete and cannot
be purchased. I have one, but it has shrunk over the years and is now
loose and it leaks water.
The part is an isolation ring for a boat engine mount. It sits between
two pieces of aluminum and is compressed by the two pieces.
This allows some movement between the engine and the engine mount and
it also seals out the water.
I am thinking that I can use the existing part to make a mold to build
a new part out of urethane. I can add bulk to the existing part to
make up for the shrinkage.
Problem is, all I can find on the web is urethane for making the mold
not the part. Does anyone have any insight into how I can do this?
Fairly complex part, but I have one to make the mold from.
The link is to a parts manual that shows this part. It is on page 14,
of 20 and it is Item Number 8. It is OMC part number 322214or OMC
393162. same part.
Thanks everyone
Dan
Reply to
Pirateer guy
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DOH here's the link
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Reply to
Pirateer guy
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 -
Reply to
Bill Noble
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
Reply to
Ed Huntress
Thanks Ed, that's exactly the direction I was trying to go. It looks like
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probably has the stuff I'm looking for. Now I have to call them and start asking lots of questions. I'm thinking Shore A 90 durometer? Maybe someone here that has already done this will chime in and push me in the right direction. Dan
Reply to
Pirateer guy
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
Reply to
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.
Reply to
Calif Bill
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
Reply to
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
Reply to
stans4
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
Reply to
Ed Huntress
Evening Ed Is this the stuff you're referring to?
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Regards
Bob rgentry at oz dot net
Reply to
Bob Gentry
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:
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There are some other Flexane products that you can find by searching around Devcon's site.
-- Ed Huntress
Reply to
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
2. Skinned Knuckles Press publishes a book on casting small rubber parts
Reply to
Bill Noble
(...)
Indeed it is.
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?sku=0682599
It's good, and cheap:
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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
Reply to
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
Reply to
Bill Noble
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
Reply to
Steve Lusardi
Part of it's on Google Books
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Reply to
kfvorwerk
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!
Reply to
K Ludger
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 8.95 ,which is also on ebay. You might want to get a sample kit at lower cost. Some of their stuff srts up in under 15 minutes . Their tooling epoxiie is very hard and they say its used for foundry paterns.
Reply to
al_bear
It is absolutely not available anywhere. I belong to a saildrive group and this part has been discontinued for at least 20 years
Reply to
Pirateer guy

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