the time has come the walrus said...

I have been doing some research and come upon a US company who supplies Mold materials and many various grades of Urethane rubber mixes for Industrial use. Some are oil resistant and can be made with various hardness levels as well.
My intention is to trail this with a Mold for making the Damper that we will all need at some time or other when the timing chain wears and stretches or we re-build an engine.



Further details will be posted as the project continues..


OZ

watching with interest

Nice one Oz, That's one thing I don't have any good ones of, and am bound to need one day. Good luck with it & put me down for a couple.
Thanks,
Matt.

There is a company here in adelaide thats makes lots of things in urathane

http://technicalurethanes.com/

Worth asking the question

Problem with asking the question is they want $50 to $70 per item and i can do Timing Chain Tensioner for half that.
May also be able to do Steering Rack Rubbers for half what we have been paying but the Mold will be more difficult to get correct. Needs to be done with a 2 piece mold.
Also may even be able to do steering rack end dust cover rubbers too. Now there is a real challenge! Stretching out accordion rubber and then making 2 molds that match.

Waiting on the scales that measure .01 grams so i can mix the correct ratio of mix to hardner.

More as soon as i have the first Damper out.

OZ

keep us informed oz, does the florian 1600 use the same tensioner?
Ill be happy to test some of your rack mounts in the red rat!
I guess this would open up a whole lot of little rubber bits that could be re produced!

Thanks Flibbles.

Florian is same in the timing chain area. Tensioner just fits up inside the cover with a tension blade in the centre. New ones with new timing chains take quite a bit of pressure to fit the cover which is why the cover has a number of locating pins to position it correctly.

if you have the skill and patience to design and make the mold, then anything is possible. Bumper over-rides is another good example of a simple mold that can be done fairly easily.
Can even add colours to make it more realistic or show the item was made by you!

Biggest problem may be getting hold of new or near new parts as donors for the mold process. If new items not available, used ones with some repairs or filling to the molds can be done. Even timber or fibreglass can be used for the dummy.
Once a mold is perfected and made, it will last for 200 or more castings.

Want to do some of my own casting first and test it before letting myself loose on the Bellett market.

Baby steps at the moment but wait and see where it goes.


OZ

Please tell me you are not taking a original piece and jamming it into a bed of plaster or some sort of pour mold medium, and simply pouring material into the cavity.

If you are making parts that require a good, accurate fit (engine internal, suspension, steering), you need to calculate the material shrinkage and make a mold out of metal that is whatever percentage over sized to result in the ending size required after the material cures. A perfectly formed original sample is less important than the pieces it fits into in good condition, so that the mating surfaces can be accurately drawn and a mold machined to match the drawing.
You are looking at a minimum of a four piece mold for a D shaped steering rack bushing. And if the material shrinkage is not calculated into the mold, it's going to have a 1/8 inch gap between the outside of the bushing at the bracket.

I'm not going to have a seminar on bushing making, but it's more involved and more expensive than pouring resin into an open top mold. If someone is selling a piece made of urethane from a multi piece mold that fits correctly, last 10+ years without wearing out, and costs $50-70, that's money I would gladly give them just so I could save the design hours and hundreds or thousands of dollars in mold costs.

it is quite a bit more complicated than that, and i am assured that the Mold material and the Urethane will produce a copy that is 99% accurate. original rubbers are checked for hardness and matched to one of 8 different grades
and yes, you are right that some Molds will need inners and outers, positioning pins for accuracy, and often 2 pours and i will be testing anything i produce for internal motor parts on my own vehicles first.
these materials are used to make a huge range of items, some only 1mm or less in a 20mm gear, and often perform better than originals. they can be as hard as steel or as soft as jelly.
plaster and fiberglass pouring would be not very functional, but plaster is not used and would only use fibreglass to produce an original if one cant be found.
sure there will be some mold failures and pour failures and frustration etc etc etc but the outcome could well be some really good near original parts that are becoming just about impossible to get today.

anyone got any better ways of getting our parts we are needing?


OZ

these materials are used to make a huge range of items, some only 1mm or less in a 20mm gear, and often perform better than originals. they can be as hard as steel or as soft as jelly.

should i say the gears are 19mm, 19.5mm, 20mm, 20.5mm etc and are as accurate in size and gear mesh and profile as the originals


OZ

[quote]

anyone got any better ways of getting our parts we are needing?


This is a interesting point the fact that some parts are not available any more. As you will be aware oz this little project you have taken on is time consuming as well as costly. With your own funds put up front.
The biggest problem is we all know that one day these parts will be needed but with the outlay to put them into production is a big enough cost without stocking 30 or so units for when some one wants them? So the end result is when you make them you make enough for yourself and who puts their hand up to stock 1 for a rainy day.
We do not profit from parts we produce and as costing order the amount to suit ourselves and cover that rainy day and as i have said in the past the cost of the tooling can be spread.
DO NOT ASSUME THAT THEY WILL BE AVAILABLE WHEN YOU WANT THEM.
b.t.w oz put me down for 8

It sounds like you have a good understanding that your adventure is not going to be an easy one. The abbreviated description in the previous post really simplified the description.
And (at least for this chain tensioner pad) you are working with a mold material that is expected to shrink the same amount as the material that the end product is made out of. This is different from using metal molds, doing drawings, and machining the molds with lathe and mill.

I'm looking at the chain tensioner pad. I am unfamiliar with it, so I may be wrong, but it looks like the face that rides against the chain is up, and the face that seats against a metal arm inside the engine is down. The sides are unimportant, but the pad would be placed into the mold material with the chain face down and the mounting face up, because that is the way it tapers.
The problem is going to be that you will not get a smooth or flat surface, or a precision thickness, with an open top mold. The polymer is going to pour into the mold thick, then cure sort of like an ice cube in a those old fashioned ice trays. There will be a dome or a dish to the face, it won't be flat, and the thickness won't be uniform from part to part or even across the same part.
The bumper cushions (for the GT), pose the same problem. The surface that seats against the bumper would be facing up in the mold, the original back has a recess in it, and there are two bolts sticking out of it that have to be located in the mold.
The example of the cog wheels or gears doesn't quite translate over, because you can lay a gear on its side, and all the important faces are submerged in the mold. The side of the gear is not a critical face.
And the same thing that makes plastic so desirable, durability, makes it impossible to machine. It's soft enough to yield against the tool, it grips and moves, it needs razor sharp tools to be cut, and even sanding it results in a surface that is not flat and straight.
Every side of the piece to be cast has to be against the mold, so that it takes a flat surface and an exact dimension. You end up with a top plate and a fill hole that gets trimmed and looks like the injection molded pieces.

The last comment about "how else are we going to get parts", is a mismatch for the previous comment about being able to do a part for less than what someone else is charging.
The more restoration and replacement parts, the better. But it would be better to be able to get one of everything needed to put a car together, than to have a choice of two or more of some items, and a long list of parts that can not be gotten at all.
But if you are going at something blind, without any idea of how much it costs, to beat the price of a product already available, then that is not making a new item available. And you will probably learn that the end price of making the same item will be within pennies or even more expensive than the other guy who is thought to be overpriced.
Unless there is a specific problem with an existing product, it is best to work on something that isn't available from anyone, anywhere, and whittle down the number of unavailable parts to zero before duplicating what's already been done.

here are some pics of the first effort. Not quite warm enough for Urethane to go off as per the supplier but i am going to fit this to my auto engine that needs a lower engine re-fit.

It looks a lot different out of the plastic bag. So the side rides against the chain, not the top face.
It might be closer with a metal center wall with straight sides and the circle at the end. The curved walls to keep the mold stronger might not pull flat when the piece is installed.
This is one where measuring from the piece it fits onto is important for the inside dimensions.



This quote sort of hit me the other day. You may be the first person I have met that really "gets it".

I think this group may be a few years older, and certainly managed to develop mentally past the age of 12. But the owners of the newer cars do not fit that description. They have a strong belief of entitlement. They are entitled to replacement parts from the vehicle manufacturer for as long as they own the car. They are entitled to lower priced replacement parts from the corner parts store for as long as they own the car. If someone makes a performance or restoration part, they are entitled to availability of that item for as long as they own their car. They are entitled to buy one original and run off cheap copies that are lesser quality, just like Napster and music. And if a product is discontinued, they are entitled to all the machine drawings and step by step instructions on how to make the item themselves.

And they can seriously ponder why no one makes parts for the newer cars.

Looking good OZ. Sure that with a bit of experimentation with different mixes and tweeking of techniques you will get it perfect. AS for whether its worth the time vs buying another repro part on the market (if you can find it) I think you are on the path to learning a skill which could become unmeasurable in value to bellett owners. I'll take one thanks.

Have not had quite the time to get the new Timing chain, Damper and bottom end of my Auto going as yet, but i have been slowly progressing on creating other rubber components.

These often require a 2 or 3 part Mold to be created and thats usually the hardest part of the process. Once the Mold is complete, then pouring tests can be done. This then shows any problems with the Mold and, in the case of steering rack isolators, issues with air bubbles and the pour material not reaching all the internal areas !@#$%^&*(*&^%$#@#$%^&*

But i have now managed to get my first successful pour from the rack rubbers and here is a photo.
Will be fitting a set to the Grey Ghost as she has bump steer due to worn rubbers!!



the two protrusions on the left and right are fill holes and air holes. The center protrusion was made later to allow the pour to reach all the way around the shape of the rubber (another air hole effectively). These will trim off with a good sharp knife.

After a few more test pours i should have this down pat. And soon have a set fitted on 67 sedan.

OZ

The new world order may just have arrived...anyone want me to reverse engineer something for them?

http://www.shapeways.com/

Could always give it a shot and find out. For those who don't know my background (erm, maybe Oz does, but certainly no-one else), I'm an Industrial Designer with about 20 years manufacturing experience, I also have my own SolidWorks CAD licence and work freelance after hours (possibly permanently if things go crap at work). I'm not sure if 3D printing will be useful in this case, but there's probably quite a few areas where it is...certainly beats casting!

Cheers,
Duane

Oz they are some great looking Rack Rubbers! I am looking at rebuilding my engine mounts with Nolathane Blocks. Do you have any idea what the best adhiesive to bond to it to the metal would be???





How close do you think this would go http://www.ebay.com.au/itm/Sunbeam-Alpi ... 765wt_1180

Gav if you get on ebay phills rotories have chev luv mounts they have a steel stopper on them and 1 hole will match you need to drill the other 1 and trim 1 the metal to size.
i used a 4 inch ryobi milling machine with a fine disc .

The US late night tv show host, and well known car nut, Jay Leno, basically endorsed a similar product:
http://www.youtube.com/watch?v=ggvzcGdZsTc
The system scans the original, allows the computer model to be manipulated, and then makes a prototype piece using a 3D printer.

But it is a prototype, not a finished product, unless you need a finished product made out of a substance that is like the stuff you load into a hot glue gun. It's like plastic, the "printer" melts it and deposits it on the thing it is printing, like making little dollops with a tiny glue gun. Great for rough fitting and getting the overall shape worked out, not so good for things requiring a precision .00X inch clearance. And not so goof for things that need to be made out of steel, polyurethane, etc.

The shapeway's website shows some different materials, including a "bronze impregnated stainless steel" (?), at $8.00 per cubic centimeter. But no details on how these materials are run through the machine, or maybe they take the 3D file and outsource the job to a machine shop. One or two of the other materials are priced per square centimeter, so they have to be flat, not 3D.

It might be great for making investment forms for pour casting.

So what happens when you want something out of a specific alloy so it can be tempered or heat treated to make it strong enough to do what you want it to do? Or a material that needs to be a solid piece that will not separate at the seams of the little dollops? Or something that can't be melted and run through a little nozzle?


And the steering rack piece looks pretty good, and maybe oz_toffa has been understating his polymer casting experience.