NLA parts

[Tim-Spruill]

Not to get ahead of myself, but....

The milano, gtv6, and 75 gas caps are exactly the same except for the handle parts. I would have to make a couple molds for each but it would be easy. If this Milano cap works out, I already have a gtv6 cap lined up for molds. If the gtv6 cap works I would be more than happy to mold any other cap in the same family, just need someone to send a sample for molds. So get ready....

Tim

[jontg428]

Great to hear you are near completion! Now you can start making interior door handles for 164's! Congrats man, great work,
Jon

[verdemilano]

Milano interior handles, too!

[Tim-Spruill]

I drove the milano today for the first time in months. She is wearing a brand new gas cap. The first prototype is now in use. I even stopped and got some gas! Today it will sit in the sun all day. After a week or so of this I will know if it will hold up.

The cap I am using is a cosmetically challeneged one. I am still working out a few bugs in the molding process of the last part. I also have to find a better way to cut out the rubber gasket so the edges are not jagged.

I think I have enough ugly parts that are funtional to make one more complete gas cap. I will put it together and send it to a friend with a milano and have him test it. I am sure he will abuse it more than I ever could. Hopefully after this week or so of testing I will have worked out all the bugs and can send one to a vendor, and maybe even sell a couple to the public. Don't reach for your wallets yet, this thing has only been on the car for about an hour.....

I will take some pics tonight or tommorow so everyone can see it on the car.

This is so exciting!! I just hope the prototype holds up!

Tim

[Tim-Spruill]

Alright!! Had my first gas cap failure this weekend!! I took the cap off the car to show to someone, and the rubber gasket had swollen up and become so distorted it would not go back on the car. I put the original cap back on and set the new one in the car. By the time I came back the gasket had resumed its original shape and size. I put it back on the car this morning to continue testing, but will call the local rubber place and pickup something different on Friday. At least the good news is that the plastic is holding up just fine!!

FYI- the rubber gasket material I am using is neoprene based. The rubber people assured me it would hold up to gasoline. I guess they are right, but this time I am going to request something that will hold up to gas and remain dimensionally stable at the same time. I guess you have to be really specific on these things...

Sorry for no pictures. My wife does the photos and I keep forgetting to drag her out to take some.

Tim

[scott.venables]

I had exactly the same thing happen on a seal I made for the petrol cap on our brush cutter and that was neoprene based too. Maybe Nitrile would be better?

Scott

[Tim-Spruill]

Called the rubber house and asked them about the gasket problems. The solution is two-fold. I am moving up to a higher grade of rubber and am using a thicker sheet. This new stuff is called buna-n. I am picking up some on Friday.

Tim

[Tim-Spruill]

Alfisti,

I am still running the prototype cap on the car. The glue is holding well, so that problem is solved. The new rubber is holding up well, so that problem is solved. In fact, I bought a special compass device so I can cut out the gaskets in perfect circles with no jagged edges.

The only problem remaining is the breaking slider piece on the inside of the cap. I broke the second one yesterday. The cap is still fully functional, but if you used the lock you would probably either not be able to lock the cap, or would not be able to get it off after unlocking it. That would be bad either way. I am going to try and find a plastic with a higher sheer strength. The originals were not reinforced with anything, so why should mine be. There has to be a plastic that can handle the loads.

It had not broken until yesterday when I applied a little more force than I usually do. I figure this thing has to be bullet proof. I should not baby it because no one else is going to, and it would be stupid to try and put a be gentle warning on the new caps. The old ones worked great forever, and so should the new ones!

I took some new pics of the prototype and posted them...

http://picasaweb.google.com/ishapespace/Gascapproject

The prototype cap pictures have comments. I apologize if you have to sort through to find them. When you see all the pictures together it is hard to tell the new cap from the original. I like to think of that as a good thing!!

I was going to make some more caps before we moved into our new house, but now I think I will hold off. Me and the in-laws had a big pissing contest last night and tempers flared. No reason to add fuel to the fire...

Tim

[Tim-Spruill]

Ok,

so I called the plastic people and asked about the problems I am having with the little sliding pieces that sheers under load. Apparently this plastic is not really all that strong once you get under about 1/8" thickness. They do not have any stuff that is stronger, and the piece is to small to fill with a fiber reinforcement. So my new ideas are to either cast a thin metal backing plate into the plastic to take the loads, or to machine metal key stock into shape and eliminate the plastic altogether. I think I will start with the backing plate, but depending on how soon I get my minimill up and running at the new house I might just move to the key stock. It is not a complicated piece.

Once again, I am sorry for the wait. Trust me, it hurts me more than you. Remember, I am living with the in-laws....

Tim

[sh0rtlife]

soooo hows the molding going..love to see a gtv6 gas cap eventualy as ive got to cracked but functional units

since you wera/are? looking for "simple" things to make...what about the surround piece for a gtv6 sunroof..small and fairly simple....i was going to mill one one out of aluminum eventualy

[Tim-Spruill]

I am finally making a small run of these things!! Right now I have three incomplete gas caps on the work bench. They are missing the sliding internal parts, and springs, and the handle. I completely worked all the kinks out of the retaining ring and threaded sections of the cap. I am having some trouble with the handle part. Previously I had issues with cosmetic problems like air bubbles. I solved those, but now I am having issues with demolding. The handle is falling apart when I remove the mold. Tonight I will probably get that solved and make the other parts. So by Monday I will hopefully have at least one cap ready to go. The only reason I would not have three is if I run out of plastic. I am going to order some more, but it will take a few days to get here.

I am thinking I will send one cap to a friend in Houston to test. He will not be as careful as I am. It will get lots of abuse and any failures will become glaringly apparent. I think the second cap will go to an undisclosed parts supplier that has contacted me in the past. And the third will maybe go to some lucky guy that recently lost his gas cap. Any takers?

I really think all the bugs are worked out. They only thing left is long term failure of the glue holding all the pieces together. I had an early failure, and solved that, but I think even the cap on my Verde is showing signs of slowly releasing glue. It is probably exposure to gasoline that does it. The good news is we can all buy glue at any store, so if one falls apart before I get the issues worked out, the owner can just glue it back and send me a nasty letter or something.

So now I just need to figure out who gets the third one, and what a reasonable price should be for a fully functional yet still testing gas cap. Any business people out there with an idea? Also, once the other two have been tested thoroughly, they will both be for sale at "used" prices.

Tim

[sh0rtlife]

texas heat and abuse is a good idea...but what about sending one for rain and moisture testing..preferably a daily driver thats not always garage kept

[116_Veloce]

Tim,

First let me commend you for your persistance and efforts. I was reading through this thread yesterday and thoughts were running so here I am to write some down. Your main problem with reproducing parts is one: Volume. When you make something by volume, i.e. a large quantity, the more chance you have to produce it to a high standard at a reasonable cost.

Impression molds are OK, not something I did myself but they work fine for reproducing light lenses and simple parts. There are some good repros done in a way similar to yours, using an impression from a good, original part and then pouring resin into the mold. I've seen excellent reproduction of Ferrari tail-lights, for example, done that way, among many other things.

There are several problems with impression molds: Possibility of distortion when taking the impression, or, during work. Air bubbles in the finished product, "swirls" in the material and poor finish.

Hang on, I'm not trying to discourage you...

You want to make a gas cap, a relatively intricate and accurate part, a part that is an assembly of several components made of several materials. You want to make more than one just for your car, you want to make a quantity for a good part of the alfa community.

If you individually make each gas cap, you're expecting many hours of labour. I've read your description of what you are going through. As someone who did and still is doing similar things, this work can get very discouraging at times, with repeated actions that carry mental and physical fatigue.

Let me say here again, that I AM, very impressed with your efforts, it shows you are a man of patience who is willing to learn through process (one of the best schools in my opinion) - but here must come a question of efficiency.

You've been playing with types of plastic, glues, o-rings for a while. Here comes the bad part: Nothing you do at home will ever match an industrial grade injection mold.

Industrial injection molds, even for the simplest parts, are heavy blocks of specially treated metal that is computer machined/milled, and worked by various methods for texture and finish. Plastics used in this process are different from the mixtures you buy, are far more durable and injected in high temp/extremely high pressure, up to 20,000 PSI in some cases, a trait necessary as the material must expand as fast as possible in every nook and cranny before it is cooled and released from the mold.

Unfortunately my friend, to make a GOOD, LASTING gas cap as the original one is, you will have to resort to industrial methods which ask for the following equasion: Parameter A, the inevitable COST (usually starts at 5-figures) of manufacture that can be devided by parameter B, large-enough quantity to make a marketable item.

I think what you're doing is great, and even if you'll have to make a new gas cap every year, you know you'll have an as-original item on your car. People who will buy a gas cap from you know they're getting an as original item for their car. This is what people with collector cars that have no parts do.

The process I mentioned above is THE MAIN AND NEARLY THE ONLY REASON WHY parts for our cars are NLA.

[5yearplan]

bump......

[Tim-Spruill]

Multiple bumps.

I have to apologize again for all the delays. The previous post about manufacturing says alot about why this is taking so long.

The other reason is there is some transition happening right now at work, and we are merging with another firm. Needless to say, by the time I get home I barely have enough energy to keep my two daily drivers running, much less do extra projects.

So, as of now, I am making no promises on anything. The gas caps and other things will happen when they happen. I am sorry for anyone out there that needs one right now. I just cannot pull it off.

I have some vacation coming up. Perhaps I can finish this up then.

Tim