As an experiment we casted a fog light grill in aluminum, just to see how nice we could make it. While the texture does leave some to be desired, we can improve it somewhat. The problem is that it will not be a finished part when cast. There will be a lot of polishing. I did about 20 min by hand in th einside of the light bezel. It shows promise, but to polish these I'm thinking we could have 4-5 hours into them to make them look nice. For me to pay someone to do these, the cost would be in the $350 range a set to provide as finished sets. I can make the blanks at about $50 a pop.

My quandary is hopw many sets could I sell at $100 that need to be polished saving about $250 in expense

Or is there a market for the $350 a set polise pulg an play ones.

Or Both.

My sweet spot to cover tooling is about 60 sets.

I honestly don't have the time to polish in house so that function would need to be farmed out, so I'm not really going to make anything on them polished.

Is it even worth pursing making these in metal as I do already do the plastic version (that we are currently doing more of now)?

Your thoughts?

Before

Semi polished - By hand
I'm sure using the right tool will yield a faster result.

Can you put them in a media tumbler to start breaking all the burs and clean up the surface before hand clean up. It may help, some.

Would that aluminum surface corrode if not anodized?

Polishing is a corrosion deterent. It reduces the surface area oxygen can react with. I did all the covers and caps on my Norton that way and they were fine for years. If I didn't always go with a black finish on mine I'd jump on the $100 version, which I assume would be as shown above, sans the light surround work.

Looks like sand-cast...die-casting would give a better surface, but the tooling might be prohibitive. I was going to try welding some pieces of bar & tubing together.
Powder-coating, anodizing & plating might be options. I like the rough as-cast look myself.

cm

I applaud the effort to make a solid aluminum one, but they would corrode if not anodized. And, the cost to produce the tooling for die cast grills would be in the thousands, so not a good route to go.

Personally, I think that Porsche's plastic design was correct. The plastic does not degrade with the elements. And, the plastic is lighter than metal. The one issue is that plastic does not have the impact strength of a metal grill. But, the repro plastic grills are relatively inexpensive.

I want to know who's flying that plane while your dreaming about which new 914 product you will offer next. Thx again Mark. + 1 on powder coated. FWIW, takes about 2.5 hours to polish the originals with a Dremel tool "if" they are not too pitted.

i worked in a foundry for 6 years. the grill pictured is pretty rough and the left behind, 'dirty', mold pitting is bad. is one set, a l&r, made per mold? the recess for the light is the easiest part to clean up. sand with more fines would help with a smoother casting. i looked into doing this about 10 years ago planning to have 2 sets in the pattern. quote for the pattern was around $1100-1200 and that didn't include any castings or clean up work. with all the intricacies of the part you might wind up with a lot of rejected castings. i couldn't made the numbers work and bagged it. bruce discovered the same issues when he tried to make them as well.

I had my plastic ones painted with chrome. Comes out great. Let me know if you want more information

Mark.....


I'd concentrate on other stuff. I don't think its worth it. I have some experience with it as well. Kevin is right.

Just a thought...Can these be made with those 3D printers in plastic? Like the cup holder that they guys made.

Mark...wondering if it would be worth you getting one (if you don't already). Opens up TONS of new options that can be made for much cheaper. You're already the go to guy for all kinds of stuff....

I will take 4 unpolished sets (at $60 a set)

914 Rubber offers reproduction "chromed" plastic fog light grills for $129 for the set. Why reinvent the wheel? I doubt that you could get replacements as cost effective.

I've looked at this option. I currently do the plastic version, and was looking at these to see if it's worth goin down this route. Thinking not at this point.
I do have a few other items that are coming, but these are probably not going to happen.

smart move mark. your plastic ones with some chrome paint are the ticket. when one looks at a set of grills you'll note the 'parting' line. its where the 2 halves of the mold come together. the part in the pattern has to be clocked at a weird angle to draw off the cope (top half of the mold) and lifting the pattern off of the 'drag'. 'free handing' the parts would be too labor intensive.

k

not sure if this would work on such a complex part, but I had a run of parts many years ago that I needed to sand and polish.
7500 pieces.

I put a load of sand in a garbage bag, and put in a large number of the parts.
i put the whole load in a conventional dryer I snagged at the dump.
I had removed the heating element, just wanted to have the tub spin.

It worked wonders at smoothing the parts out for me...
Wasted a few garbage bags, and killed off two dryers, but it did work.

rich

Electropolishing might be an option as well. I don't know any details about it, I just know it exists.

Or increasing the size of the part and CNC finishing it. I bet you could even load polishing buffs into the CNC...

But realistically, I could see the bare castings being viable and leave the metal finishing to the buyer.

how much would chrome plating add?

some of the pitting would fill in with the copper bath and polish.

Just find someone that does this...
http://www.sprayonchrome.com/index2.html

It's actually silver, not chrome but it looks just as good. Plus, you can chrome plastic...

As far as the finish on the plastic ones goes. There is a far amount of surface prep required. The Vacuum metalizing does yield the best result. I've looked at using a silver nitrate solution to drop it onto the the plastic, but I wasn't as happy with the result as the metalizing process.

Nope with the clearcoat it looks like chrome. Check out spectrachrome