Fabricating plastic tail lights

[JoshStratton]

Does anyone know where I could get a custom tail light made? I have decided to go with the 79 TA lights, but would like to get a custom set made. I could probably make a mold myself, but pouring them is something I would leave to a pro...

Any ideas?

[Hidro]

For one set you should just machine them out of plastic, making a mold for one set is not very cost effective.You should use polycarbonate plastic for the lenses.

If you do make a mold have a professional design the mold as you wont have a clue where to put the gates,vents etc etc.

For low volume of parts you can use aluminum for the mold. 6061 or 7075.

There is alot involved with making molds and plastic processes.

This is all i do is plastic injection molding.(19 yrs exp) Process engineer and mold design.

hope this helps...

[JoshStratton]

For one set you should just machine them out of plastic, making a mold for one set is not very cost effective.You should use polycarbonate plastic for the lenses.

If you do make a mold have a professional design the mold as you wont have a clue where to put the gates,vents etc etc.

For low volume of parts you can use aluminum for the mold. 6061 or 7075.

There is alot involved with making molds and plastic processes.

This is all i do is plastic injection molding.(19 yrs exp) Process engineer and mold design.

hope this helps...

EDIT: How much would something like this cost to have developed if I relenquished rights to the molds? I would just want one pair and the maker could sell/destroy/do whatever they want to the molds. This is something that would sell pretty well in the late 2nd gen community.

This helps a lot actually. I can see a product idea developing here. I have a 79 Trans Am and am not too keen on the look of the grooves in the stock tail lights. I would like to make ones like them, but smooth.



I would like them closer to this (the same shape as the 79 Tail light, but smoked and smooth):

[Hidro]

EDIT: How much would something like this cost to have developed if I relenquished rights to the molds? I would just want one pair and the maker could sell/destroy/do whatever they want to the molds. This is something that would sell pretty well in the late 2nd gen community.

A mold like that could cost 10k-30k min.You will need a left and right lense (2 molds or inserts etc), because the part appearance will have a smooth finish.

If both sides of the lense were smooth you could Vacuum Form the shape needed.This would be alot more economical way to produce the lenses.But I would guess that the backside of the lenses would need to have some kind of texture for light dispersion.ie light up the whole lense and not just show where the bulbs are.Take a look at the smoked lenses you like that look/work good and see what texture is on the back of them.Maybe plastic sheet is available textured on one side and smooth on the other?Vacuum Forming will be around 1/10 the price in mold costs compared to injection molding.

If you can get your lenses into a CAD file it will save you a lil money when getting molds quoted.(one less step)

[JoshStratton]

Yikes. Well I guess that one is out of question, unless I win the lottery

I didnt realize that this kind of work was so involved or so expensive.

[Hidro]

The initial investment is always steep, but if you were making lots of lenses the $ in the mold could take years to recoup the cost.This all depends on how many you make and sell.

FYI: I know people who make their living off of one part.One guy he makes just one style of drinking cups for people with swallowing disorders.Another makes antique guitar parts.(both these guys are doing very well)Nothing wrong with your idea you just need to sell alot of them lenses.

If you got any more questions i'll try to answer them.

ps every idea starts out this way!

[Jim Nilsen]

The biggest problem with the idea is the D.O.T in your state. The paperwork to get a lens approved will add even more and the liability cost can be even more. Years back when 67-68 Camaro tailight lens's became discontinued I looked into making them and after talking to a few experts it left the ordeal to be soooo expensive that even having a good market for them left it unprofitable for a long enough time to make it impossible to do even with a loan or investors. Quality is hard to get on a budget.

In my state if you don't get it D.O.T. approved it is also illegal. This is why you see the phrase " For offroad use only "on many items you see advertised.

The best thing is to find something you like and fab them in to look the way you want. With a good imagination you should be able to find something different but in good taste.

Goodluck, Jim Nilsen

[derekf]

Are the stock taillights grooved, or ribbed? If they're ribs, couldn't you machine them down and smooth the plastic back out?

(Actually, the same question applies if they're grooves but it'd be a lot more work if there was enough meat to the lens to do)

[JoshStratton]

They are ribbed. I guess that might work. Sadly, I sold my pair and have decided to go back to them. I just need to get some to look at.

I didnt know you could really smooth them out since they are plastic. Wouldnt the place where the ribs were still show lines?

[derekf]

Not necessarily.

It's just like paintwork -- enough effort and you can make them smooth.

Belt sander with a fine grit belt to get the ribs off -- you'd sand the unribbed part a bit too, but that's OK... progressively finer sandpaper until you're ready to buff it like stainless (Eastwood has a kit to buff plastic, if none of our fine sponsors do).

[JoshStratton]

i think i will get a POS piece and give this a shot. I would be interested in seeing how it works.

[derekf]

As am I. Theoretically it'll work; but I've never done it to know for sure. Biggest concern would be keeping the plastic cool during the buffing process.

[bretcopsey]

You could also try red tinted palstic sheet with diamond patterend (ceiling light fixture type) mounted behind. You would just need to warm it enough to mold it to the correct shape.

Somewhere at home I may still have a street rod style mag that shows a guy making homemade bullet style (fifties era) tailights using plaster molds and a hand operated hydraulic press. I'll post it up if I can find it.

[derekf]

Come to think of it, the show on the DIY Network - Classic Car Restoration - had an episode where they made a mold out of one taillight and used that to make a second, and they did it in their garage with a kit. If you've got DIY, might be worth checking out. I think it was when they were working on the Packard.

[JoshStratton]

I found this on another site. I may give it a try also:

You can make a mould from an original part by casting with something like Devcon or similar filled polyester, polyurethane or epoxy.

The resin needs to have minimal shrinkage and a good surface finish.

You will need to make the mould in at least 2 pieces that fit together to form the inside and outside surfaces. The mould will need to be accurate so the section thickness is correct.

Once you have a mould, you can cast the parts from acrylic or Poly Methyl MethAcrylate or PMMA.

It should be partially polymerised before you start so you can control the exotherm and avoid forming bubbles due to the monomer boiling.

PMMA is the resin that is used for most original equipment taillight lenses and in sheet form is often known by the trade names of "Perspex" or "Plexiglass".

PMMA is very clear and transparent. You could add colours to the resin, but for multi colour lenses, you would need to cast them in individual colour pieces. If you want to do them in one piece, do them in clear then paint the inside surface with a transparent tint.

[bretcopsey]

I would think for your situation it would be easier to start with a sheet of plexiglass. As far as I can tell, your tail lights are essentially flat lenses with a bend.

I was able to get a small piece of red plexiglass at a local plastics shop a few years ago. They have since moved on. You could try this link if you don't have any local shops. http://www.mcmaster.com/param/asp/PS...MMainWidth=768

or ebay

http://cgi.ebay.com/Transparent-Red-...QQcmdZViewItem

If you do decide to go the mould route, here is some info I found yesterday while looking for the article I mentioned earlier. Still haven't found that one.

http://www.alumilite.com/howto.cfm?ID=23

[JoshStratton]

I always thought that alumilite stuff was a scam. I think I will look into that as well. That step-by-step seems pretty thorough.

[Midwest Performance]

As an experiment I made a mold of a 1969 Camaro model and used it to make a wood body for a Pine wood derby car(ground up sawdust and wood glue). I used Smooth-on and used the dragon skin. For a tail light model I would use a stiffer mold material that they sell. You need to get a tail lights from ebay cheap and modify them to meet you need and make a mold. They would keep the reflector lense from the inside that makes it DOT legal and have the outside custom like you want. As far as that goes if you smooth out a stock set of tail lights and like how they come out use them.
I am working on a custom smooth set for my 69 camaro right now. I am not happy with the profile I have yet.
There is a guy in California that if you have the plug(part to be made) he will make the mold for you and cast them. I don't remember the site anymore off hand but will try to look. With all things custom even if you already have the plug designed the molds would not be cheap.
Attached is the pictures of the mold and parts from it and my taillight profile test piece. notice the roughness of the top of the car that is due to me not using enough mold material to make it thick enough there.

Later Kevin

[BBShark]

If you are only interested in making one set, you should modify your originals by cutting off the ribs and then buffing the lenses, If I were you, I would then spray them with clear urethane.

Beware of molding with thermosets (urethane, epoxy, etc). They will yellow with UV exposure.

[ProTouring442]

I was thinking… and that doesn’t happen very often! I was thinking about this, and if I remember correctly, ’79 Trans Am tail lights have a smoked cover over a red tail light. It seems to me that you can remove this outer cover and make a smooth cover to put in its place. Since the red tail lights with their flutings will still be behind the smoked cover, it should work rather well. I would stick with your idea of getting a junk tail light (I just threw a pair away, argh) and cut one apart to see what you might be able to make.

Just a thought!
Shiny Side Up!
Bill
’72 442 “Inamorata”