Headlamp Covers

[jonclancy]

I cracked one across a hole due to being a little keen in tightening the fastener. EMA Plastiweld isn't strong enough to stop the crack from reappearing.

As we know, these are expensive to replace. I'm wondering if it might be worth making a mould and producing a few spares - or getting a plastics company to do a run.

Any thoughts? There's loads of info about vacuum moulding on the web.

[sgrant]

Yes, very much so. Techbod was looking into this a while back and I do have a spare cover that could be used for a making a mould. I think there was a previous thread on this, but I'm happy to buy up a batch and then just sell them back at cost to whoever needs a pair as and when the need arises.

I even contacted Westfield's supplier, but really they weren't significantly cheaper.

The only slight issue is that we might need to get them made slightly oversized - Westfield certainly had a few goes at getting a pair that would fit my new front clam and ended up hand trimming a pair. Whether this was variation in the clams or in the covers I don't know, but it might be worth trying my spare on a couple of cars and seeing whether it's a good fit for all or just my old clam....It does fit my new clam very nicely, so it might be a suitable doner for a mould.

stephen

[beng4]

When i bought mine i got them from mike brotherwood, who was the cheapest after shopping around- but still very expensive for waht they are on the face of it. These are supplied over size and you trim to fit.

Ben

[techbod]

Still happy to carry on getting some made.

I took Stephens' spare cover to an engineer I know well, who said they thought they could make some. The proposal was to make a mould from the spare.
However, it all stalled a bit over the question of handedness. The cover I had certainly looked asymmetric, and looked reasonably different from the replacement which looked like the cover might fit well enough on either side.

Can anyone say for definite if the cover is handed or will fit both sides?

[jonclancy]

Yes, they are asymmetric. Just been to check.

I was looking at some of the home vacuum forming tables that are out there.

Like these:

http://www.widgetworksunlimited.com/Vac ... ng_s/4.htm

I think you'd need a plaster plug casting for both sides and with a bit of setting up, trimming could be minimised.

I can't see why these couldn't be formed with a trimming line built in.

I've yet to price up the plastic sheet, but I would hope that these were economical to make as a batch.

[Westfield 129]

With a mold, you can just heat and drape the plexi. Vacuum forming is a great idea, but I don't think that Westfield bothers. The trick is in the trimming, anyway.

[Pluscat]

Does anyone of you guys have any experience with vacuforming?
I do, and I can tell you, it is not as easy as you think.
The theory is simple: heat up a plastic sheet, put it over a mold, suck the air away......

I vacuformed windows for a model car, and I can tell you it took a lot of trial and errror (and a lot of plastic sheet) to get it right.
Vacuforming transparant pieces is quite difficult. Too much heat and the plastic turns white, too little heat and the plastic won't form.

I can give you following advice:

-Use a plastic that can be thermoformed, like polyesther. PVC plastics are not suiteble for thermoforming.
-The mold should be finished smooth, no nicks or scratches or other unevenness, cause it will show in the endresult.
-The smoother the moldsurface, the more transparent the endresult, a rough moldsurface will make the cover less transparent.
-You can use a paintstipper to add heat when the plastic is being vacuumed to make the plastic form better.
-You can build your own vacuformer with little investment, most parts can be found in any household.
-When building a vacuform table, a desent vacuumcleaner (hoover for the Yanks) can be use for the vacuumpump; it will create enough vacuum.
-Expect to fail a lot, vacuforming takes practice and experience to get it right.

[jonclancy]

They make it look so easy on YouTube.

I reckon the biggest faff would be producing the plugs. Not only do they have to be finished perfectly, but need to be mirrored in design, too.

Prices look to be around £41 per m2 for 5mm Acrylic and £58 for polycarbonate. All plus VAT and delivery. About a fiver a pop for materials.

[Pluscat]

Making the molds isn't that difficult:
Take the (old) headlampcovers and spray them with a solvent. Then fill the inside with glasfiber-bondo, so a solid lump of bondo -flat on the botomside, headlampcover shape on the upside- is formed.
After the bondo has cured, you can remove (due to the solvent) the lampcovers (with a bit of luck in one piece).
Then sand the surface, spraypaint it with carpaint, and polish the spraypainted surface to get it perfect smooth.

Use a solvent when vacuforming, so the paint won't stick to the heated plastic.

And yes, plastic sheets are expensive, and knowing that you often need several attemps vacuforming to get it just right makes this DIY-job perhaps not very economical........

[11admire]

You could try http://andywiltshire.com/index.htm he made some for the Lotus 11