blow moulding - clear material


I’m looking for a bit of advice on this,

Is it possible to blow mould in a clear material to give a wall thickness of around 1 / 1.5mm

I’ve been looking at sports drinks bottles (the re-fillable sort you’d put on your bike or take to the gym)
but i can not find any that are totally clear, most at best seem to be a milky colour.

any advice welcomed, numbers would be medium’ish at around a 1000.

thanks :smiley:


there are lots of good trans. plastic that are blow-moldable. Soft drink bottles have different requirements for thier use (cost, food contact, transport, etc…) so transparency might not be a high priority. Isoplast (Dow) while very expensive has high trans. just search around, there are lots out there. also check Omnexus for other plastic possibilities.

your volume is not conducive to blow-molding and I’d be surprised if you get any quotes at 1000 units. blow molding is high volume and most manuf. are setup for this. your setup charges will kill your piece pricing as your setup time will likely be longer than your run time (for 1000 units). either bump your volume up (10K++) or find another process…

Yeah i was a little conservitive with the numbers it’d be more like 10,000.

so it just comes down to material spec then, I could injection mould to get the clear but it’d be good to give the product a bit more shape using a blow mould.

Im curious (Mulletstyle), what process would you suggest as a cheaper alternative if you needed 1k of seamless, clear parts that would have undercuts like a drink bottle?


well…there aren’t any really good alternatives…and cost really depends if you amortize tooling into part cost or just consider it a capital expense. seamless-ness also depends a lot on tooling…B/M seperates just like any other mold, only reason why parting lines are less noticeable is the plastic doesn’t flow as well into small crevices (also why you get less texture possibilities with B/M).

if tooling isn’t a factor, you could inj. mold 2 halves and ultrasonic weld them together. but now you have higher piece pricing as labour becomes a factor…good candidate for offshore manuf. volume is also a factor here but less so.

or…rotomolding could give similiar features as B/M, but volume won’t be a issue. but…bottles are kinda small for this process.

some people have experimented with lost core inj. molding for bicyle hubs. not sure if you can get a good finish though with this process: is for sale | HugeDomains

I’ve done some design for rotomolding, and can’t honestly say I’ve ever seen a transparent material rotomolded. Vast majority is HDPE, a much smaller fraction is ABS or PVC (none of which are transparent). The polymers that come in water clear varieties, like acrylic, PC and PET, don’t appear to be used in this process. Doesn’t mean it’s not possible, but I’d check with a vendor to find out why…

good point…forgot about that. you can get clarifiers for HDPE, but yes, trans. is still not very good, forgot about that requirement from the original post.

best bet would be molding 2 and welding,similiar to this: