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Author Topic: Poor Quality Vac-forms?  (Read 1041 times)

plastic

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Poor Quality Vac-forms?
« on: January 06, 2018, 06:06:37 PM »

 What is the correct way to deal with poor quality vac-forms?

These look like the material was not hot enough to draw into the corners properly or the vacuum pump wasn’t sucking hard enough.
Sending them back is not an option (2nd hand model) so any ideas to make them better?
The huge corner radius and poor definition mean these are next to useless – so what’s to be done?
If they are cut to a good edge, the parts will be miles apart – but if cut to size, they will look like a potato.

Is this ‘normal’?
Is this just a typical ‘challenge’ of building expensive models?
 
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Colin Bishop

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Re: Poor Quality Vac-forms?
« Reply #1 on: January 06, 2018, 06:14:29 PM »

They look a bit beyond redemption really but you could try salvaging the hulls and then using the upperworks as a rough pattern for reconstructing in styrene sheet. They don't look too complicated.

Colin
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plastic

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Re: Poor Quality Vac-forms?
« Reply #2 on: January 06, 2018, 06:19:43 PM »

The hulls are no use - the plastic didn't suck down fully at the bow end so they are not full depth.

Is this normal for vac-forms included in kits?

It seems to show indifference to quality.
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Colin Bishop

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Re: Poor Quality Vac-forms?
« Reply #3 on: January 06, 2018, 06:54:46 PM »

It's not unusual I'm afraid. Still might be worth contacting the manufacturer for a replacement on a goodwill basis. Otherwise you will just have to scratch build the replacements.

Colin
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Martin [Admin]

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Re: Poor Quality Vac-forms?
« Reply #4 on: January 06, 2018, 08:13:50 PM »


Is the kit still in production?
Purchase replacement?
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plastic

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Re: Poor Quality Vac-forms?
« Reply #5 on: January 06, 2018, 08:44:24 PM »

I'll contact the manufacturer - but if this is typical of what to expect, can I expect replacements to be any better?



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Vintage

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Re: Poor Quality Vac-forms?
« Reply #6 on: January 06, 2018, 10:36:28 PM »


These look like the material was not hot enough to draw into the corners properly or the vacuum pump wasn’t sucking hard enough.


I do a bit of vac-forming here and you're correct in your assumptions.

I suspect that the material wasn't heated sufficiently, that the vacuum seal was broken whilst the plastic was being drawn down or probably a combination of both...

Those formings are of no use whatsoever, they look like the sort of result you might get whilst setting up a machine initially and should be binned.  :((

If they were commonly what was produced by the manufacturer then they'd be out of business.

Good luck with it.  :-))

Mark

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Martin [Admin]

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Re: Poor Quality Vac-forms?
« Reply #7 on: January 06, 2018, 11:13:39 PM »


It could just be that the 'hired help' wasn't the game that day... just wanted to go home early....  {:-{

Speak to the company, they may be more horrified than you!
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Neil

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Re: Poor Quality Vac-forms?
« Reply #8 on: January 07, 2018, 12:25:04 AM »

as vintage says........the plastic wasn't heated enough, but also the former wasn't left to suck out the air for long enough...........either first or last of a batch where the operator was just dog tired and fed up.......I used to vac form simple shapes for the kids in school, and at the end of the day when you had 30 plus sheets to do for prep for next day you'd try to scimp on the heating up process, and they would come out exactly like your piece.........it would take you twice as long  as if you'd waited those extra seconds for the plastic to be like a hot springy latex membrane before turning the pump on and pulling the leaver down to bring the tooling up under the plastic to make contact ............but then sometimes your eye would be taken off the job..........leave it too long and a nice hole would appear in the middle of the clamped sheet.........but get the piece just right and you'd get the perfect vac formed piece..........ahhh satisfaction!!!..
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tigertiger

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Re: Poor Quality Vac-forms?
« Reply #9 on: January 07, 2018, 02:39:21 AM »

If mass produced, it is also likely that the workers are on productivity bonus and working too fast. This coupled with poor quality control.


The hulls may be salvaged for other use, for freelance models. Just cut them lower down.
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