Author Topic: Resurrection of a 725 FLB Vacuum Former  (Read 741 times)

Offline awemawson

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Resurrection of a 725 FLB Vacuum Former
« on: June 08, 2019, 07:17:22 AM »
In a very obtuse way this is the start of resurrecting my 100kW Induction Furnace - but the Vacuum Former is getting in the way and needs to be disposed of!

I bought this some years ago in not working condition - several of the ceramic enclosed heating elements were non-functional - and I gave it a bit of TLC, got it working fully, made a few bits with it, and then it was pushed to one side.

Storage hasn't been to kind to it cosmetically, so I brought it out of storage this morning to dust it down with a view to disposal, but first it now again needs a bit of TLC, this time to the cosmetics.

How does it work? Well simply put, a plastic sheet is clamped in a frame, heated for a set time by those nine ceramic heating elements, and then a pattern is raised up pushing the soft plastic roughly into shape, which is then enhanced by the inbuilt vacuum pump sucking the plastic into intimate contact with the plastic. Once cooled the pattern is dropped and the sheet taken out.

Patterns can be very simple - just blocks of wood, or quite complex. I was amused to see an identical machine at the Herstmonceaux observatory science park  letting children make up their names using plastic notice board letters as the moulds.

Andrew Mawson
East Sussex

Offline awemawson

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #1 on: June 08, 2019, 07:26:38 AM »
The first thing that I did was to clean up the slider rails to prevent damage to the bushes that slide on them - but this is not precision stuff, the bushes are just plastic inserts. They cleaned up pretty well.

Then a quick dust down and initial clean with an oily rag on the control panel, taking as much grime as possible off the timer. I've had a spare brand new timer sat in the cupboard over my workshop desk for years ! The original one still works!

A quick test with mains shows all nine heating elements work as do their 'simerstat' controllers that adjust the temperature distribution. Also the vacuum motor still runs, and when the heaters are pulled across on the slider rails a microswitch engages and triggers the timer - all good so far.

So hopefully it will just be a cosmetic refurbishment and then it can go to a new home.
Andrew Mawson
East Sussex

Offline tom osselton

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #2 on: June 08, 2019, 03:48:40 PM »
Id have thought that there would have been a viewport to see the amount of sag or do you just push back the heater. I tried making a former 2x2 the one that raises the plastic to the heater but didnt have enough heat around the edges and the rails were aluminum on aluminum so binding occurred raising and lowering the frame, the vacuum chamber was too large and was filled with cutoffs to decrease the vacuum needed.

Offline awemawson

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #3 on: June 08, 2019, 04:07:02 PM »
Have a copy of the operating instructions  :)

Andrew Mawson
East Sussex

Offline awemawson

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #4 on: June 09, 2019, 06:58:50 AM »
A bit more clean up this morning got it looking reasonable, if not sparkling, so time for an electrical test. Well initially it failed - excessive live / earth leakage. Traced to the micro switch that starts the timer as the heating elements are slid over the plastic sheet.

This was probably due to excessive zeal cleaning things, as moisture was obvious around the switch. Warming, and then putting in a bag of Silica Gel improved the situation markedly, but as it is a current RSComponents stock item I've ordered one for delivery tomorrow.

Meanwhile I linked the switch out to continue testing, and then took a 'pull' from the simple tray mould - it worked like a champ  :thumbup:

Now I'm thinking do I really want to dispose of this toy - its rather fun  :clap:
Andrew Mawson
East Sussex

Offline carlquib

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #5 on: June 09, 2019, 12:47:40 PM »
Looks like it will boil down to a space issue. If the space is there and to spare keep it. If later the space is needed for another machine or project then dispose of said machine.

My name is Brian and I'm a toolaholic.

Offline millwright

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #6 on: June 09, 2019, 04:09:03 PM »
Clarke Vac Former Andrew, A good piece of kit. and found in most school technology departments, the main rubber seals are available from Clarke's in Ammanford, occasional problems with pump vanes sticking, an easy fix but a bugger to get to. easier to cut a hole in the back and put a plate over it for access I have the measurements somewhere for the cuts. i'm sure you can make good use of it again now.

John

Offline awemawson

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #7 on: June 10, 2019, 04:54:20 AM »
"an easy fix but a bugger to get to. easier to cut a hole in the back and put a plate over it for access"

John, I'm surprised that you say that, because removing the rear panel SEEMS to give good access to the vacuum pump on mine.

Last night I pulled the microswitch from it's bag of silica gel and measured it's leakage - back to normal ie not measurable with my Fluke. For good measure I left it in the Silica Gel bag over night.

Just as well probably, as RS emailed saying that the 'next day' delivery which should have been today will be tomorrow. So I went ahead and re-installed the original switch which now works fine with no measurable leakage at mains voltages - (of course the Fluke only measures at 9 volts).

So back to full functionality, and I've identified a corner where it can go on it's existing trolley, just need to re-locate a couple of heavy ammo boxes that hold my stash of copper and graphite for the plunger EDM machine. So it looks like I'll be keeping this toy  :thumbup:

Mind you, the trolley will need a major clean up and re-paint if it is going to earn a place in the 'clean' workshop  :lol:
Andrew Mawson
East Sussex

Offline millwright

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #8 on: June 10, 2019, 02:26:25 PM »
Think they may changed the cabinet design a bit the Andrew or perhaps the model is different from what was used in schools, easy access for you  on that one. would have to find my old work books out to check, and I have no idea where they went to.


John

Offline awemawson

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Re: Resurrection of a 725 FLB Vacuum Former
« Reply #9 on: June 15, 2019, 10:18:47 AM »
Today I paint stripped and rubbed down the trolley for the Vacuum Former and gave it a couple of coats of the silver hammer finish paint left over from spraying the Versatool cabinets.

It was remarkably rusty but has cleaned up a treat  :thumbup:

In it's new clothes NOW it's allowed into the clean workshop  :lol:
Andrew Mawson
East Sussex