Introduction: Mayku (Vac Former) - Heat Shroud Hack - Eco Moulding

About: Black sheep engineer, Chartered, and very silly. Currently living in the UK. I have been fortunate to have lived, studied and worked in Hong Kong, Norway and California. I believe physical models help people…

If you want to use a Mayku Vacuum former to make moulds out of reclaimed HDPE (from plastic milk jugs), this is a simple guide to 'convert' the machine to work with the plastic. The current Formbox was originally designed to heat plastics like ABS (c.105C), which have a lower melting point than HDPE (c.130C).

FIXING IT: Although the heating element gets plenty hot enough to melt HDPE, the hot air escapes around the edges, so this 'heat shroud' is a good fix/mod/hack to solve that, by retaining the heat and focussing it towards the plastic - and allow it to just hit the perfect temperature.

Disclaimer: this is not 'standard' practice, of course, so do so at your own risk. I did contact Mayku - and although they liked this hack, and gave a reassurance that the heater cleverly has a 'thermal cut off' switch to prevent overheating, it should of course only be performed by those who understand the risks associated, and care should be taken to ensure that it is not repeated dozens of times - without some time to cool down! With this said, it's been going strong some 20+ tests now, and doing great...


1inch wide Stainless Steel Strapping. (Best to avoid Galvanised, if possible). Or use a Biscuit Tin. (See Appendix)

Mayku Formbox: (ships worldwide).

Pliers, Snips (LINK), etc.

Step 1: Tools and Materials

The metal strip is 1 inch wide, and is just the perfect size to fit. It can be found on Amazon, see previous link), or at Builder's Merchants, or Farm Supplies.

If you do not have this to hand, you might be able to get some metal strip from a scrap yard, as they will likely have a guillotine to cut sheet steel into strips. I have not tested non-ferrous metals, but don't see why Aluminium would not work, and is easier to bend. It needs to be around 1m/50inches x 25mm/1inch, with some excess for handles if desired.

I used a Marker Pen to roll the radius. But anything round about 12-15mm diameter will do.

Step 2: Cut a 1m Strip of 1inch Wide Strapping

I would suggest keeping the tape on the end, to avoid cuts, as the edge remains sharp.

Straighten out from the coiled state, by hand.

Step 3: Form Around Corners

Take your Pen or Dowel, etc. - and by hand, bend the metal round the corners as shown.

Continue on all 4 sides, leaving the 'ends' of the metal at the 'mid-point' as shown on the third picture.

Step 4: Crimp

Crimp the end, and fold over with pliers. It need not be neat, as it will be pressed into shape later.

Allow about 3-5mm crimp.

Step 5: Join Ends & Press

Align the end of the other strip and cut to approximate (over) size.

Crimp this edge to fit the other, to interlink like hands, taking note that it needs to align at the sides.

Use a bench vice (or even hammer) to press the two crimps into each other.

Result should be flat. Although this is not a 'super strong' join, it's fine for the task, as it is not load-bearing, but if you were a perfectionist, one could double the crimp so it rolled inside each other one more loop (Interestingly, this is how tinned can foods are sealed....have a Google!).

Step 6: Handles

Although these handles didn't get super hot, I'd still suggest using gloves.

Crimp an edge again, and slide it around the 'square shroud' part. Tamp it down to be a snug fit, and crimp slightly (either in vice or in pliers).

Fold that around by hand. Bend back again, mid way up, using the Pen or dowel.

Step 7: Shape Handle & Repeat

Trim handle to the length that suits you.

Trim sharp corners, and sand any burrs off if necessary.

Repeat again, on the other side at equal distance.

Step 8: Check Fit

Check the fit of the perimeter - it should fit nicely in the rubberised flange on the platten (see first pic).

It should just come flush with the upper part of the Formbox, see Picture 2 & 3.

It need not be 100% sealed, as it's just keeping the majority of the heat inside.

Step 9: Ready Your Plastic!

I initially used 6pint Milk Jugs, but if those are not available, 5ltr Water Jugs will also do. The latter is also thicker HDPE plastic, and is easier to prepare for the Vac Former.

Cut out to approximate dimensions of your vac former platten.

Step 10: Ready...

Place the HDPE sheet into the former bracket/clamp.

Add the heat shroud, and you're ready to go!

Step 11: It's Melting!!!

For some Vac Formers, they will be hot enough, but this 'Fix' for Mayku seems to get the temperature up to the required level (ABS is around 105-110C, where as HDPE is about 130C - so that shroud really make that extra bit of difference to get it ~20C hotter).

Step 12: Vac Form! (On the Cheap!)

I think this is a great Fix for Formbox, as it extends the capability with no detrimental effects to the machine observed after some 20+ tests on mine. I do give it time to cool off, and would advise the same, as clearly one is doing the equivalent of 'overclocking' a CPU, so although it can be done, it should be done with care and consideration.

I did these shapes to test the concept, but I'm likely to work on some Easter Egg hacks I hope. Do post any you make here using this technique or a variation of it.

Best wishes,


More at:

Step 13: Appendix: Use Biscuits Tins - If No Stainless Steel Strapping Available.

Although I initially used galvanised steel for this prototype, I later moved to stainless steel. Galvanised steel I later realised can off-gas some nasty fumes at higher temperatures, so best to be safe.

Steps, are probably obvious given the above, but just in case:

  1. Gather tools and biscuit tin. This was perfect:
  2. Note rim of the tin.
  3. Cut anti-clockwise if you have right handed shears. It's easier.
  4. Keep the base.
  5. Scribe the height with a block and pen as shown on the outside...
  6. ....and the inside.
  7. Cut
  8. note burrs
  9. sand off
  10. Use some scrap for the handles...
  11. Fold as shown.
  12. Trim down
  13. Roll over
  14. Done!
  15. Use the base for something else =)
  16. Oh - and in hindsight - wear gloves. It can be sharp. And if new to this, perhaps wear goggles too!
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