vacuum forming thick sheets???

[ade123321]

hi, could anyone please give me some details about forming 3mm or 4mm sheet.

i want to form motorcycle plastics/bodywork

i will be using 3 or 4 mm hdpe or abs or ?

the bike panels are 65cm x 50cm approx.

---- how much vacuum pressure would i need ?

---- the front mudguard plug would be 50cm high, it is of course curved around the wheel, is this possible? will the sheet break from overstretch?

----- what type of former and heater should i build??


many thanks,
Ade.

[jdougn]

hi, could anyone please give me some details about forming 3mm or 4mm sheet.

i want to form motorcycle plastics/bodywork

i will be using 3 or 4 mm hdpe or abs or ?

the bike panels are 65cm x 50cm approx.

---- how much vacuum pressure would i need ?

---- the front mudguard plug would be 50cm high, it is of course curved around the wheel, is this possible? will the sheet break from overstretch?

----- what type of former and heater should i build??


many thanks,
Ade.

Hey Ade, welcome to the forum. I don't get on here as much as TK560.com which is a more active vac former forum.
----- If you're forming ABS then you'll need a regular vacuum pump such as those used by HVAC technicians.

----- The sheet will always stretch but generally sharp outside corners or deep holes are what cause breaks. It may take some creativity to get to roughly 21" (50cm) high but it should be possible.

---- I form fender flares for off-road Jeeps out of 3/16" ABS. I use a modified ProtoForm vac former. Plans are found here: Workshop Publishing
There are some very good build threads for the ProtoForm vac formers on TK560. Look for the Discussion link towards the bottom of the left hand navigation bar. I use the same screen name there.

hth, Doug

[kayaker43]

Ade

A small company in Michigan started with the same idea. They now sell about a million dollars of vintage MX plastics each year using three plans built Proto-Form machines. Through persistence and ingenuity, they have worked out the mold making techniques and solved the numerous problems involved with a project like this. Both ABS and HDPE have their own personality and forming quirks. You will have enough challenge deailing with mold and plastic issues.

Although I am the one who sells the Proto-Form plans. I am being very sincere by suggesting you don't try to invent your own machine unless that's really the part that appeals to you. Go with a proven design if your goal is to produce a product efficiently without excessive development time on the machine.

Having said that, you are looking at something above most hobby level machines. A vacuum level of 25 inches or better rules out shop vacs. ABS will need to be pre-dried and virgin plastic is more consistent than recycled grades. HDPE needs more aggressive heat than most homebuilt machines use. It doesn't need to be pre-dried, bit it expands more and is hard to heat evenly.

Others with no previous experience have done what you want to do, so you can rest assured its all possible if you're serious.