Hi everybody. Could someone tell me how I could bend a sheet of plastic around a curved shape? I'm not talking about complex shapes. Maybe like if I'm scratching a barrel, I would have two circles, or 3, then comes the part of building the body of the barrel.. which I assume is a sheet of plastic bent all around the circles. How is that done? Thanks.

for barrels, there's lots of options. Plastic tube Brass or Aluminum even it's by far the easiest way........ the other option would be to use a wood dowel and slowly heat & roll the sheet around the dowel.

If scratching your own is the desire - then a wooden mold and heat on the plastic are the route you need to take.
There are other options as mentioned - metal, AM, and plastruct also makes tubes in plastic

Thank you guys for your replies. I was using the barrels as an example. So in general you would make a wooden mold and heat and bend the sheet. How is the heat applied?Thanks

Hisham,

Never done it myself but as I understand it you can take sheet styrene stock, wrap it around a wooden dowel and hold it tightly in place with several rubber bands and dunk it in boiling water. When you take the dowel with the plastic out of the boiling water and let it cool, cut off the rubber bands and the plastic retains the circular shape. Some guy use this method to make thin blast shield rings for a 1/350th scale ship model he was building in an article in FSM.

Hope this makes a certain amount of sense.

Shaun

A heat gun.

Hisham, what are you scratching? Chances are one of us has done it and can tell you what's up.

Cuhail

Cuhail.. by heat gun you mean like what women use for their hair. I'm sorry if I sound kind of slow witted, but names of things differ a lot from country to country.

Actually, I'm not working on any particular project right now. I've ordered some sheet plastic and was looking at some drawings which members here helped me out with, and many of them have curved shapes. So I was trying to think of how I could tackle each project.This would be the first scrach building I do, but I've always wanted to try it out. Thanks guys.

It's like the Hair dryer only...Hotter.

Hisham,
The heat gun is used often by painters to strip paint. It is much hotter than a hair dryer. Check out a hardware store, paint supply store, or a home improvement center like Home Depot ( or whatever the equivelants are in Egypt). I prefer the boiling water method myself. It works well for me.

Thanks for all your input. Very helpful. I think the boiling water sounds the easier of the two ways. Plus, I don't think they have heat guns here. Third world countries are very different.. go figure!

One last question.. I assume with all this bending that you're talking about very thin plastic? Like .010 or can you bend thicker than that? Thanks again.

Depnding on how tight of a bend you want, you can bend thick plastic too. I have bent .040 into about a 2" circle with no problems.

i have a plan to build the cab of the m578. and it includes some molding also. i will use the heat method described above.

i will carve the cab out first and then either place the sheets on the mold or drape a warmed piece over the mold and heat and let it form fit as needed.

the crane boom will be a different story as it is metal in the conversion kit, but i will try to build it anyway. i have plans/blueprint coming in the mail, so i will keep ya updated as i can.....

reb

I use pieces of copper or plastic drainage pipe (household plumbing pipe) and use these as my formers. These pipes are selected slightly smaller then you want your plastic.

I then tie the plastic strip or sheet I wish to bend onto this with copper wire, twisting with pliers to get as tight as possible on the pipe.

I then place this in a bowl and boil the kettle. Once the water is boiled pour over the part until it is covered. Leave until the water is cold and there you have your curved part.

Conplex curves can be made useing two spoons of the right size with the plastic sandwiched between and the spoons wired tight.

Some times you have to remove the item from the water once the plastic is soft and tighten the wires and then put back in the water until cool.

I use metal pipe(copper) where possible because it heats quicker and gives an even heat to the part.

When one heats up the plastic and forms it over the mold, does the plastic lose some of its width in the process? Would the same be true if the plastic was vacuformed over the mold?
Kyle