Vaccuforming question

Hey-avadon--- Your biggest problem is what kind of plastic you,re using. I used to vac canopies for plane builders and motorwhaleboats ,etc. I used NOT styrene but clear polycarbonate sheet. The stuff is what the packaging industry uses for most all their bubble packs.Also, my friend you are using material that is to thin! Depending on the scale of your aircraft you should not use less than .010. The old MATTEL -VAC-U-FORM used .010 sheets. I made my own foldup vac rig and I still use a minimum of .010 and for larger pieces(A 25 inch boat hull)nothing less than .015 or .020. The hard part is, where you might be located. Here in TEXAS ,I have yet to find a place to buy my plastic. I still have to get it mail order from TAP PLASTICS of CONCORD, CALIFORNIA.------Tankerbuilder

Where do I get such thin sheets of plexiglass or lexan?

 Hi!  When I vac a part I use two things . the vac frame is homemade and the whole thing connects to my shopvac . For small parts (less then 3 ' ) I used to use a mattel vacuform But Like many fine tools acquired over the years it developed legs when I wasn,t looking . For molds I always use basswood , sometimes formed plaster with a wax coat on it . My best to date was made in a female type mold and clarity was not an issue . Having worked around plastic ,both injection and vac-molded I knew what would work . Most of My stuff is .020 or .040 lexan or other polycarbonate . I rarely use styrene for the reasons you,ve already mentioned .    tankerbuilder

a vac-machine with good suck is what you need.you need good suction. a piece of plex or lexan in  the oven and draped may not work although they make giant custom domes and spheres by draping plex on a jig.its much clearer than vac. if possible pulling into a negative buck rather than over gives better results when vac ing detail. try draping thin plex?  good luck,   fxdude(www.1madmodeler.com)

fx dude wrote:

bummer....still a problem ?....petg..(same material as a 2 liter bottle)best structurally,clarity,minimal tear factor....probably.020 thickness or .010 would be good,maybe  thicker?..unfortunately..little expensive,and hard to buy small pieces.(plastics companys for bulk)  if buck isnt sweet.. forget it on pulling a really superclear..really soft felt,laid on top of the buck helped me out .casting an  ultra clear canopy will be a pain in the..........good luck.     lemme know,(fx guy ( www.1madmodeler.com)

 

Yah I just tried a .20 and I wasn't even close to having any sort of luck with it. It would just not get elastic enough to stretch over the mold and when I got it warm enough to the point I thought it would work it just tore holes. I even tried using a heatgun and trying to warm the styrene as I pushed the mold over the master. It wasn't even close to working.  Totally depressing. Wondering how i'm gonna make this happen now.

 bummer....still a problem ?....petg..(same material as a 2 liter bottle)best structurally,clarity,minimal tear factor....probably.020 thickness or .010 would be good,maybe  thicker?..unfortunately..little expensive,and hard to buy small pieces.(plastics companys for bulk)

 if buck isnt sweet.. forget it on pulling a really superclear..really soft felt,laid on top of the buck helped me out .casting an  ultra clear canopy will be a pain in the..........good luck.     lemme know,(fx guy ( www.1madmodeler.com)

If you're interested, I can vac it for ya...

Okay i'm still having huge difficulties with vaccum forming. I used some .4mm thick clear evergreen sheet stryene and it was very difficult to work with. It was either burning right through the sheet at about 380dgs, or at 350 when it seemed to work it just would not get a clear form over the part. I guess it was just to cool by the time I immediately took it out of the oven and put it over the master.

 The master is about 4" x 1.75" so it's a rather big canopy. I don't really want a thin-flimsy canopy. It needs to be fairly tough and hopefully someone scratch proof. It seemed like the sheet styrene scratches up increadibly easy. Just sliding it out of the package you can get scratches if your not careful. I was amazed at how vulnerable it is.

 

So here I have a great model with a solid canopy :( And I wasted about 15$ today experimenting with about 6 styrne sheets. Is there a better way?

 What about casting this part in resin? Are there any tutorials on this? I suppose this means I have to hollow out the back which sounds really difficult. Because as it is right now only the top is contoured. I think contouring the inside would be a lot of difficult carving. Heck at this point i'd be willing to ship it to someone to have it vaccuformed. Anyone know anyone who does this as a service?

 Please send help :P lol

brand new to forum stuff -seriously.about.your vacuform question..A super thin.020,.010 styrene pull over your master,then your main pullover that .then its cleaner...use baby powder doing plastic over plasticexect petg...#2  -felt.....yes,.thin felt right over your buck comes out really nice(clear,materials..acrylic,petg) good luck..fxdude  oh...no pain usually when vac.

Okay I think i'll be safe. I think your right about getting all the moisture out of the paper clay before making my canopy. Thanks for the advice.

some type of separator is not a bad Idea. the mold needs to be dead smooth so I would consider making sure it is like glass, ANY imperfections will show in the final product. the mold needs to be dry as a bone. {moisture will bubble up between the mold and material}

A totally dry mold that has some vasoline applied, then heated so it is THAT thin of a coat. We use a spray but it is not available in the general market.

You could do a thin film of 20 minute casting plaster that can be polished to that level of smoothness, then if dry it may well vac fine.

If it is a very detailed mold a parting agent is needed {under cuts etc}

Dan {30 years vacuforming parts for artifical legs and braces}

I'm not real sure what paperclay is, but if it is hardened, and smooth, then you should need no sealer or coating. The plastic cools rapidly, so there shouldn't be any adverse effects on your master.