I am in need of several 4 1/2" styrene domes. I have started several trials but it cant hurt to see if Im on the right track.

I have not done any vac forming yet but Im ready willing and able...I think.

One of the trials Im working on is a foam board laminate covered in Bondo. Its going well but this is counter productive for what Id like to do. Think of it like a hull. Id like to use a pulled styrene one as the base and then detail with a second and third.

The thing is my attempt at a plaster plug went horribly horribly wrong. The above trial may work for the plug though. If not my next trial would be to rotate a template around center to shape plaster (like you would for old mouldings but in rotation rather than straight).

There it is. Any and all help is appreciated!

Thanx

are you looking for a domes end as in like on a horizontal storage tank? if that's the case Plastruct offers some in ABS

Plastruct They have eliptical / dished & hemispherical ones. the generic search term to try is head.

HTH

Yup, first place I checked. Unfortunatly its sounding more rigid and they dont have the size I need. My plan is to use one dome to cut and glue to the other as detail. I dont think acrylic would be that forgiving and ABS is tough stuff.

I have built my first vac form table! A small frame with attached 1mm styrene is ready to go! However, I forgot to get some wood filler today in order to finish off the plug. So this will have to wait untill tomorrow.

Thanx anyway and ill try to remember to post some results (if I have some).

Well, its like this...

After reading as much as I could find on the subject it was time to get a real world feel for it. All said and done its really a very cool process! No they are not perfect but Im still perty darn happy.

My quick and dirty trial vac table...


The first 2 pulls...


After adding a lifting plug to avoid the curved lip at the bottom of the buck (form)...


The best pull and loss of the original buck



Next was to try a different approach. The idea here is to cut a hole the diameter of the dome you want and pull it in reverse. Its a nice concept but hardly accurate. There are too many variables to cover to get consistent pulls. I could be missing something but for this piece a buck is the way to go.

The box/form...


Add styrene...


Add heat and vac...


A not so half of a dome...


Adding too much heat and vac...


As you can see you could get something less than half or much much more than half. Because my table does not have a central support internally, it warps a bit under vac. This is the reason I was able to get what i did. After placing some cloth to fill the gaps between the box and table the pull was so hard (and the plastic too soft) that it sucked it all the way out. Not good, not good at all

So now I know I need to make a new buck. Modulan is too pricey for me but sounds like really nice stuff. It could be made of pink foam, they say, but needs a thermal layer to protect the foam from melting (see the mushroom cloud pull, that was regular Styrofoam used as a lifting plug). Suggestions are Gesso and high temp spray paint. I could use MDF but its gonna be kind of hard to get to, cut up and shape for me at the moment.

If you have any ideas for making a buck let me know! Remember it has to handle some heat.

Thanx for reading

I finished the project...

http://s4.photobucket.com/albums/y138/usagidoug/Deff%20Star/

Very cool cool project