Hollowing out a styrene structure

Treadhead · Post by **Treadhead** » Tue Dec 18, 2007 7:36 pm

I have a styrene framework that I'm planking with styrene strip. The framework is .080 styrene formers attached to a keel of the same thickness. Once I have covered or "skinned" it, I want to hollow it out so as to add an interior.

What's the best way of doing this? What's the best attachement to use on the Dremel? I purposely built this ship in sections so that if I doink up a part of it, I won't have to rebuild the whole thing.... now how's that for positive thinking?

Umi_Ryuzuki · Post by **Umi_Ryuzuki** » Tue Dec 18, 2007 9:38 pm

Unless you have fiberglassed the exterior of the shell, the structure will
probably not hold up well with the frames removed. It may collapse.

If you begin to remove the interior frames, do not grind them out all the
way to the hull. Leave at least 3/16" to 1/4" of the frame against the hull. I think you will know how much is too little, as the hull will start to flex...

I can't recommend how much bracing to leave at your opening, as I am not sure of your hull shape, or how much material you want to remove.

Treadhead · Post by **Treadhead** » Wed Dec 19, 2007 12:07 am

Umi_Ryuzuki wrote:Unless you have fiberglassed the exterior of the shell, the structure will
probably not hold up well with the frames removed. It may collapse.

If you begin to remove the interior frames, do not grind them out all the
way to the hull. Leave at least 3/16" to 1/4" of the frame against the hull. I think you will know how much is too little, as the hull will start to flex...

I can't recommend how much bracing to leave at your opening, as I am not sure of your hull shape, or how much material you want to remove.

The cross sections for this piece are half-ellipses and it tapers towards the end. I'm planning on only removing a portion of the frame -- just enough to insert a box structure that will house the interior.

I'm just wondering how to go about cutting. I've heard that it is best to drill holes along the cut-line to weaken the section to be removed. I'll have to experiment on a piece of scrap first, I guess.

Umi_Ryuzuki · Post by **Umi_Ryuzuki** » Wed Dec 19, 2007 2:05 pm

I like to plan my frames for equipment or hollows, and sometimes I still end up grinding my way back in to get the space I need.

It sounds like you are on the right track, and have a good process in mind.
let us know how it goes...

I hope you are taking pictures as this progresses, I like seeing the process from sheet stock to finished model.

Treadhead · Post by **Treadhead** » Wed Dec 19, 2007 2:13 pm

Umi_Ryuzuki wrote:I like to plan my frames for equipment or hollows, and sometimes I still end up grinding my way back in to get the space I need.

It sounds like you are on the right track, and have a good process in mind.
let us know how it goes...

I hope you are taking pictures as this progresses, I like seeing the process from sheet stock to finished model.

I'll be happy to post pics of my progress with this thing. I ran out of strips so I will have to order some more. Your advice about trimming the strips so that they will rest on the subsequent strip really helped. Thanks

The reason that I didn't cut out hollows on my frames is because I was afraid of warpage during the skinning process. I figured that once the skin was in place, the structure would be pretty rigid.

Thanks Umi!

Shinnentai · Post by **Shinnentai** » Wed Dec 19, 2007 2:47 pm

At this point, I'd say coat the inside surfaces of the planking with a sloshing of epoxy or a rolled sheet of Aves. That should solidly reinforce the planks' bond, and provide a workable overall rigidity without increasing the hull thickness very much.