Hey guys, havent been active here for quite awhile! I am finally getting ready to make a 1/5 scale model using 1/2" thick sheets of Extruded Polystyrene all sandwiched together. I have a stack of 80 sheets of coverstock with each rib already printed out to scale sitting on my desk. I will trim each piece down and tack them to pieces of foam. This weekend I hopefully will be constructing a table top hotwire so I can relatively easily cut out each piece and stack them up.

I do have a few questions for you guys though. I have looked around on the internet for answers but its hard to get a definate answer.

One, I wanted to use bondo to cover the foam once I got it smoothed out. Because the model is small, I feel that drywall mud would be too thin and not be sturdy at all to pick up and move. From what I understand this will melt the foam underneath and not let it bond. I have read that a layer of latex acryllic paint over the foam will give the bondo something to attach to and provide a barrier between the foam and the bondo. Do you guys have any experience with this? Do you know of any other relatively strong material that wont react with the foam?

Secondly, what is the best way to bond these sheets together at this scale? Spray adhesive on each side and sit something heavy on it?

Thanks guys! Hopefully within the next few weeks I will be able to post some pictures up. I really hope it turns out the way I hope.

Hi
I used a 3M spray glue to bond together all the styro panels in my model, this is what gave me better result, I also tried a "cold silicone" specially used for styrofoam, but it took more time to dry, but also with a nice result.
I made the mistake to use PU foam to bond some parts, but it added like 2 or 3mm to each union, at the end ]I had to remove one slice to balance the lenght of the model. take a look at my build diary, you can read some of my mistakes there, so you can avoid them.
About sealing the styrofoam, you can use acrylic sealer, like the one used to seal the concrete walls before painting, or latex painting, but be sure to add a good layer of paint, because I added a thin layer, and the bondo melted like 5mm of the styrofoam, and after a few days, it started to crack.
If I can be of any help, please email or pm me. I{ll be glad to help you.

Best regards

JELP

if you have a look on ebay you will find a poly spray that wont eat away at it

Craft glue aswell

Jelpspeed, I didnt realize who you were until I looked at your build diary! I have been reading your thread everyday. You are moving along quite quick!

Goldie, I would prefer a spray over having to mix an epoxy.

Wow di48lo, you have made quite a few models on there! I hope mine turns out as well as yours did! Try coating your model with what was mentioned earlier, an acrylic sealer or an epoxy sealer should strengthen and seal the model from what I understand.

I will upload some after work. I ran out of foam last night. Finally used a full sheet. Only about 1/3 of the way done though! I dont think you can see too many details yet... Maybe after another 4x8 sheet!

Looking really good:) This is what the sites about nice work

Thanks goldie! I hope it keeps getting better!!

I would like to use that product, however I have no air compressor or spray gun. I think I may resort to using a thinned epoxy mixture to coat the model. Spraying does sound much easier but I can't see the expense being worthwhile right now as I am only making a model and have no place to put it.

It is a custom design I have been working on for quite awhile below is an in progress render I made awhile back. I dont have any completed images uploaded.

Thanks! I am working on glueing the one half together right now and cutting out the front and back templates to finish up the foam pieces! Made a mistake when I let 2 pieces dry 1/4" out of line but hopefully it will sand out!