Jim
Usually a hammer works. Seriously it is difficult. You could try scoring the back of the joint with a hobby knife but you will probably never get a clean separation. If you have access to one an ultrasonic cleaner where you immerse the parts in a soluton might work also.
I've had good luck with using a hobby knife to cut a groove along the inside corner and putting a nick at the top and bottom of the wall section joints, then tapping a putty knife or scraper down through the joint. The joint areas often need to be sanded prior to reassembly.
Have you tried just dropping them ?
Rust...... It's a good thing !
If they were sturdily assembled, this is going to be very difficult.
If the builder used glue sparingly, it is possible.
This is a question where the answer will differ from one model to another.
-Kevin
Living the dream.
This obviouly is the one downside to the fact that solvent based cements make the two pieces meld together as one. The late Art Curren used to apply the cement heavily, squeeze the two parts together tightly so that the softened plastic would "mush" out at the joint, let it harden and then cut away the hardened mush with a sharp knife, leaving a joint with absolutely no gaps. That makes a great joint but would now be the very devil to try to get apart -- because it was not meant to be separated.
Flooding the joint with MEK or other solvent might work but warning it might just soften the plastic so you pull it apart and it is like pulling apart a marshmallow that was over a fire. A gooey mess with strands of plastic. I suspect the reason is that the MEK/solvent works more on actual plastic than on the old cement itself
I think a purely mechanical approach is safer and more controllable. Scoring with a very sharp knife can work but do NOT expect the usual "score and snap" method that works with sheet styrene to work on a cemented joint - it will snap to be sure but not always where the joint between two pieces was originally, but rather where the weakest remaining joint is, creating the potential for a very jagged edge. Thus I'd score with a knife until you totally separate the pieces.
With great care it may be possible to use a thin razor saw, particularly if the pieces had beveled edges that met together. A Dremel tool's thinnest disc circular cutter (so NOT the reinforced discs which are thick) MIGHT work but warning the speed on most Dremels is so fast as to melt plastic. But if you are in the "oh what the heck what do I have to lose" phase, it might be worth a try. If you do try I'd cut with the disc a little, cool the work with a spray of water, cut some more, cool it again, and so on. That is a variant on what I do when I use a hot soldering iron to soften the plastic on a gondola's side so I can bulge out the panels between side ribs. Any melting stops immediately when cooled w/water.
Assuming you can find a method that actually works to your satisfaction, you'll likely need to dress up the ends before re-cementing. If the plastic was or is marred on the surface from the original cement, from any melting caused by a Dremel disc or saw blade, or from flodding the joint from behind with MEK or other solvent, I have had good luck removing cement/melting mars from styrene surfaces using a retractable "scratch brush" that has strands of fiberglass rather than brass or steel as many of them do. This used to called a "mechanical eraser" back around 1960, but it works on styrene too.
Dave Nelson
Try the old model car builder's trick for getting "glue bombs" apart.. Put it in the freezer for a while, overnight. It makes the joints very brittle, and they may just pop apart. Especially effective with the old orange tube Testors glop.
If your winter climate is colder than your freezer, put it out there. The colder the better. I've done it, it's a good first approach. Dan
Have you considered using cardstock buildings if you can not get them apart? Some of the cardstock these days look pretty darn good, nd they are easy to add details to (upgrade).
That old Testors welded the joints together.
Mineral Spirits seeped into the joints. I have done this with success.
If you can take the building off of the foundation, by soaking the joint with MS, then you can attack the inside of each joint of the building with a hobby knife/razor blade to open up the seem a litte. Then brush MS into it. You can then continue to score the joint as you alternate with putting more MS in the joint. There should be a final cut that takes the joint apart on a straight line.
If its very well put together, its pretty difficult to take a building apart.
Some of the other solvents eat the plastic too much.
I buy used structures at train shows. Many are in the "junk box" underneath the dealer tables. Great fodder for kitbashing. And they are usually poorly built.
- Douglas
Little Timmy Have you tried just dropping them ?
This seems to work for me unintentionally.
My best guess is using a hobby knife along the corners. This easily could go south. A steady hand is necessary. Good luck!
Works every time!
PMR
Disclaimer: Kids dont try this at home!