I've built a number of plastic structure kits, which often have very thin walls and very little gluing surface to hold those corner walls together. Before I even start gluing, I go out and get small balsa wood strip stock. I glue that to the inside of the corners using CA glue, because it binds to both wood and plastic. This gives me a much thicker glue surface that holds the joint firmly. I also gives me a light-proof corner that won't leak, providing a more attractive model.
It takes an iron man to play with a toy iron horse.
I glue Lego blocks in the corners, and hide the seams with Testors putty.
Simon
I understand that the corners are slightly off 90 degrees so they release from the molds easier. With DPM building I always run the smooth edge wall panel across a sanding block to create that 90 degree corner.
Using filler is another option, I have also covered gaps with down spouts.
If you are using Testors toothpaste tube glue, don't. I use Plastruct Bondene, which melts the styrene to form a bond.
I also use a Micro Mark right angle clamp
This and the Kalmbach Store right angle magnets have gotten extremely expensive in just a few years. Just my opinion.
Henry
COB Potomac & Northern
Shenandoah Valley
I think MR just had an article on making a right angle sanding fixture.
basementdweller I always run the smooth edge wall panel across a sanding block to create that 90 degree corner.
Hi Tim G. and basementdweller,
If I can expand on the sanding suggestion, I use a large, flat sheet of medium sandpaper on a glass sheet (or other very smooth surface), and sand the 45 degree edge until it is slightly less than 45 degrees. When you mate the two walls, the outside of the corners will make firm contact. Note that you must use a 90 degree corner brace like a small square to get the walls at the proper angle.
Once the glue has dried, you then add a corner brace to the inside of the joint to reinforce it and stop any light leakage. I use old sprues quite often. Building kits usually have lots of sprues.
basementdwellerUsing filler is another option,
In some cases filler can be difficult to work with. That is particularly the case with brick walls because it is very easy to accidentally fill in the brick detail close to the corner.
Cheers!!
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
I sand the walls as well as possible, the add styrene bracing at the corners for more glue areas and then glue them with liquid cement like Weld-on 3. Any thing that dosn't take care of can be patched up with glue putty (varius brands).
You could also create Quinn's out of brick or stone to cap that corner and also change the box stock look. A more modern steel building you could just use angle stock to do that cap. Vines growing up the side, downspout, Once one starts digging , there are many ways to hide a corner like that. That also adds a unique aspect other than box stock.
shane
A pessimist sees a dark tunnel
An optimist sees the light at the end of the tunnel
A realist sees a frieght train
An engineer sees three idiots standing on the tracks stairing blankly in space
Here is the classic method of the late Art Curren, a king of kitbashers and the guy who all but invented the kitbashing/kitmingling idea. It is perhaps not for everyone.
What Curren would do is seriously absolutely flood the joint with liquid cement to the point where the styrene would soften. He would then force the two parts together so strongly that the mushy styrene would squeeze out between the parts and look a little like, well, like toothpaste. He would leave it absolutely alone until it hardened and then with a very sharp knife, shave it off, leaving the two parts cemented with no gaps even if the beveled edges were not a perfect match. the key thing was to leave the parts alone until the mushed joint was solid styrene.
I suppose it should be conceded that (1) Curren liked using cheap kits from AHM, LifeLike, Tyco and Revell and such and thus it did not break his heart or his bank account if this method didn't work well and (2) because he was cutting up kits to create something entirely different, he was often mating parts that did not match in any way including at the corners.
Dave Nelson
Except for DPM kits, I rarely need to sand the corners of plastic kits. Maybe it's because I use Testors or Plastruct Plastic Weld liquids adhesives. The Plastruct is more agressive (has more MEK) and gives a stronger bond than the Testors but both are good. When possible, I also brace the exterior from the outside to maintain the 90o angle.
And I illuminate the interior of my structures, when possible. The only precaution I take is to paint the corners and/or interiors with black paint to eliminate light leakage.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Make sure the walls are as straight as possible. Use a hair dryer or set out in the sun under a piece of glass. Careful not to melt the pieces of course.
I still use orange Testors tube glue, and smoosh them together. Aligned with a Lego or a simply over a right angle drawn on the workbench with a carpenters triangle.
I also interupt the bead of Testors glue with a couple of dots of superglue, as to give an instant bond that stabilizes the set 90 degree corner so it won't shift around.
- Douglas
I use a carpenter's square to ensure a 90 deg setup. Should any gaps form, I glue stryene shaped as a round tube or half-moon along the entire wall height. This creates what looks like a gutter.
Hello All,
I have a Sand-It from Micro-Mark.
After seeing the article in the August 2023 Model Railroader Magazine; pgs 44-46, I decided to add a piece of aluminum angled stock to enable sanding wall sections at a 45º angle.
It was another "palm-to-face" moment of "Why didn't I think of that"!
Thanks for the great idea!
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
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Tim G.Their weakness, however, seems to be the corners, typically a right angle, where the exterior walls come together.
There are typically two ways corners come together on plastic structure kits.
On walls with butt joints, the walls must be sanded square and true to minimize the gaps. These walls are cast with a trapezoidal profile so they can be released from the molds. This angle is why they must be sanded to a rectangulat profile.
Walls cast with 45 degree metered surfaces typically do not require sanding, but they present other challenges. The brick surfaces must be aligned properly, and glue can ooze out of the joint and mar the surface.
Tim G.Any tips for how to minimize these gaps in the first place
Sand true, use sqaures to align the walls, and let the glue fully cure prior to handling the assembled wall sections.
Magnets and 1-2-3 blocks are your friends here.
As with so many things, patence is the key to success.
Tim G.how to hide them if they are present once the walls are assembled?
This will happen. With butt joint walls I just add downspouts to cover the joints. The diownspouts near the front of the building might not look prototypical, but the look better than bad joints.
If a mitered joint is bad, you will need to fill with putty and sand.
-Kevin
Living the dream.
I use corner clamps I purchased at Menards to help hold wall corners unil the glue dies
dknelson What Curren would do is abseriously solutely flood the joint with liquid cement to the point where the styrene would soften. He would then force the two parts together so strongly that the mushy styrene would squeeze out between the parts and look a little like, well, like toothpaste. He would leave it absolutely alone until it hardened and then with a very sharp knife, shave it off, leaving the two parts cemented with no gaps even if the beveled edges were not a perfect match. the key thing was to leave the parts alone until the mushed joint was solid styrene.
What Curren would do is abseriously solutely flood the joint with liquid cement to the point where the styrene would soften. He would then force the two parts together so strongly that the mushy styrene would squeeze out between the parts and look a little like, well, like toothpaste. He would leave it absolutely alone until it hardened and then with a very sharp knife, shave it off, leaving the two parts cemented with no gaps even if the beveled edges were not a perfect match. the key thing was to leave the parts alone until the mushed joint was solid styrene.
That's what I do. I call it the "squish method."
--Steven Otte, Model Railroader senior associate editorsotte@kalmbach.com
It there one liquid styrene glue that is best for the "Squish Method"?
I use Testor's liquid cement for platic models almost exclusively, but have not had much luck getting enough glue on the edges wet long enough to get a good squish going on.
Another thing I do for urban brick buildings is build a sidewalk around them so the base of the structure sits inside the sidewalk instead of on top of it. This eliminates light leakage around the base if you illuminate the building.
SeeYou190It there one liquid styrene glue that is best for the "Squish Method"?
When I have larger sections to cement and I want the cement to have more time before it 'flashes off' or evaporates I use the Faller Expert 170492. The 'Super Expert' is a bit thinner yet but not as thin as the old Tenax or the green bottle Tamiya plastic cement.
Solvent_cements by Edmund, on Flickr
Glue bottle Faller by Edmund, on Flickr
Good Luck, Ed
Tim G. I often see plastic buildings that have been nicely weathered and detailed. Their weakness, however, seems to be the corners, typically a right angle, where the exterior walls come together. These corners often have unsightly gaps. Any tips for how to minimize these gaps in the first place, and how to hide them if they are present once the walls are assembled? I'm starting on a plastic building kit that has tabs that run vertically on the inside of the corners, mostly likely intended to provide more gluing surface. But these tabs will prevent me from using any kind of a right-angle crutch on the inside of the corner as an aid to pull a corner together while keeping it at a right angle.
Yep, hear ya there Tim
Yep, right about there in the corner.
Never did do anything with that corner, but yet, it would be easier to deal with that, and the same procedure.
Now this was a nasty seam to deal with on bridge #5, the Viaduct.
Here's the repair when it was done.
You take frog tape and carefully tape off the seam on either side with your visor on, and shmooze it tight with your fingernail. Fill in the gap with Poly-Seam-Seal, available at Menards. And then one more shmooze with a damp pinkey finger after you pull the tape off. Spit works. That stuff will never fail you, but don't be in a rush, and let it dry overnight. Then you just re-paint your colors that match.
Hey, there was some bad Masons on the bridge at one time, but it's character, and it certainly looks better than that nasty seam.
TF
Track fiddler Fill in the gap with Poly-Seam-Seal, available at Menards.
Why do people from the Midwest always tell us about stuff available at Menards?
SeeYou190 Track fiddler Fill in the gap with Poly-Seam-Seal, available at Menards. Why do people from the Midwest always tell us about struff availabole at Menards? -Kevin
Why do people from the Midwest always tell us about struff availabole at Menards?
dknelson So it's not just a Midwest thing.
But the closest one is still 800 miles away.
I love Menard's. That is where I bought my outside light fixtures, homasote, electrical boxes, and countless other items.
I still have one of their rebate checks for $97.00 I need to use.
It might be time for a road trip.
SeeYou190 Track fiddler Fill in the gap with Poly-Seam-Seal, available at Menards. Why do people from the Midwest always tell us about stuff available at Menards? -Kevin
In this case, a quick check shows Polyseamseal available at HD, Ace Hardware stores, or Amazon (2 day delivery with Prime). And since it's it's a Loctite product, most likely at a bunch of other brick and mortar stores. We don't have Menards here in Oregon either but... meh.