cutting and splicing roofs/panels help needed

[fun9c1]

My current project requires cutting and repositioning body panels. I've chopped a few tops before but never messed with changing body panels. Basically I'm doing three types of joints here- one is I cut a rear 1/4 and I want to separate the two resulting pieces a little and fill the gap with filler. The other type would be one panel to another at an angle, the other is a regular butt joint between two panels. What I've been doing to butt two panels together, I put a "backing plate" behind them, using regular ol' Testors cement but that doesn't always seem to hold too well. I'm thinking there may be a better way to butt two panels together that I just don't know about yet. Any suggestions? I'll try to post a pic tonight of the type of joint I'm working on if that would help. Thanks!

[Guest]

Tamiya's extra thin cement and crazy glue is what I use. The Tamiya glue will melt the plastic together and the crazy glue will fill in any small gaps and make the bond even stronger.

[Art Anderson]

My current project requires cutting and repositioning body panels. I've chopped a few tops before but never messed with changing body panels. Basically I'm doing three types of joints here- one is I cut a rear 1/4 and I want to separate the two resulting pieces a little and fill the gap with filler. The other type would be one panel to another at an angle, the other is a regular butt joint between two panels. What I've been doing to butt two panels together, I put a "backing plate" behind them, using regular ol' Testors cement but that doesn't always seem to hold too well. I'm thinking there may be a better way to butt two panels together that I just don't know about yet. Any suggestions? I'll try to post a pic tonight of the type of joint I'm working on if that would help. Thanks!

If I might suggest something here: I've cut and stretched any number of model car bodies over the years, but have never used any sort of putty, CA or other fillers to fill in the resulting gaps, as all fillers, including CA can, and often will shrink or crack over time.

What I do use is either sections from a second body shell, or if the resulting gap isn't too wide, is to use Evergreen strip styrene to fill the gap. Evergreen styrene strips come in a wide variety of widths from .005" (generally too thin, to narrow, to be of much use in this, out to .250" wide (1/4 inch). The thinner strips are very flexible, and can be bent or curled to mate up to say, the shape of the roof of most any model to the point that CA glue (and in some cases, a good, pure solvent liquid plastic cement will hold them very well (Ambroid Pro-Weld, Tenax 7R, or Weld-On #3--which in my experience nearly every industrial plastics dealer stocks, especially if they stock plexiglas or do plexiglas fabrication work!) I've found that most modern-made plastic model car kit bodies tend to have a minimum plastic thickness of about .040", perhaps as thick as .050" in many areas of the body shell, particularly in the roof and in the body sides out to perhaps 1/4" in from either front or rear ends.

I make any cuts in a body shell with a razor saw, trying to be as straight and true with cuts as possible, and try to calculate the amount of "stretch" so I can match up an available width of .040" styrene strip to create the stretch needed. Sometimes, it takes a bit of "eyeball" engineering to trim down an added strip or panel if I can't come up with the exact width of the filler strip or panel in a ready-made strip of Evergreen.

Sometimes, particularly with any model car body shell coming from tooling originally cut, say, back in the 1960's when model companies made body shells a lot thicker (for reasons best explained some other time), thin --say .040" thick Evergreen strips-- won't work very well) I've resorted to using thicker pieces of Evergreen strip styrene, to get the width of the stretching pieces I need, which almost always results in the Evergreen strips protruding out beyond the exterior surface of the body shell--but that's generally pretty easy to dress down with needle files and sandpaper to match the exterior body surface of the model I've stretched.

If the body panels being stretched go beyond the range of Evergreen, or if the model being worked on is a conversion of say, a hardtop into a stretched limousine (extreme example here) then I've found it's a lot easier to use a second body shell to achieve that stretch. In doing this, as with the other types of stretches, often it's a wise thing to "reinforce" those splices, preferably from the inside, or if that is not an option, using a "tab and slot" arrangement: Cut one of the body panels and create a "slot" in the cut, perhaps 1/8" deeper into the panel or panels, then when cutting the second body shell or panel to mate up to that, allow extra material in the area where the "slot" is on the first body, and trim out a "tab" that at least closely matches the "slot" on the first shell. Care of course is key here, so that the two panels will line up straight and true--and then this is where gap-filling CA works very well--done carefully, this results in a stretched body or panel that is very nearly as strong as the original body shell was to start with. This I've used in making resin-casting masters of subjects such as a stretched limousine, where the master had to withstand the stresses and rigors of making the RTV rubber molds without just simply disintegrating.

I hope this helps a bit.

Art

[Ace-Garageguy]

I do a LOT of radical custom bodywork, and I really HATE to have a seam crack while I'm polishing paint. I've developed a 100% fix by reinforcing the backsides of all my joints with structural epoxy (NOT the worthless 5 minute garbage) and very fine fiberglass cloth (made for RC aircraft work).

If you're interested, I'll post links to some of my build threads that show the procedure.

[heroncustom]

If you're interested, I'll post links to some of my build threads that show the procedure.

PLEASE!!!!! lol

[fun9c1]

Thank you all for the very detailed advice. That's alot to chew on! Bill if you woudn't mind, I wouid be very interested to check out the links you mentioned.

Art, so you don't use ANY filler? Or do you mean you just fill in as much as posstible with styrene and then fill the cracks? I would think no matter how good a job is done using styrene that SOME filler would need to be used. Also, what does "CA" stand for?

Edited January 16, 2014 by fun9c1

[Art Anderson]

Thank you all for the very detailed advice. That's alot to chew on! Bill if you woudn't mind, I wouid be very interested to check out the links you mentioned.

Art, so you don't use ANY filler? Or do you mean you just fill in as much as posstible with styrene and then fill the cracks? I would think no matter how good a job is done using styrene that SOME filler would need to be used. Also, what does "CA" stand for?

I absolutely use some filler or another--however, I came up with the systems I use (and described) due to the fact that putties and even CA (Cyanoacryliate glues--chemical name for the various brands and formulae "Super/Crazy Glues) don't have the strength and resilience of a much more solid material such as styrene plastic.

Art

[fun9c1]

Thanks Art!

[Ace-Garageguy]

http://www.modelcarsmag.com/forums/index.php?showtopic=66935&page=3

See post 51

http://www.modelcarsmag.com/forums/index.php?showtopic=65965&page=3

See posts 22-46 or so.

This really works very well, every time.

PS. 5-minute epoxy, or cheap hardware store epoxy that's been sitting on the shelf for 5 years won't work here. The minimum quality you should use is the 30-minute epoxy sold in hobby shops for RC model airplanes.

Edited January 20, 2014 by Ace-Garageguy

[randx0]

An excellent adhesive for joining bodywork that is very strong is acrylic nail filler found in the fingernail polish area , it comes with a liquid and a powder you dip the brush into the liquid then into the powder then brush onto the joint . it is very strong and dries pretty fast like in five to ten minutes . I always had problems with styrene filler ,epoxies, and superglues but this stuff sticks and doesn't break . I don't remember who brought this to my attention but it was someone on this board .