Lexan Frustrates Me!

[LS1Heli 0]

Is it me or is this difficult to work with? I had a Tamiya Supra and bought like 3 bodies and screwed them all up.

How do you cleanly cut this stuff? What is the best method? I have tried Tamiya Lexan scisors but then leave a rough edge. I was also told that you "scribe and break".

What is the best method for cutting this stuff and obtaining professional results???

[HunterZero 79]

I have found the best way is the scribe and bend technique. You get a really sharp hobby blade and carefully trace once along the cut lines on the outside of the shell (to make sure you cut through the overspray masking film), then bend the lexan. You don't need to press very hard at all, about the same as if you were drawing with a pencil. After bending it back and forth a couple of times, it will snap off where you scribed with the knife, giving a clean edge.

You can further tidy the edges with a sanding block, and use small sharp scissors to cut into tricky areas.

For wheel arches, you can get circle cutters, which are a bit like a compass, and work on the scribe and bend technique.

If all else fails, get the hobby shop to do it for you

- James

[HunterZero 79]

Whoops double post

[Old-School 0]

I also had alot of trouble with lexen bodies, until i used the scribe technique. But i still have trouble sometimes with the wheel arches, I've never seen a tool for wheel arches, do you get it from a hobby shop?. I recently brought the F103GT which comes with a pre-finished body and the wheel arches are perfect.

[KEV THE REV 2440]

I also had alot of trouble with lexen bodies, until i used the scribe technique. But i still have trouble sometimes with the wheel arches, I've never seen a tool for wheel arches, do you get it from a hobby shop?. I recently brought the F103GT which comes with a pre-finished body and the wheel arches are perfect.

You can buy the wheel arch 'compass' on ebay for a few quid

[TWINSET 1797]

I also had alot of trouble with lexen bodies, until i used the scribe technique. But i still have trouble sometimes with the wheel arches, I've never seen a tool for wheel arches, do you get it from a hobby shop?

Here's a bit; http://www.tamiyaclub.com/forum/index.php?...c=12189&hl=

Only works with circular wheel arches though

For irregular shapes, a very sharp knife/scalpel is a must - just lightly score along the mold lines and snap.

Best thing to do is cut the excess material away from the 'shape' of the body, and practise your scoring on the offcuts first

[Mad Ax 11401]

I used to hate lexan - I still don't enjoy cutting new bodies, but I find it easier than I used to.

To do the "scribe and bend" method you need a very sharp knife - hobby knives aren't expensive so buy a new one for each new shell.

To begin with, I always cut off the bulk of the material with a pair of sharp scissors. This gets rid of loads of material, especially the flat parts at the base of the mould, which always get in the way when trying to scribe.

Then I lay the shell over the corner of my little hobby table (basically an old coffee table with a rubber cutting mat on top). I find the small table ideal because even tricky shells will fit over the corner so I can scribe onto a flat surface. Trying to scribe a hand-held shell is a recipe for disaster.

I do all the flat edges first - the sides of the shell from arch to arch, cutting up into the arch area with scissors so it's easy to bend the section off. Then repeat with front and rear valences, using scissors to cut carefully up to the score line near the corners so you can take the flat sections off without worrying about the corners. Then do the corner pieces carefully - you probably won't be able to get these sections over the corner of the table, so that's why I leave then until after all the flat bits are off and there's only a small section to cut.

Finally, I do the wheel arches - very carefully and in small sections.

Once all the plastic is removed you might have some rough bits where the cuts begin and end. I usually tidy up the whole area using medium grit sandpaper - I use loose sheets (folded for strength) but you can also use a flat block for flat edges and wrapped around a spray can for wheel arches if you prefer. Be careful not to sand the inside or outside of the lexan as it will scratch the surface and give a bad finish, and also remove the overspray film.

I often find the overspray film is a bit ragged after the sanding, so I run some masking tape alongside the outside edges of the shell to prevent that nasty overspray

[Fatal_Error 1]

I find it best to take the plastic film off first then use the scribe and bend technique.

For the wheel arches if you have a steady hand and a sharp knife you can score all around the wheel in one go, if you stop it will make a mess, then you make a small cut with the knife to get some leaverage at the bottom and just bend and full slowly if you feel it snag slightly then stop and try from the other direction. Normally doing this i can just pull the wheel arch completely out in one go and very cleanly.

[xmat69x 0]

I rough cut any tricky bits as close as possible then just use the trusty old Dremel with a small sanding drum, works great on wheel arches.

[Madmat 34]

I like to cut out the shell before painting so i dont scratch the paint when cutting.

Also when cutting with a body scissors dont let the blades close fully, if you do it makes it hard to cut lines and give a smooth finish

Matt

[akemag 0]

I found this very interesting. I too hate cutting lexan bodies so much that i was thinking of paying someone to do it for me. The only shell i ever cut, was my 850BTCC back in -98. It came out great. The one thing is that i just dont remember how i did it. I clearly remember the build of the car itself, but the lexan part with the painting is a complete blank. Really weird. The tips here is going to be of great help for sure.

[94eg! 839]

This thread is great. I've done about a dozen shells, and never even heard of the scribe & break method. I'm definitely going to try this next time.

Typically I would just rough cut all the edges near the body lines (not touching) with any scissors I find. Then I would take my hobby knife (x-acto with replaceable blades) and simply shave the rough edges down to the lines of the finished body. THIS IS VERY TIME CONSUMING!!! They all come out great, but I find myself dreading to work on body shell because of how long it takes.

As for the overspray film, I've only worked on one body that had it (Rising Storm). I found that it's completely useless as I cut & decal the bodies first before paint. As mentioned earlier, this leaves the edges of the film peeled & shredded. I would much rather layer some painters masking tape all over the outside of the shell. painting after cutting also gives the edges of the lexan a more "finished" appearance, since the paint rolls over the cut edges concealing the fact that they are clear.

I also really don't like that Tamiya added a texture to the Lexan's interior surface on some of the new bodies (to make the paint stick better I guess). It would have been fine except that buggy wings are typically molded inside out on the body shell form. Once the wing is trimmed, flipped over and painted on it's proper "smooth" side, the texture (now on the outside) makes the wing appear dull and doesn't match the body-shell whatsoever...

To make nice smooth curved masking lines, I take my straight edge & hobby knife and cut thin "pin-stripe" sized lengths of masking tape (as long as necessary). The thinner the "pin-stripe", the easier it conforms to tight curves while still laying flat. For joining two pieces of masking at perfect angles, cut the ends of the two pieces of pin-strip at sharp angles so they will overlap but not overhang. These techniques will give you perfect boarders EVERY SINGLE TIME. If you take your time, you can literally mask off ANYTHING in any pattern you want. I use this technique to lay down body lines before putting on even the first layer of the paint. Once the main exterior colors and base coats are done & dry, you can peel the body lines off and lay down a final under-coat of black (or whatever color) to fill them in.

As for painting itself, spray cans or air brushes do the trick. I typically fit some of the stickers to the outside of the body before masking off interior areas like windows or color changes that boarder decals. This ensures you get perfect invisible boarders that are completely hidden by the decals.

When working with multiple colors on a clear body, always start with the darkest colors and work your way to the lightest. This makes sure your dark paint isn't visible through the light colors once finished. If, however, you have to lay down final layers of dark colors to fill in things like the afore mentioned body lines (or whatever), back your lighter colors with a "base-coat" of silver. Do this before pulling those final bits of masking tape to ensure your light colors won't be semi-transparent revealing the dark colors underneath.

If the off-color base-coat layers are visible once the body shell is installed (typical with under-trays & buggies), I will lay down a final undercoat of the exterior color. This makes the model look much more "finished" once on the shelf. It's pretty much pointless on a runner though as it just makes the overall paint job thicker & more likely to peel/chip...