Technical ABS interior panel construction

The last part of the build of my wife's '31 coupe is putting an interior in it before a show she wants to take it to next month. There isn't money in the budget to have an upholsterer do it right now, so I'm doing what I can to make it presentable and give the upholsterer usable panels when that time comes.
After reading a few threads about using ABS I decided to give it a shot. I kind of like the look and after researching different types of clips it keeps a somewhat original look. I've already done the easy panels for the doors and kick panels, so I'll be showing how I make the curved upper panels. This is my first attempt so if anyone has any feedback, by all means jump in. I've already made the left side so follow along as I make the right side.
Here's the door and kick panels. I couldn't use the original style panel clips because of the thickness of the windlace, so starter researching clips. I've used them before on cars for wheelwell splash shields and are not only easy to install (and remove), but has a neat industrial look.

The upper panels need to be bent and that's where it gets interesting. The rough panels are more easily cut with a cutoff wheel as the ABS tends melt back over cuts of thin blades. Below are the tools required to start.

Painter's tape is perfect for this and you'll use a LOT of it to keep things organized. There's a little thinking required before you starting cutting plastic so take your time. The framing square is a necessity because you'll need to determine what your primary plane is and reference everything from that. You'll see as we get into it.

 

After cutting the panel roughly to size, do yourself a favor and mark the front and top with the tape and a marker. If you've bought a large sheet, the edges are factory sheared which means you have 4 straight edges and true 90* angles.

On the side panels I'm making, the bottom edge is flat so that is my primary plane and what will be referenced. It's tempting to make one of the vertical edges the other reference, but remember we're bending this panel so things are going to change. The only reference that WON'T will be the straight bottom.
Our other reference will be the middle of the bend. This bend is not consistent, so we're going to move forward knowing we need to leave the ends long and trim them as one of the last steps.
After putting tape on the radius of the package tray, I took a ruler and layed it flat on the back and side and marked where they intersect. This is what will be assumed is the middle of the bend. I also mark where the bend "starts" on each side. This will be important later when we put heat to the plastic.

 

One note if you're space challenged like me. You'll probably be working with the plastic sheet on the ground. When you cut ABS it leaves sharp melted flash all over that can scratch the finished surface. Since we'll be marking the backside for cuts and bends, that means the finished surface is on the ground and it's imperative that the we sweep up the debris constantly.
Here's a sneak peek at how our panel will come out.

 

How easy was it to bend and shape after heat? I made all my door panels out of aluminum just because I had it...

 

There's definitely an art to this. That's one reason I'm doing this thread..... some things you are SURE would work just don't. You just don't know until you've created scrap WHY it didn't work.

 

Great tutorial.
Just figuring out what works best for cutting was a learning curve for me, as you noted ABS wants to melt back on itself when cutting, tried a few different blade tpi's.
The dingleberries were tuff to remove also, don't remember what I used as it was ten years ago, may have been a coarse wood rasp.
Looking forward to the bending segment.

 

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Cut it with a sharp box cutter. Then bend it breaks loose. Smooth with belt are sanding pad.
It will work well with half of the fasteners picture. On mine I used trim screws. Sometimes when are if you cover the pad the buttons might show.

 

I use big old tin snips to cut ABS with great results.

 

I made all the interior panels for my 26 RPU out of 1/8” abs, it’s definitely an art bending it.

A tiny bit too much heat and it’s all over
It works really nice however.

A sharp olfa knife and a snap is the easiest way to cut it.
I used a couple of saw horses and a 4x8 sheet of 3/4” plywood with the outer edge framed with 2x4s for a work table.

 

Has anyone tried electric sheet metal sheers to cut this ABS ? I've seen em used to cut these new PVC/Vinyl plank flooring that's almost 1/4" thick. Might be worth a try.

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For my door panels I used political signs I gather them up after elections when I run low....lol...also you get the benefit of some free wire supports with them.

And they are sandwiched and corrugated, very strong and waterproof.

now back to ABS.

 

The ones I bought had a directional grain pattern so make sure you run them all in the same direction.

 

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They also make good targets for shooting.....

 

The main reason for that many fasteners was because of the windlace and curve of the door in the front. Those are all original Henry holes and rather than have that many on the front and as needed on the rest, I just went with it throughout.

 

In my avatar OT picture you can see my ABS air dam. It was cut using an electric sheetmetal shear. It creates a pretty nice edge, just make sure your shear has a good edge on it or it will just "squish" the plastic and not fully cut it. Also if you go to menards or home depot into the ABS/lexan section, they usually have an end cap with different styles of cutters in there. The one for lexan works pretty good for both, its just a scoring tool and then you snap the plastic (as mentioned here before)

 

I used the same ABS and it works as advertised (described above). There is also an older thread on an economical way to cover the panels. Cheap and not so hard to do.
https://www.jalopyjournal.com/forum/threads/no-sew-door-panel-tech.115914/

 

As I found out there is also differences from one panel to another. I finished the driver's rear lower panel yesterday and used material from another sheet. I'll post up a pic later, but there are also color differences from different sheets. Hopefully, this evens out over time.

 

Good info. I'll follow along.

 

You can use acetone for gluing ABS to ABS. Works incredibly well.

 

It's better to use proper ABS solvent cement ( glue) sold for that purpose. It's available in most building supply stores in the plumbing department.

 

Why? I've done many times with acetone, its handy, and has lasted for years.

 

Acetone won’t work as effectively as the proper glue.

 

Alright, time to bend! I didn't take pics of the actually torching 'cuz it takes both hands as it is and no time to grab the camera.
Remember the marks on the tape? Transfer them over to the backside of the ABS with the factory edge (primary reference) on the bottom and lines at a 90* angle to the bottom. When you start bending this it's going to try to move in ways that will confound you, so SOMETHING has to be a constant. These lines will be your guides for the torch. The tools? A torch and a cloth.

When you start heating the ABS, line the flame up with the OUTER lines because the overlap will heat the center. If you mostly heat the center, you'll have a sharp bend and inconsistent radius. Long, even, rapid strokes VERTICALLY. Trying to hold and heat it horizontally will give you a nice fold whereas vertically lets you control the bend. Play with some scrap to get a feel for how much heat you'll need, how the surface of plastic changes when it hits different temperatures and to get the feel of what temp to bend it and how much.

You'll find it will tend to wave as the temp across it changes. Keep the heat as even as possible both horizontally and vertically to get an even bend. You'll see where an edge is cold has a hard line, so apply a little more heat. The cool thing about it is you can "knead" it on the concrete floor. With the towel, knead it flat on the concrete until you can feel it stiffen up (the concrete will help it cool quicker). It doesn't have to be molten to knead it either..... you'll have a decent amount of time to work it. The idea is to bend it with as little EVEN heat as possible to bend it.

Here's the finished product. You will be tempted to keep heating and working it, but keep in mind where it's going, what will be trimmed off, and if working it is worth the effort.

 

Couldn't you use a piece of 6" diameter pipe to bend it around to get an even bend?

 

I tried a form before and when you use a form it tends to be a series of small bends rather than a consistent radius too. It takes too much heat for it to flow over the form and does some really bad things.

 

Yes, absolutely. One of those really bad things is wrinkles and permanent wavy bumps and distortion that is pretty much impossible to get rid of.
Another can be some really noxious outgassing chemical fumes from the plastic being too hot.

 

So, after bending it's time to start trimming. The shortcut is I can use the other side and mirror it. I can't trim it exactly as the other side because it's a '31 and no matter how "production" it was, tolerances were mere guidelines. The most critical area is trimming around the 1/4 window trim. I left about 3/8" of material (using a small cutoff wheel) so I can just sneak up on it and get a tight fit. The interesting thing is that no matter how clean the bend is the panel is under tension. When you start cutting and trimming it'll start to pop and move. Tomorrow I'm spending some quality time with the die grinder for finish trimming. There's only 2 weeks until the show so I have to kick it in gear.

 

Watching and learning..mine needs it bad! And where did you buy that torch setup?