7" retrofit (GDAA WRX)

[satrya]

There needs to be at least 2 holes to secure the metal plate to prevent rotation of the plate.


Tape the plate onto the area, and transfer the locations of the holes. Drill through. I used a brass plate that hardware stores sell (e.g. Ace hardware has a hobby train related parts area with small metal bars / plates / strips / sheets).


Bend the other end to form an arrowhead shape; the amount of bend on the arrowhead is adjusted to cling onto the backside of the protrusion of the 7" housing.

[satrya]

The foglight trim is now mechanically secured at 4 points.

The first 2 points are the flat tabs that go into 2 slots on the bumper cover like so:


The 3rd point is the new arresting clip, with the arrowhead piece snap fitting behind the 7" housing:


And finally, the 4th point is the screw, that goes onto a custom mounting bracket:


Like so:


Note that I've been driving with the previous configuration for many months now, so the arresting clip is not essential for securing the foglight trim. However, it helps maintain a certain gap between the foglight trim and the 7" housing. The arresting clip will be adjusted later (the pictures were taken during the functional test, without further adjustment done yet).

[csjoh]

Progress! Wooo!

[satrya]

Progress! Wooo!

Thx. Took me a while to go ahead with that arresting clip idea. I wasn't sure about the two screws getting in the way.

I'm open to other ideas; not that I'm in a hurry to finish this.

[satrya]

Experimenting with ABS cement (and hoping to deal with reaction with paint primer later; per romanster's remark in post # 851) to see how it fares to fill small gaps.

First, I taped two scrap strips from the fog trim material together.


Filled the gap with a glop of the ABS cement


An hour later, the gap seems to be filled decently. Plus the blue tape didn't actually stick to it; which may or may not be a good thing. (yes, I missed the camera's focus by a few centimeters further down where it's supposed to be)

[csjoh]

Oooh, I need to get some of that stuff!

How solid is it? Does the cement give when exposed to presure and stress, or is it like the bonded pieces were never separated?

[satrya]

Oooh, I need to get some of that stuff!

How solid is it? Does the cement give when exposed to presure and stress, or is it like the bonded pieces were never separated?

1 day in, the cement seems reasonably flexible. I tried bending it, and it cracks a bit on the part that coats the plastic pieces, but the portion that fills the gap seem to hold up. I don't imagine it will survive repeated bending though.

[csjoh]

That's kinda extreme as well, so for joining two pieces of plastic together in, say, a headlight housing, I think it should do nicely. The plastic welding works well, but the fumes that are released when plastic melts just seep into everything and doesn't seem to want to move back out; hence I'm looking for an alternative. I found the variant you use on eBay, and while the product wasn't too expensive, shipping it over here was killer. I'll try to source it locally first before spending $15 on product and $40 on shipping...

[satrya]

That's kinda extreme as well, so for joining two pieces of plastic together in, say, a headlight housing, I think it should do nicely.

For joining to panels together, it may make sense to add layers of material in addition to just the ABS cement. That way, something else can handle the tensile and shear stresses.

The plastic welding works well, but the fumes that are released when plastic melts just seep into everything and doesn't seem to want to move back out; hence I'm looking for an alternative.

Indeed. Those particulates float in the air and seem to stick to fabric etc. for a long time. You'd need an exhaust hood right above where you work and probably a semi enclosure to minimize the particulates from sticking to surrounding objects.

I found the variant you use on eBay, and while the product wasn't too expensive, shipping it over here was killer. I'll try to source it locally first before spending $15 on product and $40 on shipping...

I would think ABS cement for joining ABS pipes should be available anywhere; perhaps under different brand names. Fwiw, this one was in the plumbing area, and was intended to join ABS pipes of lawn sprinkler systems and home plumbing.

[satrya]

Filling gaps with ABS cement

Currently, there are some gaps on several areas:


The first order of business is to use tape to define where areas that need extension / filling are:


Then, ABS cement is applied on any visible backside of the tape (i.e. the sticky side of the blue tape):


Afterwards, I treat this like a fiberglass or paper-mache principle; the ABS cement is the resin, and the strips of paper is the fibrous sheet. Brush some resin on the surface, add fibrous sheet, brush some more resin. Let dry. Repeat again until a good balance of stiffness & thickness is achieved.

[romanster]

Man I looked for that black ABS cement here in canada and came up empty, even looked for it at home depot whenever I'm in the states and it's like they don't carry the black version anymore. The formulation has actual ABS dissolved into it, so it's a more sturdy goop than the regular yellow ABS cement.

For building up and bridging gaps, aluminum screen mesh works great as a structural backer, just as it does for plastic welding. Back the mesh with tape for the first layer so it doesn't just run through. A benefit of the ABS cement resin mix is that each application layer doesn't disturb the previous layer as much as a pure acetone-abs mix would. If it's being painted, a skim coat of bondo should seal it from reacting with the paint; my white grille showed a yellow tinge in areas where I had done repairs with the yellow abs cement and shavings. The body shop simply repainted it a second time, and it was perfect.

I gave myself one hell of a headache plastic welding my housings back together, learned my lesson for next time.

csjoh, you can use the acetone abs mix for a good and solid bond between close-fitting pieces of abs; rough up the edges and brush it on, once the acetone dries all that's left is abs, so it will have more plastic-like properties compared to the black abs cement.

[satrya]

^
Thanks for the tip.

I haven't looked for that ABS cement for a while, so I didn't realize that it isn't readily available in many places.

[csjoh]

Man I looked for that black ABS cement here in canada and came up empty, even looked for it at home depot whenever I'm in the states and it's like they don't carry the black version anymore. The formulation has actual ABS dissolved into it, so it's a more sturdy goop than the regular yellow ABS cement.

For building up and bridging gaps, aluminum screen mesh works great as a structural backer, just as it does for plastic welding. Back the mesh with tape for the first layer so it doesn't just run through. A benefit of the ABS cement resin mix is that each application layer doesn't disturb the previous layer as much as a pure acetone-abs mix would. If it's being painted, a skim coat of bondo should seal it from reacting with the paint; my white grille showed a yellow tinge in areas where I had done repairs with the yellow abs cement and shavings. The body shop simply repainted it a second time, and it was perfect.

I gave myself one hell of a headache plastic welding my housings back together, learned my lesson for next time.

csjoh, you can use the acetone abs mix for a good and solid bond between close-fitting pieces of abs; rough up the edges and brush it on, once the acetone dries all that's left is abs, so it will have more plastic-like properties compared to the black abs cement.

Thanks for the tip. That acetone abs mix, that's just pieces/shavings of excess abs plastic dissolved in acetone?

[satrya]

That acetone abs mix, that's just pieces/shavings of excess abs plastic dissolved in acetone?

I believe so. It doesn't seem to dissolve as fast as those polystyrene spheres though (the one that clumps together to form protective package for many electronics gadgets before they're replaced by origami cardboard structures).

[csjoh]

I'll have to give it a shot. The dragon bought a 1L can of Acetone for removing her fingernail polish, only to find out it didn't work properly, so it sits largely unused on a shelf. I also have lots of excess ABS plastic from my headlight housing build, so mixing up a small amount wouldn't take much.