Plastic Dash Pad & Other Plastic Repair

[Chadick]

I have not seen much regarding the attempted repair of the plastic shell of the dash pad on the 850s. I have recently completed a considerable amount of plastic repair on the interior of my 97 850R and I want to share with the community.

I purchased a KOHREE plastic repair kit for around $20.00. The kit came with an iron and several sheet of steel screen type material. Cutting the steel screen to shape with scissors to cover the damaged area of the crack or damage area and I then use the iron to melt the screen into the plastic.

I also purchased Atols H50 Plastic Welding gun for about $20.00. This gun comes with several hundred wire “staples”. The gun work by induction. When the staples are loaded in the gun (one at a time) and the trigger is pulled, the staple gets red hot. Push the staple into the plastic and after the staple disappears into the plastic release the trigger. Pull the gun off of the staple and use the included wire snips to cut off the exposed wire.

Both were purchased on Amazon.

The plastic interior of the 850s (and possibly other models) are made of ABS plastic.

Researching the subject of plastic repair, I found a considerable amount of information regarding plastic repair, plastic welding, and repair using the iron and screen method. One thing I saw and read plenty on was using zip ties as filler and or for additional material during the repair process. I also found lots on information about gluing plastic parts together.

I am fortunate to have a plastics engineer in the family (which I will refer to as “the engineer”), which is a wealth of information on the subject. I was enlightened on some interesting point regarding dissimilar plastic and how to tell what’s what, and which glues do and do not work with my repair projects.

To make a really long explanation short (and frankly, it was way over my head) there is no easy way to determine what plastic you have if you are not a plastics engineer and you don’t know what you have. So there’s that…
If you know what you have, you have a much better chance of getting the repair right the first time. I was told dissimilar plastics will not bold to each other. Equally, the wrong glue will not hold or hold long term under varying conditions.

Armed with this information, I saved each and every broken and carved out piece of plastic I came across while working in the interior of the car. Although, knowing the interior was ABS I could have used ASA 3D printing filament which is a UV tolerant version of ABS. More on that later.

I used the steel screen, the staples and scrap plastic to repair several badly broken areas of the dash pad shell and I was very pleased with the results of my repair. I considered melting all of the available screen material into the unbroken plastic shell, but deciding not to as the iron was rather small and a larger iron may deform the shell with too much heat.

Moving on, when I received the car I found the mounting brackets for the glove box door were badly damaged. The mounting brackets are apart of the entire dash, which made this a donating repair.

After cutting out the damaged areas with a Dremel tool and with much effort, I created a CAD model for a left and right side substitute for the broken areas that would support the glove box door, permanently. I used my 3D printer to produce these parts out of PETG, as that’s what I was using based off my 3D printers capability and of the operating temperature of the material which the parts would be subject to in the summer heat.
If anyone is interested, I can send or upload the models.

My 3D printer’s form stated to use PVC glue (sprinkler pipe glue) for PETG parts. Assuming I could simply glue the PETG parts to the ABS dash of the 850 interior, I was shut down by the engineer. I’m told the PVC glue will turn loose of the PETG part at approximately 140 degrees. I live in a hot part of the country and this would not work for me. I did attempt a test by gluing the PTGE parts together and found bond to be robust, but I would prefer to fix this once, so I went back to the drawing board.

I leaned that ASA is a comparable version of ABS. I purchased some ASA and used a friend’s enclosed 3D printer to reprint the parts in ASA.

PVC glue is an acetone based glue when used with the purple primer and PTGE plastic is resistant to acetone. Glue for ABS requires an acetone based to work and PVC glue would fit the bill, but the engineers recommendation I make an acetone / ASA slurry and used this as the bonding agent for the newly printed ASA parts to be bonded to the ABS dash. The slurry worked beautifully.

I also made several internal dash repairs consisting of cracked / split bosses (the protruding thing screw thread into), general cracks and straight up broken parts using the iron and screen material. I have to say, I love plastic repair! And that’s good because I get lots of it with this car…

By the way, I used straight acetone from the hardware store. Not nail polish remover, which has several unwanted additives.
Also, melting plastic makes toxic fumes, stinks up the house and pisses the wife off (it’s cold in the garage).

Hope this helps you guys!

[abscate]

Thanks for sharing all this. Grant kat had an awesome post making up beige abs in methyl ethyl ketone for repairing beige pieces I will link to here

[ZionXIX]

Hope this helps you guys!

You gotta pay the forum tax. Gonna need some pictures of these repairs. I never thought of just using some of the ABS filament I already have lying around as filler material. I purchased a 2nd 3d printer on sale before Christmas. I'm planning to dedicate this printer to ABS/ASA printing specifically for plastic repairs/replacements.

[pfmet]

I will be following this topic closely as our car suffers from much brittle/broken plastic. Thanks to all the plastic experts and 3D printers out there. I will be a potential shopper of your wares over time. My latest plastic repair was the third taillight cover in the rear window of the V70. Used JB plastic welder. Seems to have gone well but I haven’t tried to install it yet.

[MoVolvos]

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In my Bookmarks.
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[volvolugnut]

I am curious to try 3D printing, but do not want to spend more than a few hundred dollars.
Is that possible or just too low on the technology scale.
volvolugnut

[ZionXIX]

I am curious to try 3D printing, but do not want to spend more than a few hundred dollars.
Is that possible or just too low on the technology scale.
volvolugnut

Sure, these can be printed for very low cost but the cheaper the printer, the more work it will take to tune and get good prints. At minimum you need a printer capable of higher temperature materials like ASA. If you are fortunate to be in a cooler climate, then PETG will work for some interior parts but ASA is better. Engine bay parts are going to be more high temp but if its not mission critical then ASA might do for some things. Also these materials need an enclosed printer to retain heat as the ASA likes to warp if its cooled to quickly. And the fumes are not pleasant.

[aeg]

I'd sure be interested in a set of 3D printed plastics to replace the entire molding under the dash pad, to avoid all that tedious repair work.

[ZionXIX]

That is actually a goal of mine as well. My dash board is not really salvageable and I would like to design and print a replacement piece by piece. 2026 is gonna be interesting.