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interior plastic repair?
https://www.slantsix.org/forum/viewtopic.php?t=38715
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Author:  volaredon [ Wed Jan 20, 2010 5:18 pm ]
Post subject:  interior plastic repair?

this is on my Volare. I have a butchered old console and a plastic dash ass'y (basically the whole pass. side 2/3 of the dashboard, incl the glovebox is molded in) the dash is cracked from the bottom about 2/3 of the way up, about 2" over from the passenger side-most edge.

NOT talking about the dash pad or the metal "grille" between the dash pad and windshield.

And, before someone says to just "replace it, and don't worry about fixing it", I do have a complete set of "good" interior plastic to go in.

but, as I have some cracked up stuff, and this car is NOT being redone to totally stock specs, I want to experiment with some of the crappy pieces I have; also have a console butchered with speaker holes etc, too.

If we were talking fiberglass, I could hand lay a couple layers of cloth to the back side of the dash, while it is out and accessible, and no one would ever see my repair once installed.
but it's not. it's plastic (ABS, IIRC) and it's not "brittle" or "chalky" like some of this plastic was known to turn into. but fiberglass doesn't usually "take" that well to plastic.

But I want to play with this crappy console I have, since I am set on swapping this car over to a 5 speed (exactly which one yet to be determined) and I may have to alter the original "Slapstik" opening a bit anyway, to make that happen,
I was also thinking of adding in some gauge pods, to either the console or the dash and since these particular parts are "junk" anyway it won't hurt to use them as my "guinea pigs" to try out some of my ideas.


so does anyone know how to repair such plastic in such a way to not be visibly obvious and also being as strong (or better) as a full, new undamaged part? I have seen some "plastic-weld" kits (basically a big soldering iron) with "filler rod" that was material specific; different filler foe different grades of plastic. Or is there a plastic or epoxy type resin that I could maybe use on this plastic stuff much, like I would do with fiberglass in conjunction with some fiberglass cloth?

My plan is either A) it turns out well and I get this plastic dyed to the color that I want the interior to wind up as, or B) as it stands right now, these pieces are otherwise "scrap" anyways, so if it doesn't turn out, then I ain't out much but some time. As I said, I do have a whole set of "good" interior plastic to put in there, anyways, in that event.

Someone on here was talking about molding a "custom" console at one time for these cars.

Author:  KBB_of_TMC [ Thu Jan 21, 2010 11:24 am ]
Post subject: 

I've had good luck with (West system) epoxy to repair small cracks and breaks; I beefed up the back with scrap plastic. I used cotton wool (from a medicine bottle) mixed into epoxy to fill voids and then used bondo and paint for a smooth finish. I used scrap plastic to replace the missing fragments. Looked good from the front. I'd use generous reinforcement in a high-stress area.

POR-15 + fiberglas smooth weave cloth might stick better than typical polyester resin fiberglas. I've not tried it on plastic, but it holds up very well on metal. I'd suggest primer + Krylon paint on top.

Author:  adiffrentcity [ Thu Jan 21, 2010 5:38 pm ]
Post subject: 

I would go with an airless plastic welder if you don't mind spending the money. I've used one extensively with great success on a variety of automotive plastics. Even without access to the back of a repair area (which, since you have it, I would make use of!) you can get a very strong repair.

As far as smoothing it out just do conventional bodywork. Read below about adhesion promoters... A tiny bit of flexible filler in the crack after you've welded up the back, then sand smooth, prime and paint.

If your part needs a vinyl-like grain there are kits out there which use a special topcoat that you press down on with a cloth covered in the reverse of the grain. I have never used any of these kits though and don't know how well they work.

If you decide to use an epoxy, definitely scuff and degrease the parts well then use an adhesion promoter (bulldog brand is the best) before applying. Often the problem you run into with plastic parts is the mold release agent that can remain on the surface keeps your paint or whatever from sticking. Some plastic is even made with tiny beads of the release agent molded in. In those cases you really have to be careful about cleaning betweeen steps.

I think whichever way you go you'll achieve a repair you can be happy with.

Author:  volaredon [ Sun Jan 24, 2010 9:22 pm ]
Post subject: 

I saw one of those plastic welders at an estate auction about a year ago; it was a matco or a Mac brand (wonder who made it for them) but 2 neighbors got into a pi$$ing match and it wound up going way too high for a typical auction.

Author:  adiffrentcity [ Tue Jan 26, 2010 4:11 pm ]
Post subject: 

Go to your local auto body supply house, they should be able to source a no-name(which will work just fine) for less than $100. Or check one of the discount tool chains.

Author:  tophat [ Wed Jan 27, 2010 6:12 am ]
Post subject: 

I don't know anything about it, but Harbor Freight sells one for around $100

Let us know how it turns out

TopHat

Author:  69a100 [ Wed Jan 27, 2010 6:43 am ]
Post subject: 

There are a couple good vids here on the subject, and of course SEM has excellent products. Search the web for the same subject! http://semproducts.com/cms/Training+and ... 7s/94.html

Author:  twissty [ Wed Jan 27, 2010 9:52 am ]
Post subject: 

I've had good luck using fiberglass and plain polyester resin to repair plastic.
The key is to thoroughly rough up the surface to be repaired using a 50 to 80 grit disk or sandpaper.
Extend the repair at least a few inches on each side of the break if possible.
clamp the part together and thoroughly work the resin into the prepared surface. add cloth or mat and thoroughly work the resin into it getting all the air out from under the cloth. Add a few more layers before the resin hardens, keeping the cloth wetted and stuck down.
More resin is not better.

The front side can be made presentable with a bit of bondo. same surface prep, 50 grit.

THis has worked for me on snowmobile and motorcycle plastics.

Author:  Louise76 [ Sat Jan 30, 2010 12:40 pm ]
Post subject: 

On flexible "royalite' type plastics, I've used plumber's ABS/PVC cement from the hardware store with scrap pieces of the plastic as backing plates. Do a test piece first, as some plastics tend to melt with too much glue, and some won't adhere. But the patches that stick, really stick!. Pat,

Author:  volaredon [ Sat Jan 30, 2010 7:55 pm ]
Post subject: 

I am looking into one of those "hot air" plastic welders on Ebay. Got some other ideas that it might be useful for. I am "watching" a couple and trying to get info on them. and sources for "consumables"; tips filler rod and such.

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