Rob Edwards

I have 2 front spoilers with cracks in them, and have been toying with trying to fix them myself, so I picked up a welding kit:

http://www.urethanesupply.com/pdf/info5600HT.pdf

Here's their capsule summary for repair with fiberflex:
http://www.urethanesupply.com/step3c.php


Their videos are nicely put together and show a repair. Never having done this, I didn't want to ruin a spoiler first time out. Fortunately, I have a bunch of Hebert's parts here, and his radiator air duct is cracked. A stroker in Phoenix needs all the air it can get to the radiator. So I decided to try to fix it.

Starting point- This is the 'outside' of the piece, there's a Y-shaped crack (arrow), and the plastic is not flat around it. Probably not a good 'first try' repair candidate, but hey, it's not my part




First step is approximating the outside edges using aluminum body tape. Strong duct tape might work too. The edges on the 'inside' are back together, so they can be bridged with repair mesh.



Then you're supposed to V-groove the outside of the crack. I used a roloc disc on a straight die grinder, it was too big and too hard to control, and the molded ridges made it hard to groove evenly- I need to buy some cutting bits for my dremel. Looks worse than when I started, but you always need to rough up the edges so the fiberflex will adhere better:



The kit has stainless steel mesh to use as backing for the repair. Cut 1" strips to cover the crack. If the crack involves an edge (this one did), you wrap it over the edge and onto the front side of the repair. Turn on the welder full blast, and melt the mesh into the surrounding plastic.



This leaves high spots that you then melt and smear around, trying to get the mesh flush with the surface. I didn't really succeed at this:


Then one is supposed to add fiberflex filler rod over the mesh to bring the surface back up to flush. Soften the fiberflex rod on the iron first, then flip the rod onto the work surface and melt it in place, spreading a bit.






Then I flipped the piece over, and applied Fiberflex rod to the V-groove.




I let everything cool for 15 minutes, then put a drum sander in the dremel and ground it down a bit. Still an ugly repair, but no one's ever going to see it once the car's reassembled.




Clearly if I do a front spoiler I will have to be more careful about cosmetics. I needed to bury the mesh further into the plastic, but the air guide is so thin that I was worried about melting through it, or distorting the plastic sheet. But the spoiler plastic is much thicker, and flat, so it should be easier to completely hide the mesh and lay down fiberflex evenly. And I need to figure out what paint and texturing products to use to hide the repair. Will report back when I get around to trying a spoiler.

TYP928S

Rob,

You should put a little sticker next to the "made in Germany HGM" one. "Re-made in America RE"...

jon '84 us auto

jeff spahn

I bet you have seen worse on a human before. Don't sweat it.

Rob Edwards

Well I'm certainly no plastic surgeon. AH HA Ha ha ha ha ha....

borland

Rob,

Nice writeup. I noticed you used Fiberflex rod. Chart on web site says it is for these type of plastics:

PP, TPO, TEO, TPE, PE or other.

What type of plastic did you determine you were repairing? Have you identified other plastic parts, like the front spoiler? Best bet might be to make filling rods from scrap parts so you'd be sure your using the right filler material.

I see HFT has a similar kit on sale now for just $9.99.

Rob Edwards

I didn't definitively figure out what kind of plastic it is, but sort of decided (based on the characteristics listed in this chart: http://www.urethanesupply.com/identify.php ) that the air guide must be polyethylene, polypropylene, TPE, TPO, or EPM. Since all of these can be repaired with fiberflex, I figured I'd just try it. Seems like it 'brazed' just fine to the air guide.

I still would like to know more definitively what the front spoiler is made out of. It's probably one of the above, but it would nice to be sure.

That HF kit looks like a good deal (though it's a total ripoff of the urethanesupply kit, right down to the iron rest), except I wonder whether that soldering iron would get hot enough, and who knows what their welding rod really is. And the reviews of it on the HF site are amusingly bad. But as they say on the tool forums, how can you go wrong for $9.99? I guess you could just order 'real' fiberflex rod from urethanesupply...

Rob Edwards

Actually, now that I've bought the kit and have looked around the USC website, if in fact Fiberflex will work on the front spoilers, it looks like the more economical/better way to go on a 'real' plastic welding soldering iron is this one:

http://www.urethanesupply.com/5210.php

$70 at Amazon:

James Bailey

Swing by 928 International and grab some broken spoiler and front bumper bits and you can practice your art.....on something that really does not matter
Same thing for bodywork/painting start out with junk before you grind on something like the car you love....