ABS Plastic Repair

[GDeane]

Forgive me if this has already been covered.  Anyone tried their hand at repairing broken plastics using one of those plastic welding kits?  Broke a tab on one of the battery side covers today.  

[msbuck]

Monte has!  He has a pretty good write- up on here somewhere.  I tried somewhat unsuccessfully...  :-/

 I'll try to find the thread, but I'm sure he'll speak up soon!

[Crossrodes]

Greg I use methyl chloride to melt abs and weld it.  I buy it at my local plastic shop.  I have also used it with shavings of ABS (shaved using a cheese grater on some scrap abs) to form a liquid filler to fix gouges in abs.  I did this to fix my bags...filled the gouges, sanded it down and then sprayed the bags with an undercoating spray and then painted them...they look like new now.

[bruce_launceston]

I used to weld up the front spoiler on an old Alfasud that I owned about 25 years ago. I used my soldering iron and scraps of ABS as a filler.

Worked to a degree but I like the sound of crossrodes chemical welding and filling.

[montmil]

Monte has!  He has a pretty good write- up on here somewhere.  I tried somewhat unsuccessfully...  :-/  I'll try to find the thread, but I'm sure he'll speak up soon!

Been eatin' Thanksgiving pie. Plus, all that tryptophan -an amino acid found in turkey- done put me done for a nice, long nap. [smiley=zzz.gif]

The plastic side panels are, I think,made of a cast resin plastic that is easily repaired. One of the attach tabs was plain ol' gone on the '83 R65 when I adopted it. My fix was a bit more involved than trying to create a secure, long-lasting butt joint -they never last. It's aluminum has held up just fine since the fix.

Ace Hardware & BMW Supply sells a 2-part epoxy that works on many different plastics, including that slick PVC stuff. As you may know, epoxy is not recommended as a gap filling adhesive unless you mix in a bit of "Hamburger Helper", aka: chopped cotton flox.

http://www.wicksaircraft.com/catalog/product_detail.php/pid=1927~subid=8459/index.html

I'm still working out of a one-pound bag I bought years ago. It's magic stuff when used with resins and epoxy adhesives.



Trace a pattern off one of the existing tabs and transfer the pattern -plus a short extended bottom portion- to a scrap of aluminum that will fit down inside the space between the molded 'air vent rib' and adjacent to the busted tab. Note my pattern design and tab.

Epoxy-flox the aluminum tab into place. The slight lateral shift in position matters not as the rubber grommet on the chassis can be shifter to mate up with the new tab position.



Here's the new aluminum, lifetime tab fixed in place.



The remaining photos show similar repairs to cracks found in the side panels. make your repairs and strengthening efforts on the inside of the side panel whenever possible.

If the exterior paint is still in good shape, the epoxy repairs will not disturb the shiny side. Avoid any "super glue", ie: cyanoacrylate glues, as the fumes will ruin paintwork.

Small bits of finely woven fiberglas cloth can also be used to reinforce crack repairs. Just say NO to crack!

Hopes this is helpful info.     Monte

[GDeane]

Thanks for all the tips.  Hope to give it a shot today.

[Bob_Roller]

Even when you have a repair in place, a small tie wrap as a final security measure isn't a bad idea .