adhesion promoter before filler/

S

Steves69LS3

hey guys some bare spots on a plastic bumper that needs filler for deep chips. do i need adpro before filler?
thanks
 
Technically you do not use polyester filler on TPO plastic unless it is one of the few types designed for that, you use dedicated 2 part bumper repair material. But for chips, you'd get away with it. What I would do to achieve the best result is to apply adpro, a coat of epoxy, then fill the chips the next day.
 
Steve, on a 2010camaro nose converted to fit onto an 83 el camino I did in late 09', I tried both the urethane supply company's 2 part epoxy & evercoat polyflex. The nature of the project took a little thicker than average filler on the sides meeting to existing fender. Both were over SEM adpro or sanded factory paint. Scraped a guardrail last year at interstate speed & both products held better than expected.. I'm just gonna use the polyflex this time.
Guess that's a pretty good time & durability test.:confused: ​ In progress 2016 nose project will have the added step of epoxy, can't be anything but better.

Crash, didn't get an answer from you on my thread & don't see a place to send pm's anymore. Got me a pack of the SEM problem plastic stuff you mentioned to try out. Do you have much long term knowledge with it as far as durability, possibly also with mounting tabs??? As I mentioned there, hot air welding has held up great where properly done & some red colored Lord Fusor product I tried did not stand the test of time. What I'm dealing with is more of fabrication, not typical repair , so it's pretty critical & not much info out there on such work.
 
I'm not sure what Crash will say but for me SEM Problem Plastic works great. It's a good filler and it'll bond too. If you have experience with hot air welding though that is my preferred method for repairing cracks,tabs etc. Most everything will hold up until it gets flexed. You'd be surprised how often bumper scrapes gouges etc get filled with poly glaze straight over the plastic at many shops. In the past I've had adhesion issues with many of the 2 part bumper repair compounds. They can be very finnicky. The SEM problem plastic reapir material works well and sticks well. Evercoat polyflex works good for gouges and scrapes, we use a lot of that.
 
Some rubber repair materials do not play well with promoters and will cause it to actually fall off. Read the instructions on the package or container and if it says do not use it then don't or you will be redoing it.
 
years ago i used to use the polyflex all the time on all the sportbike bodywork. that stuff actually works great direct to the plastic. just flame treat the area first and apply like any other filler.
 
The Upol 706 is a heavy bodied filler made just for plastic. No adpro needed. It's a great product. The dolphin line doesn't need adpro and is solvent proof. So if you have a minor repair, you can just paint over it with out the fear of soaking and ringing (that's Upol's claim).
 
Jim C said:
years ago i used to use the polyflex all the time on all the sportbike bodywork. that stuff actually works great direct to the plastic. just flame treat the area first and apply like any other filler.
You just reminded me, I did the flame treating before polyflex on raw plastic areas.
 
There are polyester putties made for TPO for guys in the trade that do that kind of thing a lot. I know that every time I've bought some, it ends up going bad because it doesn't get used fast enough. So that's why I lined out the procedure that I did, it works with conventional materials that most SPI users will have on-hand, and you don't have to worry about buying a special product. The downside is that it definitely adds time and labor.

For larger repairs, I use SEM 39767 like Chris does.
 
Everything went well besides two areas that the base coat spider veined. I sanded them down and when i shot base over again it spider veined again. Maybe it was just too hot out
 
Steves69LS3 said:
Everything went well besides two areas that the base coat spider veined. I sanded them down and when i shot base over again it spider veined again. Maybe it was just too hot out
That veining is usually contamination in the cracks.
 
Steves69LS3;n84490 said:
Everything went well besides two areas that the base coat spider veined. I sanded them down and when i shot base over again it spider veined again. Maybe it was just too hot out


You must repair those or they will always come back.
 
Ok so I tried the SEM In a few sample torture tests. Was impressed at how fast it kicks off on setting time. But as Chris stated, ok until flexed, which failed my torture tests miserably. So to date I still haven't found anything to take the place of plastic welding for these plastic fabrication projects I seem to get into.


​I'm using a few types of plastic welding to build up &completely form a few areas. I'm laying down strips of donor material with a steinel hot air welder, but am using an iron type contact welder along with it at the same time to help press down layers of new material I'm building up. For adding 90 degree flanges to the inside of a few areas I experimented with A woodburning tool & thin blade to reach in between parts & also through 1 side kinda like spot welding

Due to nature of project ,some non flexing built up areas may need up to 1/8" of filler, so QUESTION. Would the extra step of a coat of adpro & epoxy 1 or 2 days before applying a made for plastic bumper filler such as polyflex give a stronger bond than direct application? Running out of time to experiment with.
 
Groove out the cracks until you get to the bottom of the surface Crack and sand good around the area and repair with the proper repair putty then use a finishing cream on your final coat. Surface cracks or webbing can be a real chore to get fixed properly.
 
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