How should I repair this!

[MNorton]

I have a 1994 GMC stepside I have been working on and I would like to repair this back section on both sides but not sure what to do. I believe Bondo, painted with a rattle can would look better than the way it does now. Any ideas? I gues it needs to be the flexible stuff? The first picture is the right side and the second is the left. Maybe I should chip it all out and lay some fiberglass?

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[Drunkcanuk]

There is a sticky in the paint and body section. They are made of SMC not fiberglass. I believe that it's polyester based materials that need to be used. Check it out, as they explain it better than I can.
And long live blue stepsides!!!!

 

[Scooterwrench]

If it's not cracked all the way through then you could use a dremel and v-trough the cracks and fill with some microfiber filler. Smooth it and paint with rattle can then rattle clear. Wet sand then polish. If your paint color matches no one will ever know you were there. If it is all the way through you will want to start with tiger hair filler first.

 

[Scooterwrench]

There is a sticky in the paint and body section. They are made of SMC not fiberglass. I believe that it's polyester based materials that need to be used. Check it out, as they explain it better than I can.
And long live blue stepsides!!!!

Not fiberglass? That sucks! That plastic sh*t doesn't like to bond to anything.

 

[Drunkcanuk]

Not fiberglass? That sucks! That plastic sh*t doesn't like to bond to anything.

I was partially right, it's polyester material that need epoxy products to fix.
Ya, I wish it was fiberglass. I have a lot of experience with it, as I used to work at a place that turned Harley's into trikes. I built the fiberglass bodies. High as a kite all day!!! Lol

 

[Scooterwrench]

I did 6 weeks in a boat plant,fumes didn't bother me near as bad as the glass itself,hence only 6 weeks!

 

[Drunkcanuk]

I did 6 weeks in a boat plant,fumes didn't bother me near as bad as the glass itself,hence only 6 weeks!

I was there about 6 months, no PPE at all, other than nitrile gloves. Seeing all the glass floating in the air when the sun shone in was nasty!!! Between that, asbestos at all the plants I've worked at and smoking.....not going to be a surprise how I leave this world!!! Lol

 

[Hipster]

Evercoat has an SMC resin that's brutally expensive these days, it's probably not much more than epoxy resin. I typically repair them in a fiberglass layup fashion, other then Smc needs thoroughly degreased in between lay-ups after sanding, and epoxy resin needs thorough sanding for the next lay-up. Chopped strand mat and epoxy resin.

Total Boat and West Marine are other brands of epoxy resins. Products like fiber reinforced body fillers and all body fillers(Tiger hair, Claw Glass, Dyna hair, etc) are all polyester based products and not what you want to use as they can ghost line through primer and new paint. If I need filler material I use epoxy resin thickened into a paste with milled glass or cabosil. Different products expand and contract at different rates so try I try to duplicate the way it was made close as possible to avoid ghost lines etc. Do not cheap out and use polyester waxed or unwaxed laminating resins.

 

[johnckhall]

I've used JB Weld KwikWeld Expoxy on several applications. One was filling holes instead of welding. Of course, that was on metal application. It does dry really hard and is sandable. If this isn't the right application, maybe someone can chime in. As said, I would chip away excess and channel out any cracks before filling. Once sanded smooth, a primer filler and light/wet sanding before painting to match. And mask, mask, mask.

 

[Jeepwalker]

You can use just normal clear epoxy on SMC. Like the clear dual-syringe cartridges you can get at a home center. And fiberglass strand. Do the prep work, then apply your fiberglass mat, mix the epoxy and apply the epoxy over the mat. Work it in so the fiberglass get's constituted into the epoxy. Apply multiple layers of fiberglass matt ...for strength. Then do bodywork over the 'cured' epoxy like you would normally do. Prime & paint.

I've done lots of SMC repairs like that ..and on Corvettes too. Never had one fail. Even if it's fiberglass, epoxy will still work fine. But polyester fiberglass resin will NOT adhere to SMC ...like the others have said. It will literally just 'flake off' ...like a dried scab.