Reddit reviews Car Builder Supply Fiberglass Resin Spreader Epoxy Squeegee Brown 3pc Set

Now that you've done structural work, you want to fill the other side. I'm not a fan of bondo (polyester) - it cracks when you look at it wrong and it doesn't bend at all. Polyester fillers are for pinholes at most 1-2mm in diameter.

Instead, use resin mixed with a polyethylene balloon filler - this allows it to be sandable like bondo but takes overnight to set obviously since it's epoxy resin, but actually bonds to the underlying fiberglass and it far more flexible and structurally sound. Mix in around 1:1 with resin, it should nearly stand on it's own (think baking meringue) so it doesn't run when applied to the outer surface of your part. Dry overnight, sand by hand with 80 grit, repeat until you have a surface you are happy with painting.

Bondo is literally the last step you do 1h beforehand, just run it with the rubber squeegee into all the little pinholes.

As for painting, lots of guides on this... Generally you'll want everything at least down to old primer before painting, work through the grits. 80/120/180 at least and 220, you can use a festool or good soft palm sander for big spots like a bellypan but at least 75% of it is done by hand with a soft block and sandpaper. Use your hand or sander around corners and it will not turn out, trust me. Clean meticulously with acetone and then tack wipes before priming. Then sand primer with 120 grit and then paint.

This process took me about 30-35 hours of work over a month, I did around 30 structural repairs and 25-30 fills on the outside.

Parts list:

• cheap kitchen scale accurate to ~1-2g
  
• Big picnic table / workbench
  
• Thick drop plastic (100 sq ft)
  
• West system epoxy plus hardener
  
• Acetone
  
• paintbrushes
  
• soft block for sanding
  
• sandpaper of all the grits
  
• scrapers /squeegees/spreaders like these
  
• high density silica (West 404) and low density balloons (West 407)
  
• Bondo
  
• Masks - these
  
• loads of nitrile gloves
  
  Last words - patience here. You are the master of the engineered product - you can take it down and add to it as many times as you want if you screw up. Doing the structural repairs in pieces, small batches of resin mixing, just take your time and do a couple hours of work, let it cure overnight, then sand and do some more.
  
  PPE is NOT optional. (masks, gloves, etc).
  
  Also your arms will be itchy from the fiberglass dust for eternity.
  
  Edit: cleaned things up a bit.