Bondo wood Filler

[Tom&Shelly]

Last year, our hatch shifted just slightly and I damaged the wood trying to close it



I was thinking of Bondo, but found they have a product that they say is better suited for wood

https://www.3m.com/3M/en_US/p/d/b40069621/

Only averages 2.5 stars, even on 3M's own site. That said, has anyone tried it, and if so, what are your thoughts?

Many of the negative reviews concern stainability. Of course, it won't do that well. As one reviewer said, 3M mis-marketed the product when they claimed it would take stain, because it simply won't take stain like the wood around it. In my case, of course, I'll prime and paint it black, so it's not an issue (as long as it takes primer).

Other negative reviews concerned the color of the hardener. They seem to have changed it from blue to red, making it look more like wood. Again, not an issue.

The third topic of negative reviews was that it cured too quickly. One person suggested putting it in the refrigerator before use. Another suggested using 1% hardener, instead of the directed amount, which itself is a little squirrely: "place a three inch diameter circle, 1/2 inch thick of wood filler on a clean non-porous mixing surface. Knead the included hardener tube thoroughly to ensure contents are well mixed. Squeeze a 3 inch strip/bead of hardner across the filler on the mixing board. Note, working time after you have mixed the filler and hardner will be 3-5 minutes at 75 degrees."

Doesn't seem to list a low end working temperature. Since I keep the teardrop in an unheated shed, I can pick my day and get anywhere down to and below freezing. If it's like epoxy, it might not set until Spring if I wait too long!

Anyone have any experience before I start experimenting?

Thanks!

Tom

[swoody126]

IMPO anything "Bondo" branded is contra indicated when it comes to use w/ wood

last i heard/read the labels their products are Polyester based

suggest looking at EPOXY based products

sw

[Pmullen503]

You can thicken epoxy will lots of fillers; wood sanding dust, cabosil, microballoons, etc.

For a small area like that, a small heater or an incandescent bulb (if you can find one) and a reflector would be enough to keep it warm.

[Tom&Shelly]

OK, I'm sensing a trend.

Thanks guys! I was hoping I could use the bondo on a vertical surface, but I suppose I should take the hatch off, use epoxy thickened with sawdust and do it right.

Tom

[KCStudly]

If you add enough thickener you won't need to take the hatch off. Also, if you cover a nice flat piece of wood with packing tape and clamp it to the side of the repaired rib while the epoxy is curing, the repair area will be molded back smooth and very close to flat, requiring very little sanding on the broad side. The edge side will be easier to sand back due to it having less surface area. Any pits or low spots in the first application can be touched up with thickened 3-min epoxy. Sand while it is still green (first 24 hrs) and it won't be as hard. Always wear PPE when working with epoxy.

[Pmullen503]

Using a plane or chisel on green filled epoxy is a good way to remove a lot of excess quickly before you sand to the final contour.