Working with bondo....need some guidence.

[SteveL]

It's been about 40 years since I've done any bondo work and when mixed like the directions say, I seem to only get about 3-4 minutes of work time. Is this normal or am I using too much hardener?

Working on a project that has lots of little spots and it's a real PITA to mix up tiny little batches of bondo so it does not go to waste. Using the standard Bondo brand Stage 3 mix if that makes any difference.

Would appreciate any help you can share.

 

[metaleltr]

Use a little less hardener work time is dependent on the amount of hardener. Although you are not supposed to I vary the amount of hardener based on how much work time I need.

 

[tcianci]

Yeah use a little less. as long as it hardens you should be ok. Take advantage of the longer cure time by using a "cheese grater" type of body file to shape the filler while it's still pliable. After it's shaped and it's done curing, finish it up with sandpaper

 

[ghnl]

The chemical reaction that cures the bondo makes heat. The warmer the it is the faster it'll cure. Cool down the mix and it'll cure a little slower. Spreading out the mixed filler rather than having in a big pile will also slightly slow down the reaction (less heat build-up).

 

[Crusty Nut]

Bondo brand *****. Try Rage Gold. It is more money, and worth every penny. It spreads and sands so nice. Also, how much hardener is dependent on the temperature, and how much work time you want.

 

[Blake150]

Too much hardener will also cause pinholes as well I usually put one line across a tennis ball sized puddle

 

[compyello]

The temperature will affect cure time as well

 

[trainer]

Experiment until you get the cure time you want. Work in small batches, shape and sand as soon as it is hard enough to work . Bondo brand has always worked well for me.

 

[clarkjg33]

If you are using bondo and red hardener you should mix about a pea sized amount of hardener to a golf ball size glob of bondo. Also if your spreader is flesh/pink colored that color should match your mixed bondo color for the right mixture.. And in normal temps will give you around 7-10 minutes of working time.. Using the cheese style grader does allow for quick body forming and takes away all the extra time of sanding.. Of course cheese grater is for rough sanding not final..also there is many other great products like the Rage previously mentioned above.

 

[SteveL]

Thanks for all the tips!

 

[HMCFab9]

Rage is a great product. Sands good & doesn't plug up the paper. Rage gold is ok, but I don't think it's worth the additional cost.
I don't like regular "bondo".... poor quality.
When you mix it up, use a little less hardener & spread it out thin on your mixing board. If you leave it all in one big lump, it sets up faster because of more heat produced.