On tv when I see them mixing and spreading bondo it appears to be very runny and spreads easily. But when I open the big can of bondo and add the hardener it is much more stiff and doesn't look like on tv. What's the deal???

 

There’s about 100 choices of “bondo” (generic term) catalyzed body filler products of widely varying quality, character and price. Chances are the shops you see on tv are using the good stuff. Another variable is the use of “honey,” another generic term for thinner/conditioner that makes the catalyzed filler more creamy and flowable.

It is my impression that “Bondo” products have been relegated towards the bottom of the barrel and sold to the generic, retail consumer that doesn’t know much or doesn’t care.

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^^^This. My reaction to the original post is "buy better quality filler". I've found Evercoat and UPol to be pretty good. Also be sure you fully mix the filler in the can before taking any out to add hardener. The liquids separate over time.

 

Be careful when you first open up a can of any filler, Bondo included. The product separates over time just like paint. You have to stir the product in the can to get proper consistency before you add the catalyst. If you don't thoroughly mix/stir the base filler you will get inconsistent hardening, forcing you to take it all back off and start again.

 

glazing putties seem to be a little runny.

 

Glazing putties will separate also. Thoroughly knead the tube for a few minutes before dispensing.

 

Roger, bondo that’s been on the shelf too long will thicken like that.
I buy filler at the auto body paint store where it’s alway fresh.
hardware store bondo you never know how long it’s been there.
plus it’s lower quality than filler from the paint store. More pits and pin holes