Bondo Glazing & Spot Putty - okay guys, what did I do wrong here?

[lcorinth]

My tube of Bondo Glazing and Spot Putty hardened after I hadn't used it in a while, so I ordered what I thought was a replacement. But, instead of a single tube with a thick rust-colored paste, what arrived was this:



One tube of a thin, white cream and one small tube of rust-colored hardener. Not exactly what I was looking for.

Are there multiple formulations of the Glazing & Spot Putty, and what should I be looking for?

 

[tsmith1315]

My tube is #907, not a two-part and dries quickly.

 

[tsmith1315]

And I just noticed that nitrocellulose is the 3rd ingredient... maybe it's time to dig out a couple of igniters and see how it responds!

 

[DeltaVee]

And I just noticed that nitrocellulose is the 3rd ingredient... maybe it's time to dig out a couple of igniters and see how it responds!

That 907 stuff is what I've got (picked it up at a home depot... ugh! The mom-n-pop hardware store was out). Never occurred to me to read the ingredients!

 

[rharshberger]

There are two different formulations (duh right!) the "professional" is a two part just like regular bondo a polyester epoxy based filler, the second formulation is a very high solids "lacquer" hence the nitrocellulose. The nitrocellulose version has best results over primer, the other stuff will stick pretty well to most surfraces, obviously for ease of use most of us use the lacquer version.

 

[lcorinth]

There are two different formulations (duh right!) the "professional" is a two part just like regular bondo a polyester epoxy based filler, the second formulation is a very high solids "lacquer" hence the nitrocellulose. The nitrocellulose version has best results over primer, the other stuff will stick pretty well to most surfraces, obviously for ease of use most of us use the lacquer version.

Exactly the information I was looking for. Thanks!

 

[rharshberger]

Exactly the information I was looking for. Thanks!

I would much rather work with the single part any day rather than the two part stuff.

 

[DeltaVee]

I would much rather work with the single part any day rather than the two part stuff.

Well I hear that!

I do so much prefer the simple glue types like titebond, except for the loathsome property of pinching the body tube where the engine mount piled up the glue! Epoxy is toxic and a pain IMO but what are you going to do? I'm still going back and forth on bondo vs. elmer's CWF on spirals. Just depends on the mood!

BTW I just tried dipping a few of the estes starter in the bondo goop... results were kind of "meh". It did burn but the entire head didn't exactly flare up!

 

[DarthMuffin]

The two part stuff like that is easier to sand, but beware that it sets up FAST. You don't get much work time but the upside is you don't need to wait hours before sanding like the single stage spot putty.

 

[MClark]

I bought by mistake the two part stuff. I used it once and into the trash.
Got the regular type and the World is good again.

 

[David Schwantz]

I always use the 2 part. It does not shrink as it dries. I am sure you know if you add less hardener you get more working time.

 

[caveduck]

They both have their uses! The 2-part is a good ol' polyester resin (aka gelcoat) with fillers. As noted it will stick to nearly anything and cures quickly by catalyzing, even in a thick layer. It is a little gummy to sand if not fully cured and especially if not enough hardener is used. Very short working time and serious fumes while curing. You can slather it on in pretty broad areas to level a surface. Machine or block sanding is really the ticket for this stuff...to really cut it you may need to start with fairly coarse stuff - 80 to 120 grit. It's a good bit stronger than the spot putty and can withstand some flexing.

The single-part spot putty is completely different. It cures by solvent evaporation (the 3M good stuff is also photoreactive) and thus needs to be kept in a thin layer. Too thick and you'll have a long cure time and possible shrinkage cracking. It's designed to be applied *over* primer in small areas (hence the name "spot putty"). It sands really easily compared to the 2-part filler. It won't necessarily stick well to arbitrary bare surfaces, and it's rather brittle when dry. 3M actually has 3 different grades with different working times (all pretty short).

Not all 2-part fillers are created equal. Bondo brand is now owned by 3M but it's kinda the low end of the line. You can check out the massive variety of available fillers here: https://www.autobodytoolmart.com/category/auto-body-filler

 

[teepot]

My Bondo Glazing and Spot putty says Stage 2. Upper right. And the number 651 at the bottom right of the tube. I read the precautions and decided not to use it. To toxic. What have I got?