Bondo putty

Hey guys. I started using Bondo as a putty to fill seams etc, but think I bought the wrong one. This stuff is gray and comes with a small tube of blue hardener. It seems to have worked ok on my ASU-57 project, but the first time I used it I forgot to add the hardener and the putty never dried. I added the hardener the second time while filling a gap in the rear hull and it came out ok. Should I be using the red Bondo for “ glazing and spot filling” ?

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Yes. The two-part putty is filler putty for larger dents. The red glazing and spot putty is intended to be applied over the filler putty to fill in small holes and imperfections and smooth it all out. The red spot putty is best for modeling.

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Ok that’s what I thought thanks Gino. I’ve heard nothing but great things about that stuff but I guess I bought the wrong one.

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Hi Richard, yes you bought the wrong one. If it comes with hardener that’s not the one you want. The one you want is Bondo Glazing and Spot Putty and it’s red and comes in a large tube. No hardener. I’ve been using this putty for decades as my go-to putty for styrene, resin, and metal as it adheres to all three. It dries fast, rock hard, but is easy to sand, glass smooth, and get a feathered edge. For me, it performs better than any dedicated hobby putty on the market.

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Yeah I recall you mentioning that and others as well. The gray stuff seemed to flake off a bit because I had no idea how much hardener/ putty amounts to use. Apparently the you tube video I checked used a tiny bit of harder but was for car repair. So I’ll get the red stuff

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All is not lost. You can use that two part Bondo to make a large form for vacu-forming when scratch building. It files off nicely and is easily shaped. Sometimes you don’t need to get it glass smooth as vacu-forming will only pick up the small imperfections on the inside of the part.
Similary, you can use it to make a buck for shaping things like fenders out of brass.

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I’d like to see an instructional video on this use. It sounds like it would be interesting.

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And I was just at Home Depot earlier. I will give this a try myself as I seem to have the worst time with the epoxies and fillers that require 2 or more components. Especially the one with the two tubes and the plunger; every time one tube clogs a little and they don’t come out in equal amounts. I used Perfect Plastic Putty for a while but kept having issues with it drying up before I had used half a tube.

Plus I have prior experience with Bondo products via body work.

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I din’t even know that using bondo was a thing. I just figured it would suit my needs, and it did. You can make your buck completely from Bondo, or use another material underneath it and finish with Bondo. Apparently it’s been a thing for quite some time. I Googled it - some folks like Bondo, others don’t.

Check out Ktsu’s reply from July 30, 2013 near the bottom:

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I’ve seen it used to repair holes in vinyl siding . I have a few, I’ll definitely give it a try.

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What is the consistency of Bondo similar to? Can you use it like an epoxy too?

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When mixed properly (for two ounces of Bondo filler, squeeze out a few corn-kernel-sized drops of hardener), it is about the consistency of peanut butter and sets in about 10 minutes, or less. If more hardener is added, it will set up even faster.

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The chemistry is the same whether models or cars, golf ball of paste, pea of hardener

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I should have stated referencing for glazing and spot putty, my bad. Hopefully the consistency isn’t like “crunchy PB” :stuck_out_tongue_winking_eye:

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The Glazing and Spot Putty is about the consistency of toothpaste. It’s very workable and can be thinned with acetone.

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I’m going to pick up a tube, some acetone (need it for Mr. Surfacer too) and try it out.

I’ve had success using Perfect Plastic Putty diluted with a bit of water to get the consistency I want much better than Tamiya Putty. I don’t like Tamiya as I find the chemical reaction on plastic too much. Perfect Plastic is water soluble, so I’m thinking you can’t use soap and water to wash the model prior to paint?

I use this one (the red/brick colored), and love it!

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There’s always this:

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I picked up and tried the Bondo Glazing and Spot Putty today. I had to redo some welding cut marks and the Bondo worked fantastic.

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Looks great Steve. I’ll be getting the red stuff this weekend.