3M Bondo Wood Filler 30 oz (850.49 g) with Bondo Cream Hardner 0.5 oz (14g), Repairs Chips and Cracks in Wood, Sandable, Paintable, and Stainable (WF-QT-ES)

I am restoring old French windows and the wood needed a lot of patching, reinforcing and rebuilding. I had never used Bondo wood filler, but everyone assured me it was the best product for the job. The results are fantastic, but what a MAJOR pain in the neck Bondo is to use! First, you need to figure out how much of the tiny tube of hardener to use for the big quart of filler. After watching a bunch of YouTube videos, I got the idea, and the fact that I went through the entire quart of filler and had just a tiny bit of hardener left probably means I got the ratio about right. If you’ve never used Bondo, I highly recommend watching the videos — you really do need just a tiny bit of hardener for the small amount of Bondo you can reasonably use before it hardens. I also bought the pink Bondo spreaders (https://www.amazon.com/dp/B000BOC9K4) because one video said that the Bondo spreaders are the color that the mixed filler/hardener should be. Either that video was using a different formulation or Bondo changed the color of the hardener — it’s blue, not red, so when you mix it, you’re aiming for a sickly, light-green color. Even so, for a few bucks, the Bondo spreaders worked quite well; they’re stiff enough to mix the Bondo thoroughly and apply it, but have just enough flexibility to help smooth the product (which, based on my experience, is definitely an skill that requires a fair amount of practice). You need to mix this in very small batches (at most, a few tablespoons at a time) because each batch must be used in literally 2-3 minutes. When time is up, the mixture quickly starts caking and getting hard, making it utterly useless. And on the topic of mixing, I ended up mixing it on an 8”x10” piece of acrylic, which is non-porous (so it won’t soak up any of the oils in the product), sturdy to mix the heck out of the two components quickly, and perfectly smooth, which makes clean-up much easier after each batch. And yes, you need to clean the mixing board and the utensils after each batch; otherwise, your next batch could be contaminated and your spreaders will be caked with hard Bondo which will prevent smooth spreading of the next batch. As for the results, they are amazing, despite the TOTAL PITA this product is to use. The product can fill deep holds solidly, but can also build up pretty delicate shapes (sometimes requiring 4-5 thin layers and lots of sanding to get perfect). It really does dry hard in 15-20 minutes and is easily sandable. If Bondo would just invent an additive that would increase the working time — even by a few minutes — this would be a lot easier and less frustrating to work with. As it is, however, it is a total pain to use, but worth the effort given the excellent results. Final note: Be sure to wear thin gloves (thin latex/surgical gloves) when mixing and applying the Bondo. However careful you think you can be, Bondo will end up on your fingers and it is absolutely miserable to remove! 5 (begrudging) stars.

This is a high quality very strong filler. It fills and holds extremely well. It is easy to get in to a complicated hole or edge and is easy to sand. BUT - the fumes and dust are toxic. I have to wear a mask if I don't have very good ventilation (like from moving air). It is like two part fiberglass resin/catalyst which stinks terrible and is actually dangerous. Small amounts are fine and larger if well ventilated as I said. I used my respirator with organic solvent filters if I was doing much of it. The big issue is that it cures very, very fast. Even if you spread it out which is a trick you can do with a lot of fiberglass resins. This sets fast so you can't really use it slowly or do large areas at the same time. It is easy to mix though. I think I used too much of the catalyst at times which will make it cure too fast. You have to eyeball how much to use though so that is easy to do. If I used it more often I would be able to calibrate the amounts by eyeball better. I do like it though. It does a good job for permanent jobs. The fast setting means you don't have to wait for it to cure. It may be too fast if you need more time to fill and work it. Easy to sand. Sands smooth. It cures a medium green and my latex primer didn't hide it very well so plan on using a high-hide primer/paint. I didn't need to drill and tap for screws or bolts but I suspect it will be pretty good at that. Whether it would be as strong as wood I'm not sure but it may actually be stronger. Recommended if all this sounds right for you.

I have used this product on a number of projects, and have found it to be a great tool in the arsenal. It is only for paint grade work, and has a few characteristics that you must be aware of before you use it. === The Good Stuff === * The product is great for larger repairs I use it to hide countersunk lag bolts, or to repair gouges or knot-holes in wood where a smooth appearance is desired. * The product sets up pretty quick, and depending on the thickness of the repair, can be sanded and painted fairly quickly. A quarter inch thickness will dry in less than an hour, and can be sanded and painted immediately. It sets and dries quicker than the one-part bondo filler available in tubes. * The product will shrink a bit, so really deep repairs may require multiple applications. I never saw the product crack, and once you have a smooth surface, it seems to hold up both indoors and outdoors. I always paint and prime as soon as possible, so no idea how well it will hold up unpainted. === The Not-So-Good Stuff === * The downside of the quick drying times is that you only have a couple minutes (maybe 2-3) to use up the product once it is mixed. * The instructions are fairly specific about how to mix the product. To be honest, I cheat, and just mix the compound and hardener just enough to get a consistent color. That seems to give me an extra minute or two to work with. I seem to get away with it. * The filler comes in a large can-sort of like a quart paint can. Since the filler is a thick putty, it is a bit of a challenge to get the last 10% out of the can. * Consider using disposable plastic putty knives- it is a tough job to get the dried product off of metal tools. === Summary === This is a great product for hiding any number of sins and problems with paint-grade wood. It dries quickly and hard, is easy to sand and paint, and holds up well to use and weather. However using it is a bit of a challenge, and requires you to work fast.

Had a lot of wood filling to do and needed something really tough. This does a really good job of filling, smoothing sanding and priming. The only real drawback is the extremely short working time. You really gotta move quick! This has a tendency to sag on vertical surfaces so you have to work the product as it starts to stiffen up. The warmer the day, the faster it hardens. you have almost no working time in direct sun in the summer. I was told putting the unmixed can in the refrigerator helps with increasing working time, but makes it harder to mix the harder in.

Great product! I like this stuff, it does dry fast sometimes if you use lots of activator and if it's hot outside. Very strong smell! Quick to sand and holds/grabs very well. I wish 3M had a variant of this that is like a resin/epoxy, allows more manipulation and requires life to set

I love this product - used it to fix rotten door frame and slightly damaged wood siding. Hoping since it's not wood, it won't rot again. Although once the hardener cream is mixed in, I could use a little bit more time. Additional couple of minutes would be nice.

I was scared to death when applying this to the stair landing I've been working on. I decided to measure, glue, sand, cut etc.,a large portion of the landing using LL Flooring's, red oak select, tongue and groove flooring. After sanding and prepping I tried Minwax colored filling which is great on smaller spaces, but this time it cracked over night. I sanded most of it off as the Amazon truck pulled up with this stuff. So many reviews complained about work time, color, and ability to take stain. I still have one more landing to do so I will post pictures as I go with that one. As you see in these after stain pictures, it seems to take it just fine. I used Minwax semi-transparent, water based stain. This is one coat, allowed to sit 12 minutes before wiping down. I'm thinking the error must be by user and maybe lack of experience mixing and using epoxy products and also experience applying stain. I can't speak to the review that used oil based stain as this stuff feels like hard plastic when dry. I can still see where the epoxy is applied but it is covered enough that I'm sure after drying and getting the second coat, it will only be my critical eye that will know its there. I sanded it down starting with 50 grit then stepped up to a final 220, then I stained the next day after building up some nerve. I mixed very small amounts maybe three or four teaspoons and then added a little dap of the activator. I mixed for about a minute and applied. I had to repeat this in a smaller amount to touch up a couple places that I felt needed attention. I was able to do all the seams in about 7 minutes first round and still had workability. I then gossiped with my neighbor for about 15 minutes and by then it was set pretty good. I let it rest another 10 or fifteen minutes while I gathered my sanding crap again. I sanded all of the protruding layers starting with 50 and going down again, just to keep consistent with the wood. I also filled a couple chipped spots from the circular saw, but again, my eye will not go there come second coat. My anxiety now put to rest, I am excited about this product. I wanted to post pics right away to help anyone looking to see how it takes stain specifically, because no one else posted transparent stain pictures that helped me much. This was truly a shot in the dark for me. Next landing I'll post more before, during, and final pics when my project is finished. For reference I used a darker stain, Aged Barrel. But as you can see there's plenty of wood grain character. I posted a picture of the stairs too so you can see the depth of color. The epoxy dried like the color of a shelled peanut prior to sanding. This DIY queen is happy thus far. UPDATE: I uploaded pictures of yesterday's mess leftover in the small cabinet paint roller dealy. I scraped it out pretty good and scraped the plastic putty knife. This epoxy is for wood so it's possible to reuse hard plastic container and putty knives by breaking off or scraping it off with something stronger. I'm finding that the less activator the longer working time but a bit longer to dry. I went back and got a place I missed after about 12 minutes and though it is hardening a little I was still able to get a space filled. I was not in a rush so I left it to dry and took a break, so I can't say how quick or slow it dried. Lastly, use in a well ventilated area. Yes it stinks, it's epoxy. I hope this helps. Good luck to you all.

Works well but the unmixed product is horrendously noxious. Don’t mix it in a confined space or leave the container open. I found even when I used less hardener it cures too fast. I was trying to build up an area and had to mix really small batches. Because it hardens so fast you pretty much junk whatever spackle knife you used to apply it since it’s not coming off.