Sealing the grain with car putty.

sound a little werd to me Ian
since ´product´s for metl is very hard in the way it can´t move with the wood
as I know of …....... but my only knowledge about it is becourse the former owner
off our house had used paint on the windows that normaly is used on ships and they
are oilbased i don´t know about the newr waterbased paints they use in the car industry today
if they are more flexiple

Dennis

If your wood is sanded, then you can get the same kind of super smooth paint finish by just priming first and fine sanding the primer.

-- Carpenter assembles with hands, Designer builds with brains, Artist creates with heart!

I have seen contractors years ago fix termite damage with car putty (bondo). They used drills, saws, and whatever they needed to remove all damage from some posts they were fixing under an old porch. Then they filled it with bondo. They let it sit a few days and then come back, sanded and painted it.
Like you, I noticed it looked good. However, I was only there to fix the roof. I have no idea what the long term results were.

-- http://wddsrfinewoodworks.blogspot.com/

I’ve used sheet rock compound for the edge of MDF. I would put a thin layer on, forcing it into the grains with a little pressure and 2 hours later I would sand it off. Works great for painting.

-- New Auburn,WI

I have used “bondo” to repair window sills and whatnot from time to time. You can adjust the drying time by varying the amount of hardener you add to the mix. Very similar to using epoxy, except bondo is a lot cheaper! But be warned: Bondo is a little “fumey.” You had better be in a well ventilated area when using it.

Drywall mud is great for the edges of mdf. That is a great tip.

The idea of using Bondo to fill problems areas, under a painted finish, has been around for years. I was doing it at least 30 years ago and I’m sure I wasn’t the first. Also, never had any customer call with any issues related to it.

-- Sam Hamory - The project is never finished until its "finished"!

I have used bondo in many applications. It sticks, flexes a little, and doesn’t change shape.

-- When the moderator chooses sides, his site sucks.

I have used bondo to fill grain on a painted project. Works great. The only problem I had was it cured way to fast. I am sure that was user error.

Dennis, unless you put a ‘continuous layer’ on, the expansion and contraction won’t be a problem. Simply filling pores is generally ok.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

As others have noted, using bondo on wood is fairly common. It’s great for painted applications, but I wouldn’t want to try staining it. :-)

-- Charlie M. "Woodworking - patience = firewood"

A while back I bought some glass-paned wood doors to be assembled to replace a wide sliding glass door. These came from a surplus place. The doors appeared to be new doors that had an error in the placement of the holes drilled for the door knob units. I used Bondo to fill in the holes and then used a belt sander to sand down the filled in areas. The doors were painted and now after seven years of use with one side exposed to the weather the filled in spots are still undetectable.

I have also used Bondo to fill in other imperfections in doors and other wood items bought from surplus suppliers and all applications have worked very well as long as you are painting over the repaired area. You can’t even see the repair if it is sanded well before painting. The repair holds up well too.

Planeman

-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

Bondo is great stuff. If it can withstand the movement of metal and extremes of temperature typical of most cars, it’s good for wood. I keep it around.

The conundrum is how much to buy. Large amount is significantly cheaper by the pound, but if you don’t use it, it gets, well, useless. Maybe the small size is a better buy.

Tip: If your hardener dries up and the paste is still good, drop by your local auto body supply place. A little chat and you may well walk out with a free or cheap tube of hardener alone.

Kindly,

Lee

-- "...in his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

I have seen it used and used it for paint grade work and it works
very well. It doesn’t seem to shrink too much. I suppose it
can be tinted darker as a grain filler, but there are other options
that involve less toxicity and are simpler to use.

Yeah, bondo is good all around stuff. There is very similar product that I like even better. It is a stone adhesive with the trade name Akemi and they use it to fill in holes in marble and granite. They have a couple of different formulas…. the ‘knife grade’ which has a finer texture than the bondo and comes in transparent, white and buff color. The other is a ‘flowing’ grade and I don’t remember if it is available in the buff color, but it is in white and transparent.

Like I said, it has a finer texture and you can pigment it any color or tint that you want. We used it for stone but also on fiberglass, acrylic, cultured marble, stone, etc. Same as the bondo you kick it off with a catalyst (paste or liquid). In any case, it sands to a fine finish and can even be polished with compounds. I made my living with that stuff for 7-8 years. Really versatile stuff.

-- I just got done cutting three boards and all four of them were too short. (true story)

I would have thought this was totally unnecessary and a waste of money and time too. I like wood as it is not plastic looking wood.

-- excuse my typing as I have a form of parkinsons disease