Working With Bondo

[Smart-Resins]

Alright I have done the leap and bought some Bondo to work with and try something new. It does sand easier then liquid plasticfor sure!! However, Imixed itup, using less hardener then recomended by the company to make the work time longer as suggested by fellow modelers. That even seemedtodomefine as I had almsot 5 minutes to slap it on. However,itwas very thick and goopy and hard to put onina smooth coat.I had toglop it onand gave me more sanding to do and was harder to get it to a smooth even covering. Is there a way to maybe thin it down and make it spread smoother for a more even smoother coat??

[MrObsessive]

Jody what are you using to apply it?

I generally use popsicle sticks (They can be had at the arts and crafts store) or toothpicks depending on the area and spread it on in somewhat thin coats. I know of no way to thin it down...........that may not be recommended insomuch that you may reduce some of the putty's effectiveness.

Yes, if you spread it on too thick, it can be a bear to sand down.........not to mention all the dust that it leaves behind. I hope you're wearing some type of mask or respirator btw--------you wouldn't want to keep breathing those dust particles in but for so long.

[BIGTRUCK]

On some bondo products the base chemical is ''acetone'' , but I never tried thinning, final coat for pinholes I used a glazing putty made by 3-M . That is nothing more than a very thick primer and can be thinned. It comes in 3 colors , or a ''flowable finishing putty'' as a skin coat and is brushable..

[Smart-Resins]

Since I am working with a 1/16 scale body, and most of my areas were give or take, 1/2" and the biggest being 3" on the hood area, I cut down some scrap styrene to about a 1" paddle figuring this would give me a area to feather with. I can say that it was very grainy and goopy. Also it did not stick to all of my areas, but have to admit this may have been my fault as after primering, I did not scuff the paint job?? As thick as it was though,I can not see spreading it with a tooth pick?? Maybe putting on a tic tack size glob at best??

[MrObsessive]

As thick as it was though, I cannot see spreading it with a tooth pick?? Maybe putting on a tic tack size glob at best??

Okay, 1/16 is a good size........but as I mentioned with much smaller scales I've used putty on, (1/43) I have used a toothpick. The Dynatron I use may be of a different consistency..............but it is a Bondo product so it's pretty much all the same.

Yes, you want to scuff up the area a bit to give it some bite.................it could be that you don't have your mix quite right and in some spots it didn't cure fully. When I've used putty in the past, I try to go with whatever the product says the ratio should be. In my case with the Dynatron, the color should be a light greenish hue-----then I know it's fully mixed.

[Rick]

Years ago I worked for a place that used Bondo many different ways. To thin it we used to add fiberglass resin and it worked very well. Bondo is actually fiberglass resin, fillers, and maybe a few other chemicals.

Rick

[Smart-Resins]

I find that mixing it with the proper amount of hardner seems to give it a slightly smoother consistancy. Also gets more maroonish. I see that it is styrene and resins, and cleans up with laquor thinnner, so I may try to play around with it some. Other wise,I think I may want to try either the spot putty or the liquid resin stuff. That may give me more what I am looking for wich is a smooth thin film for filling small areas,or slowly building up on larger areas.Thanks Bill

[LDO]

You might want to try glazing putty. It's finer-grained, and IMHO, better for models since they're so much smaller than real cars.

I apply putty with a tool I got from Squadron years ago. It looks like a rectangular blade at the end. The blade part is maybe .015" thick. I clean it off with lacquer thinner.

I've found that putty sticks better to primer than bare plastic, although Mark Gustavson advises against that. He's a lead sled guru so he's obviously doing something right that I'm not doing.

[Smart-Resins]

That putty will be what I have to try next.Any tips on how to use that stuff?? Also any brands to shy away from?? I know I found some Bondo glazing putty at Wally World??

[BIGTRUCK]

3M putty , just spread it on over the area your filling , no mixing , let it dry and sand. On a 1:1 vehicle we used a 2x3 inch x1/4 thick rubber applicator...on a small 1/25th , I used a cut down index card , this stuff is for scatch filling and pin holes , not for shaping or contour

[LDO]

This is what I use:

It's great. It feathers beautifully, doesn't chip. It doesn't just sit of top of the plastic like some putties do. It becomes one with the plastic.

Beware of any single-stage putty. They "cure" by solvents evaporating out of them. That leaves them brittle and causes shrinking. Maybe not an issue on an ultra-thin skim coat, but why take chances?