Mixing putty?

When mixing the smaller amount we use in the hobby (if you need a "golf-ball" sized amount for your model you have bigger problems than a seam...) I use the old "Mark 1 Eyeball" The stuff I use, "ICING" is best mixed by color. It is an off-white color and the hardner I use is red so I can determine the mix by the pretty pink color. Although sometimes I mix it too "hot" and it kicks off too soon I would rather have this problem than have it NOT harden. I just made this error and thought well, it will set. One day later it was still rubbery and could not be sanded cleanly. I had to dig it out and re do it.

Experiment and find the color that works best for your material. I am using my free formica samples to mix it on and just toss 'em when done. Otherwise I have used a piece of glass and can clean it off with a razor blade when done.

You will get a feel for the ratio but other than mixing it without enough hardner you reall would have to overdo the hardener to screw it up.

BTW, they make a product called "Thin Ice" that can be poured, it is possible to do small casting with it.

Rick

Ray,
I use Bondo spotting and glazing putty. It comes in a tube and doesn't need a catalyst. Dries quick and can be sanded very nicely. It can be feathered out very thin. Also dissolves and thins with a little nailpolish remover if needed (I use Cutex acetone-free with good results). Highly recommended.

I also have some Milliput based on Domi's recommendation, but I haven't had a good chance to use it yet. I expect it will work well also.

M.

Hi Ray,

I use a waxed paper plate and place a bit of the putty on one side and a small amount of the hardener on the other - the amount is what I estimate what I will use over the next hour or so.

I then use a toothpick or painters knife to pick up both a bit of putty and hardener and mix it together on another spot on the plate, kind of like how an oil painter might mix colors on a palatte. Using this techique, you can easily make pea size amounts of catalyzed putty.

For more information, please see my page on the subject:

http://wmunderway.8m.com/cont/putty/putty.htm

I hope this helps a bit

Kurt

If I use a 2-part, I usually mix up a good bit of the stuff. Best to have more than enuff than not enuff sometimes.

A single can of base and tube of cat will last a long time. And if you do run out, it's a helluvalot cheaper than buying tubes of Squadron or some other such putty.

I also use spot/glazing putty as well as the aforementioned Squadron and a gazillion others! For small filling jobs, I LOVE Mr.Surfacer. Just depends on what I'm doing and what happens to be on the bench at the time! But this is getting away from the topic, so...

In conclusion, I shall finish by ending.

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RE: Single part putty. Yes, this stuff is very handy BUT remember it dries by evaporation. After a day or so when it seems to be hard and you can sand it, it is still "outgassing" solvents. The problem comes in when you prime and paint it only to find weeks or months later it has "shrunk" and sanding scratches are now eveident in your project.

Just as with a lacquer primer, single part filler will shrink for some months. If you have the time to wait before you finish it, OK. Otherwise a two part filler which sets via chemical reaction will be more stable.

The full scale automotive trade has gone to two part fillers and paints almost exclusivly for this reason. EPA evaporative emissions standards and durability reasons have virtually eliminated the old lacquer and single parts enamels. Urethane is the standard now, dries quickly, can be sanded and polished like lacquer and is MUCH more durable.

A large tube or tin of automotive finishing filler (you don't want the normal "Bondo" type filler, too coarse) will cost under $20.00 and last a long time. Try it, you'll like it. It is a real handy thing to be able to sand and finish the filler in less than 30 minutes.

Rick

Rick,

Thanks for the tip. I'll have to pick some up. I've never really had a problem with the spot/glaze putty that I use shrink, but maybe I'm just lucky. Sounds like it's worth getting used to using the two-part stuff...

M.

Thanks for all the info guys!! It was a big help.

Ray

Mkish, you're not lucky...

True, one parts shrink. But one has to remember; we're not using this stuff on a 1/1 car in fairly large amounts. We're dealing with very small applications here. And though the stuff will shrink, it won't take months, it will do so in a fairly short period of time. There's just not enough material there for the evaporation process to last that long. (Unless, of course, you're building the ICM Yak-9! ) If this were the case, then all my built-ups would be exhibiting cracks and sinkmarks and such. Another factor that must be considered is the atmosphere in which you model. Is it humid, is it dry? There are many variables.

Squadron green and white have been around forever. They're used by the vast majority of modelers that I have come in contact with and they work well. A real problem is that alotta folks just don't know how to use the stuff properly.

This stuff starts to dry as soon as it hits air. When you put it on a model, you should swipe it on and leave it. Don't try to gob on as much as possible and move it around. All this does is increase the drying time, and because it starts drying very quickly the stuff will actually "tear" apart when you're manipulating it.

Also, the chemical reaction between the putty and the plastic results in the softening of the plastic, further resulting in the chemical bonding of putty and plastic which ultimately results in a solid bond. Moving the putty around during this process will also do funky things with the putty/plastic mixture. All of this causes a good deal of the pitting that you may encounter, as well as other problems.

If you have a big gap or hole to fill, build it up gradually and in thin coats. Better yet, if it's a sizable gap, fill it in with plastic scrap first, then the putty. The less putty you have to use, the better.

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Blackwolfscd..

Blackwolfscd..

You are correct, the "one parts" are generally OK IF used correctly and in thin layers. The advantage two part has you can build up faster with no shrink. However many people glob filler on in what they think is thin, i.e. 1/8" or more. In reality this is somewhat thick. Even two part should not be put on thicker than 1/16 or so. Any filler is best in layers. The other advantage to a two part is the ability to fill a hole such as a locating pin hole without shrinking in. My experiance (your mileage may vary) in filling such hole with single parts results in the filler dimpling in and requiring another application.] Two part does not do this.

Bottom line-Use what works for you, but if I was going out today to buy filler I would start with two part.

Rick

That's one thing that hadn't crossed my mind despite bad experiences in the past! The one-parts generally will not take a cut, drilling, scribe or whatever too well. Although if I'm going to do any of that I usually use CA in the appropriate area.. But we'll not go there!

The key phrase is, indeed, personal preference. It also depends on the job to be done. Some fillers are good where others fail miserably. I guess that's why I have every type of filler known to man in the workshop! Is this a good thing, or bad?

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