Mixing Putty with Solvents

[James W]

I recently tried mixing Squadron White putty with Pactra Racing Finish lacquer thinner to keep it from drying too quickly.

I only used a small amount to smooth some framerails. Dose anyone have experience with this sort of thing on larger surfaces?

It seemed to work really well and remained spreadable until I had the putty where I needed it, but what will happen on a larger area?

Have any of you mixed solvents with this type of putty? What works and what does not?

[LDO]

The only thing I have tried is mixing Mr Surfacer with lacquer thinner. I have sprayed it through an airbrush and applied with a paint brush. I think it makes a great "high fill" primer. I swear by it, but some swear at it.

[bobss396]

I don't see any advantage gained from thinning down a filler material. I never liked Squadron putty, it was too coarse and shrunk too much for me. I've been using spot body putties like 3M and Nitrostan. They have a fine grain when they are dry, very sandable and little shrinkage.

Bob

[gearjammer]

Hi James, when I was building aircraft and armor I used Squadron Green and thinned it with acetone. It went on smooth and was not hard to sand. Be careful if you use it, the fumes are pretty bad.

[Guest Davkin]

Seems to me by thinning those puttys you are making them even more susceptible to shrinkage. Personally I won't use anything but catalyzed putty.

David

[Olle F]

I use Squadron White Putty mixed with Tamiya liquid glue or Tenax when I have to fill small pinholes, scratches and minor repair in general. I discovered this trick when I had a problem getting small dabs of putty to spread and adhere. I'm sure you know what it's like when you try to spread a very small amout of putty, you're almost there, and all of a sudden it crumbles up and falls off. :evil: Some thinner in it makes it much easier to spread, it feathers great, it won't dry up on you, and because of the glue I mix in it, it will stick like... well, glue. Brushing some Tenax on the surface before you apply the putty seems to make it stick even better.

I wouldn't use it for a thick coat though, because I'm sure it will shrink quite a bit, but it works great for small repairs.

[m3m]

I don't see any advantage gained from thinning down a filler material. I never liked Squadron putty, it was too coarse and shrunk too much for me. I've been using spot body putties like 3M and Nitrostan. They have a fine grain when they are dry, very sandable and little shrinkage.

Bob

i agree i always use a real spot filler on my models just like i use on my real cars i have never had a problem with it eating the plastic( although reading the magazine i see that this can be a problem) or shrinkage if u use it right, layerd coats on big gaps. i use it to build all my hood scoops, filing in door handels, just my 2 cents, i am not into all the modeling stuff out there so i just try to use what i have.

[gearjammer]

I am always willing to try new things. Is the 3M and the Nitrostan auto body filler? I am not sure if I know what catalyzed putty is.

[Guest Davkin]

Catalyzed filler require a catalyst that you have to mix in to putty to activate the curing process.

Non-catalyzed puttys cure by evaporation of the solvents in them, much like paint does. It take take quite some time for all that solvent to escape, especially if you paint over the putty before it has fully cured, (and it's impossible to know for certain when it's fully cured.) The paint can trap some of the solvent in the putty for a time, however months later that solvent can finally escape through the paint causing the putty to shrink leaving a nice little crater in your paint job. You can take some precautions to minimize the risk, (such as only putting it on in very thin layers, and heat curing it.) but I don't consider it worth the risk.

Tamiya makes a catalyzed putty I heard it pretty good. I use Evercoat Glaze Coat.

David

[ramonesblues]

Nitro Stan is a lacquer based spot putty that has been around for decades. Originally it had lead in it and when dry, DID NOT shrink or move around. At the time it was the best on the market. Haven't seen a tube of that stuff in a long time.

[James W]

I use Squadron White Putty mixed with Tamiya liquid glue or Tenax when I have to fill small pinholes, scratches and minor repair in general. I discovered this trick when I had a problem getting small dabs of putty to spread and adhere. I'm sure you know what it's like when you try to spread a very small amout of putty, you're almost there, and all of a sudden it crumbles up and falls off. :evil: Some thinner in it makes it much easier to spread, it feathers great, it won't dry up on you, and because of the glue I mix in it, it will stick like... well, glue. Brushing some Tenax on the surface before you apply the putty seems to make it stick even better.

I wouldn't use it for a thick coat though, because I'm sure it will shrink quite a bit, but it works great for small repairs.

Thanks Olle, this is the same problem I was having. The Squ. Wt. putty forms a skin almost instantly and balls up instead of spreading. I'm only talking about small sink holes and surface fills. I'll try the Tanex. Sometimes it dose not pay to mix a batch with a catalist for a cubic millimeter of putty.

On the subject of catalyzed fillers, I went to the local paint store and told them what I do and what I needed. 5 minutes and three clerks later I was talking to a guy who knows his product. For ten bucks I got a tube of Dolphin Glaze by U-POL. It is very thin, a self leveling finish glaze.

What sold me besides the price was that it contains 20% styrene.

It seems to work well and sticks to the bodywork. I'll tell you in ten years if it still holds up.

[Modelmartin]

The reason the lacquer thinner or acetone works to thin out spot putty is that the spot putty is merely thick primer. I have used 3M and green and white Squadron and as long as it is used as it is supposed to it works great. It is for surfacing and very small imperfections. I always use lacquer primer on top of it and that helps "fill" the spot putty so it doesn't shrink down the road. For a lot of my filling I keep a jar of unthinned primer on my bench and brush it into imperfections. It works great. 8)