Squadrons white putty

[mnwildpunk]

I am not new to modeling but I am new to adding detail and fixing mold issues. I was at the L.H.S. And picked up squardons white putty in fact that's all I see at the L.H.S. Around here. I don't like the stuff at all. What do you pros. use? I'm willing to try anything because this stuff is not good I.M.O

[Mike Kucaba]

I use Squadron white sometimes,but in very thin layers. Tamiya white is also good,but not as readily available in Hobby Stores as Squadron. Any solvent based putty is bad if misused.It should be used very sparingly,and never be glopped on real thick.

[Harry P.]

Any putty that you squeeze out of a tube is bad stuff. It hardens via evaporation, which means the solvent (the liquid part) gradually evaporates, leaving the hardened solid putty behind. But because it hardens by evaporation, there are two basic problems.

First, if you lay it on thick, it might seem to be hard (and it will be, on the surface)... but it can still be soft inside. So you can sand, prime, and paint your model thinking all is well, but a week or a month or more later, after the putty has fully dried. you'll see flaws under your paint where the putty has actually shrunk over time. Of course, now it's too late to fix it!

Which brings me to the second problem: shrinkage. Every one-part putty (the kind you apply directly, without mixing it with something else) hardens via evaporation of the solvent, just like paint "dries." Same exact process... the liquid part evaporates away, leaving the solid part behind. But because the putty is literally losing a part of it's volume as it dries (remember, the liquid part is evaporating away), the putty will shrink as it dries. If you apply the stuff in very thin layers and let it completely dry before sanding, priming and painting, you should be ok... but how can you really know if the drying (and shrinking) process is fully finished?

The answer is to ditch one-part putties and go with two-part catalyzed putties (like "Bondo," for one example). Two part putties are mixed before applied... resin (putty) plus hardener, like you mix epoxy. And like epoxy, two-part putties don't "dry," they set chemically via the chemical reaction between resin and hardener. There is no loss of volume due to evaporation (in other words, no shrinking), and once the chemical reaction has happened, it's done. The putty has set, and you're good to go. There won't be any further "drying" and shrinking over time, like there is with one-part putties.

[Chuck Most]

Single-part solvent putty is okay for filling in very minor blemishes, but for anything significant, two-part catalyst putty is the only way to go.

[JunkPile]

And BONDO type fillers dry or cure within say five minutes give or take.

[Guest]

I'm not a pro,but I don't use anything but Squadron white putty. I've never had shrinkage problems with it that some people have claimed. It may shrink slightly from evaporation,but nothing significant. I've put some pretty thick gobs of it on builds and it's still just like it was when I first done it. It DOES NOT take months or days to dry and once it is dry,that's it,it's dry. It WILL NOT shrink after it's dry. If you put it on fairly thin,it's dry in thirty minutes or less and ready to sand. If you put it on really thick like a quarter of an inch,it's best to wait a few hours. I've built entire fenderwell arches with it. I've filled in tail light sockets that were a quarter of an inch deep. It's never cracked,shrank or anything else.

[mnwildpunk]

Thank you Harry P. I wasn't thinking I would get a science lesson with this answer he-he. I know what you mean by drying from evaporation the first tube I bought I had to return because it was already dried out before I got it home. Something must of been wrong with the tube? So I know epoxy is for bonding things together but would it work as filler or would it melt the model like plastic cement does. Ok I have some Ppgglazing putty for sheetmetal would that work?

Thanks guys for putting up with what are probably silly questions for you pros

[Skip]

OK, I'm being a little obtuse here but, what brand and type of two-part catalyzed putty are you guys using? How much do you keep on hand, as in what's the smallest container you were able to buy?

[Fat Brian]

"Epoxy" refers more to how a product works than what it does. An epoxy can be an adhesive or putty or other things but they all have two parts, a resin and a catalyst or hardener that causes the resin to set up.

http://en.wikipedia.org/wiki/Epoxy

[Mike Kucaba]

Bondo Two part putty comes in a tube,and works quite well thank you. It is about the smallest amount of two-part putty you can get. I also like epoxy glue.I use the 30-minute type and mix it with Micro-balloons and apply it and let set for about 24 hours.It sands easy too. I also use Magic-Sculpt and have done some wild stuff with it. I need to take some pics of the latest thing I did.