What is the best putty

[car lover 1996]

Hello

I know this was probably already covered but I was wondering what is the best putty to use for model cars. I dont know much about what kinds are out there so what is the best kind?

[MrObsessive]

This question is subjective because everyone will have their favorites. I personally like to use something called Dynatron Putty-Cote. It's a two part automotive putty (the best type to use for models BTW) and once dry, it feather edges great and of course doesn't shrink.

DON'T get the hobby putties such as Squadron (green or white) as I think they're pure junk and will show up long after you've painted over them.

If you need a good one part hobby putty, the best that comes to mind might be Tamiya Putty. Very little if any shrinkage as it has some aluminum in it. Unfortunately, it's unobtainium at the moment as Tamiya had to reformulate a few of their products, and I believe that was one of them.

HTH!

[Guest]

I like Squadron white putty myself. I never have had the shrinking problem some people claim to have with it. I've built entire fender flares and filled tail light housings with it.

[MrObsessive]

Perhaps Squadron changed their formula for their white putty. Years ago, I had a TERRIBLE time trying to use it as it caused a number of problems with the paint down the road.

I swore never to use it again and got real familiar with the two part putties, and have been sold on them ever since.

[Harry P.]

There are two basic types of putty: one-part and two-part.

One-part putties (what everyone knows as "model putty") are applied directly from the tube, and they dry via evaporation of the solvent, leaving the "putty" part behind. Obviously, if they dry by losing a part of their volume (the liquid solvent part), there is shrinking as the putty dries. It's inevitable. ALL one-part putties shrink as they dry, some more than others, depending on the ratio of solvent to hardener in the putty. The shrinking becomes a problem when you apply the putty and let it set up. You think it's completely dry, so you sand, prime and paint... only to find that days or weeks or even months later, there are telltale bumps and uneven spots in your paint caused by the putty that was still drying (and shrinking) even after you had painted your model. Too late to fix it now!

Two-part putties work in a completely different way. You have to mix the putty (the "resin") with the hardener, like mixing two-part epoxy. Once you mix the two, the putty hardens not by evaporation, but by a chemical reaction between the two components. The putty doesn't "dry" like one-part putties; it chemically "sets," and once that chemical reaction has taken place, it's over. There won't be any shrinking, because evaporation is not part of the process.

There are several brands of two-part putty. I like Bondo's "Professional" glazing putty. It's cheap, available everywhere, and it works great.

[Rade8boy]

I am a fan of Tamiya putty, and while it has been is short supply, Squadron Mail Order has it available, I just got a tube 2 weeks ago. For large areas a 2 part auto putty is best, I use the store brand of premium putty from the local auto paint supply house, it is cost effective . Squadrons' putty has ruined a couple of my works with shrinkage over time, cracks showed up where the putty filled a seam, the putty was under a good automotive priomer and automotive enamel paint.

[car lover 1996]

Thanks

[car lover 1996]

There are two basic types of putty: one-part and two-part.

One-part putties (what everyone knows as "model putty") are applied directly from the tube, and they dry via evaporation of the solvent, leaving the "putty" part behind. Obviously, if they dry by losing a part of their volume (the liquid solvent part), there is shrinking as the putty dries. It's inevitable. ALL one-part putties shrink as they dry, some more than others, depending on the ratio of solvent to hardener in the putty. The shrinking becomes a problem when you apply the putty and let it set up. You think it's completely dry, so you sand, prime and paint... only to find that days or weeks or even months later, there are telltale bumps and uneven spots in your paint caused by the putty that was still drying (and shrinking) even after you had painted your model. Too late to fix it now!

Two-part putties work in a completely different way. You have to mix the putty (the "resin") with the hardener, like mixing two-part epoxy. Once you mix the two, the putty hardens not by evaporation, but by a chemical reaction between the two components. The putty doesn't "dry" like one-part putties; it chemically "sets," and once that chemical reaction has taken place, it's over. There won't be any shrinking, because evaporation is not part of the process.

There are several brands of two-part putty. I like Bondo's "Professional" glazing putty. It's cheap, available everywhere, and it works great.

Thanks for the tips. Where can I get the bondo professional glazing?

[aarondupont]

Hi all: I too have had shrinkage problems with squadron. In fact I bought a new tube about six months ago, it still shrinks. I've tried using spot putty. It too has some shrinkage. It is best applied over primer. Seems to work better that way. It is designed for automotive use as a finishing or "glazing" putty. Lately I've been using Bondo two part filler. It's working great. Dries fast. Sands and feathers well. It's cheap at Walmart or other box stores. I've seen over the years folks recomending two part resin putty. It's available at auto part stores. But at $24. I felt it was too pricey to try. Hope that helps! Aaron Dupont

[Harry P.]

Thanks for the tips. Where can I get the bondo professional glazing?

Most auto parts stores. Maybe Walmart? Or online.

Here's one place:

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_x_7100031-P_x_x?cm_mmc=CSE-_-Google-_-VALUE3-_-VALUE4&ci_src=14110944&ci_sku=7100031

[Art Anderson]

Brands of catalyzed putties are like brands of bread--everybody seems to have one! Seriously though--all catalyzed putties as used in the autobody trade that I have ever seen are polyester putty, which in itself is polyester resin with a filler added, the finer the grade of putty, the finer grind the filler material is.

In short, in my experience--if you find spot-and-glaze catalyzed putty, it really matters very little the brand--chances are that in any event, many of these brands come out of the same holding tanks--just packaged in whatever label you see on the shelf.

But in any event, as Harry P wrote--all one-part (evaporative solvent-based putties shrink upon drying--they have to, as a portion of their "bulk" is provided by the solvents that evaporate. And my experience with Squadron Green Putty has never been satisfactory--that stuff is what was known in the Autobody Trade 50 years ago as "Green Stuff", and it was simply not worth the powder and shot to blow it to kingdom come, IMO.

Art

[CAL]

I use autobody glaze or Testors red for the fine stuff and Milliputt two part.

[mr moto]

I've had similar experience with Squadron. LONG after you use it you might discover one day that it has shrunk. In fairness, all the one part putties have some shrinkage. Right now my favorite "convential" one-part is Acryl Blue. It's a body shop type product that sets really fast - you can sand in 20 minutes or so - and doesn't seem to have much shrinkage. Maybe that's because most of the shrinkage occurs during the fast setting process.

The other one-part that I'm using more and more is super glue. Sets fast (I keep the kicker handy) and doesn't shrink. I thought it might be hard to sand but that hasn't been the case. The main problem is that the lack of color makes it hard to judge your work until it's primed.

The problem I have with two-part putties is getting a consistent mix. You have a giant tub of resin and a tiny tube of hardener and it's hard to get a consistent ratio. So sometimes it doesn't set right and sometimes it sets before you can use it. When the mix is right it's good. The directions usually say something about adding the contents of the tube of hardener to the contents of the tub of resin. Not much help!

I plan to try Milliput because it's a 1 to 1 mix but right now I'm pretty happy with super glue.

Edited June 16, 2011 by mr moto

[Monty]

Can someone tell me what the difference is between Tamiya gray primer and Tamiya white primer? I Googled this yesterday and couldn't seem to find out much, with the exception that a couple people on different military-hobby sites said it's hard to shoot white primer over the gray stuff for some reason.

Oh, and IMHO, the Squadron stuff is worthless.

[Harry P.]

The problem I have with two-part putties is getting a consistent mix. You have a giant tub of resin and a tiny tube of hardener and it's hard to get a consistent ratio.

Bondo Professional Glazing and Spot putty (two-part system) comes in a 3 oz. tube, not a giant tub. It's the perfect size/amount to keep on hand for modeling needs. Getting the ratio of resin and hardener right is very simple... it's roughly 10:1. That is, a blob of the putty should be about 10 times the size of the blob of hardener... but an exact ratio isn't critical. If you use too much hardener it'll set up faster; too little hardener and it sets up slower. Getting the ratio right is easy after a few tries... you don't even have to think about it, it just becomes automatic and you can "eyeball" it easily. When you have it right, the mixed putty should be a pale pink color.

[CAL]

Can someone tell me what the difference is between Tamiya gray primer and Tamiya white primer? I Googled this yesterday and couldn't seem to find out much, with the exception that a couple people on different military-hobby sites said it's hard to shoot white primer over the gray stuff for some reason.

Oh, and IMHO, the Squadron stuff is worthless.

One is medium (gray)and one is fine (white). To be honest I have used both and can't tell a whole lot of difference between the two.

I agree, the Squadron stuff is junk.

Edited June 16, 2011 by CAL

[Harry P.]

This is the stuff.

About $7-8 at most auto parts stores.

[CAL]

This is the stuff.

About $7-8 at most auto parts stores.

+1 great stuff and is said to be the exact same thing that is in Testors Red.

[mr moto]

This is the stuff.

About $7-8 at most auto parts stores.

Is that a two-part? I only see the one tube. I've used a one-part Bondo glazing putty before and had shrinkage problems but that might not be the same thing.

[Zoom Zoom]

Is that a two-part? I only see the one tube. I've used a one-part Bondo glazing putty before and had shrinkage problems but that might not be the same thing.

Yes, it's the 2-part, and the packaging is nearly identical to the 1-part, so you have to be careful. Just look inside the blister pack for the small white tube of catalyst, and I'm pretty sure that the word "professional" is only on the package of 2-part putty. They're sold side-by-side at the Pep Boys where I've found it.

As for the amount of catalyst, roughly 10-1 is what is called for, but as long as you have a color change in the putty from the hardener, it will work. Too much...and it will kick too fast, too little, and it will kick a bit slower.

[Harry P.]

...I'm pretty sure that the word "professional" is only on the package of 2-part putty.

Right. The one-part and the two-part putties are in very similar packages so you have to be careful. The two-part stuff has "Professional" in the name.

[Lownslow]

for body work i use evercoat for fabbing parts tamiya epoxy putty

[Terry Sumner]

I'll add one more vote for the Bondo brand Professional Finishing glaze. This stuff is very very fine grained and sands beautifully! I got it in a slightly bigger size at Advanced Auto Parts.

Hosted on Fotki

And here's the pinkish color that Harry alluded to when it's mixed and applied...

Hosted on Fotki

[Ryan S.]

Great. I read all this AFTER I've just done a bunch of body work with Squadron green putty. Are the problems with this putty shrinking over a long time pretty much guaranteed? Or are they just a sometimes thing? I'd really hate for the 2 builds I'm working on to be ruined down the road from shoddy putty.

[Harry P.]

Great. I read all this AFTER I've just done a bunch of body work with Squadron green putty. Are the problems with this putty shrinking over a long time pretty much guaranteed? Or are they just a sometimes thing? I'd really hate for the 2 builds I'm working on to be ruined down the road from shoddy putty.

Guaranteed.

Like I said in my post, all one-part putties harden via evaporation. They literally lose a part of their volume (the solvent) as they dry. In other words, the volume of the applied putty gets smaller as the solvent evaporates away–it shrinks. Your best bet is to wait a long time and be sure the putty is really dry before you go any further. Of course, there's no real way of knowing exactly when that'll be.

I suppose you could put the puttied parts in a dehydrator to speed up the evaporation process, just like you would for paint. But again, depending on how thick you layed it on, exactly how long it will take for the putty to truly harden and lose all of the solvents (and finally stop shrinking) is unknown.