Filler

[Big Messer]

I use Bondo or Evercoat glaze and spot putty. Sold at auto parts stores, a 4 or 5 oz tube costs less than $10 and lasts a long time. Attaches great to metal and plastic, sands easily and has excellent feathering properties. 

[Mike 1017]

12 hours ago, Big Messer said:

I use Bondo or Evercoat glaze and spot putty. Sold at auto parts stores, a 4 or 5 oz tube costs less than $10 and lasts a long time. Attaches great to metal and plastic, sands easily and has excellent feathering properties. 

👍

[rattle can man]

Some say the one part shrinks and you should use the two part. From my experience, I have some 20 yol builds with one part spot putty that have shown no sign of shrinking. So I stick with the one part.

[Ace-Garageguy]

50 minutes ago, rattle can man said:

Some say the one part shrinks and you should use the two part. From my experience, I have some 20 yol builds with one part spot putty that have shown no sign of shrinking. So I stick with the one part.

One part stuff is fine for thin fills if allowed to dry completely.

It dries by evaporation, so if it's recoated with anything with solvents, it WILL swell and then shrink again..

But you can't do heavy fills on heavy mods with it in one application.

Modelers used the one-part stuff very effectively before the two-part catalyzed fillers became widely available and accepted, and I still use one-part for pinholes and very minor imperfections.

But using one-part putty for heavy fills takes repeated thin applications to prevent excessive shrinkage and cracking.

The two-part catalyzed stuff can achieve a very heavy fill (for a model) in a single application, saving a lot of drying time and inter-coat sanding in the process.

This is not opinion. It is actual observed and repeatable fact.

 

EDIT: Don't even think about trying something like this with one-part filler

Edited August 12 by Ace-Garageguy

[Mark]

The one-part is good in certain instances, like smoothing ejector pin marks.  I've got Tamiya white putty and white 3M automotive spot putty, both work for that.  

For anything where you would need to build up multiple applications of the one-part putty, just use the two-part instead.  Why wait around for multiple layers to dry?

[Big Messer]

I forgot to say that it is intended to fill scratches on final thin coats. All the scratches on the roadster's final pic are what it is intended for. One coat, dries in about 15 min and ends ready for paint.

Edited August 12 by Big Messer

[FoMoCo66]

I did some sink marks on my 63 galaxie. Have had it sitting for about a week and a half. It's nice and solid now. Used 3m spot putty (some wet sanding after fully cured removed that red in the sanding marks).

[mini trucker]

I use superglue and baking soda for my initial “fill” sometimes and then skim it with some 1k putty. I like the USC brand because it is grey rather than red which helps with bleed through. I also like 2k glazing putty with white hardener if I have adequate ventilation available. 

[NOBLNG]

I use Milliput Fine White almost exclusively. I only use Tamiya or AK putty for an extremely thin coat or small scratches.

[Bugatti Fan]

Milliput Fine White is a excellent product. I believe that it was originally developed for restoring fine ceramics.

De Luxe Materials Perfect Plastic Putty is very good, and just recently as it was locally available, I picked up a tube of Revell's own filler and found it to be quite good.

[rattle can man]

Bill is correct. Spot putty is intended to fill minor imperfections. But you also don't want to apply heavy coats of two part either too heavy and the heat from it curing can warp parts. I made that mistake on a '69 charger hood and it ended up looking like a potato chip from a can. I stick too several light coats of whatever filler I use and let the coats dry between coats.

[NOBLNG]

I don’t believe Milliput heats up substantially if at all while curing.

[Ace-Garageguy]

6 hours ago, rattle can man said:

...But you also don't want to apply heavy coats of two part either too heavy and the heat from it curing can warp parts. I made that mistake on a '69 charger hood and it ended up looking like a potato chip from a can. I stick too several light coats of whatever filler I use and let the coats dry between coats.

While catalyzed fillers can indeed generate excessive heat from runaway exotherm, it really shouldn't be a problem if the material isn't over-catalyzed.

Too much "hardener" in polyester putties will make them "kick" faster, but will also make them much more susceptible to runaway exotherm.

I've seen less-experienced real-car bodymen over-catalyze the stuff so much that it literally smokes, and can even burst into flame.

By the same token, too little hardener or layers that are too thin can inhibit curing of catalyzed materials.

With "bondo"-like products, including 2-part polyester glazing putties, there is most definitely a sweet-spot for mix-ratios that you only learn through experience, and mixing the small amounts of catalyzed polyester materials modelers tend to use is particularly challenging, even for seasoned real-car bodymen who are very familiar with the products.

The generation of heat during curing, called "exothermic reaction", is part of the curing-cycle chemical reaction, and is necessary for the material to work correctly. BUT...too much heat from over-catalyzing, especially easy to do during hot weather, can be damaging.

Edited 17 hours ago by Ace-Garageguy

[Ace-Garageguy]

11 minutes ago, NOBLNG said:

I don’t believe Milliput heats up substantially if at all while curing.

Part of the reason for that is because it's epoxy, not polyester, and with its very forgiving 1:1 mix ratio, it's almost impossible to over-catalyze the stuff.

EDIT: Though we're not addressing it here, many liquid epoxy products ARE highly susceptible to runaway exotherm if they're contained in a too-small volume after mixing, and can also smoke/bubble/burst into flame.

Edited 18 hours ago by Ace-Garageguy