I want to discuss puttys and fillers.

[NOBLNG]

18 hours ago, Richard Bartrop said:

My go to filler is Milliput 2 part putty.   It doesn't shrink,you can sculpt it like clay, and it's strong enough when it hardens that you can carve and sand even relatively thin pieces.

I've tried sprue goo, and I'd only recommend it for very small areas and shallow indents.   On the up side, it becomes one with the plastic,  you can feather the edge of your patch without having to worry about it crumbling.  

This^^. I too prefer Milliput, the fine white stuff, for major sculpting work. It has zero shrinkage but does take a day or two to really harden up.
I have used sprue goo to cover the cuts on a roof chop. It works really well but takes weeks to revert back to solid styrene. A little patience is required sometimes, which is why I have a few builds on the go at once.

Edited June 27, 2023 by NOBLNG

[ctruss53]

I always heard that CA was harder than plastic so it was difficult to work with to fill in seams.

I gave it a try last night. There were some low spots where I used Tamiya putty and it shrunk. I dabbed in some thick CA. Gave it 15 minutes to cure. Then sanded it down. Yes it was harder than the plastic around it so it was a little challenging to feather it out. But going into the work knowing this might happen and taking steps to fix it, worked pretty well.

I am going to buy one of the fillers recommended above to add to the CA and give that a shot.

Ace, if I ever need to do bulk filling, I will definately check out West. Knowing your background I understand that you have done the work and know those products are probably best.

[peteski]

5 hours ago, ctruss53 said:

I always heard that CA was harder than plastic so it was difficult to work with to fill in seams.

That is not quite the whole story.  Yes, if you wait couple of days for the CA to *FULLY* cure, it is basically acrylic (similar to Plexiglas), so yes, it is harder than average polystyrene.  But if you work it (sand, etc.) within couple of hours after curing, it is actually softer than the polystyrene you applied it to. Adding fillers (talcum or microbaloons) also changes its hardness.

[RW033]

One of the issues I’m having using the Bondo brand putty is it reacts to the glues I use and softens the glue and parts loosen up and the Duplicolor primer I use also un-hardens the Bondo and turns into a gloopy mess 

[TDHofstetter]

On 6/27/2023 at 12:37 AM, Dave Ambrose said:

Mr. Dissolved putty is great stuff, but it's seriously odiferous. 

No way around that. Like all other spot putties I know about, it's acetone-based... and acetone dissolves polystyrene. That means that it bonds to the model like gangbusters, though.

[Chris V]

Another vote for Milliput Superfine White 2K putty here! 

As mentioned by others, it can be sculpted in shape and has excellent “feathering” capabilities when sanded. Furthermore it’s virtually odorless and doesn’t shrink once it’s properly cured.

For improved adhesion and strength I recommend lightly sanding the surface prior to application. 

As a general recommandation, putties don’t adhere as well to smooth and sharp edges (like door jambs and panel lines for instance). To improve the adhesion and finish I like to bevel such edges with a round milling-bit in my Proxxon (Dremel-type drill/rotary tool).

[Mark]

Besides routing out panel lines, I like to rout out seams between different parts that are being joined (especially when joining resin to plastic).  Ideally, you don't want the seam between those parts right at the surface.  You want a thin "stripe" of putty at the seam: plastic, putty, then the adjoining part.

The two-part putty is also great for filling those cut lines on the underside of hoods, so they don't appear as ghost lines on the finished and painted panel.

[robdebie]

One more vote for epoxy clay, like Milliput, Tamiya epoxy, or Apoxy Sculpt - I use the latter. No shrinkage, no solvents that make the plastic swell, good hardness after cure, nice to sand. If required, you can use water to smoothen the putty.

The drawback is the mixing required, but for me the advanteges outweigh that completely. I do the mixing by squashing the two compenent under a modeling knife, and repeating that a number of times. I try to limit skin contact as much as possible.

Here are some recent examples of work with ApoxySculpt.

Rob

 

Edited April 6 by robdebie