I want to discuss puttys and fillers.

[ctruss53]

This topic has probably been covered, but I want to compile information on puttys and fillers.

As you might have seen from my other thread, I am converting a 5 door hatchback into a 3 door hatchback. I have done a lot of the plastic work. Now I need to fill in the cracks and seams and all that.

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So far I tried my standard go to putty. Tamiya grey putty in the tube. I really don't care for this stuff. You only have a few minutes to work with it, but it requires at least a day to cure. Then it always shrinks, so you have to apply it two or three times. And it stinks.

Then I tried a little Mr Hobby putty. Same thing as the Tamiya putty. It only allows a few minutes to work with, it takes a while to cure, and it shrinks requiring more than one coat. And it stinks as well.

The other problem with both of these modeling puttys is you can't add on material where nothing exists. They are fragile if they are not bonded to something behind them.

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I also gave Bondo a try. It had a slightly longer window of time to work with. It fully cured in about an hour. And it did not shrink. But it stinks even worse than the modeling puttys above. It smelled so bad that I can't use it in my room. If I continue with Bondo I'll have to take it out in my garage.

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Then I watched some youtube videos and discovered 2 part epoxy putty. All the videos I watched used Tamiya. This Tamiya 2 part epoxy putty gives you 1-2 hours to work with it. It cures in 24 hours. You can build it up as thick as you need it. You can extend parts with it. This putty cures solid and it is strong. This sounded like it was just what I needed.

Well, I couldn't find anyone with Tamiya 2 part putty in the US. So the soonest I could get some was weeks out. So I found some 2 part epoxy putty from Green Stuff World that I was able to get in a couple days.

I followed the directions. This GSW putty never fully cured. And it didn't even stick to the plastic. It peeled right off. I might have done something wrong, but I am positive I followed directions.

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I started mixing up some sprue goo. There are a lot of seams though. I am worried sprue goo will take a while to cure. Or it might cure too hard and be tough to sand it. My sprue goo is Tamiya cement in the orange cap, not the extra thin stuff. And I have a bunch of sprue melted into it. I have probably half a bottle all melted down and ready to use.

So, 

What do you use for putty and / or filler?

And if you suggest trying this sprue goo, can you give me any tips or best practices?

Edited June 26, 2023 by ctruss53

[MrMiles]

i tried both of the mr putty i could find, and hated both. its the first mr product i didnt like

[peteski]

Yes, a wide range putties have been covered here repeatedly.

Compiling info means doing research of already exacting knowledge/topics, then compiling the info into a single document.  Just saying  . . .

You will also run into examples where something what works well for one modeler, but does not work for another modeler.  One thing I would warn about is about using "sprue-goo".  It will likely come back and bite you after some time passes.

Edited June 26, 2023 by peteski

[Ace-Garageguy]

Everyone has opinions. I've done considerable testing.

If you really want a stable, tough-enough to withstand scribing new lines without flaking off, easy-to-sand filler with no shrinkage and excellent adhesion, I recommend West 105/205 epoxy, thickened with microballoon.

It's used as a lightweight filler on sport/experimental aircraft because of its superior performance.

EDIT: If you're in a big hurry, forget it. It takes 12 hours to cure to the point it can be sanded and scribed.

Below, I've used it over styrene inserts in the engine cover, to backdate the car to the non-supercharged configuration.

Finished...and it still looks like this 11 years later.

It's also tough enough to accept scribed lines, even very close together...without edge-flaking or breaking up...as shown on the Challenger roof extension below.

NO other filler, in my experience, will do this.

 

Edited June 26, 2023 by Ace-Garageguy

[ctruss53]

25 minutes ago, Ace-Garageguy said:

Everyone has opinions. I've done considerable testing.

If you really want a stable, tough enough to withstand scribing new lines without flaking off, easy to sand filler with no shrinkage and excellent adhesion, I recommend West 105/205 epoxy, thickened with microballoon.

It's used as a lightweight filler on sport/experimental aircraft because of its superior performance.

EDIT: If you're in a big hurry, forget it. It takes 12 hours to cure to the point it can be sanded and scribed.

Below, I've used it over styrene inserts in the engine cover, to backdate the car to the non-supercharged configuration.

Finished...and it still looks like this 11 years later.

It's also tough enough to accept scribed lines, even very close together...without edge-flaking or breaking up...as shown on the Challenger roof extension below.

NO other filler, in my experience, will do this.

 

Great info.  I have no problems waiting overnight for something to cure. My problem is those modeling puttys require 24 hours to cure, then require multiple coats because they shrink. Meaning a 24 hour cure takes 3 days.

I'll have to look up this stuff you suggested. What about smells? Is it really bad?

EDIT:  Oh man, they don't seem to sell those West products in anything smaller than a lifetime supply. haha

Edited June 26, 2023 by ctruss53

[Ace-Garageguy]

10 minutes ago, ctruss53 said:

Great info.  I have no problems waiting overnight for something to cure. My problem is those modeling puttys require 24 hours to cure, then require multiple coats because they shrink. Meaning a 24 hour cure takes 3 days.

I'll have to look up this stuff you suggested. What about smells? Is it really bad?

It hardly smells at all. Really.

And because it cures all the way through by polymerization, you can do thick fills. On a model, usually one fill is enough.

[D.Pack]

CA and talc. The only (for me) filler that works consistently. And with fresh glue, if open for a few month or so, the mix is weak when drying out.

Sprue goo is the worst! Constant air bubbles is panel lines. But it is great for blending fender to body.

Last month I had to remove it and replace with CA into the panel lines.

Also, do you use a Sharpie pen to check putty seams? The ink, or any other (paint?) will have to be removed if re-filling.

I discovered this after spending three weeks trying to fill in nascar roof flaps. Only three!?

[ctruss53]

17 minutes ago, D.Pack said:

CA and talc. The only (for me) filler that works consistently. And with fresh glue, if open for a few month or so, the mix is weak when drying out.

Sprue goo is the worst! Constant air bubbles is panel lines. But it is great for blending fender to body.

Last month I had to remove it and replace with CA into the panel lines.

Also, do you use a Sharpie pen to check putty seams? The ink, or any other (paint?) will have to be removed if re-filling.

I discovered this after spending three weeks trying to fill in nascar roof flaps. Only three!?

How can CA glue be any good for a filler? It cures so much harder than the plastic surrounding it. I have filled seams with CA before and it was a struggle to sand smooth. At least in my limited experience.

I had a feeling sprue goo had a limited effectiveness.

When I putty, I sand and shape after curing. Then I primer to check for smoothness. It it needs touchups, I sand off the primer in those areas before I reapply.

I really like what I am reading about that West product line. But I don't know if I want to commit to buying that much material.

[Ace-Garageguy]

12 minutes ago, ctruss53 said:

I really like what I am reading about that West product line. But I don't know if I want to commit to buying that much material.

Yes, it's a fair bit of money to commit to filler you may only use a small amount of...and you have to buy microballoon too (Aircraft Spruce is my supplier).

You can TRY Bob Smith 30-minute epoxy for a lot less money, and it's routinely filled with microballoon for lightweight filler on RC planes.

I have NOT tested it, however, and have no idea how well it will accept scribing.

https://bsi-inc.com/hobby/slow_cure.html

[Lunajammer]

1 hour ago, ctruss53 said:

If I continue with Bondo I'll have to take it out in my garage.

Yes, but if you buy it in the tubes and are only working with dabs (as opposed to opening a can) I find the smell is manageable. For quick and easy, it's my go-to.

[ctruss53]

10 minutes ago, Lunajammer said:

Yes, but if you buy it in the tubes and are only working with dabs (as opposed to opening a can) I find the smell is manageable. For quick and easy, it's my go-to.

That is the stuff I tried. Very smelly.

[ctruss53]

32 minutes ago, Ace-Garageguy said:

Yes, it's a fair bit of money to commit to filler you may only use a small amount of...and you have to buy microballoon too (Aircraft Spruce is my supplier).

You can TRY Bob Smith 30-minute epoxy for a lot less money, and it's routinely filled with microballoon for lightweight filler on RC planes.

I have NOT tested it, however, and have no idea how well it will accept scribing.

https://bsi-inc.com/hobby/slow_cure.html

This might be worth a try. I'll have to do some microballoon searches though.

 

[Ace-Garageguy]

3 minutes ago, ctruss53 said:

This might be worth a try. I'll have to do some microballoon searches though.

This is where I buy it. You might be able to get smaller quantities from an RC airplane supplier.

https://www.aircraftspruce.com/catalog/cmpages/bubbles.php

[ctruss53]

6 minutes ago, Ace-Garageguy said:

This is where I buy it. You might be able to get smaller quantities from an RC airplane supplier.

https://www.aircraftspruce.com/catalog/cmpages/bubbles.php

That is pretty affordable. Roughly how much volume is a poind of those microballoons. I mean is it like a cubic foot?

[ColonelKrypton]

CA and acrylic nail powder.

Paul Budzik, a dentist, promoted the use of CA with dental acrylic powder 

 

Acrylic dental powder is not easily available but common acrylic nail powder is easily sourced from sources like eBay or Amazon. 

I use medium CA and mix to a "whipped cream" texture.  Works for me.

cheers, Graham 

 

 

 

 

[Ace-Garageguy]

5 minutes ago, ctruss53 said:

That is pretty affordable. Roughly how much volume is a poind of those microballoons. I mean is it like a cubic foot?

Comes in a double-sealed bag, contents of the smallest one would occupy roughly a 6"X6"x6" cube.

And it doesn't take much at all to make the goo.

I usually mix on a gram scale to get repeatable performance, but that's really not necessary.

Edited June 26, 2023 by Ace-Garageguy
TYPO

[1972coronet]

I've watched just about every build by Mr. Lin  (he's a member here, though I've forgotten his username) on his YouTube channel. He employs some "black CA glue" as a filler ; check out his (fantastique) videos here : 

 

[ColonelKrypton]

2 hours ago, Ace-Garageguy said:

If you really want a stable, tough-enough to withstand scribing new lines without flaking off, easy-to-sand filler with no shrinkage and excellent adhesion, I recommend West 105/205 epoxy, thickened with microballoon.

West Systems has a large selection of fillers, each with it's own characteristics and application:

https://www.westsystem.com/product-categories/filler/   ** note: the westsystem web page is NOT HTTPS compliant and your browser may complain

an extensive user guide here:  https://www.westsystem.com/app/uploads/2022/10/User-Manual-2015.pdf

I have used West System epoxies and fillers for many years and it is a very good product.

As an alternative to the large and expensive sizes of West System products you might consider Zap Z-Poxy surfacing resin

https://robart.com/products/4-oz-118ml-z-poxy-finishing-resin  available in much smaller sizes 4oz and 8oz 

Micro balloons can be found at hobby stores which cater the RC airplane and boat crowd, for example:

https://www.horizonhobby.com/product/microballoons-filler--250cc/DLMBD15.html

Micro balloons can be either teeny tiny wee glass balloons usually white in colour or phenolic ( plastic ) usually a redish brown but there may also be other plastic types that I have not encountered.  The tiny balloons are very light weight and very small. Be careful, use at least a dust mask of some sort and mix carefully least you fill the air with particulate matter you do not want to breath in or be dusting off all work surfaces for a long time.

I have found the Z-poxy surfacing resin to be a better choice for mixing with a filler ( i.e. micro balloons ). It seems to cure to a harder consistency and is easier to sand.

cheers, Graham 

[Richard Bartrop]

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.

This figure is four and a half inches tall, and was sculpted almost entirely from Milliput, so the stuff supports some very fine detail.

I've tried JB Weld, and, while very strong, doesn't sculpt all that well.

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.  

[ColonelKrypton]

1 hour ago, Ace-Garageguy said:

You can TRY Bob Smith 30-minute epoxy for a lot less money, and it's routinely filled with microballoon for lightweight filler on RC planes.

I have NOT tested it, however, and have no idea how well it will accept scribing.

I would not recommend any of the 5 minute/ 10 minute/ 20 minute / 30 minute ( whatever ) quick cure epoxies. These all tend to be relatively flexible and softer when cured compared to other epoxies.

There are exceptions, for example JB Weld original and JB Weld quick cure both cure to a hard finish that can be cut, filed, sanded (etc) and come to think of it, I must stop at the local store later today and pick up some to try on current project as catalyzed Bondo just isn't doing it for me at the moment.

cheers, Graham 

 

[ColonelKrypton]

3 hours ago, ctruss53 said:

Then I watched some youtube videos and discovered 2 part epoxy putty. All the videos I watched used Tamiya. This Tamiya 2 part epoxy putty gives you 1-2 hours to work with it. It cures in 24 hours. You can build it up as thick as you need it. You can extend parts with it. This putty cures solid and it is strong. This sounded like it was just what I needed.

Well, I couldn't find anyone with Tamiya 2 part putty in the US. So the soonest I could get some was weeks out. So I found some 2 part epoxy putty from Green Stuff World that I was able to get in a couple days.

I followed the directions. This GSW putty never fully cured. And it didn't even stick to the plastic. It peeled right off. I might have done something wrong, but I am positive I followed directions.

I have always Green Stuff World epoxy putty to be a bit flexible and soft when cured.

The Tamiya epoxy putties cure to a much harder finish.

Some have found that they prefer to mix Green Stuff epoxy putty with Tamiya epoxy putty and get the best of both - something that cures hard but not quite as hard as Tamiya alone nor as flexible as Green Stuff alone. I have tried it but am not fully sold on it at the moment.

One of the issues I have with any of these epoxy putties ( and even catalyzed Bondo ) is that for thick applications on largish areas of styrene or areas subject to flexing, is that these putties to do not really bond that well to the styrene even when well prepared by sanding to leave a rough surface with some tooth for putties to bond to. Give the styrene a bit of flex and the putties will pop right off.

I have found however, and am still experimenting,  that if you first cover the area where you are applying the epoxy putting with a bit of CA ( I use a medium CA ) before applying the putty that the putty will bond much better to the styrene ( actually, the putty is bonding to the CA and CA is bonding to the styrene ). May not be the right choice for all applications but has worked for me when just applying the epoxy putty to bare styrene has not.

cheers, Graham

 

 

[ColonelKrypton]

Something for the more adventurous are UV cure resins.

UV cure resins are widely used in the beauty industry for making pretty finger nails. Also used by miniaturists https://www.theguardian.com/artanddesign/2021/apr/25/meet-the-miniaturist-whose-tiny-homes-are-a-delight to make tiny detail bits in molds and by those who make fishing lures ( and many other uses ).

I have on occasion been using a product sold under the name of Solarez  https://solarez.com/

They have resins which cure hard and in thin and thick viscosities as well as flexible types. 

You will find many varieties on Amazon aimed at the finger nail crowds.

They are typically clear but can be tinted. The challenge is that in order to cure, the resin needs to be exposed to UV light. An application of the resin on the surface of a piece can be cured through but an application on an inner surface cannot be exposed to UV light will not cure on it's own.  I have tried to use as a glue to fix pieces together but always run into that problem of not curing all the way through because of lack of UV exposure.

Once cured, the hard resins cut and sand easily and I have found bond nicely to styrene. I have used to fill gaps and have also used to make clear head light lenses. A drop on piece of parchment paper exposed to UV light will often cure to a nice head light lens shape or a drop in a simple shallow round hole might also work depending on your wants.

Not for everyone, not for every task, but some may find them useful.

cheers, Graham

[D.Pack]

A food dehydrator, is great for drying out putty's or goo if needed. And it really dries them out.

I had a painted bodyshell air-drying for a month, looked smooth, but then put into my newly bought dehydrator and goo/putty filler lines were suddenly visible. 

Also check out the VMS site and their CA fillers.  With CA/filler of any type, to sand smooth in 30 minutes is a bonus.

[yh70]

10 hours ago, ctruss53 said:

That is the stuff I tried. Very smelly.

you not suppose to sniff it Chad..lol.. i been using it many years and dont find it smelly at all.

[Dave Ambrose]

I've been using the Vallejo acrylic putty. I like that it's a bit softer than the plastic, so you don't get sanding shadows. That's my main filler. If I need to fill a gap finer than the acrylic will get into, I use Mr. Dissolved Putty. And, I use primer and a brush to fill scratches. 

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