Liquid plastic

[Ahajmano]

Got a tip from my local hobby shop, and it works great! Once you are about half-way done with your Tamiya styrene cement, cut up a bunch of white styrene sprue. Throw the little pieces into your glue bottle and wait overnight. The plastic will resolve into the cement. Keep adding sprue until you get the desired consistency and viscosity. I use this to fill cracks now and also glue pieces that lack surface area (it will fill corners like a filet or radius). Works great! 

[Mark]

It will shrink as the cement evaporates.  I have used it, it can be useful provided you know, and work within, its limitations though.

[afx]

Any liquid cement will work, I prefer Plast-I-Weld.  If the plastic solidifies just add a little more liquid and it will soften up again and become workable

[RAT-T]

BEEN USING IT FOR YEARS, I USE TO USE AMBROID, BUT SINCE THAT'S NO MORE, I USE THE WELD ON 3 (I THINK) ITS IN THE PLUMBING DEPT AT LOEWS OR HD

[djflyer]

14 minutes ago, afx said:

Any liquid cement will work, I prefer Plast-I-Weld.  If the plastic solidifies just add a little more liquid and it will soften up again and become workable

I have heard of this but never tried it.  Have you had any issues with shrinking or cracks over time?  Do you use this instead of other fillers in certain situations only or most all of the time?

 

[afx]

5 hours ago, djflyer said:

I have heard of this but never tried it.  Have you had any issues with shrinking or cracks over time?  Do you use this instead of other fillers in certain situations only or most all of the time?

 

I haven't had any issues with shrinking or cracking.  I like to use it mostly to reinforce joints similar to a welder would use weld. I use it to reinforce joints when I make a roll cage or I will brush it on the backside of a joint that has very little contact surface.  I also like to use it to build up edges, for instance if I need to change the shape of a wheel opening.  I let it dry overnight then I can sand it just like virgin plastic.

I built up the edge of this air dam (the white plastic) then sanded it to shape after it setup.

[Ahajmano]

I have been using it the same way as the previous poster. Of course it shrinks, but so does any other filler I’m aware of. It least it is self leveling. The other fillers”cake” on and don’t conform to surfaces without adding an excessive amount. Just my oppinion. 

[peteski]

1 hour ago, Ahajmano said:

I have been using it the same way as the previous poster. Of course it shrinks, but so does any other filler I’m aware of. It least it is self leveling. The other fillers”cake” on and don’t conform to surfaces without adding an excessive amount. Just my oppinion. 

The 2-part (catalyst and resin) fillers do not shrink appreciably, and neither does CA glue when used as a filler.

I'm not a fan of "liquid plastic" mentioned here, especially applied fairly thick.  While the solvent will evaporate from the surfaces, it can stay trapped in the center of the "filler" for quite some time. It might even soften the plastic part it is applied to. It might take weeks or months in some instances.  But different modelers use different techniques. Whatever works for you . . .

[Ahajmano]

Havebyou had good experiences sanding CA glue? I have not. 

[peteski]

7 minutes ago, Ahajmano said:

Havebyou had good experiences sanding CA glue? I have not. 

If applied to a clean plastic surface and sanded within few hours of setting up, it sands well. But if you wait a day or two, it is not so good (it sets harder then styrene).  Of course I assume that you use accelerator to set the glue (I use the BSI brand accelerator).

[Tommy124]

I have used this technique occasionally. IMHO the downside is that styrene/glue mix is likely to contain small bubbles which may appear no sooner than after sanding, making it necessary to fill and sand again.

However, as we know that the application of glue helps to prevent ghostlines, this is a good way to go for filling panels lines etc. I did it on my Porsche in order to fill the sunroof lines and it worked well:

5 hours ago, peteski said:

If applied to a clean plastic surface and sanded within few hours of setting up, it sands well. But if you wait a day or two, it is not so good (it sets harder then styrene).  Of course I assume that you use accelerator to set the glue (I use the BSI brand accelerator).

Yes, the CA is much harder than styrene once it's dried. That's why it's important to apply a CA layer as thinly as possible. See Dann's tutorial here: 

And as (almost) ever, Tamiya have a product solution to this: 

https://www.tamiya.com/english/products/87187/index.htm

This is a "softer" type of CA, designed especially to be easily sanded...

 

Edited April 3, 2019 by Tommy124

[afx]

No, liquid plastic is not a cure all filler just another tool in the tool box. 

[Foxer]

46 minutes ago, afx said:

No, liquid plastic is not a cure all filler just another tool in the tool box. 

Yeah, I used to use this as a quick, cheap filler (and casting medium) for small parts and holes. But, it has been replaced with shrink free, even quicker, Bondic light cured plastic.

[Ahajmano]

9 hours ago, Tommy124 said:

I have used this technique occasionally. IMHO the downside is that styrene/glue mix is likely to contain small bubbles which may appear no sooner than after sanding, making it necessary to fill and sand again.

However, as we know that the application of glue helps to prevent ghostlines, this is a good way to go for filling panels lines etc. I did it on my Porsche in order to fill the sunroof lines and it worked well:

Yes, the CA is much harder than styrene once it's dried. That's why it's important to apply a CA layer as thinly as possible. See Dann's tutorial here: 

And as (almost) ever, Tamiya have a product solution to this: 

https://www.tamiya.com/english/products/87187/index.htm

This is a "softer" type of CA, designed especially to be easily sanded...

 

Phenomenal work on that Porsche paint job 

[#1 model citizen]

On 4/2/2019 at 10:32 PM, Ahajmano said:

Havebyou had good experiences sanding CA glue? I have not. 

I generally have had good luck sanding CA. However I have had some issues on a current project. I have what looks like strings after sanding. (Somewhat like fiberglass that was not completely saturated with resin) I have tried pulling he "strings" with tweezers but ended up pulling up a chunk of the CA patch. (The CA was used to fill a seam) This was a project that had been on hold so the CA had been applied several months previous. Don't know if that has caused a long term issue, although I doubt it...

[BigTallDad]

On 4/2/2019 at 1:25 PM, afx said:

Any liquid cement will work, I prefer Plast-I-Weld.  If the plastic solidifies just add a little more liquid and it will soften up again and become workable

Out of idle curiosity, why are you buying styrene for this purpose instead of using left-over sprue?

[afx]

8 hours ago, BigTallDad said:

Out of idle curiosity, why are you buying styrene for this purpose instead of using left-over sprue?

The photo was from a previous thread showing what I used to build a roll cage.  The styrene rod is for scratch building.  I do use bits of scrap for my liquid plastic mixture.

[Oldmopars]

BTW, for those of you tired of spending the money on expensive solvent glue, I have been using MEK and it works great. I have even mixed it like above and it gives it some body if needed. Main ingredient in solvent glue is MEK, so it works just like any other. I saved an old Plastructs bottle with brush and just refill from my quart can. $7 for a quart is way cheaper than the $5 or so for the little bottles. 

I have used the old sprue and MEK to fill, weld, and even make small parts. Works good.

**PSA** MEK is hazardous, use appropriate PPE when using. That is all.