Filling and sanding joins between parts of 7mm carriage kits...

Dog Star

Dog Star

Western Thunderer
... predominately the two parts of a Slater's coach side or the many parts of an Ian Kirk coach side, maybe even the parts of a Jig-Saw Bits resin kit.

So having built a carriage side from two or more "slices" of styrene mouldings there is a need to fill / sand the individual joints so as to achieve a smooth surface for painting. My preference for filler is Milliput white (for surface smoothness after sanding and minimal shrinkage on hardening) and 320 / 400 / 600 emery used wet for sanding - these choices are based upon filling sink holes in 7mm styrene wagon kits.

The carriage body that I am building is to be used as a master for resin casting so I do wish to achieve "joins" in the styrene master which are not visible after casting in resin. What do WTers think about my choice of filler and method of sanding the joins after filling?

thank you, Graham
 
Rob Pulham

Rob Pulham

Western Thunderer
Hi Graham,

I cant offer advice because on my only effort of this sort to date the joints are :shit: so I will be interested to see how you get on with this as mine will reappear on the bench at some point.....
 
G

graham thorp

Member
Hi Dog Star.

A great technique for styrene modelling is to dissolve chopped up lengths of sprue from the same kit into a suitable jar of liquid poly cement.

It may take overnight to do this but once you have a nice consistency, its perfect for filling. The great things is, because its made from the same grade plastic, once set, it sands at the same rate as the surrounding model so no unwanted divots and is the same colour.

I've seen it used on aircraft modelling and very effective.

Not sure how deep you gaps are though so that would be the only caveat :)

Best.

Graham
 
Dog Star

Dog Star

Western Thunderer
Although I have read, in modelling magasines since the late 1960s, about sprue in solvent as a filler that is an approach which neither I nor my modelling friends have got to work - so for this job I shall stick with tube / paste fillers. Humbrol filler as being softer than HIPS is worth thinking about - thanks Steph, I am concerned that Milliput might be on the hard / tough side compared to the soft nature of Slater's styrene hence sanding across a joint might become like "ridge and furrow".

Whilst I do not have any Humbrol filler there is some Squadron putty here. Squadron is another brand of filler which I find difficult to use, getting the paste to fill the joint without leaving a gap on hardening / falling out over time are concerns to me. How do other WTers get on with this product?

regards, Graham
 
Pugsley

Pugsley

Western Thunderer
I find correction fluid useful for the final finishing. Apply and gently sand off as required.

I now also use Holts knifing putty for filling - it's of the same consistency as model fillers, but you can buy a much bigger tube for the same amount of money.
 
Dog Star

Dog Star

Western Thunderer
Anyone care to comment on the filler "paint" from Vallejo?

I have looked at some U-tube vidoes on using the Vallejo product and several suggest avoiding sanding the joint after filling.
 
Steph Dale

Steph Dale

Western Thunderer
Nope. Not sure about its adhesion either. If you're preparing a pattern that's a consideration - hence mentioning a solvent-based filler, which I know sticks like the proverbial to a blanket...
 
john lewsey

john lewsey

Western Thunderer
Hi Graham which coach are you. Building
Ps I seem to have missed some phone calls from you I'll catch up
Regards
John
 
SimonT

SimonT

Western Thunderer
I won't use anything other than Squadron green, having tried sprue and Humbrol. I apply it with a chisel made from an old flat needle file.
 
Dog Star

Dog Star

Western Thunderer
john lewsey said:
Graham which coach are you building
Click to expand...
The K14 / K15 / K16 has surfaced from the bottom of the Shelf Queens pile and I am conscious that some of the joins are going to need attention. Why "K14 / K15 / K16"? Still not sure as to which diagram to do:- a K14 is the easiest as the ends are the same as those in Slater's kits; a K15 is an interesting diagram as the vehicle had a gangway connection... and I know of just two suitable photos; a K16 maybe the choice because this diagram was a K15 end without the gangway doors.... and I know of no photograph!

regards, Graham
 
Dog Star

Dog Star

Western Thunderer
So far the consensus seems to be Squadron over Humbrol. Whilst I am comfortable with Milliput white for filling sink holes and ejector pin marks I think that I shall make up a test joint with some of the left overs, from cutting sides earlier in the build, and then work with Squadron for some experience.
 
Heather Kay

Heather Kay

Western Thunderer
Don't forget, Graham, thin layers of Squadron. It relies on the chemicals evaporating to dry properly. If layers are too thick, it doesn't dry hard.

I find it best to fill, let it dry, sand, then assess if further filling might be required. It can sometimes take a few goes to get a really good smooth fill.
 
Dog Star

Dog Star

Western Thunderer
Dikitriki said:
... can I recommend Perfect Plastic Putty by Deluxe Materials?

Not necessarily as a primary filler - it's a bit soft to use - but as a 'top coat' filler it's great. very quick drying, reasonably hard (harder than Squadron) but nothing like as hard as Milliput, and it feathers well.
Click to expand...

The task in hand is to fill and sand the joints in the side so as to achieve a smooth surface to each panel... here is a link to a photo of one of the assembled sides. I am not sure what Richard means by "primary" filler, as the photo shows there are no gaps in the joins... rather the small variations in the thickness of the mouldings means that some of the joins have steps (which are detectable with a finger nail even if not obvious to the eye).

I am nervous that a different filler (to Milliput which is my preferred stuff) is going to give me troubles downstream especially as the finished body is going to be used as a pattern for resin casting. I have read the reports on Perfect Putty, link above and ponder in just how well a thin layer (say less than 5 thou thick) is going to "stick" to a styrene surface when feathered out across a joint.

Your thoughts please, Richard.

regards, Graham
 
Phill Dyson

Phill Dyson

Western Thunderer
I have always found Squadron Green & White very poor & use Milliput in most applications....although I have ordered some Holts Knifing Putty (thanks Pugsley)
 
Dikitriki

Dikitriki

Flying Squad
Dog Star said:
I am not sure what Richard means by "primary" filler, as the photo shows there are no gaps in the joins... rather the small variations in the thickness of the mouldings means that some of the joins have steps (which are detectable with a finger nail even if not obvious to the eye).

I am nervous that a different filler (to Milliput which is my preferred stuff) is going to give me troubles downstream especially as the finished body is going to be used as a pattern for resin casting. I have read the reports on Perfect Putty, link above and ponder in just how well a thin layer (say less than 5 thou thick) is going to "stick" to a styrene surface when feathered out across a joint.

Your thoughts please, Richard.

regards, Graham
Click to expand...

Hello Graham,

By 'primary filler', I meant if you had a hole or groove, then I would use another filler in preference initially. For a perfect top coat, I would then use PPP to cover any blemishes in the original fill.

If it is just a fine surface fill, I would use PPP immediately.

I think PPP would stick very well to styrene, but I would always say test it on scrap first. I have not used it for this application so can't really comment further. I have used it to repair Depron, and it feathers extremely well on this surface.

Richard
 
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