Parts fitting on some Airfix models

[Dave C]

I do wonder if its my lack of skill.

On some recent Airfix builds, I have found that that a lot of filing/fettling/sanding has been necessary to get parts to fit accurately

Blenheim & Gladiator - assembling cowlings around Mercury engines without a visible joint

Spitfire PR X1X and 22 - accurately fitting wing to fuselage without a visible gap

Blenheim and Beaufort  - assembling fuselage halves  around cockpit interior.

I'd welcome any advise, thanks

[alt-92]

Dry fit, dry fit, dry fit. 

Sounds stupid, but especially with the Spits, you run the risk of squeezing the fuselage too much resulting in larger gaps.

So a test fit of just the halves, bottom and top wing will indicate whether there are major issues or not.

 

And yes, the radials & cowlings need fettling to get a good clean fit - but that is usually a couple of swipes with a sanding stick to get the burrs off of the cylinder heads.

[Armchair]

I had the same issues of poor fit on a 1/48 Meteor kit.

 

Bryan

[tomprobert]

I’ve built a few of the latest new tool Airfix kits and tolerances are very tight indeed. Once glue/paint are added it can throw the fit out. I’ve just done the B-17 and Vulcan and am currently building the 1/24 Hellcat. Before I glue or paint I go over the mating surfaces with a sanding stick and it’s meant all three kits have fitted perfectly - even tiny mould lines can be problematic. And as others have said, dry fit… dry fit… dry fit.  
 

Tom

[PatG]

Built the Airfix Zero and the fit was generally very good, the only minor issues was with where the rear section of the wing mates with the fuselage which is common on many kits from various makers as this always a bit tricky.

 

Dry fitting is a must as any slight bur or flash can be removed, plus I always remove the locating pins on fuselages and gently rub both sides on a flat piece of fine glass sand paper/emery paper.

 

If you do need filler then I can recommend using Milliput fine white as any excess can be easily removed with a damp cloth leaving it just where you want/need it to be.

 

Pat.

[ckw]

8 minutes ago, PatG said:

 

If you do need filler then I can recommend using Milliput fine white

Milliput is great, but be aware that if rescribing is required it has a tendency to crumble at the edges of the scribe.

 

And yes, ironically, the precision design of the Airfix new tool (and some other companies) can make part fit a challenge - there is very little tolerance. The slightest misalignment or surplus paint/glue at step 1 can lead to problems at step 17. I find one of the biggest risks is being overly aggressive when clamping of parts as this can cause minor, often undetectable changes to the profile. Remember that polystyrene glue melts plastic, so squeezing two drying parts together too tightly can change the profile from the design.

 

Cheers

 

Colin

[Graham Boak]

I always dry fit, and am very experienced in filing and trimming to get cockpit interiors to fit inside fuselages, but it still took me ages to get the Blenheim rear fuselage to fit into the centre-section.  Much more than the fiddling to get the cowlings on, but I've still not got a happy result with the front fuselage.   The less said about the bomb bay the better.

 

I don't agree that it is simply a matter of precision - there are other companies where the parts fit together so well it is difficult to distinguish the join from a fine panel line.  Airfix - on some subjects - appear to have had a problem with manufacturing tolerances.  They also appear to have gone through a stage of trying an adventurous approach to breakdown and assembly: good for them when it worked.  I don't think that it did on the Blenheim.

 

The PR.XIX is from the early stages of the revival, when they were perhaps more noted for inaccuracies than over-sensitive fits.  I didn't have the XIX, but it's sister the Mk.IX gave me no problems.  The Mk.22 was equally no problem, nor does it seem to have drawn any comment on that side of things.  However, it does seem that fit appears surprisingly variable: many people make these kits without comment whereas other examples are just plain awful.

[Troy Smith]

3 hours ago, Dave C said:

Spitfire PR X1X and 22 - accurately fitting wing to fuselage without a visible gap

Try fitting upper wing to fuselage halves, you may need some plastic card  to reinforce, and then fit lower wing. 

 

 

I added some detail and boxing in as well.   

 

It well worth thinking about the overall build early on, dry run anf adjust the main parts  including test fitting canopies. 

 

HTH

 

[PatG]

Each to their own as there is no 'right' way.

 

If some want to go to the 'nth' degree then fine, but equally if another wants a kit that is fairly straightforward to assemble and looks like the subject in question then that is fine too, after all both need a decent kit to start with.

 

Pat.

 

Ps. as Colin says the white Milliput is not great if you need to scribe any details into it as it does crumble around the edges but for filling gaps/holes it works a treat and is easy to apply and remove, especially when working in small or confined areas such as wing/fuselage joints

Edited October 12, 2023 by PatG

[PatG]

Just to add that the type/brand of glue you use is also important and I suspect we all have our own favourites.

 

For me when joining fuselage halves and joints that will be visible I prefer Slaters Mek Pak as it runs into the joints very well indeed without running on to the outer surfaces and damaging them. There again my eyesight and hands are not as precise as they used to be so others such as the Tamiya liquid cements are also pretty good too.

 

Pat.

Edited October 12, 2023 by PatG

[Mark Harmsworth]

My earlier remark meant as joke. 

 

No offence intended.

Mark

 

[noelh]

I think perhaps it's a combination of issues. Many of the newer Airfix kits have very tight tolerances, which is good. Today I was assembling 😗😃 a kit which is well regarded. It went together nicely after I very carefully removed paint from the mating surfaces. Yet a review complained of poor fit in some areas which I simply did not experience. 

 

I  wonder sometimes if there's a variation within Airfix kits? A bit of warpage?

 

I too am a fan of white milliput. The ability to wipe away the excess before it sets is great. It doesn't attack the plastic either. I was a fan of mek pac too but Tamiya extra thin is my favourite now. 

 

But to get back to the point. I think there is quite a lot of variability with Airfix kits. Some almost fall together. Others seem to fight the builder. 

 

That's the way it is.

Edited October 12, 2023 by noelh

[IanC]

7 hours ago, Dave C said:

I do wonder if its my lack of skill.

On some recent Airfix builds, I have found that that a lot of filing/fettling/sanding has been necessary to get parts to fit accurately

Blenheim & Gladiator - assembling cowlings around Mercury engines without a visible joint

Spitfire PR X1X and 22 - accurately fitting wing to fuselage without a visible gap

Blenheim and Beaufort  - assembling fuselage halves  around cockpit interior.

I'd welcome any advise, thanks

 

I would steer clear of the Me 262, which has problems with the wing/engine nacelles. I also had major problems with the Blenheim.

 

Most of the others have been fine, and build into very nice models, although I've found that none are quite as refined or as easy to assemble as some other manufacturers' products. 

[PatG]

When it comes to the quality/ease of fit then in my experience Tamiya take some beating as they go together with a minimum of fuss and are not over engineered,  unlike Eduard kits which themselves can have fit issues such as the cowling ring on their 72nd scale Hellcats.

 

Hasegawa kits also fit together nicely but at their UK prices you would expect nothing less!

 

Pat.

[Troy Smith]

4 hours ago, noelh said:

I  wonder sometimes if there's a variation within Airfix kits? A bit of warpage?

Yes, indifferent quality control again in India is a factor, we have have the short shorts, but the plastic can vary as well, even over a batch.

 

I had the pleasure of an impromptu lecture on the art of injection moulding plastic by the owner of Plastech in Newhaven, who are the UK firm who does some Airfix kits.

It was a  fascinating insight into the process, which seems to be both and art and a science, and also including the effect of plastic mixes can have.  

Quote " the mix we used in the 1/24th Airfix Spitfire was something from 1995, but gave the characteristics we wanted"

He was passionate and proud about getting a quality product, its not just a job.   And Plastech now have a model shop at the front of their unit, Modelworx.

 

This plastic mix, and getting it right, can, and does vary, and is a factor the way in some Airfix kits the plastic can tear, being both rubbery and weak, and having layers, which can delaminate.  

So, this can affect how will assemble.   

10 hours ago, Graham Boak said:

Airfix - on some subjects - appear to have had a problem with manufacturing tolerances.  They also appear to have gone through a stage of trying an adventurous approach to breakdown and assembly: good for them when it worked. 

Some maybe due to factors above,  design spec being let down by poor quality control.  Not really awful, but just a bit underwhelming as a result.

 

[Graham Boak]

@Mark Harmsworth @alt-82  Sorry for making myself unclear.  The point I wished to make was that it didn't matter what kind of modeller you were, you didn't need badly fitting parts.

 

@Troy Smith   Sometimes just a bit underwhelming, but sometimes awful.  On my Hurricane I, if you aligned the upper and lower wing profiles, the ailerons and gun positions didn't align.  Also the fuselage didn't fit into the assembled wings.  If you aligned the ailerons, the upper wing overlapped the lower by a fair amount, but the fuselage fitted fine.  I ended up aligning the ailerons, and then filing down the wingtip, leading and trailing edges.  To me, that's "awful".  I noticed some people ended up having to put work into thinning down the inner parts of the cockpit to make the fuselage thinner and so fit into the wings: I wonder if they ever compared top and bottom of the wings.  After all, regardless of the quality control, you can't get that much variation on the same parts.

 

On the other hand, I've never had this plastic some people find so terrible.  If it is a bit softer, so what?  A minor variation which doesn't affect the assembly.  Better than plastic so hard/brittle it is difficult to work.  But I've not had delamination, thankfully.

[Giorgio N]

15 hours ago, PatG said:

When it comes to the quality/ease of fit then in my experience Tamiya take some beating as they go together with a minimum of fuss and are not over engineered,  unlike Eduard kits which themselves can have fit issues such as the cowling ring on their 72nd scale Hellcats.

 

Hasegawa kits also fit together nicely but at their UK prices you would expect nothing less!

 

Pat.

 

 I personally believe it's hard to beat Tamiya's approach to the design and manufacturing of kits when it comes to ease of construction. They are the best at designing the easiest solutions and implementing them with the kind of quality in the moulds and plastic to guarantee a stress-free build to modellers of every skill level.

Not that others have not been able to do it, but Tamiya do it consistently. Even Hasegawa kits, that are generally also excellent, can have tricky spots, Tamiya's rarely do.

 

[Julien]

On 12/10/2023 at 13:22, Armchair said:

I had the same issues of poor fit on a 1/48 Meteor kit.

 

Bryan

Which is quite surprising as mine went together like a dream