discussion capillary action?

[Guest]

I was watcgung a video on an alternative forum. The chap there held two fuselage halves together and brushed Tamiya extra thin liquid cement onto the seam. He sad that the glue would soak in through capllary action. I've never seen this before. I have two questions please. Surely this will cause a very tricky problem in that the surface if the model, where the join was, will have a load of dried cement which will have to be sanded off. Isn't this best avoided? And secondly will Humbrol liquid cement work as well as Tamiya extra thin?

Thanks

Aidan

 

[Guest]

Can only add my experience of this way of bonding, if Im doing a fuselage, I use the capillary action, and then I apply a little pressure to squeeze the glue out of the seam to form little beads, when this has set, I sand down, and it removes the seam line, not a fan of Humbrol cement,and as I dont use it, cant really comment, but must admit I love the Tamiya extra thin and also getting very good results from Mr Cement.

 

[Guest]

Capillary action is the effect of liquid moving without external pressure or force. It's caused through surface tension & is often seen in modelling when doing a pin wash.

Personally I'd doubt the Humbrol stuff is thin enough to work this way.

Patrick

 

[Guest]

Morning Aidan

Look at this on John's Shop. model supplies, model making supplies, model making tools, uk cheap

This does the same thing as the Tamiya Thin Cement. Tried both. If you want Tamiya only Hong Kong will supply although some body did say it was available in the UK at one outlet. Suprising as their is an EU ban. Look on Ebay for Tamiya. Same goes for Tamiya liquid filler.

I started using the Tamiya a couple of models ago. Great thing is you can line up the parts strap them together then apply the Tamiya. I tack between the strapping on large parts remove the strapping after setting & then finish with the Tamiya.

Depends on what you want ie a protrusion of plastic by squeezing or to just let it drift in & leave. Any gap or seam then filled with Tamiya liquid filler. If you just let it drift in without squeezing I find that there is hardly any disturbance to the plastic surface. Fors & against just preference.

If you go to Flory Models he has a video on using the above latter method ie I learnt from Flory.

Laurie

 

[stona]

Like Ray I apply the cement to the seam and let it move along and into the seam by capillary action. I do then give the parts a gentle squeeze after a few seconds. The "ooze" described by Ray is easily removeable once it has dried and it is this "molten" plastic that fills the seam. If you get it right no further treatment of the seam will be required,the join will be invisible.

I always try to apply the glue from the inside if possible. When this is not an option I use a fine brush to apply the glue,not the rather chunky monkey that comes in the cap of the Tamiya Extra Thin. There are several types of applicator available,the object is not to get the glue on the plastic surrounding the seam.

I put a drop of black enamel paint into the pot of glue. It tints it grey and makes it easier to see how far along the seam it has run. It doesn't seem to have any adverse effect on the glue!

Here's my current pot. It looks worse than it is.

Cheers

Steve

 

[BarryW]

I use Mr Cement S and find it excellent for this. I would be a bit careful with the welds though, they are very good but are more 'aggressive' in melting the plastic and need to be used with more care. The Mr Cement S barely marks the surface as it quickly evaporates, like the Tamiya.

 

[Guest]

Not sure if the Tamiya glue is possible to get in the UK, but you can get it here Scale Models - Super-Hobby - Model shop, Plastic Models but the postage makes it expensive glue !

 

[Guest]

I think I will try the Plast-I-weld from John's shop that Laurie mentions above. I assume you're happy with it Laurie?

 

[Guest]

Thanks to all for our replies. I am still unclear about one thing. The glue works by melting tne plastic. Whilst I appreciate how capillary action works, surely, as tne brush is wider than the gap between two fuselage halves, some glue will lie on the top surface and melt it, thus creating work of sanding and filling?

Aidan

 

[Guest]

Mark I have used Plasti Weld and have not found any discernible difference. Also if you look at Albion Alloys in the shop they do a number of ways of applying the glue. Not really a glue or adhesive as normally thought of as it just melts the plastic & then disappears

Aidan also use the Tamiya for convenience as it has the brush which is convenient. Just experimented & joined to pieces together. I twice pulled the brush down the joint overlapping the joint well for experiment & inspected after 5 minutes. Actually I usually only use a single stroke as you hardly need any Tamiya to make the joint (for the passive method anyway). No tackyness whatsoever & no discernible deterioration of the plastic (when I looked through the magnifier) where the Tamiya had over lapped. Any slight deterioration that I have found at times where I have been over zealous with Tamiya the use of a very light rub with 1500 wet & dry removes all

Like you I worried about this when I first used this technique. But I have found it remarkable. May say that I use the passive method & not the squash together method. Not a criticism just use the one that suits you. Best thing is to try both methods & see Aidan. One thing once used I would be surprised if you returned to Humbrol or similar others.

Laurie

PS The Tamiya evaporates so quickly on the surface while when in the joint it's evaporation rate is limited. I think !

 

[Guest]

Brilliant. Thanks Laurie.

Aidan

 

[stona]

I don't apply the glue all the way along the outside of the seam. I touch the applicator to the seam,the glue will run a couple of centimetres or so along the join. I leave this a few seconds before pressing the two halves together,clamping or taping if neccessary. I then make another application at the next unglued section and repeat the process working my way along the seam. With care you won't get glue outside the joint but beware that it will cappillate along the edge of tape and along engraved detail.

If any glue gets where you don't want it you must leave it alone! Once dry any damage can usually be sanded and polished out with fine sandpaper (I use 1500 grit to start) followed by something like micromesh if needed.

As usual there is no right or wrong way of doing this.You can see that my method and for example Laurie's are variations on a theme. There are,as I've said before,many ways of skinning a cat. I suggest experimenting on something like an uneeded drop tank to see what works best for you.

Whatever you decide works it is definitely a better and cleaner method than smearing those awful gels on the plastic before positioning the two halves!

Cheers

Steve

 

[Swagman 070]

Hi Aidan, I recently tried Revell Contacta liquid. Not a bad substitute.

Steve

 

[Guest]

Resurrecting an old thread. Finally, after all these months, I got hold of a bottle of Tamiya Extra Thin Cement. I'm mildy athsmtic. I opened theottle to look at the width of the brush and put the top back on. Must have taken all of ten seconds. I'm gasping for breath! My word it's powerful stuff. I'll have to use it while wearing a world war two gas mask and sitting in an open field!!!!

Wheeze wheeze

Aidan

 

[Guest]

The Plastic-Weld also gives off high fumes so becareful if you get some of that stuff too.

 

[Guest]

Got bottles of all three.

In this order of "smell".

Tamiya real yucks pear drops. Mr Cement S not so bad & Plastiweld the least stinky.

In use I found Cement S the best Tamiya next & Plastiweld last. Mr Cement goes off the quickest & causes the least damage. Tamiya causes damage if it gets away but gives chance for slight readjustment.

Plastiweld I found was a poor third. Slower leaves the most damage if it gets away from the required path. But definetly the least smelly.

Laurie

 

[Adrian "Marvel" Reynolds]

The Plastic-Weld also gives off high fumes so becareful if you get some of that stuff too.

I just got hold of some of this and just a really stupid question, but can I use an old brush to apply it, and if so is it right the brush will go soft everytime I re-dip it in the bottle?

 

[Guest]

yeah, it does soften up when you dip it in the bottle

 

[stona]

Indeed.

I was using an old paint brush for my Mr Hobby cement which comes with a brush more suitable for painting window frames than model making! I then realised the old brush from a bottle of Tamiya Extra Thin,which is a more sensible size,could be swapped into the Mr Hobby top! Definitley a "Doh!" moment.

Steve

 

[Guest]

I use Humbrol liquid poly .. this is probably the cheapest mentioned here but it works perfectly and with a manageable aroma similar to acetate (nail polish remover) i have to be careful around vapour etc as a bad bronchial infection earlier this year popped a load of bullous in my lungs and accellerated my emphysema issue.