Super glue filler

Hello all, good afternoon.

I have read in the past of powder being mixed into superglue to act as a filler. I thought this was a potentially useful trick to know, but I've forgotten what the filler powder was. For some reason bicarbonate of soda comes to mind.

Does anyone know any better?

Thanks (as ever) in anticipation.

Simon

Yes, Sodium Bicarbonate or "baking powder" is correct. You put the powder in the hole to be filled first, then drip the glue on. The thin version works best. It will fume copiously for a few seconds though.

You can also use "micro balloons" used for thickening epoxy resin into a paste.

aka ballotini? The product I am thinking of is also used to ensure a micro gap between mating faces.

ballotini are glass beads, micro balloons are hollow phenolic resin balls

I use a similar method on my woodturning to fill voids I tend to put the glue into the void first then push in the filler clean out any loose and then repeat. The reason for this is that some filling mediums will just allow the glue to sit on top and not soak in so all you get is the top set and the inside still in a powder form.

If you want to do this on metal for cosmetic reasons there is available Copper, Brass and Ali powder available which is very fine

https://www.oliverswoodturning.co.uk/product-category/wood-finishes/powdered-fillers/

Edited By Derek Lane 2 on 25/01/2019 14:33:13

Microballoons is a fairly broad term and not exclusively phenolic resin. Most of the ones you encounter used for balsa aircraft (because of their inherent lightness) are usually white. https://www.christinedemerchant.com/filler-micro-balloons.html

As Chris says, Microballoons is a broad term - The phenolic micro-beads do well with most superglues, although the chemical reaction can be very fast and cause the mix to bulge and splurge about - the outer surface tends to film over while the inner remains liquid longer and when the reaction sets in the heat and subsequent outgassing is trapped and makes the mess take on strange shapes and not stay in the intended place - Bicarb can do the same, by the way. The effect is increased when using thin glues.

Glass microballoons are better behaved, but the cure rate in all cases is relatively uncontrolled..

If your application requires strength as though it were just superglue, the joint is much weaker with any of the above fillers - also if there is any flexing, the filler cracks easily. I build carbon fibre UAV's, and hate superglue for anything structural! Do you need fast setting bonds? If not, use epoxy resin with Cab-O-Sil, a thixotropic agent, and you get a strong filler/bond result.

Joe

All very interesting.

Am I right in thinking that these fillers are also accelerators? I thought bicarb was and that this was its main use (apart from domestic uses).

I use Supa Fix which comes as two bottles of CA plus a bottle each of grey and black calcium oxide (lime) powder. Don't get it in your eyes!

It works exceptionally well.

Neil

<edit> it is definitely an accelerator.

Edited By Neil Wyatt on 25/01/2019 18:27:24

Bicarb seems to be used as an accelerator in the absence of the real McKoy, but all superglues start the cure process in the presence of water ( or rather, Hydroxil Ions). So any moisture sets them off. The control of the cure when using bicarb is a bit of a hit and miss affair, depending on its moisture content. There are spray accelerators that work very well and the rate of cure can be controlled to some extent by the amount you spray. Micro balloons and Cab-O-Sil are not accelerators, but if they have absorbed any moisture they will set the glue off.

Bicarb tends to work as an accelerator since commercial Bicarb has a starch ( normally corn or potato starch) added which absorbs moisture to prolong the efficacy of the powder in storage. It is the moisture in the starch that triggers the cure.

As I said before, any of the fillers that are powder based as opposed to fibre based have little strength in shear, and any flexing will crack the filler. Most superglues also cure to a glass hard bond, which cracks if flexed. Loctite Ultra-Gel is a flexible superglue that is rubber infused and remains very flexible, but is a thick gel prior to curing and does not flow well. There is also a 'Gorilla glue' that claims to be more flexible than normal superglues - I disagree...

Since you have not explained the intended application ( other than filling a gap..) I cannot comment on the suitability or otherwise of any of the aforementioned products..

Joe

I am an aeromodeller and have used cyano for years.

Bicarb is OK but it is difficult to sand.

I prefer to use micro balloons for gap filling as others have said fill the gap then drip on a little cyano. My micro balloons are from West System.

West System also supply a product called wood fibres that seems to grip better than balloons.

Working with wood I often sand to fill the gap and add cyano.

It was many years ago but I’m pretty sure the hollow glass spheres were sold to me as micro balloons.

Agreed,not to be confused with bead blasting glass spheres which are somewhat more heavy duty.

I seem to remember they used to make something called Syntactic foam with glass microballoons years ago to form a very tough but lightweight filler. I’ve probably still got a small pot of them somewhere.

Wow!

It's always incredible to tap the depth of expertise latent in the forum, and this is a case in point. Thank you everyone for your knowledge, and also the generosity of sharing it.

Joseph asked en passant what the application was - when I posed the question I hadn't any idea that there would be so many possibilities, so the idea that the application would affect the recipe was something I hadn't envisaged.

There are several applications where I have used superglue as a fix for something that is broken, and there is a bit missing or a minor gap to fill. Oft times this has been the rear light lens on something agricultural or something of that ilk.

This week I have been rebuilding a poorly chainsaw, and wanted to repair several cracks in a complicated plastic baffle directing the cooling air around the internals. I could buy a spare part, but the project has cost more than the saw is worth already, and the point of the project was to do the job with as many reclaimed or non original spares as I could. And before someone starts lecturing me on the safety consequences of grey market parts yes I know, I know. Suffice it to say I am choosy what risks I take.

I got the original idea of filler - and I'm guessing this is where I got the bicarb recollection - from a YouTube video of someone repairing guitar frets this way. I hadn't given enough thought to the issues of flexibility - so I need to work on that aspect.

So many thanks to all those who have taken part - if there are other ideas do please carry on - and my best rgds to all.

Simon

Small hollow glass microbeads used to be recovered from the flyash of coal-fired powerstations. They were known and markerted under the name Armospheres. In the match industry they were used as a way to control the density of the match composition applied to the end of the match stick. I guess with the demise of coal fired power stations they are less available than they used to be.

Mike

Think I will try the Sodium Bicarbonate Thanks for the tip