ciscovet

Hey guys,
when do you use microballoons w/ epoxy?

combatpigg

My Feedback: (3)

.......as seldom as possible. I'd much rather build up a fillet with balsa or high density foam, then fill the imperfections with a skim coat of a new formula BONDO that is easier to sand than the old formula.

There are times when you want a high viscosity mix of epoxy, like when inbedding aileron torque rod linkages, and micro ballons work well for that.

ciscovet

Well thats exactly what I want to do... I'm trying to attach an elevator joining wire.

aussiesteve

Ok
Lets see now I will answer your question and add a few other choices too

Microballoons are a filler that are used to add to resins to thicken them (thixotrope) whilst also giving them excellent sandability. There are 2 common types of microballons - Glass bubbles (usually white in color) and Phenolic bubbles (usually brown in color). Unless the glass beads are coated with a bonding agent, the Phenolic ones are the better choice for epoxies but even those should be coated. There is also a microballon that is made from "flyash" that are often sold as "ceramics" or as Pozzolanic spheres - these are often quite heavy. All types are generally made by quenching molten material after air blasting it - this forms the balls (yes - each particle of those powders is a hollow sphere).

Microfibers are a filler that is a thixotrope but alos gives some strength to the resin (much the same as Fibreglass mat is used to make a boat). These are made by milling fibreglass.

Fumed silica (Cabosil, Aerosil etc) is a Thixotrope that is added to give the resin a high viscosity and hold it in place whils the resin sets up It generally doesn't leave very good sanding properties. this product is what is used to make toothpaste a paste (otherwise it would be mostly peppermint oil). It is made by heating then "fuming" silica (sand) - often in the process of manufacturing a product used in the concrete industry. -it is a very fine particle of Silica dioxide that can find itself in parts of your body where you really dont want it to be - such as lungs, respiratory membranes etc.

Talc (powder) used to be used as a basic thixotrope that gave reasonable sanding and reasonable thixotropic properties. It is ground up chalk rock and can actually be quite nasty if very fine particles (especially smaller than 3 microns) find their way into your body.

Those products are what make up the powders etc in many of the epoxy systems on the market out there (such as west Systems) but can be very nasty to deal with. Companies that "premix" the compounds for us usually have very good controls and once the products are mixed into a resin, they are harder to ingest until the sanding stage.


As combatpigg stated - the best thing for gap filling is the original material, resin mixtures tend to be more heavy and generally don't have the tensile strength of the original material (some milled fiber formulations excepted).

qldviking
Long time no speak mate.
I agree with you, those can be some very nasty substances once ingested and keeping them at home uneccessarily is never a good idea - especially if there is a preblended alternative available sensibly. Being in Qld and in the industry, I guess you have come across the product I suggested.

Having said all that, this is a hobby so do what makes you happy -just be very caustious of some of the substances we use - they can be pretty toxic if not handled correctly.

My kids are in their late teens now but they survived me owning a Fibreglass supply, Resin blending, epoxy manufacturing and filler manufacturing business when they were young. They still don't listen to me but I could at least keep them away from the factory - some very nasty substances are used in that industry and nowadays I am paying the price for the exposure to them.

Oh to be half as smart as my toddler thought I was and only half as stupid as my teenager now thinks I am

Warbirdguy

Aussisteve: You went into specific detail and maybe I should have too, most on here dont have a clue as to what you said but alot do. Ive been in the f/g business pretty much all my life and Im 51 now. I agree with you about keeping dangerous stuff away from your kids. I have a shop building that is away from home to work on my models and that is where I keep ALL of my materials and liquids. ANY glue, or mixing materials should always be kept out or reach or locked away from small children. The one kid that got the milled glass in the face is unfortunate and I hate that. Makes me wonder how he was able to get to them at all in the first place. But accidents do happen so be carefull. I also agree with adding filler blocks with balsa or other materials and go easy on the actual epoxy cause epoxy is heavy I love this hobby and I didnt mean to tick anyone off about my suggestions on what I do as an individual. I was just stating that all the products are out there to make your own "thick" glue if you want to save some money and do it yourself. There are warnings on everything I mentioned that should be followed as with any dangerous thing you buy or use. Like I said before, a little comon sence goes a long way. Take it as for what you want. I feel like Ive made my point and if anyone wants any more information email me directly and I will help all I can. If your building 1 or 2 airplanes a year, then by all means buy the premixed stuff.

Have a great day.

WBG

Warbirdguy

Also, one more thing, about warranty. Yes, I have had bad resin and hardner before. I buy no less than a gallon at a time , and I buy alot. The supplier I use and the brand I use rarely ever has a problem. But the times I did have a problem It was replaced at no cost to me at all. Maybe whom ever you buy from gldviking does not have that good of a product or just dont care about his clients. But this issue is off topic and this will be my LAST post to this thread. All have a good day and remember, ITS JUST A HOBBY TO GET AWAY FROM REAL LIFE AND HAVE FUN.

wep0520

Has anyone tried the PC line of epoxy from home depot. Its a paste like Epo. How would or could u use these pasts with class cloth.