How make fillers mixing much easier?

I'm in my first boat building project and I'm just begining with fillers in Epoxy.

I mix in a roller tray with a small trowel. I lost my time in mixing particulary with colloidal silica.

What do you suggest to me for easier mixing ?

 

If you use it for bonding get premade adhesive with the filler mixed in at the factory.

 

I use it for bonding, fairing and fillet with differents viscosity

 

mixing fillers

Use a deep can then pour in the tray.
Marco

 

In case you have to mix your epoxy for making fillets etc. you are using the wrong type.
Because if you mix, the potlife of your epoxy shortens considerably. Yoy better not use silica, they do not improve your fillets and they are more dificult to sand.
Use fibers or microballoons instead, or use a specific type of epoxy that does not run and that remains applicable for general use as glue and fillet. This is a type with a high viscosity.
It depends of course of the brands you have available in your environment.

 

Mixing in fillers is no big deal.

You need to get some clear, plastic, straigh side cups from the grocery store. Make a master cup. Measure one part (using water). Then add this to the Master cup until you have added as many parts or resin required by your epoxy. [(2:1) add 2 parts of water] Make a felt marker mark on the side of the cup. Then add one more part of water to make the 1 part needed for the hardner. Make another mark.

Then lower the marks the same distance on the master cup. Slide another cup on the outside of it. Then marks can be traced on to the outside cup. Test to see that the quantities are transfered correctly.

This will give you an excellent way to mix small amounts of epoxy and have enough space to stir in the silica or filler. I use wood sticks bought by the thousand for $10.

For bigger amounts there are plastic tubs available. I never mix more than 1 liter at a time. Even when I glassed the inside half a 14 meter cat hull.

The biggest thing to get over is the cost of each pot your mixing. You'll get used to working with the time constraints quickly.

 

Today, I made many batch of epoxy with fillers. I need differents viscosity.

I tried to mix Epoxy in a plastic can for car painting and that work well.

Micro-balloon alone is hard to mix. Colloidale silica alone is hard to mix. Wood floor alone is midrange to mix.

I found that it is really easy to mix epoxy with all fillers together in the same shot.

 

Colloidal silica is mixable. Just add a small amount and push it into the epoxy. Do not stir it until some of it has been mixed in. Also, mix slowly until it starts to take.

Chopped fiber are the easiest to mix.

 

I use an old worn out drill with a paint mixing paddle. Do not use the drill at full speed
(need an old verable speed drill). If the speed is to fast you will get air bubbles in the mix. For overhead glueing we use a consistancy of (almost) peanut butter maybe more like mayo) side glueing more like a thick (cold day) molasses.
Good luck
Ben

 

Fillers

Don't use microballoons for bonding. They are non-structural and best left fairing and smooth and maybe for cosmetic fillets. I'd stick with codiodal silica where added strength is desired and wood flour just about anywhere else. Wood flour is cheap and I know you can get it in maple (dark brown) and pine (medium brown). You can mix the two to get a specific color if that area of the boat will be visible. The maple is the finer of the two.

If you're filleting and taping, the glass tape lays down easier if the fillets are still soft. I think it uses less epoxy to wet out also. It makes for a more complex procedure, though. If there are two of you, one could fillet and one could tape. If you mask off the fillet area, it will save on clean up. Put the where the edge of the fillet will be and pull it up before you lay the glass tape.

I've never had a problem with mixing, but I never mixed in large amounts. Just go slow until the filler starts to combine and if it's a large batch, try to spread in out over a large area, once it's mixed, so it doesn't heat itself up.

 

Boat project

JF,

So you finally got it going. Good luck in your project.

Regards,

Rx

 

I know this sounds stupid (but it could happen) make sure you mix the filler into the resin first, then add the hardener. At least that way it's not setting as you go. I tend to either use normal car repair polyester resin (which seems really good for Dinghy repairing, of SP113 for accurate, strong, light layups. SP113 is distributed by RIPMAX in the model aircraft world, and there is another supplier in the UK. It is a thin (low visc) laminating and finishing resin, and it is very nice to work with.

If you're just doing cosmetic fillets, either use a little wood strip finished to match (use Balsa strip, it's soft and stainable to colour), or use some expanding foam, remove the excess with a wire-brush-disc on a drill, then put a layer of filler in (soft modelling filler is good, it's only fairing the surface) then sand the surface fair and apply a layer of glass and resin. then finish as everything else on the boat.

Hope this helps,

Tim B.

 

Mix resin first

Tim B,

It is best to mix the resin and initiator (or epoxy and hardener) first as you would want a homogenous mixture of the resin/initiator (others call it catalyst) epoxy/hardener.

Then mix in the filler little by little until you get the correct goo you want.
This prevents unmixed initiator or hardener that could bring problem in the future.

The key word is "work fast" or "mix only what you can comfortably handle".

Rx

 

First of all, I would like to concur with Rx's advice, but I do have a slight bit of an issue with D'Artoises assessment, yes, silica is rock-hard to sand, because that's essentially what it is, rock. but on the other hand, silica is really the only thixotropic filler we have to play with, it really does help against sag and makes putties a lot easier to apply accurately, just don't add too much.

Yoke.

 

Rx is right. If you do not get the hardener mixed with all of the resin: the resin will not harden. If this happens you will have nothing but goo and that has to be removed. You can not add hardener afterwards (after it has been applied) to make it hard. I tried it one time, made a bigger mess, took longer to remove. So yes mix the two (proper proportions and do not add acitone to make it go further) together and then add your cabacil or what ever you use. Again good luck and enjoy
Ben