The volume 6 #4 issue of RodMaker detailed plans and instructions for making and using a motorized epoxy mixer. Some mixers work great, others don't work so well. There are quite a few fine points (angle, speed, time, etc) to making and using a good one - the article showed how to make a really good one that will work and provide perfect batches each time.

I've had several emails from various builders who have bought pre-made mixers lately. Each has asked about the round stir stick that is used with them. Simply put, a round stir stick is a very, very poor mechanism for blending finish. If your unit employs a stick rather than a heavy steel or glass ball, you want that stick to be flat, not round. You may get by with a round stick, but it will require much longer mix times and even then you may not get thorough mixing of your 2 component parts. A good mixer should give verbatim results each time. Not a few good batches with the occasional bad one every now and then.

Good results are obtained by the use of well designed tools coupled with proper operating procedure. I don't know how many people are making and selling motorized epoxy mixers these days, but there are some good ones and there are others that leave something to be desired. Round mixing sticks are not a good idea whether used on motorized devices or for hand blending. Go flat and you'll be better off.

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have been wondering... when mixing by hand and not using one of these power mixers, is it ok to use wood sticks? i hear some use popsicle sticks to success. any possible problems with that? i grabbed some wood coffee stirring sticks and they're flat...

eric
fresno, ca.

Popsicle sticks are porous, thus release air as they suck up the mix in the stirring process, use a cured/sealed popsicle stick .

plastic drink mixers work well too for this... I need to get that Rodmaker back issue and build my own motorized mixer. Tom - are there options as far as motor RPM goes, or is it pretty much 18rpm is the speed to have???

When I first read about Motorized Epoxy Mixers in Rodmaker Magazine I decided to get a Flex Coat 18RPM drying motor and adapt it to the task. I bent the steel support back to an appropriate angle (about 40 degrees) and then covered the rubber front with a solid facing of aluminum. A strip of velcro there and on the bottom of my stainless steel measuring cup completes the unit. Although this is a bit pricey way to go it has proven to be outstanding and totally reliable. The mixing process has been flawless and I am confident in the longevity of the unit. I rate the overall cost of about $70.- a great investment for the workshop.
Dave

Wooden popcycle or craft sticks are just fine. If you're worried about them being porous (although that shouldn't be a problem) just keep the next one you use - it wil have been sealed by the last coat of epoxy.

18 RPM is the optimum speed for an epoxy mixer (anything from 15 to 20 is probably okay). Any slower and it takes far too long to mix, any faster and you'll overcome the weight of the mixing ball or speed the mix by the stir shaft too fast and create bubbles.



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I use new popsicle sticks all the time and the plastic cups, no problems.

I've owned three epoxy mixers. I made one a few years ago on my own design. It just didn't work well. It was still faster just to do the job by hand. I bought one of the then new @#$%& mixers a few months ago and it mixed the epoxy fine but I always got bubbles with it. I don't know if it was the round stem or the higher speed but it just made too many bubbles. I made one of the rodmaker mixers after that and it worked better. Mixed the epoxy good and no bubbles at all. My speed is 20rpm and that seems to work fine. I still wonder if mixing by hand isn't just as fast but I will say that the motorized mixes at the right speed have no bubbles. Could be a plus.

Whether you buy one or make one there will be at least some small expense involved. And, I don't want to represent the reason for having one of these as anything having to do with saving time. Except for certain situations where you may be mixing large batches and using the mixing time to prepare your finishing station, etc., I would agree with you that time savings is not going to be a good reason for owning one. But, you will get a bubble free, well blended and consistent batch each time with such a unit.

A lot of things in rod building aren't really necessary, but many of them are certainly nice to have at your disposal.

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I made one of the mxers from plans in Rodmaker. Because I work in a basement that is pretty cold my epoxy can be a little on the thick side at times. So I had to move up to a 1/2" steel ball for a mixer. It works great and I no longer have bubble problems.

FishStix4U used to have 18 rpm motors pretty cheap. Not sure if they have any left but I got mine from them and don't think I paid more than $20 if that. It wasn't hard to make a stand and get the angle right with some aluminum flat bar stock. I don't think I have more than maybe $25 or so in my whole unit. It works great. Nice addition to the shop.

Many ago I tried the cement mixer idea, and went back to mixing by hand for various reasons. However, not more than 5 years ago I again tried a cement mixer thingie made from a flexcoat 18 rpm dryer, GM-18 model I think, and not having a "calibrated" ball for the mixing I used an alligator clip mounted on a small goose-necked base to hold a spatula in place while the motor and cup turned. Also, I did not want to bend the metal bracket for the dryer, so I lay the motor on its back, placed the cup upright in a rubber buttcap stuck in the dryer rubber diaphram, and positioned the spatula in the cup by positioning the base of the gooseneck so that the sides of the cup were being scavenged by the spatula edge. The thing worked great. Keeping the cup upright increases the amount of finish you can load into it since the cup is afterall upright.

I still mix by hand, but then I still spine blanks by hand, and eyeball guide alignments. I guess I am just a hands-on guy....

Lou

Epoxy mixers? Really? I never imagined....I din't think it was that complicated.

I just use the wooden coffee sticks from 7-11.....put the two parts of epoxy on an aluminium foil "tray"....mix, stir and fold for 3 minutes. Have never had a problem.

I didn't know they had mixers...Huh...

Keith

Keith

That's high teck ???

Mixers aren't complicated, but they do generate a better batch if properly made and used.

Same with expensive rod lathes and wrappers - not necessary at all, but they sure are nice to have and use.

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