View Full Version : epoxy mixing station
10-27-2002, 07:25 PM
I am looking for a good design for a workstation to prepare large batches of epoxy/fillers. Ideally the station would be large enough to work from 5 gallon epoxy resin containers. As it gets colder, I am trying to include a warmer to keep the resin from getting too thick. I wonder if it would be worth investing in a better dispensing device than the hand pumps?
Appreciate your help.
10-27-2002, 07:41 PM
No it isnt worth it except to get sum plastic cylinders which are clearly marked with different volumes- its plenty easy and kills two birds with one stone
10-28-2002, 07:17 AM
Get a good balance and weigh in a single container instead of measuring and mixing volumes to be neat and far more accurate.
10-28-2002, 12:58 PM
There is a nice plan for a mixing station in The Gougeon Brothers on Boat Construction. It's nothing real fancy, the key points are that it is on wheels so that you can move it to where you are working, and it has shelves for the various supplies, paper towels, etc. that you want to have handy. One way to keep the epoxy warm would be to build a 'hood' with a door to go around the epoxy containers and put a couple of incadescent lighbulbs inside.
As to upgrading from the hand pumps to something like the gear pumps, I think a lot depends on how much epoxy you are going to be going through and how much your time is worth. For a professional doing repeated large jobs I think the gear pumps would pay for themselves in time and materials saved. For a home-builder I would only consider it if you are building a LARGE cold-molded boat. I use a scale on occasion to check my pumps but it takes a lot longer to use a scale than it does to push a couple of pump handles up and down a few times. Also, it takes a high quality scale to do this with small quantities of epoxy -- I happen to have a triple beam balance that does the job quite nicely, but these scales are quite pricey so I wouldn't buy one just for epoxy.
10-28-2002, 11:57 PM
After using over 100 gallons on my project I have never regretted buying a pump from:
The pumps are available in different ratios and reasonably priced. They do require some maintenance. I am on my second pump and it is a better updated design than the first one. I rebuilt the first one once but after that I thought it better to buy a new one. The model I got was the manual "Sticky Stuff" dispenser.
I keep the pump in an insulated box with a light bulb and a thermostat. The thermostat is designed for an oil fired space heater like the ones you see at a construction site. The thermostat simply plugs into an outlet and the light plugs into the thermostat.
10-29-2002, 04:05 AM
Ehh - I thought this is the "wooden"-boat related section.
So, what is this epoxy-thread doing here.
In my opinion wooden boats have been build for more than 1000 years without the use of epoxy. I know a lot of boats (1869 built VALDIVIA, 1870 built NORDEN, 1886 built WILLOW WREN...) that were built traditionally with planks and caulking and still don't make any water - so why use epoxy?
10-29-2002, 04:57 AM
Originally posted by Dave Carnell:
Get a good balance and weigh in a single container instead of measuring and mixing volumes to be neat and far more accurate.Dave I just don't understand what you mean. I can't see how a person who can't get accuracy by volume, is going to be more accurate by weight. I use high quality graduated vessels, and replace them often.
If I'm accurate in measureing 100mls of resin and 50mls of hardener, I've got 150mls of working strength solution.
If I'm accurate in weighing 100 gms of resin and 50 gms of hardener, I've got 150 gms of working strenghth solution.
I can't see the difference in preparing a working strength solution in either way.
Accuracy is paramount in both ways.
Today I followed the manufacture's recomendations for surface coverage, mixed exactly 450 mls of working strenghth solution (in one hit), and wasted 80-100mls.
I knew I would. Just watch greedy manufacturer's wastefull recomendations. They are the inherant inaccuracy.
10-29-2002, 05:16 AM
Martin, You funny man. Great comment.
Do you mean replace epoxy with the new polys? :D . At least you can get epoxy off.
Did you read 'Epoxy is crap'? .... a top read if anyone hasn't read it.
[ 10-29-2002, 05:33 AM: Message edited by: Wild Wassa ]
10-29-2002, 06:04 AM
Ok Warren - actually I wanted to be a little provoking. I get the feeling that most people earnestly think that a fibreglass hull is more safe, and even some of those with wooden boats think that putting epoxy on planks guarantees them an eternal sorrow-free life.
I am afraid that that kind of thinking of spreads.
I just wanted to make sure that it is not forgotten that still people build great boats, without ever touching any chemical fluid.
And I love the sight of caulked planks with seams. Most of the cold moulded wooden boats look more like fg-boats with wooden veneer to me.
10-29-2002, 09:41 AM
Thanks to Dave, Bruce, and Fritz for your helpful replies. To clarify and redirect, I am building a 33' strip planked sailboat. My batches are relatively small, but repetitive. I have been working from 5 gallon epoxy containers on the floor, and suffering the mess, cranky pumps, and sore knees long enough to take some time to build a dedicated workstation set-up. The handpumps just don't work well once the resin gets below 50 deg.F, so I have been looking a thermostat arrangements to warm the resin. Alternatively, a better pump system might be worth the investment. One argument against a better pump is the potential to change from 5:1 to 2:1 mixtures with different resins and hardeners. Appreciate your insights.
10-29-2002, 12:17 PM
Not just to be contentious, but my scale weighs to 0.1 g or less. I don't have any volumetric measure I can read 100ml in to anywhere near 1ml, let alone 0.1ml. I can weigh batches of only a couple of grams and have them accurate to within 0.1 g. No way can I do that by volume.
On top of that I do the weighing all in one container and don't have to transfer viscous fluids. In half a century plus as a chemical engineer I have never seen a volumetric pump as accurate and reliable as a scale.
Cecil, why not get pumps all the same size? That way if you're mixing 5:1 you can pump five shots resin, one shot hardener. And if you switch to 2:1 simply pump two shots resin to one pump hardener. As long as you remember what brand you're pumping you can't go wrong. Aside from that just use clean pumps, ie separate pumps for each epoxy brand.
10-30-2002, 08:22 AM
Hey there, how are ya'? Maybe I missed it but as to the warming up thing why all the thinking? I work in an unheated building and cold epoxy is a pain. So all I did was cut out a cardboard box to fit the containers and pump heads with a little space heater (on low) at one end and a vent hole in the other. Regular pumps work fine with it. My low tech epoxy oven, works great. Dan.
as for warming it up, sometimes i just sit the can of resin in a bucket of hot water for a while, or simpler still, bring it in the house overnight before hand
10-30-2002, 04:39 PM
I went to tune in Norm Abrams and the New Yankee workshop the other morning only to find Martha Stewart had now taken that slot on HGTV. Bummer. However the subject matter that Day was the building of her "Picnic Launch" by Hodgsen Bros up in Southwest Harbor. They were using 55 gal drums full of MIXED epoxy which was flowing into the vacuum created in the hull to surround the balsa core and bond it to the outer "matrix", How do they mix so much without it "going off" If I mix a pint I am usually in deep trouble. Roger
Not all epoxy mixes kick off at room temp. The majority of them require heat to cure. I work in a composite manufacturing facility and the epoxies that we use have a pot life (working time) of 8 hours or more. After that they get kind of gummy and don't flow very well. A buket of our resin will stay a gummy liquid forever until it is subjected to a 250F cure. I am sure that most hobby boat builders would love to use the stuff, but you have to have a great big oven!
I forgot to add. Cecil we have an epoxy mixing station for sale. Everything you would need. Computer controlled, heated storage, highly accurate about one pint minimum mix continuous mix of about 60 gallions per hour. Only $200,000. Where should I ship it?
10-31-2002, 09:45 AM
Years ago I was in an Explorer Scout post that built canoes in epoxy. The leader was a guy that worked for an automotive pattern maker and we had access to the entire factory, including supplies. Epoxy stations were at several locations in the plant and used 55 gallon drums of the stuff. The mixers were hand-cranked devices similar to the Goo-Grinder but fed directly from the drums. No heaters were used since the plant was always kept at around 70, even in the summer. I have pictures of all that tucked away someplace at home. I'll post something if it's worth while.
One of our favorite get-in-trouble sports was to hot-mix about a pint of polyesther and watch it smoke, turn purple, and then blow itself out of the container, finally looking like a big sponge.
11-07-2002, 02:07 AM
Originally posted by martin schulz:
[qb]Ok Warren - actually I wanted to be a little provoking....
....I just wanted to make sure that it is not forgotten that still people build great boats, without ever touching any chemical fluid.
....And I love the sight of caulked planks with seams. Most of the cold moulded wooden boats look more like fg-boats with wooden veneer to me.Martin I couldn't agree more.
It would be fantastic to dump epoxy and other similar googes. But while I'm doing what I'm doing (racing dinghies only), I'll embrace it with a passion. It's the only job I've got, to be 'Epoxyman'. I also paint the hulls that I've faired.
There is one characteristic that I like greatly, that I have not found on boats, that have used other media (again racing dinghies), that is, how simple Epoxy is to remove.
I wish you could see the boats that I work on they are absolute wrecks. Only epoxy is practical for us.
Here is an example of an exhausted NS 14. There is no epoxy on this boat, but there are a dozen other things. This boat 'looks' like crap.
Here is a restored hull from a little Mirror. The boat was salvaged from the tip. It was a good salvage because we now have two Mirrors for the younger kids who can't handle the heavier or more difficult boats. This hull sure does look like FG, is as smooth as a new FG, but does not have FG's weight. A win for epoxy. This boat races and has now had 3 placings in 3 starts, in fields in the mid twenties and low thirties. Not bad for a 42 year old boat, the boat has been racing against Olympic class dinghies, in handicaps.
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