[deltaten]

Having a few small projects to do over Winter, I'm seeking others input on how they measure resin in small quantities; say, less than 3 oz.?
Too small, given the viscosity, for graduated containers. Would try pumps; but haven't found any with the accuracy at miniscule amounts.
So.... how do *you* measure small amounts?

Scales? Measuring spoons (icky!)? Mark 1 eyeball?? Then how do ya get alla the goo offa the utensil? Even at wholesale rates, it sure seems a waste to make up four times as much needed to get an accurate mix. Having a few small projects ready to go at the same time seems to work; but then running out mid-point isthe norm

I'mk thinking a "drizzler", sorta like those honey dealies that drip as much as ya want into your tea to dispense into//onto some sorta mixing container that can be quantified and utilize alla tthe well-mixedresin. Nothing likeusinc plastic cups and having un-mixed resin in tthe bottom; but only finding out when a section of goo doesn't cure! :redface:

What's yer process?


TIA,
Paul

 

[celenoglu]

Use medical injectors. One for the resin and another for the hardener. They are available from 1 cc up to 50 cc.

 

[Faster]

Have also used the small, clear graduated cups used for dispensing cold medicines. Graduated in several units, they hold about a fluid ounce. The viscosity/slow flow is always going to make small amounts tricky, though.

 

[CLucas]

Use medical injectors. One for the resin and another for the hardener. They are available from 1 cc up to 50 cc.

Available other places, too, but these from Jamestown Distributors work great.

Epoxy Syringes

 

[Barquito]

I just eyeball. I look at the small puddle that forms in the bottom of the mixing container, and add hardener that looks like the correct proportion. I may err, just a little, on the side of more hardener. If you are using the right kind of plastic stick and bowl, you should be able to let it dry and break it off to re-use the bowl and stick again.

 

[desert rat]

Mark 1 eyeballs, in a little clear plastic cup, hardener by the drop. Like mixing bondo. sometimes to fast and sometimes to slow. Small quantities are always harder to measure plus or minus a %.

 

[MarkSF]

I just eyeball. I look at the small puddle that forms in the bottom of the mixing container, and add hardener that looks like the correct proportion. I may err, just a little, on the side of more hardener. If you are using the right kind of plastic stick and bowl, you should be able to let it dry and break it off to re-use the bowl and stick again.

That's just what I do. Now, if I were doing something that would be critical to the structural integrity of the boat, I think more accuracy would be good. However, none of my repairs ever have been. I'm usually filling small holes. The hardener bottle always seems to run out early, so I must be erring on the generous side.

Tip : We keep all the plastic yoghurt pots. The ones for individual Greek yoghurts are particularly ideal for mixing small quantities of epoxy.

 

[capta]

For small amounts (a few table spoons or so) I use cardboard, like a cereal box, cut large enough to mix the quantity on. Being a flat surface, it's pretty easy to eye ball 1 to 1 or whatever, and very easy to insure even mixing. Usually there is enough leftover on the cardboard to test drying. Tooth picks and appetizer wooden forks work great as mixing and application sticks.

 

[miatapaul]

I think if you get one that is supposed to be mixed one to one, it will make it much easier for small quantities. The ones that have an uneven ratio are going to be tough given small quantities. Perhaps a small electronic scale using a small mixing cup(they are quite inexpensive on line so not a big deal if you get it on the scale). From my experience it is better to error slightly on too much hardener especially in the winter if working in the cold. I once had a kit that came with just enough in 2 containers, but it was too cold and it never hardened. But I did not have the option of adding more hardener to compensate for the ambient temperature.

 

[sailordave]

I just eyeball. I look at the small puddle that forms in the bottom of the mixing container, and add hardener that looks like the correct proportion. I may err, just a little, on the side of more hardener. If you are using the right kind of plastic stick and bowl, you should be able to let it dry and break it off to re-use the bowl and stick again.

NO, NO, NO... This is NOT the way to do it! (sorry for sounding heavy handed)

W/out going into a chemistry lesson that I would probably screw up anyway, epoxy needs to be mixed in the correct measured ratio. If not it will not cure properly and you'll be left w/ a gooey, sticky mess that needs to be scraped off and hopefully you won't have a ruined project.
Only exception to this is 5 min. epoxy where you can control the hardening time a little by how much hardener you put in and how warm the ambient temperature is.

If I'm not mixing up a large batch using the calibrated pumps I use small graduated cups of up to 50 CC as others have mentioned. The other thing I do is keep a pair of plastic ketchup/mustard bottles in my shop w/ resin and hardener so I can very accurately control how much I squeeze out into the cup. So far I've not had a bad batch!

 

[gbgreen59]

Epoxy resin is being referred to??


If you already have the pumps for epoxy resin, just use one push of resin and then hardener. If you want exact, then the syringe is the way to go. I know many who are really strict when it comes to measuring exact amounts of epoxy resin. Depends on what you are doing...like others have said. I've used one push from each pump before. The resin hardens and can be sanded without gumming the paper (I let it cure for 3 days before sanding). To me, it was a very good result.

 

[travellerw]

That's just what I do. Now, if I were doing something that would be critical to the structural integrity of the boat, I think more accuracy would be good. However, none of my repairs ever have been. I'm usually filling small holes. The hardener bottle always seems to run out early, so I must be erring on the generous side.

Tip : We keep all the plastic yoghurt pots. The ones for individual Greek yoghurts are particularly ideal for mixing small quantities of epoxy.

I tried that once and got distracted during the hardner pour.. Poured too much.. I thought, ha better too much than too little.. That is until it kicked off! Damn I thought it was going to catch fire..

Now I use Syringes and store them in a ziplock (separate bag for each one). I reuse them to reduce waste and cost (MARK THE BAG).

 

[gbgreen59]

When I didn't care so much, I've eyeballed it and the resin hardened and was sanded without gumming up the paper. I know eyeballing it is risky though. I eyeballed it when one of my pumps got screwed up and I didn't want to wait to get a better solution.

 

[Seaduction]

I find the West System pumps work with small amounts (1 pump or squirt of resin and 1 pump of hardener is far less than 3 ounces. They do sell a small patching kit as well:WEST SYSTEM Fiberglass Repair Kit, 105-K Repair Kit | West Marine

 

[BluemanSailor]

get a small electronic scale and weigh it out in grams.
Here's a weight chart -

http://www.duckworksbbs.com/supplies/epoxy/marinepoxy/MarineEpoxyChartByWeight.pdf

it's for a mixture of 2:1 but can be adapted..

 

[Faster]

Suspect Barquito was talking about catalyzing polyester resin rather than epoxies..

 

[BluemanSailor]

He's talking about using pumps- actually he didn't specif either one.. would help!

 

[gbgreen59]

Epoxy is measured by volume when reading the containers. I would check before assuming that the density of resin and hardener are the same. Did a quick search and came up with the following for one manufacturer:

Raka 2:1 by volume is 100:43 by weight.

I measured West Systems by weight and found that 2:1 in weight did not yield 2:1 in volume. I really never checked to see if I made wrong measurements; nor did I check West Systems web site. Should check before doing...

 

[Barquito]

NO, NO, NO... This is NOT the way to do it! (sorry for sounding heavy handed)

W/out going into a chemistry lesson that I would probably screw up anyway, epoxy needs to be mixed in the correct measured ratio. If not it will not cure properly and you'll be left w/ a gooey, sticky mess that needs to be scraped off and hopefully you won't have a ruined project.
Only exception to this is 5 min. epoxy where you can control the hardening time a little by how much hardener you put in and how warm the ambient temperature is.

If I'm not mixing up a large batch using the calibrated pumps I use small graduated cups of up to 50 CC as others have mentioned. The other thing I do is keep a pair of plastic ketchup/mustard bottles in my shop w/ resin and hardener so I can very accurately control how much I squeeze out into the cup. So far I've not had a bad batch!

You are probably right. I would imagine some epoxy is more sensitive to the exact ratios than others. I think the only time I didn't have a batch work very well was when the pumps got screwed up. I must admit, I don't eyeball mixtures very often. I would rather waste a little, than mess up the ratio. But, in my experience (West System with medium hardener) it has worked eyeballing in the past.

 

[Squidd]

For small amounts/projects, you can get the epoxy in squeeze bottles in 5 min 10 min and 30 min formulas...(any Hobby shop)

Squeeze bottle with a nipple and cap on top...squeeze as much as you need...

As long as the level in the bottle is the same before and after mixing (minus what was used), you should have an accurate mix...