Using epoxy mini pumps.

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FairweatherDave

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I've done a little fiberglassing in the past using materials usually from Autofactors type places. Now I want to use the proper stuff although not a lot of it, in order to reseat various deck fittings (by drilling oversize holes, filling with epoxy and then redrilling for the fitting). I am looking at the West system and in particular the pumps that make getting the ratios right easy. My question is basically is this a good investment? Do the pumps need cleaning after use or with careful storage do you keep the pumps mounted and they remain ready for use indefinitely for other jobs? I am thinking of approximately a kilogram of resin and slow hardner (£35 approx) then £14.50 ish for the pumps, plus some colloidal silica. My previous experience of mixing epoxy in little cups attracts me to those pumps :). Thanks for any advice
 
The pumps are fine.

I have a West set that I have had in place for over 20 years. The larger one has snapped at the pump head, I suspect the resin has weakened the plastic over time but it took about 15 years. I have never cleaned them and they have never clogged up.

You might also be reassured that the epoxy itself has remained perfectly usable, so it is no problem to get more than you require right now. The resin is so useful, for such a range of stuff, in my view they are a terrific buy.
 
I find that the pumps are OK for about a month without dismounting and cleaning. After that the hardener one seems to last OK but the resin tends to go solid, especially if stored outside in winter. They are not difficult to clean, just empty each pump back into its container, then pump through hot soapy water. If some sticky stuff remains a small rinse in methylated spirits will remove it all.
 
I used the pumps for several years. They're ok, but inevitably they end up going manky after a while and you also have the problem where the barrel of the pump has partly drained, so you press it down and get a spit of resin (or more usually hardener) of unknown volume. If it's the first one into the cup then it really has to be thrown away; if it's a spit of hardener into a full cup of resin, then what?

Nowadays I use a small digital scale instead - idea actually put into my head by Dan Crane of all people :). Put the cup on, press Tare, pour in the desired amount of hardener, then multiply the actual number of grammes by 5 (or whatever your epoxy needs), press Tare again, and pour in that much resin.

This is far easier, and cleaner, and the only thing in contact with the mix is the disposable cup.

Pete
 
vyv_cox said:
I find that the pumps are OK for about a month without dismounting and cleaning. After that the hardener one seems to last OK but the resin tends to go solid, especially if stored outside in winter. They are not difficult to clean, just empty each pump back into its container, then pump through hot soapy water. If some sticky stuff remains a small rinse in methylated spirits will remove it all.
Click to expand...
In a PBO article a few years ago, it was advised to protect your resin against frost by storing in a cupboard with a permanently illuminated 100W bulb. To maintain the shelf-life of your resin, indoor storage might be the best option in the absence of tungsten filament bulbs.
 
Yes, the West pumps are very convenient, with the provisos mentioned above.
However:
1. they sort of commit you to using West resins. I happen to prefer others, partly because they're usually cheaper, partly because West is particularly susceptible to amine blush (no problem with the job the OP describes, but can be a pain in the butt with coating and sometimes laminating work).
2. They're no use for very small mixes.

So I'm with prv in preferring scales.
 
FairweatherDave said:
I've done a little fiberglassing in the past using materials usually from Autofactors type places. Now I want to use the proper stuff although not a lot of it, in order to reseat various deck fittings (by drilling oversize holes, filling with epoxy and then redrilling for the fitting). I am looking at the West system and in particular the pumps that make getting the ratios right easy. My question is basically is this a good investment? Do the pumps need cleaning after use or with careful storage do you keep the pumps mounted and they remain ready for use indefinitely for other jobs? I am thinking of approximately a kilogram of resin and slow hardner (£35 approx) then £14.50 ish for the pumps, plus some colloidal silica. My previous experience of mixing epoxy in little cups attracts me to those pumps :). Thanks for any advice
Click to expand...

As said the pumps are fine. I have just left then on the tins!

Its important with epoxy that the ratio of resin: hardener is accurate because it sets by chemical reaction between the two, unlike ordinary polyester fibreglass resin which is a catalysed reaction where you can vary the proportions to vary the rate at which it cures.


I'd think again about the slow hardener if I were you. The minimum temp for its use is 15°C IIRC. I used the fast hardener


I bought a load of stuff a couple of years ago, Resin, tools, glass cloth, pigment fillers etc, from East Coast Fibreglass Supplies. Prices seem competitive and the service exemplary. http://www.ecfibreglasssupplies.co.uk/default.aspx
 
macd said:
Yes, the West pumps are very convenient, with the provisos mentioned above.
However:
1. they sort of commit you to using West resins. I happen to prefer others, partly because they're usually cheaper, partly because West is particularly susceptible to amine blush (no problem with the job the OP describes, but can be a pain in the butt with coating and sometimes laminating work).
2. They're no use for very small mixes.

So I'm with prv in preferring scales.
Click to expand...

+1 on electronic kitchen scales.
 
Hmmmm. The scales idea makes a lot of sense given the frequency of me doing epoxy work. And then a bit easier to store without pumps attached. Points taken about storage.
I usually raid our recycling box to mix stuff up in and I presume others do too but is there an optimum plastic cup for mixing small amounts other than buying dedicated fibre glass chandlery priced pots?
cheers Vic, just seen your post.
 
I stick a stubby screw in the end of pump after use which may or may not help. I think it does. I found pot noodle pots to be quite useful mixing.

prv said:
Nowadays I use a small digital scale instead
Click to expand...

Of course as with knives, I can see you might not want to get stopped by the rozzers on the way to the boat with that:
"What do you intend doing with this then sunshine?"
"It's for measuring out resin officer"
 
FairweatherDave said:
is there an optimum plastic cup for mixing small amounts other than buying dedicated fibre glass chandlery priced pots?
Click to expand...

I use cheap supermarket plastic cups for small amounts, but I also have a big stack of the dedicated disposable pots. The volume scale on the side is useful when tipping out bigger quantities of polyester resin. They cost very little on eBay, I certainly wouldn't buy from a chandler.

Pete
 
Pumps work and last well but I now use digital scales (cheap from Argos), as this results in less wasted epoxy. Often you only need a small amount to do a quick repair and using a whole pump or two pumps worth can be wasteful.

Also after pumping I found that they can drip whish is messy.

Keep your epoxy in the house in the winter, the garage is too cold and it can crystallise (although this can be fixed by putting the tub in very hot water).
 
Bit of thread drift but whilst building my order I have remembered that at some point I will also be doing some very shallow surface filling on the deck. In places the deck paint has lifted and the loose paint removed and then the surface painted over. So I plan to skim these small shallow patches after the appropriate surface preparation. Can I use epoxy mixed with a suitable filler as I would be repainting over or should I buy gelcoat filler?
 
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