Thread: Issues with Diggers brand Casting and Embedding Resin

most of the Diggers resin does have the yellow tinge to the resin, when it sets it does loose the yellow and sets clear

the biggest problem i had was that it only comes in 500gram tins and it was all i could purchase locally at the time

i now purchase resin in 20kg drums, which takes me 3-4 months to use

i was told that when polyester resin gets old it starts to crystallize and if you strain the crystals out, then it will still work fine ... i have never had this happen so i don't know for certain, but the info came from a resin company

MIK

Do you need to use a pressure chamber when casting with polyester resin?

Did they tell you what to strain it through? The resin is kind of thick and I'm picturing it taking some time to strain a pail. We get resin in 20 litre pails I haven't seen any crystals in any of it. The company we buy from makes it and the stuff is very fresh. The last pail had a date stamp of a week before we bought it. I'll add that it is water clear in the pail, no colour to the resin at all.

Pete

Originally Posted by george mavridis

Do you need to use a pressure chamber when casting with polyester resin?

i pretty much only use PR and you could count on one hand the amount of times i have used the pressure pot
it does however depend on what you are casting, worthless wood or sheoak pods and things along that line embed in resin definitely need the pressure pot
just general colored resin needs no pressure

my basic resin casting system
measure the required amount of resin into a mixing jug that has a number 5 in the recycle symbol (the resin wont melt it and they can be reused)
get another container and fill it with hot tap water ... not boiling water from the kettle
place the jug of resin into the hot water container (make sure NO water gets into the resin ... trust me ... its not good)
warm the resin, around 3-5 minutes and stir gently bubbles are your enemy ... it will become more liquid, you will notice the difference
if its a color cast ... add your colorant now, i use pearlex from here
add catalyst (MEKP) ... generally i use 0.75% catalyst by volume, my new batch of resin needs more ... don't ask coz i don't know
100ml or resin = 0.75ml or catalyst, some say 4 drop per ounce which to me is highly inaccurate, a drop is relevant in size to the hole it is coming out of, i use pipettes to measure the catalyst, they are very cheap on ebay
Stir well, i use the black plastic spoons from Maccas they are reusable and cheap, wooden icy pole sticks work to but i find they add bubbles as the air escapes from the wood
pour into the mold
now the hard part ... wait, if you think its long enough ... wait longer
generally 12 hours as a rule, you will learn to tell when you can demold it

i don't think i missed anything

just because this system works for me, doesn't mean it will work for you, things like climate & humidity can and will make a difference to everything above, but its a starting point ... until someone shoots me down in flames

i hope this helps someone

MIK

Originally Posted by QC Inspector

Did they tell you what to strain it through? The resin is kind of thick and I'm picturing it taking some time to strain a pail. We get resin in 20 litre pails I haven't seen any crystals in any of it. The company we buy from makes it and the stuff is very fresh. The last pail had a date stamp of a week before we bought it. I'll add that it is water clear in the pail, no colour to the resin at all.

Pete

while i had the guy from the company on the phone i asked him, what the shelf life was on PR and how you knew it was starting to die, i had heard many stories and thought it was a great time to find out from the horses mouth

the resin i buy from them some times has a slight blue tinge, but like water has a slight blue tinge, the current container is dead clear

he didn't say what to strain it with, when he said it i just imagined a household strainer like a big tea strainer and nearly laughed at trying to do four hands work with only 2, none of my lot will come in the shed when i am pouring resin they hate the smell

My cast from the new tin stayed yellow.

I do to bring any air bubbles to the surface. Mine is a modified paint pot from Super Cheap. Pressurise to 50-60 PSI.

Mik, is there any value in using a vacuum setup to degass the PR before the pour for simple casts? Or is there insufficient time to degass then pour before the resin starts to gel?

Originally Posted by Mobyturns

Mik, is there any value in using a vacuum setup to degass the PR before the pour for simple casts? Or is there insufficient time to degass then pour before the resin starts to gel?

there is plenty of time to vacuum if you wanted to, roughly 10-15 minutes before it needs to be in the mold

if you warm the resin then it will be thinner and the bubbles will float to the surface by themselves

Do NOT use a vacuum pump on PR, the styrene vaporises and gets sucked into the pump, you can only use a air vacuum generator or another resin.

My experience with PR going off is that it gets thicker and thicker until it is rubber and then the rubber gets harder. I have never seen crystals forming. My experience with going off however was due to heat in the back of my trailer whilst travelling, whereas with old age perhaps it is different.

You do not need pressure when casting small amounts of pure resin only, or if using resin saver type molds with the tubes in, although bubbles can still form. It is always better to use pressure when casting, the higher the better, no matter what resin or what you are casting. BUT, when using resin saver molds, I would not use >20psi otherwise the resin goes down the tube and is a pain to get out.

Diggers is a convent way of buying PR as it is generally available from hardwares in the 0.5 litre tin. It may be convenient but it is also the most expensive way of buying it, it is ~$50 per litre from the hardware, compared with ~$8 to $25 per litre at the resin suppliers for 20 litre and 1 litre tins respectively.

I only use a pressure pot and not vacuum. 500mm of Diggers at Bunnings is $21. I have just ordered 1ltr of resin from Barnes in Brisbane for $28. Unfortunately I cannot get to their shop so an extra $12 for courier delivery. The silicon moulds I use have hard rubber plugs that fit inside the ends of the tube so no resin can get into the tube when pressurised. I have used the resin saver moulds but find that the silicon nipple inside the mould breaks off. The ones I use are from Luv 2 Turn in the USA. I have tried not using a pressure pot and always get air bubbles but never had a problem under pressure. I like the idea of pre-heating the resin, even if it only to give more time.

Originally Posted by daryl1

I only use a pressure pot and not vacuum. 500mm of Diggers at Bunnings is $21. I have just ordered 1ltr of resin from Barnes in Brisbane for $28. Unfortunately I cannot get to their shop so an extra $12 for courier delivery. The silicon moulds I use have hard rubber plugs that fit inside the ends of the tube so no resin can get into the tube when pressurised. I have used the resin saver moulds but find that the silicon nipple inside the mould breaks off. The ones I use are from Luv 2 Turn in the USA. I have tried not using a pressure pot and always get air bubbles but never had a problem under pressure. I like the idea of pre-heating the resin, even if it only to give more time.

1. Heating the resin will not give you more time, it encourages the chemical reaction by getting the heat started
2. Try Trojan Fiberglass for your resin, their prices include postage/courier ... $32 delivered for 1 liter or as i buy it 20 Liters $220 delivered
3. Not sure on the Luv2Turn molds but i use the ones from PTownsubbie they have hard silicon stoppers and are extremely durable

MIK

Originally Posted by MBUMIK

1. Heating the resin will not give you more time, it encourages the chemical reaction by getting the heat started
2. Try Trojan Fiberglass for your resin, their prices include postage/courier ... $32 delivered for 1 liter or as i buy it 20 Liters $220 delivered
3. Not sure on the Luv2Turn molds but i use the ones from PTownsubbie they have hard silicon stoppers and are extremely durable

MIK

They are 2km from my house, I love the epoxy it's always water, clear and is almost odour free.

Looks like PTownSubbies and Luv2turn are the same business. Fred Wissen is the owner.