Thread: Epoxy gum vein filling

Start at one end of the gum vein and slowly work towards the other end. This is to allow air to come out. If you do the complete gum vein all at once, it will trap air and prevent the epoxy from penetrating fully.

It depends on the size of the cracks

For smaller cracks and even to start with with on large cracks I use plastic disposable transfer pipettes to deliver drops of epoxy rather than flooding the cracks.

I bought a selection of these on ebay ( ~5c each when you buy by the 100 pack) and use separate pipettes to draw the epoxy from their respective containers, and combine the components by weight in a small takeaway food sauce container on a small balance.
For drawing up the combined components and squirting them out again I use the Z135003.
They are also a really good way of mixing the components

The graduated pipettes (Z135011 & Z354309 are are useful if you want to know how much you have drawn up.


pippettes.jpg


I usually use the Z135011 to deliver the epoxy to the cracks as the outlet is just big enough to deliver a reasonable "gobby" of epoxy or a small amount if needed.
If the deep cracks are wide enough I use the pipette that has a long thin nozzle (Z135046) and push the pipette into the crack and deliver the epoxy into the crack, this minimises bubble formation.
I find I can work with about 15g max with these 2 pipettes before the epoxy becomes too viscous to work with.

If the cracks are larger I use the Z135003 which has a bigger nozzle and it means you can work with larger amounts for about the same time period

Don't be tempted by the very fine nozzle Z350958 or similar because it is very difficult to draw and eject epoxy from such a fine nozzle. These may be useful on very fine cracks but your working window will be narrower.

The pipettes are useful for lots of things like oiling bearings or cutting lube in small amounts as opposed to spraying the stuff all over the place.

Thanks for the tips!

also dont use a heat gun, you need a gas torch, from what i understand it is the gas and not the heat that pops the bubbles.

Before you start, wash out the cracks with acetone. Use a toothbrush to get in as far as possible.
I use a syringe (no needle) held vertical, to try to force the epoxy in. Also,as Cava says, start from one end and work along, then go back & top up where necessary.

I use a heat gun - I believe it's the heat that causes the bubbles to come out. Works for me, anyway.

I like both the wood and resin to be warm, about 25 degrees, as this makes the rein run better. The pores in wood contain air which will expand when the wood is heated and bubble out of the pores. I poor resin later in the day when it has started to cool so the wood is going to cool after the poor and minimise off gassing. I don't poor the resin with the wood in direct sunlight as the heat of the sun will also cause off gassing.

Tony

Originally Posted by AlexS

Before you start, wash out the cracks with acetone. Use a toothbrush to get in as far as possible.
I use a syringe (no needle) held vertical, to try to force the epoxy in. Also,as Cava says, start from one end and work along, then go back & top up where necessary.

I use a heat gun - I believe it's the heat that causes the bubbles to come out. Works for me, anyway.

Thanks. Does it have to be acetone? is meth spirits ok (only cause I have heaps of it and always have some). What do you use to clean you syringe?

Originally Posted by tony_A

I like both the wood and resin to be warm, about 25 degrees, as this makes the rein run better. The pores in wood contain air which will expand when the wood is heated and bubble out of the pores. I poor resin later in the day when it has started to cool so the wood is going to cool after the poor and minimise off gassing. I don't poor the resin with the wood in direct sunlight as the heat of the sun will also cause off gassing.

Tony

How do you heat up the wood/resin to 25deg?

Originally Posted by qwertyu

Thanks. Does it have to be acetone? is meth spirits ok (only cause I have heaps of it and always have some). What do you use to clean you syringe?

I don't use anything, I just blow anything loose out with a compressor. It either blows it out or further into the crack.

How do you heat up the wood/resin to 25deg?

In winter or early in the morning I use a hot air gun on low heat at another times my shed will be about 25º anyway.

Thanks. Does it have to be acetone? is meth spirits ok (only cause I have heaps of it and always have some). What do you use to clean you syringe?

I've used metho with no problems. However, I've found that acetone is good for removing resin from blades etc, so usually use that in case there's some in the gap.

Metho is fine for cleaning up the syringe & kit. If you use the little sauce containers from Chinese/Japanese restaurants to mix the resin in, you can let any leftover set and just pop it out - it doesn't stick to the plastic.

I blow it out with air then wash out with thinners. I then build a well using plasticine/blu-tac or similar around hole/fault/crack and pour resin from one end only so it flows pushing any air out. I use a heat gun as it blows well whilst keeping the resin warm and thus aiding bubble removal

Thanks for the tips guys. How do you guys then flatten the resin? Belt sander and some 40grit?

I use a card scraper.

I have been experimenting with West System in the last few days, and have noticed that with the 'slow' hardener I get less bubbles/air pockets to contend with vs the 'fast' hardener.

Whilst it can't work in all situations, I have also started filling from the reverse side of the timber with good results as any bubbles rise to the surface on the unseen side.

To clean up epoxy I use 91% Isopropyl Alcohol. It works great and also cleans it off my hands easily. I even use it to clean up dried epoxy. It works great and is less toxic then Acetone or methy spirits.