I have a large burr oak bowl blank that I have cleaned up, removed the accessible bark inclusions and filled the biggest holes with pieces of bowl blank offcuts using CA glue. The blank still has numerous voids that I'd like to fill with black epoxy before turning. The question is, how do I stop the epoxy running through the voids and out under gravity. I've read that Flex Paste (a rubberised paste from Flex Seal) would do the trick but it's expensive and I only need a seal for a few hours while the epoxy cures,. not permanent waterproofing. I'm guessing that ordinary glazing putty should do the trick as it sticks to wood and is thick enough to hold its shape. I'm also guessing that the oils in the putty won't penetrate far into my blank and will be removed when I turn it. Does anyone have any experience of doing this, or any better ideas?
Stopping epoxy leaks with glazing putty?
- Thread starter Bluetit
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Ollie78
Established Member
I am not sure the putty will work here, my guess is that the epoxy when wet will seep through where it is sticking to the wood.
You might be better off with parcel tape, the cheap brown one is good.
You might be better off with parcel tape, the cheap brown one is good.
Thanks for the thought. I am worried that the surface I need the barrier to stick to is very rough. I had to use a wire brush wheel to get rid of the bark (and some rotten bits) so the surface is finely grooved in places. It's also the areas I need to fill don't have simple curves, so the tape would need to be stretchy. I thought about masking tape which has a bit of stretch to cover the big open areas and then maybe seal the edge of the tape with putty to fill in the fine grooves
I've just read this from another thread:
Mould for epoxy
This is very similar to my problem. I'll also have to do multiple pours from different directions. I don't have a pressure vessel so I can't do the total immersion in epoxy trick.
Mould for epoxy
This is very similar to my problem. I'll also have to do multiple pours from different directions. I don't have a pressure vessel so I can't do the total immersion in epoxy trick.
woodieallen
Established Member
The trouble with cheap brown tape that I find is that when you peel it off, it leaves residue behind. And/or rips into pieces and you then spend ages peeling it off bit by bit.
A small hot melt glue gun might help you achieve this
Keith
Keith
Last edited:
Inspector
Nyuck, Nyuck, Nyuck!
I haven't tried it but I have a suggestion that might work. A big bead of hot melt glue around the void and while hot push a thin piece of wood or plywood over it. The hot glue will stick to the uneven surfaces. The wood and glue will turn off, likely in chunks, so wear a face shield.
Looks like MF1000 beat me to it.
Pete
Looks like MF1000 beat me to it.
Pete
Ollie78
Established Member
You can get fillers to make the epoxy thixotropic, it might be colloidal silica or those micro bubbles I forget now.
Effectively you should be able to modify the epoxy to be thicker and not run out of the cracks.
It might need priming ( wetting )with a thin epoxy first to aid adhesion, and depending on consistancy may need to be forced into the holes etc.
Effectively you should be able to modify the epoxy to be thicker and not run out of the cracks.
It might need priming ( wetting )with a thin epoxy first to aid adhesion, and depending on consistancy may need to be forced into the holes etc.
Paul Hannaby
Established Member
You could just use epoxy putty to fill the holes or put masking tape over one side and pour epoxy in the other side.
alex robinson
Established Member
From my experience since that, no sort of tape seems to work except on a really smooth and clean surface. Hot glue to stick small covering plates is ok, but I find bathroom silicone to be the best as it is easy to get leaks with a long run of hot glue.
Stick a piece of of scrap over all the holes in the base and a strip of plastic round the edge and pour in the top. A dam of silicone round the surface can give a reservoir as it will fill little holes in the blank over the course of several hours. Make sure you get your mould right first time as it is a right pain to try and seal once you see you have a leak!
I am not sure if a thickening agent will be helpful. You want it to be as runny as possible to try and fill the little voids, especially if you don't have a vacuum or pressure chamber to help.
I would strongly suggest sealing it with clear epoxy before you do the filling pour. Otherwise you risk bubbles and the black colour bleeding into the timber giving a stained messy edge. If you get one of the slow setting deep pour versions they are nice and runny (only downside is they take ages to set).
I have used Blue-Tack for damming resin on irregular surfaces sometimes backed up with any adhesive tape I had at hand at the time. A combination of Blue-Tack and silicone sealant could be a consideration as Alex suggested above. I tend to look at the piece and decide at the moment which to use, not always the correct solution, I'll add. Also, consider UV resin as a small hole sealer before filling it with regular resin. When used clear, it will take seconds to set. I've used it on large beetle/wormholes. Squeeze a blob in then, before it sinks through, hit it with the UV light and Roberts your auntie's brother, hole is blocked and ready to receive regular coloured resin.
Robbo3
Established Member
Mini pallet cling film tightly wrapped around the outside should stop the leaks & be removable. Might need the filling to be done in several orientations so that gravity fills the voids at the bottom as the piece is rotated.
A cling film dispenser/handle allows a really tight application of the film.
I also use the cling film to stop green wood from drying out as well as for wrapping items to be posted.
I noticed that several professional turners also now use it when they bring wood to turn at club demonstrations.
A cling film dispenser/handle allows a really tight application of the film.
I also use the cling film to stop green wood from drying out as well as for wrapping items to be posted.
I noticed that several professional turners also now use it when they bring wood to turn at club demonstrations.
I use 100mm film on a handle often. It's great for keeping my pallet planks together and transporting them to the woodshed. I have used it for what you've suggested but only a couple of times. I wrapped the piece around some worm-riddled Robinia burr while it was still on the lathe then put a piece of firm packing foam against the work and wrapped it tight against it. It's like putting pressure onto a wound. I think most of the above ideas work but of course, it depends on the shape of the piece, how deep the pour needs to be and the effect you want to achieve. Looks like the OP has a good arsenal of ideas for this and future projects.
Use Tyvek tape. More expensive but sticks well and epoxy doesn't seep past it like masking/parcel/Sellotape. I use hot melt glue quite a bit to make dams or to glue bits of wood scrap around an area to fill with epoxy. Sometimes needs multiple pours so avoid deep pour epoxy that takes seven days to fully cure!
Thanks for all the advice. I went with acetate sheet and hot melt glue, and the odd bit of wood fixed in with CA glue. Once I'd learned the technique of working quickly, it all worked fine. I'll also look into Tyvek tape, which might be quicker
