PVA or CA

[Glossopguy]

Having had a go at this wood turning lark, particularly bowl turning, now and starting to get the hang of it. Most of my wood is still very green. About 2 years or so. On the advice of "Turn a wood bowl" on You tube, I blocking out rough bowls to allow for twice turning. Now the biggest problem I'm having is not warping but splitting. I searched around on here and can not find a definitive answer to my question

When a first cut bowl starts to crack - Which Adhesive serves the best repair before second turning.

PVA wood Glue
Cyano Acrylate (superglue)

 

[Adam Pinson]

PVA is not the best wood filler, CA is good for small fills, if the wood is dry enough, epoxy or Milliput are good large gap fillers.

 

[Glossopguy]

I'm not really looking to fill at this stage just to arrest any furtner cracking

 

[Phil Pascoe]

. Most of my wood is still very green. About 2 years or so. On the advice of "Turn a wood bowl" on You tube, I blocking out rough bowls to allow for twice turning.

Your wood is neither green nor dry. When they turn green it's freshly cut, so it will distort rapidly rather than spilt.

 

[Glossopguy]

Your wood is neither green nor dry. When they turn green it's freshly cut, so it will distort rapidly rather than spilt.

OK...point taken ! So it's not green , but I need to stop it cracking any further... so which glue is best to prevent further cracking

 

[Phil Pascoe]

I doubt you will.

 

[Glossopguy]

OK...point taken ! So it's not green , but I need to stop it cracking any further... so which glue is best to prevent further cracking

Bugga....!

 

[Phil Pascoe]

Get some coloured resin, bronze powder or similar and fill the cracks when the wood is fully dry. It's practice even if it's not 100% successful.

 

[Lazurus]

What flavour of wood, some like fruit woods are very difficult to dry without cracking or shakes etc. You could make a feature of the cracks with leather or wire "stitching" when finished

 

[J-G]

OK...point taken ! So it's not green , but I need to stop it cracking any further... so which glue is best to prevent further cracking

You're far too late. The green timber should have been sealed immediately after being cut down/felled - with wax or PVA, even paint would have helped - to reduce the rate of drying. This is called 'seasoning' and can take many years - about 1 year per inch of thickness.

 

[Glossopguy]

The 'green' wood was wax sealed when felled. After a couple of yearst the wood was first turned it was sound, but still damp. Now the cracks are starting. It's these cracks I'm trying to stop before the final turning

 

[Stigmorgan]

Did you reseal the end grain after you rough turned it? If not then that's why you're getting cracks.

 

[Orraloon]

Not sure it will help now but some CA drizzled into the cracks may slow it down. It wont harm if you look at it that way. Wet rough turning does have a degree of failure and I have had some large bowls that ended up small platters and some just firewood. Some woods like the fruit woods are bad for cracking during drying. Hot summers dont help either.
Regards
John

 

[Glossopguy]

Did you reseal the end grain after you rough turned it? If not then that's why you're getting cracks.

No ... I didn't. That's worth knowing !
But that doesn't solve the problem of how to stop it cracking any further

 

[Cooper]

I've probably come too late to this conversation, as I presume that you have already roughed out your bowls and they are splitting now.
But I had a similar problem when I was turning some bits of Bay that I rescued from being shredded. My first attempts split and I gave up. When I came back I noticed that the logs had all developed a radial split down the whole of their length. I had a go at splitting the logs in half which was obligingly easy. I then cut the logs in to squares and turned lots of little bowls and pots with lids. I am far too impatient and found that my first attempts warped dramatically if I turned them to their finished shape in one go, so I roughed them out and then popped them in the microwave for a few seconds at a time. So they became hot but not dry and let them dry out. I repeated until they didn't feel damp when they came out of the cooker. Then finished them off and polished with Briwax.
This won't help with splits in your bowl but it may mean you can make use of logs you haven't touched yet?
I had a lot of fun working with Leylandii logs that were very wet, they hadn't split but I managed to split them. Turning them was like unwrapping a spaghetti tree and the fragrance was like rose water, again I roughed and cooked etc. The bowls kept their smell for a long time and if popped onto a radiator much later on they got their sent back for while.
Good luck
Martin

 

[Shan]

No ... I didn't. That's worth knowing !
But that doesn't solve the problem of how to stop it cracking any further

Funnily I'm having similar problems, cracking and warping combined with wood bora holes in to boot. I'm pretty sure that no filler will arrest any cracking as mentioned above and the movement of the wood when it dries is really strong, too strong for any fillers to stop.
I've tried both pva and ca glue but after the effects have shown themselves. PVA mixed with saw dust tends to shrink and discolour and CA glue runs into any crevice and stains badly.
Sorry I can't offer too much help but others more experienced and knowledgeable will for sure.

Good luck

 

[Jonzjob]

I remember turning some rhododendron a good while back to make a bowl. It was so wet I got a shower! It was turned to quite thin and polished. I just wanted to see what happened.

It literally went pear shaped and split as you can see. SWMBO LOVES it and it's been taken along to craft fairs just to show what happens to wet wood. A not for sale notice on it but I have still been asked to name a price for it and not a small one. It takes pride of place in our household!

 

[Terry - Somerset]

Unless the wood has dried to "ambient" levels it will continue to shrink. Partially turning a bowl means that the sides will become relatively thin, compared to the base which will be a full disc, and is likely to be much thicker as it will also have a chuck recess or tenon.

It is not altogether surprising it splits due to differential speed of drying. The normal advice is to slow the drying by putting the partially turned bowl, together with the wood turning debris in a polythene bag and leave it for a few weeks/months. This slows drying and minimises (not eliminates) cracking.