Posts Tagged ‘ PVA ’

Glue and finishes.

I was unhappy with the results of the Vise Polyurethane glue. Not with the bonding, but mainly for the outside of the shell, there was alot of glue seeping through the veneer. I decided to try out some PVA glue, It works ok. The bonding between the two leaves of veneer was great, The less I have applied, the better it bonded. But When in the mould I found that there was problems with the amount of glue, In this case I think that the more glue the better.

Im going to see how the shell I am currently doing turns out but I might end up using both glues, the PVA on the outside plys, and the VISE for the internal plys.

The previous drum, the 10×7″ shell turned out bad. I found out that some of the plys in the mould didn’t bond properly. The shell that I buffed out turned pretty good, But I screwed up the drilling so it turned out bad. I will show some pictues of it. Im also trying out some spray on poly. So far its going good.  I am also trying to do it on a 10×3.5″ but I am having a bit of trouble, I was using wipe on Poly but it ran a fair bit, and trying to get a smooth is a little harder than I thought it was going to be.

The Big Reveal

Today I pulled the shell out of the mould. Everything went OK, could have been better and could have been a lot worse. So there was no gaps in-between any plys which is a good thing. There has been a few issues with the plys moving after the pressure has been applied, I think this is to do with the PVA glue. And the only other issue is the seams, I Need to get the each leaf of veneer measured exact; the seams looked perfect in the mould, but moved out about 2-3mm.

Some things that I have learnt from this shell:

  • PVA glue takes WAY too long to cure – 24hr isn’t enough. The time is too long, so I will switch back to Titebond III.
  • PVA glue is more prone to rippling – this could also be an issue with clamp time, not sure.
  • The shell will stick to the mould – this is pretty common sense, if the shell has glue being squeezed out at the sides, it is going to glue itself to the mould. I think this can be overcome by either coating the shell in a few coats of tung oil or similar (because that stops glue from sticking so well or using wax paper in between the shell and the veneer.
  • I need a new mould – This mould has broken, glue has become unstuck and I don’t think it’s strong enough.

Any suggestions? Feel free to contact me/leave a comment.

Some New Glue

OK, so I went out and got some new glue, as suggested by Fezz on the PDF. All I got was some PVA hopefully it works as its about half the cost for over double the volume. I put two laminated plys into the mould about half an hour ago with the new glue, and i went crazy with it. I also laminated up another set of leaves and went crazy with the glue (so if glues my problem it wont be anymore. )

Its got an open time of about 30min and a drying time of at least 6hours so probably in 8 or more I will take it out and let you know how its going.

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