Replies

1. 
   Steve50 | Jun 18, 2005 04:32pm | #1

   It looks like you are experiencing bleedthrough.  I have observed bleedthrough over as much as 10% of the surface area so what your picture shows doesn't look bad to me as long as you can get rid of the stain.  I have not experienced the blue staining but, I typically use darker woods and may just not see it.  My last project used carpathean elm burl and I was really concerned about bleedthrough so I used Unibond 800 with a new product called Uniblocker.  While it did not completely eliminate bleedthrough, it was much less severe than what I expected with the elm burl (a whole lot less than 1% of the area).  For more info on this product check out http://www.vacupress.com/

   I don't know whether it is available in your part of the world.  I live in Arkansas and still have to use mail order to get this.

   Steve

1. 
   macalex | Jun 19, 2005 01:24am | #3

   With porous and burr-like veneers I commonly get bleed through. I like to use lots of glue! It doesn't (usually) affect to finish I use.

   One reason why I'm moving to a vacuum press is so that I can use less glue.

   I've glued up another two panels this weekend with no stain problem. I think it may be contamination of some sort - has anyone recorded blue stain from metal reacting with PVA glue?

   MalcolmNew Zealand  |  New Thinking0.06% of the world's people are Kiwis

1. 
   Steve50 | Jun 19, 2005 05:50am | #4

   PVA glue will react with iron and blacken some woods.  Oak and ash are particularly bad for this.

   Steve

1. 
   mikegagne | Jun 20, 2005 09:17am | #6

   I thought it looked like iron stain too. Oxalic acid removes it in 20 minutes. I use a product called Dekswood Cleaner form Flood Co available at paint stores. It has always worked well for me. Aloha, Mike

1. 
   macalex | Jun 20, 2005 11:54am | #7

   So what's the likely cause? Could it be steel wool particles? I need to be able to take precautions so it doesn't happen again!

   I will be more careful about cleaning up before assembling veneer projects in future, but with no real idea about where the contamination comes from, I'm puzzled!

   Malcolm

   Edit: Oh, and I'll try the oxalic acid test (if I can find a source of oxalic acid - aka what?)

   New Zealand  |  New Thinking0.06% of the world's people are Kiwis

   Edited 6/20/2005 4:55 am ET by kiwimac

2. 
   mikegagne | Jun 20, 2005 08:10pm | #8

   I'll try the oxalic acid test (if I can find a source of oxalic acid - aka what?)Oxalic is used to clean decks like redwood and cedar to bring them back to brand new looking. Its also a bleach when used in a stronger form.

2. 
   WillGeorge | Jun 18, 2005 09:47pm | #2

   I have never tried it but... Would a wash coat of de-waxed schellac on the wood before gluing help?

3. 
   jazzdogg | Jun 19, 2005 06:36am | #5

   Have you also experienced this problem when using hide glue, or just when using PVA or aliphatic resin glues?

   Does oxalic

   acid remove the stains?

   -Jazzdogg-

   Whether you think you can, or you think you can't, you're right.