PDA

View Full Version : Preparing HDF panel - why water?


thisisnotatoy
01-19-2019, 03:53 PM
From my online search, it seems that the recommended way of preparing the HDF panel for painting is painting it with GAC100 or PVA, and then with oil ground.

Why is rejected the method of painting the panel with boiled linseed oil until it ceases to soak, and then oil ground? :confused: We would avoid going through the watery medium, controversial for both wood and oil paints. Linseed oil is a traditional means for impregnating wood, so I can not understand this use of acrylic or PVA.

Delofasht
01-19-2019, 04:52 PM
Soaking a panel with oil takes an extremely long time to dry. Water based glues have been used for ages, whether rabbit skin, hide glue, fish glue, or otherwise. I just prefer not to use Acrylic or PVA because their shrinkage is far greater in it's early stages of drying than old glue types.

Edit: Assuming I do any preparation, because painting directly on the HDF is an option as well.

contumacious
01-19-2019, 05:29 PM
My understanding is that sealing with an acrylic medium or some other non absorbent sealer, before applying an ACRYLIC ground is to prevent SID and it is only necessary if you plan to paint with acrylics and possibly other water based paints. It has been proven that Acrylic Gesso may not stop SID from wood based grounds when painting with acrylics. It has also been proven that SID can discolor Acrylic Gesso if a sealing coat is not applied. I have experienced this several times in the past. The stain continues to move forward no matter how many layers of acrylic gesso are applied. Golden's testing has also shown that their Acrylic Gloss Medium is better at blocking SID than their previously recommended product - GAC100.

https://www.justpaint.org/blocking-support-induced-discoloration/

I always seal my wood based panels on all 6 sides / edges with a sealing bonder / primer to help prevent warping and swelling from absorption of moisture. The added benefit of reducing SID comes into play if I end up painting with acrylics. You don't have to seal the panel if you plan to paint only in oils but it is still a good practice if you are wanting a more stable and longer lasting wood based support.

You can certainly paint directly on the wood as Delofasht has mentioned, with oils. In my opinion if you paint on the raw wood face, it would still be wise to seal all other surfaces of the panel with something, not just the front with your paint.