Staining

[Eindride]

Hi all.

Newbie question, is it best to stain the planking for a hull prior to assembly or once it's done ?

Asking as I'm concerned that if there is any slight overspill with the glue the stain might not take. 

 

[Canute]

Certainly, stain before gluing. The wood doesn't absorb most anything, once you get glue in there.

[Eindride]

14 minutes ago, Canute said:

Certainly, stain before gluing. The wood doesn't absorb most anything, once you get glue in there.

That's what I thought but wanted to check before I did 😁

[Jaager]

"Stain"  can have more than one meaning as it is commonly used.

it is often used to describe any product that colors wood.  This comes from turning the verb "to stain", meaning anything that colors, into a noun.

In general two different agents are used.

 

An actual "stain" is a semi transparent paint.  If you use this on wood before using PVA, there is a possibility of the pores and fiber irregularities being filled. A weak PVA bond is possible.

If CA is used - it will bond to the paint layer.  Its strength will be the strength of the paint to the wood.

Some stain products advertise as being "penetrating".  This probably means that there is a mixture of paint and dye in the product.

 

A dye soaks into the wood. It is a clear solution of dye molecules in the solvent base,  It does not affect the surface or the pores.

There are two types of dye - water based and alcohol based. 

The water based dye soaks in more deeply.  On a piece of furniture, this can make a difference in the quality of the look.

At model scales,  the surface is too small for a deeper color to be visible.  Water base will cause wood to swell with the first application or two - sanding and or scraping is needed to fix this.

Just water can be used first, sanded and then dyed - it may save a second dye application to hide what the sanding did to the color.

Alcohol based dye saves all that. The wood does not swell and it dries more quickly.

 

A stain product makes its living by turning cheap and poor quality wood into something that looks better - to partially hide boring grain - often on open pore wood species that need a thick pore filler.

A dye is meant for high quality wood, where the grain wants being accentuated instead of being hidden.

Edited July 15, 2023 by Jaager

[Eindride]

4 hours ago, Jaager said:

"Stain"  can have more than one meaning as it is commonly used.

it is often used to describe any product that colors wood.  This comes from turning the verb "to stain", meaning anything that colors, into a noun.

In general two different agents are used.

 

An actual "stain" is a semi transparent paint.  If you use this on wood before using PVA, there is a possibility of the pores and fiber irregularities being filled. A weak PVA bond is possible.

If CA is used - it will bond to the paint layer.  Its strength will be the strength of the paint to the wood.

Some stain products advertise as being "penetrating".  This probably means that there is a mixture of paint and dye in the product.

 

A dye soaks into the wood. It is a clear solution of dye molecules in the solvent base,  It does not affect the surface or the pores.

There are two types of dye - water based and alcohol based. 

The water based dye soaks in more deeply.  On a piece of furniture, this can make a difference in he quality of the look.

At model scales,  the surface is too small for a deeper color to be visible.  Water base will cause wood to swell with the first application or two - sanding and or scraping is needed to fix this.

Just water can be used first, sanded and then dyed - it may save a second dye application to hide what the sanding did to the color.

Alcohol based dye saves all that. The wood does not swell and it dies more quickly.

 

A stain product makes its living by turning cheap and poor quality wood into something that looks better - to partially hide boring grain - often on open pore wood species that need a thick pore filler.

A dye is meant for high quality wood, where the grain wants being accentuated instead of being hidden.

Thanks. I have a Danish oil stain I was thinking of using left over from a turning I did.

[Jaager]

2 hours ago, Eindride said:

Danish oil stain

You may wish you had done a test first.  Take some scrap pieces of the same wood to the stain shop.  Color the part that will be so treated on the model, dry. bond. After a time, test the bond strength as compared to a control of bare wood to bare wood.  

A strength over time test could be done but it is not worth the trouble -  i.e.  a chemical reaction rate doubles with every 10 degree C rise in temp.  a low temp oven -

[Roger Pellett]

I personally would not stain a ship model with any kind of wipe on oil or resin based product intended for full sized objects.  I believe that like everything else involving models the coating thickness needs to be to scale.  Heavy buildups of wipe on oils is undesirable.  If you use classic ship model woods to scratch build Dockyard type models staining should not be required.  Most woods supplied with kits are better painted.

 

Roger

[Chuck Seiler]

    Am I hearing this correctly?-

 

1.  If I intend on staining all or part of a model's hull I need to stain the planks BEFORE I affix them to the frames/bulkheads?

 

2.  A coat of Minwax stain is thicker than paint and therefore is out of scale?

 

    I'm skeptical on both.

[OllieS]

A paint or oil finish is a surface application whereas a stain penetrates the wood, so you can stain and gently sand when dry etc.

I use stain because I like the natural grain effect. It's not to scale but MBMR wins every time  

Glued wood will not take a stain so I always stain first and touch up with a similar tone of paint.

Personally I would steer clear of oil  or anything oil based unless you use nothing else.

As to scaled painting: thin thin thin. 

[Jaager]

1 hour ago, Chuck Seiler said:

If I intend on staining all or part of a model's hull I need to stain the planks BEFORE I affix them to the frames/bulkheads?

 

34 minutes ago, OllieS said:

A paint or oil finish is a surface application whereas a stain penetrates the wood, so you can stain

 

It all depends on just which products you are calling a stain. 

If it is a commercial product in the US and it is labeled as being a Stain - think surface product - a wood shade pigment in a binder that is thin enough to let some grain show thru.  It may also include a dye component,  but a commercial product = Stain - is intended to be used on a 1:1 scale object.

This is not an especially favorable product to have in the way of a bonding surface.

 

If it is a true solution.  a pigment - in alcohol or water - or a dry powder that you get into solution -  and a solution does not need mixing or shaking - it is a single unit that requires a physical action to separate -

it goes into the wood - it becomes part of the wood - it does not affect a glue bond.

 

We need to be on the same page as far as the definition of the terms.  

 

Chuck :  a commercial STAIN - would probably have an unfavorable outcome if that is used before bonding.  

A dye has very little surface tension. it runs everywhere.  if you have adjacent planks with different colors dying after bonding and avoiding bleed over would be difficult.

 

OllieS :   if the UK terms a dye as being a stain - you are correct -  but  noun stain  and verb stain  are causing confusion.

 

Chuck :

An oil finish -   does leave layer on a primed surface.

A primer can be a coat of half saturated shellac or half saturated oil.  It fills the pores and voids in the wood.  follow on coats stay on the surface.  Unless the coat is too thick or the oil has deteriorated - it then polymerizes and is a layer - one big single unit.  How thick the layer is depends - on the volume applied - which oil it is - 

I think the thickest is polyurethane -  but then polyurethane is a true synthetic plastic -  it might as well be polyethylene - polyvinyl - polypropylene - etc  a better living thru chemistry sort of thing

 

 

 

[OllieS]

5 minutes ago, Jaager said:

OllieS :   if the UK terms a dye as being a stain - you are correct -  but  noun stain  and verb stain  are causing confusion.

 

5 minutes ago, Jaager said:

Yes. To me a stain is just a dye, so very controllable in a build. everything else happens after.

So you finish the construction then you get the brushes out.

 

 

 

 

[Gregory]

On 7/16/2023 at 12:54 PM, Chuck Seiler said:

    Am I hearing this correctly?-

 

1.  If I intend on staining all or part of a model's hull I need to stain the planks BEFORE I affix them to the frames/bulkheads?

 

2.  A coat of Minwax stain is thicker than paint and therefore is out of scale?

 

    I'm skeptical on both.

Agree particularly with number 2.  The Minwax & Varathane stains I am familiar have a consistency similar to mineral spirits.  Unlike paint, there is no obvious build up on the surface  of the wood.

 

How would a layer of anything, measured in microns, appear out of scale?