A Clear Finish Coating Strategy

[Neil10]

I have decided that I would like a clear finish on my wood model and I’m thinking of using brush applied acrylics. I assume that a sanding sealer would be beneficial but apparently some will leave a whitish cast. Any recommendations here? For the finish coat I’m planning acrylic mat polyurethane. 

[Bob Cleek]

A lot depends upon the type of wood you're planning to finish bright (clear.) If the wood has open grain, it will be difficult to finish bright and obtain a smooth finish without considerable filling and that filler will have to match the appearance of the wood, which can sometimes be tricky. When finishing a model, "less is more." Others may have a different opinion, but I am not a big fan of clear acrylic or polyurethane finishes for models, although they are great for finishing bar and table tops. That said, some claim good results using thinned polyurethanes (sometimes marketed pre-mixed as "wipe on polyurethane.") If you plan to apply a finish with a brush, you will have to apply a very thin coat, or coats if you want to avoid brush strokes, puddles in the corners, and overall loss of fine detail. Because models are viewed up close, the finish must be perfect if the artistic impression of the model is to be effective. Assuming the wood that is to be finished bright is a suitable species (i.e. a closed grain "finish" wood, such as pear, boxwood, ebony, or the like,) I would opt for a thin coat of clear shellac, hand rubbed with fine steel wool and/or pumice and/or rottenstone after drying, if necessary. If the surface is well prepared and perfectly smooth, the thin shellac should soak into the wood well and little, if any, hand-rubbing should be necessary. If, after that, the surface appears a bit too flat, I'd apply a light coat of Renaissance Wax. https://en.wikipedia.org/wiki/Renaissance_Wax 

 

If the wood species isn't suitable for fine clear finishing, I would not finish it bright, but would fill it in the usual way and paint it. As the saying goes, "You can't polish a turd."

[Old Collingwood]

Some great advice from Bob, its can be a learning curve getting right finish  with a clear coat.

 

OC.

[Landlubber Mike]

Are you thinking of applying the finish to the entire model?  Have you considered using a rattle can finish?  I made some wooden magic wands for my girls and used a spray which worked really well.  Easy and quick to apply, and left no residue.

[Old Collingwood]

1 minute ago, Landlubber Mike said:

Are you thinking of applying the finish to the entire model?  Have you considered using a rattle can finish?  I made some wooden magic wands for my girls and used a spray which worked really well.  Easy and quick to apply, and left no residue.

To follow Mikes comments  -  Tamiya make a good Flat Laquare  rattle can  - it dries really flat and covere really well.

 

 

OC.

 

[Landlubber Mike]

Here is what I used for the wooden wands:

 

 

I checked my Mr Hobby Clearcoat sprays that I’ve used on plastic models and they didn’t list wood as material to use it on.  

 

Have you thought about using Tung oil?  I really like how it brings wood to life.  Easy to apply with a rag and I’m sure you could similarly brush it on.

[Roger Pellett]

The model below was finished by me in 1982 so it is 38 years old.  Hull and deck framing is domestic pear wood.  Deck planking is holly and hull planking is boxwood- not Costello, all finished with clear finish, no stain.

 

When the model was finished, I went to a local auto body paint supplier who mixed up a quart of matte finish lacquer.

 

i hung the model from a hook in my basement and sprayed it with a Badger sprayer propelled by canned air.  38 years later finish is still good as new, and there is no visible buildup of finish.  Any sort of wipe on finish would have been very difficult to apply and with the oil based finishes you run the risk of discoloration as the finish ages.

 

you could do the same thing.  If you don’t have spray equipment, look into a Preval sprayer, inexpensive and disposable.  Otherwise use rattle cans.  My favorite is Testor’s Dulcote or use one of the hardware store sprayable clear coats.  These range from full gloss to matte finish.

 

Roger

[Bob Cleek]

2 hours ago, Roger Pellett said:

The model below was finished by me in 1982 so it is 38 years old.  Hull and deck framing is domestic pear wood.  Deck planking is holly and hull planking is boxwood- not Costello, all finished with clear finish, no stain.

 

When the model was finished, I went to a local auto body paint supplier who mixed up a quart of matte finish lacquer.

 

i hung the model from a hook in my basement and sprayed it with a Badger sprayer propelled by canned air.  38 years later finish is still good as new, and there is no visible buildup of finish.  Any sort of wipe on finish would have been very difficult to apply and with the oil based finishes you run the risk of discoloration as the finish ages.

 

you could do the same thing.  If you don’t have spray equipment, look into a Preval sprayer, inexpensive and disposable.  Otherwise use rattle cans.  My favorite is Testor’s Dulcote or use one of the hardware store sprayable clear coats.  These range from full gloss to matte finish.

 

Roger

 

Lovely model, Roger! I'd say a great example of "understated elegance."

 

The original poster was specifically asking about finishes applied with a brush, so I didn't mention spraying. I'll say this about that...

 

I do a lot of spraying and, for a long time now, even more spraying than brushing, especially on "the wide open spaces." I use my trusty old Badger double-action airbrush. I would never approach a model with a "rattle can!"  I hate them. They are expensive in original cost and more often than not, they crap out before they're empty. And more importantly, they're risky, since, for me, at least, I never know when one is going to start spitting and sputtering and ruin an entire finish job.  I do my spraying as a model is built, paying attention to masking schedules and accessibility. While the model you have pictured is somewhat unusual in its lack of detail and bright finish throughout, which lends itself to spraying the whole model when complete, you're a more daring man than I, shooting the entire finished model as you did. I'd be afraid I would never get a sufficiently even application with a gun. How did you ever get the hard-to-reach places done? I'd never be able to get the "innards" coated evenly without getting too much build up on the outside of the framing. Congratulations on a job well done !

[Roger Pellett]

I’ve had much better luck with the non-pigmented finishes in rattle cans.  You’re right, the ones dispensing pigmented finishes gum up quickly.

 

As an old timer passing on my experience to others ( although I don’t feel old) It is difficult to know what equipment someone has and what solutions fit their finances.  As a much younger man raising a family I remember when buying an air brush and air compressor would have been a big deal.  Also, while building model ships is for me an avocation, for others buying and assembling a kit does not warrant a well equipped workshop.

 

My suggestions are, therefore, often the poor boy approach to accomplishing a task.  I’m also prone to experimenting with ideas that I dream up.  Some work, some don’t.  

 

Thanks for the  nice complement on the model.

 

Roger

[Neil10]

Interesting to read the feedback to my query. Nobody mentioned sanding sealer so I guess that’s out! My workshop is an apartment dining room table, an area that clearly falls within the Admiral’s personal jurisdiction, so any form of spraying is out of the question. Not yet sure how sanding will survive scrutiny from this higher authority but at least have access to a vacuum cleaner! 
 

Finishing the hull and deck with anything that involves rubbing, see tung oil and thinned poly comments above, sounds feasible but it’s tough to visualize this as practical for deck furniture. So it looks like super thin un-rubbed brushed on poly might be the answer in this area.

[Canute]

Sanding sealer is not a finish coat. If you want a flat finish, use Dullcote or similar. If you have a porous wood, sanding sealer. might be of use.

[Jaager]

Sanding sealer is for use on open pore species, such as Oak, Hickory, Ash, Walnut.  The pore and grain structure places them in the category of woods that scale in an undesirable  way and are not appropriate for our uses.  The desired species do not need their pores filled and there is no need for a sanding sealer type product. 

The material itself tends to leave a layer that is too thick for scale uses.

[Guillermo Eduardo Madico]

I seal the wood with water based stain conditioner and follow with water based polyurethane. 

I have tried several brands but recently I used the top coat below.  The paints from this brand are absolutely matte and though it was worth a try with the translucent top coat.  What I liked the most, is that the finish hardened really well after 2 days and there was no tackiness that you get with most finishes.

The hull below the whales is finished with this product in my Whinshelsea log.

Best,

G